diff options
Diffstat (limited to 'kernel')
62 files changed, 2972 insertions, 1819 deletions
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 080a2dfb5800..bf4495fcd25d 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -99,7 +99,7 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr) if (err) goto free_smap; - err = get_callchain_buffers(); + err = get_callchain_buffers(sysctl_perf_event_max_stack); if (err) goto free_smap; diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 75c0ff00aca6..33a2f63d4a10 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -61,7 +61,6 @@ #include <linux/cpuset.h> #include <linux/proc_ns.h> #include <linux/nsproxy.h> -#include <linux/proc_ns.h> #include <net/sock.h> /* @@ -1160,18 +1159,12 @@ static void cgroup_exit_root_id(struct cgroup_root *root) { lockdep_assert_held(&cgroup_mutex); - if (root->hierarchy_id) { - idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id); - root->hierarchy_id = 0; - } + idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id); } static void cgroup_free_root(struct cgroup_root *root) { if (root) { - /* hierarchy ID should already have been released */ - WARN_ON_ONCE(root->hierarchy_id); - idr_destroy(&root->cgroup_idr); kfree(root); } @@ -5146,6 +5139,8 @@ static struct cgroup_subsys_state *css_create(struct cgroup *cgrp, lockdep_assert_held(&cgroup_mutex); css = ss->css_alloc(parent_css); + if (!css) + css = ERR_PTR(-ENOMEM); if (IS_ERR(css)) return css; @@ -6172,7 +6167,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry, struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss) { WARN_ON_ONCE(!rcu_read_lock_held()); - return id > 0 ? idr_find(&ss->css_idr, id) : NULL; + return idr_find(&ss->css_idr, id); } /** diff --git a/kernel/cgroup_pids.c b/kernel/cgroup_pids.c index 303097b37429..2bd673783f1a 100644 --- a/kernel/cgroup_pids.c +++ b/kernel/cgroup_pids.c @@ -49,6 +49,12 @@ struct pids_cgroup { */ atomic64_t counter; int64_t limit; + + /* Handle for "pids.events" */ + struct cgroup_file events_file; + + /* Number of times fork failed because limit was hit. */ + atomic64_t events_limit; }; static struct pids_cgroup *css_pids(struct cgroup_subsys_state *css) @@ -72,6 +78,7 @@ pids_css_alloc(struct cgroup_subsys_state *parent) pids->limit = PIDS_MAX; atomic64_set(&pids->counter, 0); + atomic64_set(&pids->events_limit, 0); return &pids->css; } @@ -213,10 +220,21 @@ static int pids_can_fork(struct task_struct *task) { struct cgroup_subsys_state *css; struct pids_cgroup *pids; + int err; css = task_css_check(current, pids_cgrp_id, true); pids = css_pids(css); - return pids_try_charge(pids, 1); + err = pids_try_charge(pids, 1); + if (err) { + /* Only log the first time events_limit is incremented. */ + if (atomic64_inc_return(&pids->events_limit) == 1) { + pr_info("cgroup: fork rejected by pids controller in "); + pr_cont_cgroup_path(task_cgroup(current, pids_cgrp_id)); + pr_cont("\n"); + } + cgroup_file_notify(&pids->events_file); + } + return err; } static void pids_cancel_fork(struct task_struct *task) @@ -288,6 +306,14 @@ static s64 pids_current_read(struct cgroup_subsys_state *css, return atomic64_read(&pids->counter); } +static int pids_events_show(struct seq_file *sf, void *v) +{ + struct pids_cgroup *pids = css_pids(seq_css(sf)); + + seq_printf(sf, "max %lld\n", (s64)atomic64_read(&pids->events_limit)); + return 0; +} + static struct cftype pids_files[] = { { .name = "max", @@ -300,6 +326,12 @@ static struct cftype pids_files[] = { .read_s64 = pids_current_read, .flags = CFTYPE_NOT_ON_ROOT, }, + { + .name = "events", + .seq_show = pids_events_show, + .file_offset = offsetof(struct pids_cgroup, events_file), + .flags = CFTYPE_NOT_ON_ROOT, + }, { } /* terminate */ }; diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index 179ef4640964..e9fdb5203de5 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -104,7 +104,7 @@ fail: return -ENOMEM; } -int get_callchain_buffers(void) +int get_callchain_buffers(int event_max_stack) { int err = 0; int count; @@ -121,6 +121,15 @@ int get_callchain_buffers(void) /* If the allocation failed, give up */ if (!callchain_cpus_entries) err = -ENOMEM; + /* + * If requesting per event more than the global cap, + * return a different error to help userspace figure + * this out. + * + * And also do it here so that we have &callchain_mutex held. + */ + if (event_max_stack > sysctl_perf_event_max_stack) + err = -EOVERFLOW; goto exit; } @@ -174,11 +183,12 @@ perf_callchain(struct perf_event *event, struct pt_regs *regs) bool user = !event->attr.exclude_callchain_user; /* Disallow cross-task user callchains. */ bool crosstask = event->ctx->task && event->ctx->task != current; + const u32 max_stack = event->attr.sample_max_stack; if (!kernel && !user) return NULL; - return get_perf_callchain(regs, 0, kernel, user, sysctl_perf_event_max_stack, crosstask, true); + return get_perf_callchain(regs, 0, kernel, user, max_stack, crosstask, true); } struct perf_callchain_entry * diff --git a/kernel/events/core.c b/kernel/events/core.c index 43d43a2d5811..79dae188a987 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -335,6 +335,7 @@ static atomic_t perf_sched_count; static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); static DEFINE_PER_CPU(int, perf_sched_cb_usages); +static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events); static atomic_t nr_mmap_events __read_mostly; static atomic_t nr_comm_events __read_mostly; @@ -396,6 +397,13 @@ int perf_proc_update_handler(struct ctl_table *table, int write, if (ret || !write) return ret; + /* + * If throttling is disabled don't allow the write: + */ + if (sysctl_perf_cpu_time_max_percent == 100 || + sysctl_perf_cpu_time_max_percent == 0) + return -EINVAL; + max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; update_perf_cpu_limits(); @@ -3686,6 +3694,39 @@ static void free_event_rcu(struct rcu_head *head) static void ring_buffer_attach(struct perf_event *event, struct ring_buffer *rb); +static void detach_sb_event(struct perf_event *event) +{ + struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); + + raw_spin_lock(&pel->lock); + list_del_rcu(&event->sb_list); + raw_spin_unlock(&pel->lock); +} + +static bool is_sb_event(struct perf_event *event) +{ + struct perf_event_attr *attr = &event->attr; + + if (event->parent) + return false; + + if (event->attach_state & PERF_ATTACH_TASK) + return false; + + if (attr->mmap || attr->mmap_data || attr->mmap2 || + attr->comm || attr->comm_exec || + attr->task || + attr->context_switch) + return true; + return false; +} + +static void unaccount_pmu_sb_event(struct perf_event *event) +{ + if (is_sb_event(event)) + detach_sb_event(event); +} + static void unaccount_event_cpu(struct perf_event *event, int cpu) { if (event->parent) @@ -3749,6 +3790,8 @@ static void unaccount_event(struct perf_event *event) } unaccount_event_cpu(event, event->cpu); + + unaccount_pmu_sb_event(event); } static void perf_sched_delayed(struct work_struct *work) @@ -5875,11 +5918,11 @@ perf_event_read_event(struct perf_event *event, perf_output_end(&handle); } -typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data); +typedef void (perf_iterate_f)(struct perf_event *event, void *data); static void -perf_event_aux_ctx(struct perf_event_context *ctx, - perf_event_aux_output_cb output, +perf_iterate_ctx(struct perf_event_context *ctx, + perf_iterate_f output, void *data, bool all) { struct perf_event *event; @@ -5896,52 +5939,55 @@ perf_event_aux_ctx(struct perf_event_context *ctx, } } -static void -perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data, - struct perf_event_context *task_ctx) +static void perf_iterate_sb_cpu(perf_iterate_f output, void *data) { - rcu_read_lock(); - preempt_disable(); - perf_event_aux_ctx(task_ctx, output, data, false); - preempt_enable(); - rcu_read_unlock(); + struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events); + struct perf_event *event; + + list_for_each_entry_rcu(event, &pel->list, sb_list) { + if (event->state < PERF_EVENT_STATE_INACTIVE) + continue; + if (!event_filter_match(event)) + continue; + output(event, data); + } } +/* + * Iterate all events that need to receive side-band events. + * + * For new callers; ensure that account_pmu_sb_event() includes + * your event, otherwise it might not get delivered. + */ static void -perf_event_aux(perf_event_aux_output_cb output, void *data, +perf_iterate_sb(perf_iterate_f output, void *data, struct perf_event_context *task_ctx) { - struct perf_cpu_context *cpuctx; struct perf_event_context *ctx; - struct pmu *pmu; int ctxn; + rcu_read_lock(); + preempt_disable(); + /* - * If we have task_ctx != NULL we only notify - * the task context itself. The task_ctx is set - * only for EXIT events before releasing task + * If we have task_ctx != NULL we only notify the task context itself. + * The task_ctx is set only for EXIT events before releasing task * context. */ if (task_ctx) { - perf_event_aux_task_ctx(output, data, task_ctx); - return; + perf_iterate_ctx(task_ctx, output, data, false); + goto done; } - rcu_read_lock(); - list_for_each_entry_rcu(pmu, &pmus, entry) { - cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); - if (cpuctx->unique_pmu != pmu) - goto next; - perf_event_aux_ctx(&cpuctx->ctx, output, data, false); - ctxn = pmu->task_ctx_nr; - if (ctxn < 0) - goto next; + perf_iterate_sb_cpu(output, data); + + for_each_task_context_nr(ctxn) { ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); if (ctx) - perf_event_aux_ctx(ctx, output, data, false); -next: - put_cpu_ptr(pmu->pmu_cpu_context); + perf_iterate_ctx(ctx, output, data, false); } +done: + preempt_enable(); rcu_read_unlock(); } @@ -5990,7 +6036,7 @@ void perf_event_exec(void) perf_event_enable_on_exec(ctxn); - perf_event_aux_ctx(ctx, perf_event_addr_filters_exec, NULL, + perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL, true); } rcu_read_unlock(); @@ -6034,9 +6080,9 @@ static int __perf_pmu_output_stop(void *info) }; rcu_read_lock(); - perf_event_aux_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false); + perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false); if (cpuctx->task_ctx) - perf_event_aux_ctx(cpuctx->task_ctx, __perf_event_output_stop, + perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop, &ro, false); rcu_read_unlock(); @@ -6165,7 +6211,7 @@ static void perf_event_task(struct task_struct *task, }, }; - perf_event_aux(perf_event_task_output, + perf_iterate_sb(perf_event_task_output, &task_event, task_ctx); } @@ -6244,7 +6290,7 @@ static void perf_event_comm_event(struct perf_comm_event *comm_event) comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; - perf_event_aux(perf_event_comm_output, + perf_iterate_sb(perf_event_comm_output, comm_event, NULL); } @@ -6475,7 +6521,7 @@ got_name: mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; - perf_event_aux(perf_event_mmap_output, + perf_iterate_sb(perf_event_mmap_output, mmap_event, NULL); @@ -6558,7 +6604,7 @@ static void perf_addr_filters_adjust(struct vm_area_struct *vma) if (!ctx) continue; - perf_event_aux_ctx(ctx, __perf_addr_filters_adjust, vma, true); + perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true); } rcu_read_unlock(); } @@ -6745,7 +6791,7 @@ static void perf_event_switch(struct task_struct *task, }, }; - perf_event_aux(perf_event_switch_output, + perf_iterate_sb(perf_event_switch_output, &switch_event, NULL); } @@ -8667,6 +8713,28 @@ unlock: return pmu; } +static void attach_sb_event(struct perf_event *event) +{ + struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); + + raw_spin_lock(&pel->lock); + list_add_rcu(&event->sb_list, &pel->list); + raw_spin_unlock(&pel->lock); +} + +/* + * We keep a list of all !task (and therefore per-cpu) events + * that need to receive side-band records. + * + * This avoids having to scan all the various PMU per-cpu contexts + * looking for them. + */ +static void account_pmu_sb_event(struct perf_event *event) +{ + if (is_sb_event(event)) + attach_sb_event(event); +} + static void account_event_cpu(struct perf_event *event, int cpu) { if (event->parent) @@ -8747,6 +8815,8 @@ static void account_event(struct perf_event *event) enabled: account_event_cpu(event, event->cpu); + + account_pmu_sb_event(event); } /* @@ -8895,7 +8965,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, if (!event->parent) { if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { - err = get_callchain_buffers(); + err = get_callchain_buffers(attr->sample_max_stack); if (err) goto err_addr_filters; } @@ -9217,6 +9287,9 @@ SYSCALL_DEFINE5(perf_event_open, return -EINVAL; } + if (!attr.sample_max_stack) + attr.sample_max_stack = sysctl_perf_event_max_stack; + /* * In cgroup mode, the pid argument is used to pass the fd * opened to the cgroup directory in cgroupfs. The cpu argument @@ -9290,7 +9363,7 @@ SYSCALL_DEFINE5(perf_event_open, if (is_sampling_event(event)) { if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) { - err = -ENOTSUPP; + err = -EOPNOTSUPP; goto err_alloc; } } @@ -10252,6 +10325,9 @@ static void __init perf_event_init_all_cpus(void) swhash = &per_cpu(swevent_htable, cpu); mutex_init(&swhash->hlist_mutex); INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu)); + + INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu)); + raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu)); } } diff --git a/kernel/exit.c b/kernel/exit.c index 9e6e1356e6bb..84ae830234f8 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -211,6 +211,82 @@ repeat: } /* + * Note that if this function returns a valid task_struct pointer (!NULL) + * task->usage must remain >0 for the duration of the RCU critical section. + */ +struct task_struct *task_rcu_dereference(struct task_struct **ptask) +{ + struct sighand_struct *sighand; + struct task_struct *task; + + /* + * We need to verify that release_task() was not called and thus + * delayed_put_task_struct() can't run and drop the last reference + * before rcu_read_unlock(). We check task->sighand != NULL, + * but we can read the already freed and reused memory. + */ +retry: + task = rcu_dereference(*ptask); + if (!task) + return NULL; + + probe_kernel_address(&task->sighand, sighand); + + /* + * Pairs with atomic_dec_and_test() in put_task_struct(). If this task + * was already freed we can not miss the preceding update of this + * pointer. + */ + smp_rmb(); + if (unlikely(task != READ_ONCE(*ptask))) + goto retry; + + /* + * We've re-checked that "task == *ptask", now we have two different + * cases: + * + * 1. This is actually the same task/task_struct. In this case + * sighand != NULL tells us it is still alive. + * + * 2. This is another task which got the same memory for task_struct. + * We can't know this of course, and we can not trust + * sighand != NULL. + * + * In this case we actually return a random value, but this is + * correct. + * + * If we return NULL - we can pretend that we actually noticed that + * *ptask was updated when the previous task has exited. Or pretend + * that probe_slab_address(&sighand) reads NULL. + * + * If we return the new task (because sighand is not NULL for any + * reason) - this is fine too. This (new) task can't go away before + * another gp pass. + * + * And note: We could even eliminate the false positive if re-read + * task->sighand once again to avoid the falsely NULL. But this case + * is very unlikely so we don't care. + */ + if (!sighand) + return NULL; + + return task; +} + +struct task_struct *try_get_task_struct(struct task_struct **ptask) +{ + struct task_struct *task; + + rcu_read_lock(); + task = task_rcu_dereference(ptask); + if (task) + get_task_struct(task); + rcu_read_unlock(); + + return task; +} + +/* * Determine if a process group is "orphaned", according to the POSIX * definition in 2.2.2.52. Orphaned process groups are not to be affected * by terminal-generated stop signals. Newly orphaned process groups are @@ -700,10 +776,14 @@ void do_exit(long code) exit_signals(tsk); /* sets PF_EXITING */ /* - * tsk->flags are checked in the futex code to protect against - * an exiting task cleaning up the robust pi futexes. + * Ensure that all new tsk->pi_lock acquisitions must observe + * PF_EXITING. Serializes against futex.c:attach_to_pi_owner(). */ smp_mb(); + /* + * Ensure that we must observe the pi_state in exit_mm() -> + * mm_release() -> exit_pi_state_list(). + */ raw_spin_unlock_wait(&tsk->pi_lock); if (unlikely(in_atomic())) { diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile index 2ee42e95a3ce..1d3ee3169202 100644 --- a/kernel/irq/Makefile +++ b/kernel/irq/Makefile @@ -9,3 +9,4 @@ obj-$(CONFIG_GENERIC_IRQ_MIGRATION) += cpuhotplug.o obj-$(CONFIG_PM_SLEEP) += pm.o obj-$(CONFIG_GENERIC_MSI_IRQ) += msi.o obj-$(CONFIG_GENERIC_IRQ_IPI) += ipi.o +obj-$(CONFIG_SMP) += affinity.o diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c new file mode 100644 index 000000000000..f68959341c0f --- /dev/null +++ b/kernel/irq/affinity.c @@ -0,0 +1,61 @@ + +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/cpu.h> + +static int get_first_sibling(unsigned int cpu) +{ + unsigned int ret; + + ret = cpumask_first(topology_sibling_cpumask(cpu)); + if (ret < nr_cpu_ids) + return ret; + return cpu; +} + +/* + * Take a map of online CPUs and the number of available interrupt vectors + * and generate an output cpumask suitable for spreading MSI/MSI-X vectors + * so that they are distributed as good as possible around the CPUs. If + * more vectors than CPUs are available we'll map one to each CPU, + * otherwise we map one to the first sibling of each socket. + * + * If there are more vectors than CPUs we will still only have one bit + * set per CPU, but interrupt code will keep on assigning the vectors from + * the start of the bitmap until we run out of vectors. + */ +struct cpumask *irq_create_affinity_mask(unsigned int *nr_vecs) +{ + struct cpumask *affinity_mask; + unsigned int max_vecs = *nr_vecs; + + if (max_vecs == 1) + return NULL; + + affinity_mask = kzalloc(cpumask_size(), GFP_KERNEL); + if (!affinity_mask) { + *nr_vecs = 1; + return NULL; + } + + if (max_vecs >= num_online_cpus()) { + cpumask_copy(affinity_mask, cpu_online_mask); + *nr_vecs = num_online_cpus(); + } else { + unsigned int vecs = 0, cpu; + + for_each_online_cpu(cpu) { + if (cpu == get_first_sibling(cpu)) { + cpumask_set_cpu(cpu, affinity_mask); + vecs++; + } + + if (--max_vecs == 0) + break; + } + *nr_vecs = vecs; + } + + return affinity_mask; +} diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index 2f9f2b0e79f2..b4c1bc7c9ca2 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -426,6 +426,49 @@ out_unlock: } EXPORT_SYMBOL_GPL(handle_simple_irq); +/** + * handle_untracked_irq - Simple and software-decoded IRQs. + * @desc: the interrupt description structure for this irq + * + * Untracked interrupts are sent from a demultiplexing interrupt + * handler when the demultiplexer does not know which device it its + * multiplexed irq domain generated the interrupt. IRQ's handled + * through here are not subjected to stats tracking, randomness, or + * spurious interrupt detection. + * + * Note: Like handle_simple_irq, the caller is expected to handle + * the ack, clear, mask and unmask issues if necessary. + */ +void handle_untracked_irq(struct irq_desc *desc) +{ + unsigned int flags = 0; + + raw_spin_lock(&desc->lock); + + if (!irq_may_run(desc)) + goto out_unlock; + + desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING); + + if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) { + desc->istate |= IRQS_PENDING; + goto out_unlock; + } + + desc->istate &= ~IRQS_PENDING; + irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS); + raw_spin_unlock(&desc->lock); + + __handle_irq_event_percpu(desc, &flags); + + raw_spin_lock(&desc->lock); + irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS); + +out_unlock: + raw_spin_unlock(&desc->lock); +} +EXPORT_SYMBOL_GPL(handle_untracked_irq); + /* * Called unconditionally from handle_level_irq() and only for oneshot * interrupts from handle_fasteoi_irq() @@ -1093,3 +1136,43 @@ int irq_chip_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) return 0; } + +/** + * irq_chip_pm_get - Enable power for an IRQ chip + * @data: Pointer to interrupt specific data + * + * Enable the power to the IRQ chip referenced by the interrupt data + * structure. + */ +int irq_chip_pm_get(struct irq_data *data) +{ + int retval; + + if (IS_ENABLED(CONFIG_PM) && data->chip->parent_device) { + retval = pm_runtime_get_sync(data->chip->parent_device); + if (retval < 0) { + pm_runtime_put_noidle(data->chip->parent_device); + return retval; + } + } + + return 0; +} + +/** + * irq_chip_pm_put - Disable power for an IRQ chip + * @data: Pointer to interrupt specific data + * + * Disable the power to the IRQ chip referenced by the interrupt data + * structure, belongs. Note that power will only be disabled, once this + * function has been called for all IRQs that have called irq_chip_pm_get(). + */ +int irq_chip_pm_put(struct irq_data *data) +{ + int retval = 0; + + if (IS_ENABLED(CONFIG_PM) && data->chip->parent_device) + retval = pm_runtime_put(data->chip->parent_device); + + return (retval < 0) ? retval : 0; +} diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c index a15b5485b446..d3f24905852c 100644 --- a/kernel/irq/handle.c +++ b/kernel/irq/handle.c @@ -132,10 +132,10 @@ void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action) wake_up_process(action->thread); } -irqreturn_t handle_irq_event_percpu(struct irq_desc *desc) +irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags) { irqreturn_t retval = IRQ_NONE; - unsigned int flags = 0, irq = desc->irq_data.irq; + unsigned int irq = desc->irq_data.irq; struct irqaction *action; for_each_action_of_desc(desc, action) { @@ -164,7 +164,7 @@ irqreturn_t handle_irq_event_percpu(struct irq_desc *desc) /* Fall through to add to randomness */ case IRQ_HANDLED: - flags |= action->flags; + *flags |= action->flags; break; default: @@ -174,7 +174,17 @@ irqreturn_t handle_irq_event_percpu(struct irq_desc *desc) retval |= res; } - add_interrupt_randomness(irq, flags); + return retval; +} + +irqreturn_t handle_irq_event_percpu(struct irq_desc *desc) +{ + irqreturn_t retval; + unsigned int flags = 0; + + retval = __handle_irq_event_percpu(desc, &flags); + + add_interrupt_randomness(desc->irq_data.irq, flags); if (!noirqdebug) note_interrupt(desc, retval); diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index 09be2c903c6d..bc226e783bd2 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -7,6 +7,7 @@ */ #include <linux/irqdesc.h> #include <linux/kernel_stat.h> +#include <linux/pm_runtime.h> #ifdef CONFIG_SPARSE_IRQ # define IRQ_BITMAP_BITS (NR_IRQS + 8196) @@ -83,6 +84,7 @@ extern void irq_mark_irq(unsigned int irq); extern void init_kstat_irqs(struct irq_desc *desc, int node, int nr); +irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags); irqreturn_t handle_irq_event_percpu(struct irq_desc *desc); irqreturn_t handle_irq_event(struct irq_desc *desc); @@ -105,6 +107,8 @@ static inline void unregister_handler_proc(unsigned int irq, struct irqaction *action) { } #endif +extern bool irq_can_set_affinity_usr(unsigned int irq); + extern int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask); extern void irq_set_thread_affinity(struct irq_desc *desc); diff --git a/kernel/irq/ipi.c b/kernel/irq/ipi.c index 89b49f6773f0..1a9abc1c8ea0 100644 --- a/kernel/irq/ipi.c +++ b/kernel/irq/ipi.c @@ -76,14 +76,14 @@ int irq_reserve_ipi(struct irq_domain *domain, } } - virq = irq_domain_alloc_descs(-1, nr_irqs, 0, NUMA_NO_NODE); + virq = irq_domain_alloc_descs(-1, nr_irqs, 0, NUMA_NO_NODE, NULL); if (virq <= 0) { pr_warn("Can't reserve IPI, failed to alloc descs\n"); return -ENOMEM; } virq = __irq_domain_alloc_irqs(domain, virq, nr_irqs, NUMA_NO_NODE, - (void *) dest, true); + (void *) dest, true, NULL); if (virq <= 0) { pr_warn("Can't reserve IPI, failed to alloc hw irqs\n"); diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index 8731e1c5d1e7..a623b44f2d4b 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -68,9 +68,13 @@ static int alloc_masks(struct irq_desc *desc, gfp_t gfp, int node) return 0; } -static void desc_smp_init(struct irq_desc *desc, int node) +static void desc_smp_init(struct irq_desc *desc, int node, + const struct cpumask *affinity) { - cpumask_copy(desc->irq_common_data.affinity, irq_default_affinity); + if (!affinity) + affinity = irq_default_affinity; + cpumask_copy(desc->irq_common_data.affinity, affinity); + #ifdef CONFIG_GENERIC_PENDING_IRQ cpumask_clear(desc->pending_mask); #endif @@ -82,11 +86,12 @@ static void desc_smp_init(struct irq_desc *desc, int node) #else static inline int alloc_masks(struct irq_desc *desc, gfp_t gfp, int node) { return 0; } -static inline void desc_smp_init(struct irq_desc *desc, int node) { } +static inline void +desc_smp_init(struct irq_desc *desc, int node, const struct cpumask *affinity) { } #endif static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node, - struct module *owner) + const struct cpumask *affinity, struct module *owner) { int cpu; @@ -107,7 +112,7 @@ static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node, desc->owner = owner; for_each_possible_cpu(cpu) *per_cpu_ptr(desc->kstat_irqs, cpu) = 0; - desc_smp_init(desc, node); + desc_smp_init(desc, node, affinity); } int nr_irqs = NR_IRQS; @@ -158,7 +163,9 @@ void irq_unlock_sparse(void) mutex_unlock(&sparse_irq_lock); } -static struct irq_desc *alloc_desc(int irq, int node, struct module *owner) +static struct irq_desc *alloc_desc(int irq, int node, unsigned int flags, + const struct cpumask *affinity, + struct module *owner) { struct irq_desc *desc; gfp_t gfp = GFP_KERNEL; @@ -178,7 +185,8 @@ static struct irq_desc *alloc_desc(int irq, int node, struct module *owner) lockdep_set_class(&desc->lock, &irq_desc_lock_class); init_rcu_head(&desc->rcu); - desc_set_defaults(irq, desc, node, owner); + desc_set_defaults(irq, desc, node, affinity, owner); + irqd_set(&desc->irq_data, flags); return desc; @@ -223,13 +231,32 @@ static void free_desc(unsigned int irq) } static int alloc_descs(unsigned int start, unsigned int cnt, int node, - struct module *owner) + const struct cpumask *affinity, struct module *owner) { + const struct cpumask *mask = NULL; struct irq_desc *desc; - int i; + unsigned int flags; + int i, cpu = -1; + + if (affinity && cpumask_empty(affinity)) + return -EINVAL; + + flags = affinity ? IRQD_AFFINITY_MANAGED : 0; for (i = 0; i < cnt; i++) { - desc = alloc_desc(start + i, node, owner); + if (affinity) { + cpu = cpumask_next(cpu, affinity); + if (cpu >= nr_cpu_ids) + cpu = cpumask_first(affinity); + node = cpu_to_node(cpu); + + /* + * For single allocations we use the caller provided + * mask otherwise we use the mask of the target cpu + */ + mask = cnt == 1 ? affinity : cpumask_of(cpu); + } + desc = alloc_desc(start + i, node, flags, mask, owner); if (!desc) goto err; mutex_lock(&sparse_irq_lock); @@ -277,7 +304,7 @@ int __init early_irq_init(void) nr_irqs = initcnt; for (i = 0; i < initcnt; i++) { - desc = alloc_desc(i, node, NULL); + desc = alloc_desc(i, node, 0, NULL, NULL); set_bit(i, allocated_irqs); irq_insert_desc(i, desc); } @@ -311,7 +338,7 @@ int __init early_irq_init(void) alloc_masks(&desc[i], GFP_KERNEL, node); raw_spin_lock_init(&desc[i].lock); lockdep_set_class(&desc[i].lock, &irq_desc_lock_class); - desc_set_defaults(i, &desc[i], node, NULL); + desc_set_defaults(i, &desc[i], node, NULL, NULL); } return arch_early_irq_init(); } @@ -328,11 +355,12 @@ static void free_desc(unsigned int irq) unsigned long flags; raw_spin_lock_irqsave(&desc->lock, flags); - desc_set_defaults(irq, desc, irq_desc_get_node(desc), NULL); + desc_set_defaults(irq, desc, irq_desc_get_node(desc), NULL, NULL); raw_spin_unlock_irqrestore(&desc->lock, flags); } static inline int alloc_descs(unsigned int start, unsigned int cnt, int node, + const struct cpumask *affinity, struct module *owner) { u32 i; @@ -453,12 +481,15 @@ EXPORT_SYMBOL_GPL(irq_free_descs); * @cnt: Number of consecutive irqs to allocate. * @node: Preferred node on which the irq descriptor should be allocated * @owner: Owning module (can be NULL) + * @affinity: Optional pointer to an affinity mask which hints where the + * irq descriptors should be allocated and which default + * affinities to use * * Returns the first irq number or error code */ int __ref __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node, - struct module *owner) + struct module *owner, const struct cpumask *affinity) { int start, ret; @@ -494,7 +525,7 @@ __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node, bitmap_set(allocated_irqs, start, cnt); mutex_unlock(&sparse_irq_lock); - return alloc_descs(start, cnt, node, owner); + return alloc_descs(start, cnt, node, affinity, owner); err: mutex_unlock(&sparse_irq_lock); @@ -512,7 +543,7 @@ EXPORT_SYMBOL_GPL(__irq_alloc_descs); */ unsigned int irq_alloc_hwirqs(int cnt, int node) { - int i, irq = __irq_alloc_descs(-1, 0, cnt, node, NULL); + int i, irq = __irq_alloc_descs(-1, 0, cnt, node, NULL, NULL); if (irq < 0) return 0; diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 8798b6c9e945..4752b43662e0 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -481,7 +481,7 @@ unsigned int irq_create_mapping(struct irq_domain *domain, } /* Allocate a virtual interrupt number */ - virq = irq_domain_alloc_descs(-1, 1, hwirq, of_node_to_nid(of_node)); + virq = irq_domain_alloc_descs(-1, 1, hwirq, of_node_to_nid(of_node), NULL); if (virq <= 0) { pr_debug("-> virq allocation failed\n"); return 0; @@ -567,6 +567,7 @@ static void of_phandle_args_to_fwspec(struct of_phandle_args *irq_data, unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec) { struct irq_domain *domain; + struct irq_data *irq_data; irq_hw_number_t hwirq; unsigned int type = IRQ_TYPE_NONE; int virq; @@ -588,15 +589,46 @@ unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec) if (irq_domain_translate(domain, fwspec, &hwirq, &type)) return 0; - if (irq_domain_is_hierarchy(domain)) { + /* + * WARN if the irqchip returns a type with bits + * outside the sense mask set and clear these bits. + */ + if (WARN_ON(type & ~IRQ_TYPE_SENSE_MASK)) + type &= IRQ_TYPE_SENSE_MASK; + + /* + * If we've already configured this interrupt, + * don't do it again, or hell will break loose. + */ + virq = irq_find_mapping(domain, hwirq); + if (virq) { + /* + * If the trigger type is not specified or matches the + * current trigger type then we are done so return the + * interrupt number. + */ + if (type == IRQ_TYPE_NONE || type == irq_get_trigger_type(virq)) + return virq; + /* - * If we've already configured this interrupt, - * don't do it again, or hell will break loose. + * If the trigger type has not been set yet, then set + * it now and return the interrupt number. */ - virq = irq_find_mapping(domain, hwirq); - if (virq) + if (irq_get_trigger_type(virq) == IRQ_TYPE_NONE) { + irq_data = irq_get_irq_data(virq); + if (!irq_data) + return 0; + + irqd_set_trigger_type(irq_data, type); return virq; + } + pr_warn("type mismatch, failed to map hwirq-%lu for %s!\n", + hwirq, of_node_full_name(to_of_node(fwspec->fwnode))); + return 0; + } + + if (irq_domain_is_hierarchy(domain)) { virq = irq_domain_alloc_irqs(domain, 1, NUMA_NO_NODE, fwspec); if (virq <= 0) return 0; @@ -607,10 +639,18 @@ unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec) return virq; } - /* Set type if specified and different than the current one */ - if (type != IRQ_TYPE_NONE && - type != irq_get_trigger_type(virq)) - irq_set_irq_type(virq, type); + irq_data = irq_get_irq_data(virq); + if (!irq_data) { + if (irq_domain_is_hierarchy(domain)) + irq_domain_free_irqs(virq, 1); + else + irq_dispose_mapping(virq); + return 0; + } + + /* Store trigger type */ + irqd_set_trigger_type(irq_data, type); + return virq; } EXPORT_SYMBOL_GPL(irq_create_fwspec_mapping); @@ -640,8 +680,12 @@ void irq_dispose_mapping(unsigned int virq) if (WARN_ON(domain == NULL)) return; - irq_domain_disassociate(domain, virq); - irq_free_desc(virq); + if (irq_domain_is_hierarchy(domain)) { + irq_domain_free_irqs(virq, 1); + } else { + irq_domain_disassociate(domain, virq); + irq_free_desc(virq); + } } EXPORT_SYMBOL_GPL(irq_dispose_mapping); @@ -835,19 +879,23 @@ const struct irq_domain_ops irq_domain_simple_ops = { EXPORT_SYMBOL_GPL(irq_domain_simple_ops); int irq_domain_alloc_descs(int virq, unsigned int cnt, irq_hw_number_t hwirq, - int node) + int node, const struct cpumask *affinity) { unsigned int hint; if (virq >= 0) { - virq = irq_alloc_descs(virq, virq, cnt, node); + virq = __irq_alloc_descs(virq, virq, cnt, node, THIS_MODULE, + affinity); } else { hint = hwirq % nr_irqs; if (hint == 0) hint++; - virq = irq_alloc_descs_from(hint, cnt, node); - if (virq <= 0 && hint > 1) - virq = irq_alloc_descs_from(1, cnt, node); + virq = __irq_alloc_descs(-1, hint, cnt, node, THIS_MODULE, + affinity); + if (virq <= 0 && hint > 1) { + virq = __irq_alloc_descs(-1, 1, cnt, node, THIS_MODULE, + affinity); + } } return virq; @@ -1144,8 +1192,10 @@ int irq_domain_alloc_irqs_recursive(struct irq_domain *domain, if (recursive) ret = irq_domain_alloc_irqs_recursive(parent, irq_base, nr_irqs, arg); - if (ret >= 0) - ret = domain->ops->alloc(domain, irq_base, nr_irqs, arg); + if (ret < 0) + return ret; + + ret = domain->ops->alloc(domain, irq_base, nr_irqs, arg); if (ret < 0 && recursive) irq_domain_free_irqs_recursive(parent, irq_base, nr_irqs); @@ -1160,6 +1210,7 @@ int irq_domain_alloc_irqs_recursive(struct irq_domain *domain, * @node: NUMA node id for memory allocation * @arg: domain specific argument * @realloc: IRQ descriptors have already been allocated if true + * @affinity: Optional irq affinity mask for multiqueue devices * * Allocate IRQ numbers and initialized all data structures to support * hierarchy IRQ domains. @@ -1175,7 +1226,7 @@ int irq_domain_alloc_irqs_recursive(struct irq_domain *domain, */ int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base, unsigned int nr_irqs, int node, void *arg, - bool realloc) + bool realloc, const struct cpumask *affinity) { int i, ret, virq; @@ -1193,7 +1244,8 @@ int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base, if (realloc && irq_base >= 0) { virq = irq_base; } else { - virq = irq_domain_alloc_descs(irq_base, nr_irqs, 0, node); + virq = irq_domain_alloc_descs(irq_base, nr_irqs, 0, node, + affinity); if (virq < 0) { pr_debug("cannot allocate IRQ(base %d, count %d)\n", irq_base, nr_irqs); diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index ef0bc02c3a70..73a2b786b5e9 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -115,12 +115,12 @@ EXPORT_SYMBOL(synchronize_irq); #ifdef CONFIG_SMP cpumask_var_t irq_default_affinity; -static int __irq_can_set_affinity(struct irq_desc *desc) +static bool __irq_can_set_affinity(struct irq_desc *desc) { if (!desc || !irqd_can_balance(&desc->irq_data) || !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity) - return 0; - return 1; + return false; + return true; } /** @@ -134,6 +134,21 @@ int irq_can_set_affinity(unsigned int irq) } /** + * irq_can_set_affinity_usr - Check if affinity of a irq can be set from user space + * @irq: Interrupt to check + * + * Like irq_can_set_affinity() above, but additionally checks for the + * AFFINITY_MANAGED flag. + */ +bool irq_can_set_affinity_usr(unsigned int irq) +{ + struct irq_desc *desc = irq_to_desc(irq); + + return __irq_can_set_affinity(desc) && + !irqd_affinity_is_managed(&desc->irq_data); +} + +/** * irq_set_thread_affinity - Notify irq threads to adjust affinity * @desc: irq descriptor which has affitnity changed * @@ -338,10 +353,11 @@ static int setup_affinity(struct irq_desc *desc, struct cpumask *mask) return 0; /* - * Preserve an userspace affinity setup, but make sure that - * one of the targets is online. + * Preserve the managed affinity setting and an userspace affinity + * setup, but make sure that one of the targets is online. */ - if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) { + if (irqd_affinity_is_managed(&desc->irq_data) || + irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) { if (cpumask_intersects(desc->irq_common_data.affinity, cpu_online_mask)) set = desc->irq_common_data.affinity; @@ -1117,6 +1133,13 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) new->irq = irq; /* + * If the trigger type is not specified by the caller, + * then use the default for this interrupt. + */ + if (!(new->flags & IRQF_TRIGGER_MASK)) + new->flags |= irqd_get_trigger_type(&desc->irq_data); + + /* * Check whether the interrupt nests into another interrupt * thread. */ @@ -1409,10 +1432,18 @@ int setup_irq(unsigned int irq, struct irqaction *act) if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc))) return -EINVAL; + + retval = irq_chip_pm_get(&desc->irq_data); + if (retval < 0) + return retval; + chip_bus_lock(desc); retval = __setup_irq(irq, desc, act); chip_bus_sync_unlock(desc); + if (retval) + irq_chip_pm_put(&desc->irq_data); + return retval; } EXPORT_SYMBOL_GPL(setup_irq); @@ -1506,6 +1537,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id) } } + irq_chip_pm_put(&desc->irq_data); module_put(desc->owner); kfree(action->secondary); return action; @@ -1648,11 +1680,16 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler, action->name = devname; action->dev_id = dev_id; + retval = irq_chip_pm_get(&desc->irq_data); + if (retval < 0) + return retval; + chip_bus_lock(desc); retval = __setup_irq(irq, desc, action); chip_bus_sync_unlock(desc); if (retval) { + irq_chip_pm_put(&desc->irq_data); kfree(action->secondary); kfree(action); } @@ -1730,7 +1767,14 @@ void enable_percpu_irq(unsigned int irq, unsigned int type) if (!desc) return; + /* + * If the trigger type is not specified by the caller, then + * use the default for this interrupt. + */ type &= IRQ_TYPE_SENSE_MASK; + if (type == IRQ_TYPE_NONE) + type = irqd_get_trigger_type(&desc->irq_data); + if (type != IRQ_TYPE_NONE) { int ret; @@ -1822,6 +1866,7 @@ static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_ unregister_handler_proc(irq, action); + irq_chip_pm_put(&desc->irq_data); module_put(desc->owner); return action; @@ -1884,10 +1929,18 @@ int setup_percpu_irq(unsigned int irq, struct irqaction *act) if (!desc || !irq_settings_is_per_cpu_devid(desc)) return -EINVAL; + + retval = irq_chip_pm_get(&desc->irq_data); + if (retval < 0) + return retval; + chip_bus_lock(desc); retval = __setup_irq(irq, desc, act); chip_bus_sync_unlock(desc); + if (retval) + irq_chip_pm_put(&desc->irq_data); + return retval; } @@ -1931,12 +1984,18 @@ int request_percpu_irq(unsigned int irq, irq_handler_t handler, action->name = devname; action->percpu_dev_id = dev_id; + retval = irq_chip_pm_get(&desc->irq_data); + if (retval < 0) + return retval; + chip_bus_lock(desc); retval = __setup_irq(irq, desc, action); chip_bus_sync_unlock(desc); - if (retval) + if (retval) { + irq_chip_pm_put(&desc->irq_data); kfree(action); + } return retval; } diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c index 38e89ce7b071..54999350162c 100644 --- a/kernel/irq/msi.c +++ b/kernel/irq/msi.c @@ -324,7 +324,7 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev, struct msi_domain_ops *ops = info->ops; msi_alloc_info_t arg; struct msi_desc *desc; - int i, ret, virq = -1; + int i, ret, virq; ret = msi_domain_prepare_irqs(domain, dev, nvec, &arg); if (ret) @@ -332,13 +332,10 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev, for_each_msi_entry(desc, dev) { ops->set_desc(&arg, desc); - if (info->flags & MSI_FLAG_IDENTITY_MAP) - virq = (int)ops->get_hwirq(info, &arg); - else - virq = -1; - virq = __irq_domain_alloc_irqs(domain, virq, desc->nvec_used, - dev_to_node(dev), &arg, false); + virq = __irq_domain_alloc_irqs(domain, -1, desc->nvec_used, + dev_to_node(dev), &arg, false, + desc->affinity); if (virq < 0) { ret = -ENOSPC; if (ops->handle_error) @@ -356,6 +353,7 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev, ops->msi_finish(&arg, 0); for_each_msi_entry(desc, dev) { + virq = desc->irq; if (desc->nvec_used == 1) dev_dbg(dev, "irq %d for MSI\n", virq); else diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 4e1b94726818..feaa813b84a9 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -96,7 +96,7 @@ static ssize_t write_irq_affinity(int type, struct file *file, cpumask_var_t new_value; int err; - if (!irq_can_set_affinity(irq) || no_irq_affinity) + if (!irq_can_set_affinity_usr(irq) || no_irq_affinity) return -EIO; if (!alloc_cpumask_var(&new_value, GFP_KERNEL)) @@ -311,7 +311,6 @@ void register_handler_proc(unsigned int irq, struct irqaction *action) !name_unique(irq, action)) return; - memset(name, 0, MAX_NAMELEN); snprintf(name, MAX_NAMELEN, "%s", action->name); /* create /proc/irq/1234/handler/ */ @@ -340,7 +339,6 @@ void register_irq_proc(unsigned int irq, struct irq_desc *desc) if (desc->dir) goto out_unlock; - memset(name, 0, MAX_NAMELEN); sprintf(name, "%d", irq); /* create /proc/irq/1234 */ @@ -386,7 +384,6 @@ void unregister_irq_proc(unsigned int irq, struct irq_desc *desc) #endif remove_proc_entry("spurious", desc->dir); - memset(name, 0, MAX_NAMELEN); sprintf(name, "%u", irq); remove_proc_entry(name, root_irq_dir); } @@ -421,12 +418,8 @@ void init_irq_proc(void) /* * Create entries for all existing IRQs. */ - for_each_irq_desc(irq, desc) { - if (!desc) - continue; - + for_each_irq_desc(irq, desc) register_irq_proc(irq, desc); - } } #ifdef CONFIG_GENERIC_IRQ_SHOW diff --git a/kernel/jump_label.c b/kernel/jump_label.c index 4b353e0be121..0dbea887d625 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -452,7 +452,7 @@ jump_label_module_notify(struct notifier_block *self, unsigned long val, return notifier_from_errno(ret); } -struct notifier_block jump_label_module_nb = { +static struct notifier_block jump_label_module_nb = { .notifier_call = jump_label_module_notify, .priority = 1, /* higher than tracepoints */ }; diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 81f1a7107c0e..589d763a49b3 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -46,6 +46,7 @@ #include <linux/gfp.h> #include <linux/kmemcheck.h> #include <linux/random.h> +#include <linux/jhash.h> #include <asm/sections.h> @@ -309,10 +310,14 @@ static struct hlist_head chainhash_table[CHAINHASH_SIZE]; * It's a 64-bit hash, because it's important for the keys to be * unique. */ -#define iterate_chain_key(key1, key2) \ - (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ - ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ - (key2)) +static inline u64 iterate_chain_key(u64 key, u32 idx) +{ + u32 k0 = key, k1 = key >> 32; + + __jhash_mix(idx, k0, k1); /* Macro that modifies arguments! */ + + return k0 | (u64)k1 << 32; +} void lockdep_off(void) { diff --git a/kernel/locking/mutex-debug.h b/kernel/locking/mutex-debug.h index d06ae3bb46c5..57a871ae3c81 100644 --- a/kernel/locking/mutex-debug.h +++ b/kernel/locking/mutex-debug.h @@ -29,12 +29,12 @@ extern void debug_mutex_init(struct mutex *lock, const char *name, static inline void mutex_set_owner(struct mutex *lock) { - lock->owner = current; + WRITE_ONCE(lock->owner, current); } static inline void mutex_clear_owner(struct mutex *lock) { - lock->owner = NULL; + WRITE_ONCE(lock->owner, NULL); } #define spin_lock_mutex(lock, flags) \ diff --git a/kernel/locking/mutex.h b/kernel/locking/mutex.h index a68bae5e852a..6cd6b8e9efd7 100644 --- a/kernel/locking/mutex.h +++ b/kernel/locking/mutex.h @@ -17,14 +17,20 @@ __list_del((waiter)->list.prev, (waiter)->list.next) #ifdef CONFIG_MUTEX_SPIN_ON_OWNER +/* + * The mutex owner can get read and written to locklessly. + * We should use WRITE_ONCE when writing the owner value to + * avoid store tearing, otherwise, a thread could potentially + * read a partially written and incomplete owner value. + */ static inline void mutex_set_owner(struct mutex *lock) { - lock->owner = current; + WRITE_ONCE(lock->owner, current); } static inline void mutex_clear_owner(struct mutex *lock) { - lock->owner = NULL; + WRITE_ONCE(lock->owner, NULL); } #else static inline void mutex_set_owner(struct mutex *lock) diff --git a/kernel/locking/qrwlock.c b/kernel/locking/qrwlock.c index fec082338668..19248ddf37ce 100644 --- a/kernel/locking/qrwlock.c +++ b/kernel/locking/qrwlock.c @@ -93,7 +93,7 @@ void queued_read_lock_slowpath(struct qrwlock *lock, u32 cnts) * that accesses can't leak upwards out of our subsequent critical * section in the case that the lock is currently held for write. */ - cnts = atomic_add_return_acquire(_QR_BIAS, &lock->cnts) - _QR_BIAS; + cnts = atomic_fetch_add_acquire(_QR_BIAS, &lock->cnts); rspin_until_writer_unlock(lock, cnts); /* diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 5fc8c311b8fe..b2caec7315af 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -90,7 +90,7 @@ static DEFINE_PER_CPU_ALIGNED(struct mcs_spinlock, mcs_nodes[MAX_NODES]); * therefore increment the cpu number by one. */ -static inline u32 encode_tail(int cpu, int idx) +static inline __pure u32 encode_tail(int cpu, int idx) { u32 tail; @@ -103,7 +103,7 @@ static inline u32 encode_tail(int cpu, int idx) return tail; } -static inline struct mcs_spinlock *decode_tail(u32 tail) +static inline __pure struct mcs_spinlock *decode_tail(u32 tail) { int cpu = (tail >> _Q_TAIL_CPU_OFFSET) - 1; int idx = (tail & _Q_TAIL_IDX_MASK) >> _Q_TAIL_IDX_OFFSET; @@ -268,6 +268,63 @@ static __always_inline u32 __pv_wait_head_or_lock(struct qspinlock *lock, #endif /* + * Various notes on spin_is_locked() and spin_unlock_wait(), which are + * 'interesting' functions: + * + * PROBLEM: some architectures have an interesting issue with atomic ACQUIRE + * operations in that the ACQUIRE applies to the LOAD _not_ the STORE (ARM64, + * PPC). Also qspinlock has a similar issue per construction, the setting of + * the locked byte can be unordered acquiring the lock proper. + * + * This gets to be 'interesting' in the following cases, where the /should/s + * end up false because of this issue. + * + * + * CASE 1: + * + * So the spin_is_locked() correctness issue comes from something like: + * + * CPU0 CPU1 + * + * global_lock(); local_lock(i) + * spin_lock(&G) spin_lock(&L[i]) + * for (i) if (!spin_is_locked(&G)) { + * spin_unlock_wait(&L[i]); smp_acquire__after_ctrl_dep(); + * return; + * } + * // deal with fail + * + * Where it is important CPU1 sees G locked or CPU0 sees L[i] locked such + * that there is exclusion between the two critical sections. + * + * The load from spin_is_locked(&G) /should/ be constrained by the ACQUIRE from + * spin_lock(&L[i]), and similarly the load(s) from spin_unlock_wait(&L[i]) + * /should/ be constrained by the ACQUIRE from spin_lock(&G). + * + * Similarly, later stuff is constrained by the ACQUIRE from CTRL+RMB. + * + * + * CASE 2: + * + * For spin_unlock_wait() there is a second correctness issue, namely: + * + * CPU0 CPU1 + * + * flag = set; + * smp_mb(); spin_lock(&l) + * spin_unlock_wait(&l); if (!flag) + * // add to lockless list + * spin_unlock(&l); + * // iterate lockless list + * + * Which wants to ensure that CPU1 will stop adding bits to the list and CPU0 + * will observe the last entry on the list (if spin_unlock_wait() had ACQUIRE + * semantics etc..) + * + * Where flag /should/ be ordered against the locked store of l. + */ + +/* * queued_spin_lock_slowpath() can (load-)ACQUIRE the lock before * issuing an _unordered_ store to set _Q_LOCKED_VAL. * @@ -322,7 +379,7 @@ void queued_spin_unlock_wait(struct qspinlock *lock) cpu_relax(); done: - smp_rmb(); /* CTRL + RMB -> ACQUIRE */ + smp_acquire__after_ctrl_dep(); } EXPORT_SYMBOL(queued_spin_unlock_wait); #endif @@ -418,7 +475,7 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) * sequentiality; this is because not all clear_pending_set_locked() * implementations imply full barriers. */ - smp_cond_acquire(!(atomic_read(&lock->val) & _Q_LOCKED_MASK)); + smp_cond_load_acquire(&lock->val.counter, !(VAL & _Q_LOCKED_MASK)); /* * take ownership and clear the pending bit. @@ -455,6 +512,8 @@ queue: * pending stuff. * * p,*,* -> n,*,* + * + * RELEASE, such that the stores to @node must be complete. */ old = xchg_tail(lock, tail); next = NULL; @@ -465,6 +524,15 @@ queue: */ if (old & _Q_TAIL_MASK) { prev = decode_tail(old); + /* + * The above xchg_tail() is also a load of @lock which generates, + * through decode_tail(), a pointer. + * + * The address dependency matches the RELEASE of xchg_tail() + * such that the access to @prev must happen after. + */ + smp_read_barrier_depends(); + WRITE_ONCE(prev->next, node); pv_wait_node(node, prev); @@ -494,7 +562,7 @@ queue: * * The PV pv_wait_head_or_lock function, if active, will acquire * the lock and return a non-zero value. So we have to skip the - * smp_cond_acquire() call. As the next PV queue head hasn't been + * smp_cond_load_acquire() call. As the next PV queue head hasn't been * designated yet, there is no way for the locked value to become * _Q_SLOW_VAL. So both the set_locked() and the * atomic_cmpxchg_relaxed() calls will be safe. @@ -505,7 +573,7 @@ queue: if ((val = pv_wait_head_or_lock(lock, node))) goto locked; - smp_cond_acquire(!((val = atomic_read(&lock->val)) & _Q_LOCKED_PENDING_MASK)); + val = smp_cond_load_acquire(&lock->val.counter, !(VAL & _Q_LOCKED_PENDING_MASK)); locked: /* @@ -525,9 +593,9 @@ locked: break; } /* - * The smp_cond_acquire() call above has provided the necessary - * acquire semantics required for locking. At most two - * iterations of this loop may be ran. + * The smp_cond_load_acquire() call above has provided the + * necessary acquire semantics required for locking. At most + * two iterations of this loop may be ran. */ old = atomic_cmpxchg_relaxed(&lock->val, val, _Q_LOCKED_VAL); if (old == val) @@ -551,7 +619,7 @@ release: /* * release the node */ - this_cpu_dec(mcs_nodes[0].count); + __this_cpu_dec(mcs_nodes[0].count); } EXPORT_SYMBOL(queued_spin_lock_slowpath); diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h index 21ede57f68b3..37649e69056c 100644 --- a/kernel/locking/qspinlock_paravirt.h +++ b/kernel/locking/qspinlock_paravirt.h @@ -112,12 +112,12 @@ static __always_inline int trylock_clear_pending(struct qspinlock *lock) #else /* _Q_PENDING_BITS == 8 */ static __always_inline void set_pending(struct qspinlock *lock) { - atomic_set_mask(_Q_PENDING_VAL, &lock->val); + atomic_or(_Q_PENDING_VAL, &lock->val); } static __always_inline void clear_pending(struct qspinlock *lock) { - atomic_clear_mask(_Q_PENDING_VAL, &lock->val); + atomic_andnot(_Q_PENDING_VAL, &lock->val); } static __always_inline int trylock_clear_pending(struct qspinlock *lock) diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 3e746607abe5..1ec0f48962b3 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1478,7 +1478,7 @@ EXPORT_SYMBOL_GPL(rt_mutex_timed_lock); */ int __sched rt_mutex_trylock(struct rt_mutex *lock) { - if (WARN_ON(in_irq() || in_nmi() || in_serving_softirq())) + if (WARN_ON_ONCE(in_irq() || in_nmi() || in_serving_softirq())) return 0; return rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock); diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index 09e30c6225e5..447e08de1fab 100644 --- a/kernel/locking/rwsem-xadd.c +++ b/kernel/locking/rwsem-xadd.c @@ -80,7 +80,7 @@ void __init_rwsem(struct rw_semaphore *sem, const char *name, debug_check_no_locks_freed((void *)sem, sizeof(*sem)); lockdep_init_map(&sem->dep_map, name, key, 0); #endif - sem->count = RWSEM_UNLOCKED_VALUE; + atomic_long_set(&sem->count, RWSEM_UNLOCKED_VALUE); raw_spin_lock_init(&sem->wait_lock); INIT_LIST_HEAD(&sem->wait_list); #ifdef CONFIG_RWSEM_SPIN_ON_OWNER @@ -114,12 +114,16 @@ enum rwsem_wake_type { * - the 'active part' of count (&0x0000ffff) reached 0 (but may have changed) * - the 'waiting part' of count (&0xffff0000) is -ve (and will still be so) * - there must be someone on the queue - * - the spinlock must be held by the caller + * - the wait_lock must be held by the caller + * - tasks are marked for wakeup, the caller must later invoke wake_up_q() + * to actually wakeup the blocked task(s) and drop the reference count, + * preferably when the wait_lock is released * - woken process blocks are discarded from the list after having task zeroed - * - writers are only woken if downgrading is false + * - writers are only marked woken if downgrading is false */ static struct rw_semaphore * -__rwsem_do_wake(struct rw_semaphore *sem, enum rwsem_wake_type wake_type) +__rwsem_mark_wake(struct rw_semaphore *sem, + enum rwsem_wake_type wake_type, struct wake_q_head *wake_q) { struct rwsem_waiter *waiter; struct task_struct *tsk; @@ -128,13 +132,16 @@ __rwsem_do_wake(struct rw_semaphore *sem, enum rwsem_wake_type wake_type) waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list); if (waiter->type == RWSEM_WAITING_FOR_WRITE) { - if (wake_type == RWSEM_WAKE_ANY) - /* Wake writer at the front of the queue, but do not - * grant it the lock yet as we want other writers - * to be able to steal it. Readers, on the other hand, - * will block as they will notice the queued writer. + if (wake_type == RWSEM_WAKE_ANY) { + /* + * Mark writer at the front of the queue for wakeup. + * Until the task is actually later awoken later by + * the caller, other writers are able to steal it. + * Readers, on the other hand, will block as they + * will notice the queued writer. */ - wake_up_process(waiter->task); + wake_q_add(wake_q, waiter->task); + } goto out; } @@ -146,15 +153,27 @@ __rwsem_do_wake(struct rw_semaphore *sem, enum rwsem_wake_type wake_type) if (wake_type != RWSEM_WAKE_READ_OWNED) { adjustment = RWSEM_ACTIVE_READ_BIAS; try_reader_grant: - oldcount = rwsem_atomic_update(adjustment, sem) - adjustment; + oldcount = atomic_long_fetch_add(adjustment, &sem->count); + if (unlikely(oldcount < RWSEM_WAITING_BIAS)) { - /* A writer stole the lock. Undo our reader grant. */ - if (rwsem_atomic_update(-adjustment, sem) & - RWSEM_ACTIVE_MASK) + /* + * If the count is still less than RWSEM_WAITING_BIAS + * after removing the adjustment, it is assumed that + * a writer has stolen the lock. We have to undo our + * reader grant. + */ + if (atomic_long_add_return(-adjustment, &sem->count) < + RWSEM_WAITING_BIAS) goto out; /* Last active locker left. Retry waking readers. */ goto try_reader_grant; } + /* + * It is not really necessary to set it to reader-owned here, + * but it gives the spinners an early indication that the + * readers now have the lock. + */ + rwsem_set_reader_owned(sem); } /* Grant an infinite number of read locks to the readers at the front @@ -179,7 +198,7 @@ __rwsem_do_wake(struct rw_semaphore *sem, enum rwsem_wake_type wake_type) adjustment -= RWSEM_WAITING_BIAS; if (adjustment) - rwsem_atomic_add(adjustment, sem); + atomic_long_add(adjustment, &sem->count); next = sem->wait_list.next; loop = woken; @@ -187,17 +206,15 @@ __rwsem_do_wake(struct rw_semaphore *sem, enum rwsem_wake_type wake_type) waiter = list_entry(next, struct rwsem_waiter, list); next = waiter->list.next; tsk = waiter->task; + + wake_q_add(wake_q, tsk); /* - * Make sure we do not wakeup the next reader before - * setting the nil condition to grant the next reader; - * otherwise we could miss the wakeup on the other - * side and end up sleeping again. See the pairing - * in rwsem_down_read_failed(). + * Ensure that the last operation is setting the reader + * waiter to nil such that rwsem_down_read_failed() cannot + * race with do_exit() by always holding a reference count + * to the task to wakeup. */ - smp_mb(); - waiter->task = NULL; - wake_up_process(tsk); - put_task_struct(tsk); + smp_store_release(&waiter->task, NULL); } while (--loop); sem->wait_list.next = next; @@ -216,11 +233,11 @@ struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem) long count, adjustment = -RWSEM_ACTIVE_READ_BIAS; struct rwsem_waiter waiter; struct task_struct *tsk = current; + WAKE_Q(wake_q); /* set up my own style of waitqueue */ waiter.task = tsk; waiter.type = RWSEM_WAITING_FOR_READ; - get_task_struct(tsk); raw_spin_lock_irq(&sem->wait_lock); if (list_empty(&sem->wait_list)) @@ -228,7 +245,7 @@ struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem) list_add_tail(&waiter.list, &sem->wait_list); /* we're now waiting on the lock, but no longer actively locking */ - count = rwsem_atomic_update(adjustment, sem); + count = atomic_long_add_return(adjustment, &sem->count); /* If there are no active locks, wake the front queued process(es). * @@ -238,9 +255,10 @@ struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem) if (count == RWSEM_WAITING_BIAS || (count > RWSEM_WAITING_BIAS && adjustment != -RWSEM_ACTIVE_READ_BIAS)) - sem = __rwsem_do_wake(sem, RWSEM_WAKE_ANY); + sem = __rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q); raw_spin_unlock_irq(&sem->wait_lock); + wake_up_q(&wake_q); /* wait to be given the lock */ while (true) { @@ -255,17 +273,29 @@ struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem) } EXPORT_SYMBOL(rwsem_down_read_failed); +/* + * This function must be called with the sem->wait_lock held to prevent + * race conditions between checking the rwsem wait list and setting the + * sem->count accordingly. + */ static inline bool rwsem_try_write_lock(long count, struct rw_semaphore *sem) { /* - * Try acquiring the write lock. Check count first in order - * to reduce unnecessary expensive cmpxchg() operations. + * Avoid trying to acquire write lock if count isn't RWSEM_WAITING_BIAS. */ - if (count == RWSEM_WAITING_BIAS && - cmpxchg_acquire(&sem->count, RWSEM_WAITING_BIAS, - RWSEM_ACTIVE_WRITE_BIAS) == RWSEM_WAITING_BIAS) { - if (!list_is_singular(&sem->wait_list)) - rwsem_atomic_update(RWSEM_WAITING_BIAS, sem); + if (count != RWSEM_WAITING_BIAS) + return false; + + /* + * Acquire the lock by trying to set it to ACTIVE_WRITE_BIAS. If there + * are other tasks on the wait list, we need to add on WAITING_BIAS. + */ + count = list_is_singular(&sem->wait_list) ? + RWSEM_ACTIVE_WRITE_BIAS : + RWSEM_ACTIVE_WRITE_BIAS + RWSEM_WAITING_BIAS; + + if (atomic_long_cmpxchg_acquire(&sem->count, RWSEM_WAITING_BIAS, count) + == RWSEM_WAITING_BIAS) { rwsem_set_owner(sem); return true; } @@ -279,13 +309,13 @@ static inline bool rwsem_try_write_lock(long count, struct rw_semaphore *sem) */ static inline bool rwsem_try_write_lock_unqueued(struct rw_semaphore *sem) { - long old, count = READ_ONCE(sem->count); + long old, count = atomic_long_read(&sem->count); while (true) { if (!(count == 0 || count == RWSEM_WAITING_BIAS)) return false; - old = cmpxchg_acquire(&sem->count, count, + old = atomic_long_cmpxchg_acquire(&sem->count, count, count + RWSEM_ACTIVE_WRITE_BIAS); if (old == count) { rwsem_set_owner(sem); @@ -306,16 +336,11 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem) rcu_read_lock(); owner = READ_ONCE(sem->owner); - if (!owner) { - long count = READ_ONCE(sem->count); + if (!rwsem_owner_is_writer(owner)) { /* - * If sem->owner is not set, yet we have just recently entered the - * slowpath with the lock being active, then there is a possibility - * reader(s) may have the lock. To be safe, bail spinning in these - * situations. + * Don't spin if the rwsem is readers owned. */ - if (count & RWSEM_ACTIVE_MASK) - ret = false; + ret = !rwsem_owner_is_reader(owner); goto done; } @@ -325,10 +350,15 @@ done: return ret; } -static noinline -bool rwsem_spin_on_owner(struct rw_semaphore *sem, struct task_struct *owner) +/* + * Return true only if we can still spin on the owner field of the rwsem. + */ +static noinline bool rwsem_spin_on_owner(struct rw_semaphore *sem) { - long count; + struct task_struct *owner = READ_ONCE(sem->owner); + + if (!rwsem_owner_is_writer(owner)) + goto out; rcu_read_lock(); while (sem->owner == owner) { @@ -349,22 +379,16 @@ bool rwsem_spin_on_owner(struct rw_semaphore *sem, struct task_struct *owner) cpu_relax_lowlatency(); } rcu_read_unlock(); - - if (READ_ONCE(sem->owner)) - return true; /* new owner, continue spinning */ - +out: /* - * When the owner is not set, the lock could be free or - * held by readers. Check the counter to verify the - * state. + * If there is a new owner or the owner is not set, we continue + * spinning. */ - count = READ_ONCE(sem->count); - return (count == 0 || count == RWSEM_WAITING_BIAS); + return !rwsem_owner_is_reader(READ_ONCE(sem->owner)); } static bool rwsem_optimistic_spin(struct rw_semaphore *sem) { - struct task_struct *owner; bool taken = false; preempt_disable(); @@ -376,12 +400,17 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem) if (!osq_lock(&sem->osq)) goto done; - while (true) { - owner = READ_ONCE(sem->owner); - if (owner && !rwsem_spin_on_owner(sem, owner)) - break; - - /* wait_lock will be acquired if write_lock is obtained */ + /* + * Optimistically spin on the owner field and attempt to acquire the + * lock whenever the owner changes. Spinning will be stopped when: + * 1) the owning writer isn't running; or + * 2) readers own the lock as we can't determine if they are + * actively running or not. + */ + while (rwsem_spin_on_owner(sem)) { + /* + * Try to acquire the lock + */ if (rwsem_try_write_lock_unqueued(sem)) { taken = true; break; @@ -393,7 +422,7 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem) * we're an RT task that will live-lock because we won't let * the owner complete. */ - if (!owner && (need_resched() || rt_task(current))) + if (!sem->owner && (need_resched() || rt_task(current))) break; /* @@ -440,9 +469,10 @@ __rwsem_down_write_failed_common(struct rw_semaphore *sem, int state) bool waiting = true; /* any queued threads before us */ struct rwsem_waiter waiter; struct rw_semaphore *ret = sem; + WAKE_Q(wake_q); /* undo write bias from down_write operation, stop active locking */ - count = rwsem_atomic_update(-RWSEM_ACTIVE_WRITE_BIAS, sem); + count = atomic_long_sub_return(RWSEM_ACTIVE_WRITE_BIAS, &sem->count); /* do optimistic spinning and steal lock if possible */ if (rwsem_optimistic_spin(sem)) @@ -465,18 +495,29 @@ __rwsem_down_write_failed_common(struct rw_semaphore *sem, int state) /* we're now waiting on the lock, but no longer actively locking */ if (waiting) { - count = READ_ONCE(sem->count); + count = atomic_long_read(&sem->count); /* * If there were already threads queued before us and there are * no active writers, the lock must be read owned; so we try to * wake any read locks that were queued ahead of us. */ - if (count > RWSEM_WAITING_BIAS) - sem = __rwsem_do_wake(sem, RWSEM_WAKE_READERS); + if (count > RWSEM_WAITING_BIAS) { + WAKE_Q(wake_q); + + sem = __rwsem_mark_wake(sem, RWSEM_WAKE_READERS, &wake_q); + /* + * The wakeup is normally called _after_ the wait_lock + * is released, but given that we are proactively waking + * readers we can deal with the wake_q overhead as it is + * similar to releasing and taking the wait_lock again + * for attempting rwsem_try_write_lock(). + */ + wake_up_q(&wake_q); + } } else - count = rwsem_atomic_update(RWSEM_WAITING_BIAS, sem); + count = atomic_long_add_return(RWSEM_WAITING_BIAS, &sem->count); /* wait until we successfully acquire the lock */ set_current_state(state); @@ -492,7 +533,7 @@ __rwsem_down_write_failed_common(struct rw_semaphore *sem, int state) schedule(); set_current_state(state); - } while ((count = sem->count) & RWSEM_ACTIVE_MASK); + } while ((count = atomic_long_read(&sem->count)) & RWSEM_ACTIVE_MASK); raw_spin_lock_irq(&sem->wait_lock); } @@ -507,10 +548,11 @@ out_nolock: raw_spin_lock_irq(&sem->wait_lock); list_del(&waiter.list); if (list_empty(&sem->wait_list)) - rwsem_atomic_update(-RWSEM_WAITING_BIAS, sem); + atomic_long_add(-RWSEM_WAITING_BIAS, &sem->count); else - __rwsem_do_wake(sem, RWSEM_WAKE_ANY); + __rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q); raw_spin_unlock_irq(&sem->wait_lock); + wake_up_q(&wake_q); return ERR_PTR(-EINTR); } @@ -537,6 +579,7 @@ __visible struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem) { unsigned long flags; + WAKE_Q(wake_q); /* * If a spinner is present, it is not necessary to do the wakeup. @@ -573,9 +616,10 @@ locked: /* do nothing if list empty */ if (!list_empty(&sem->wait_list)) - sem = __rwsem_do_wake(sem, RWSEM_WAKE_ANY); + sem = __rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q); raw_spin_unlock_irqrestore(&sem->wait_lock, flags); + wake_up_q(&wake_q); return sem; } @@ -590,14 +634,16 @@ __visible struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem) { unsigned long flags; + WAKE_Q(wake_q); raw_spin_lock_irqsave(&sem->wait_lock, flags); /* do nothing if list empty */ if (!list_empty(&sem->wait_list)) - sem = __rwsem_do_wake(sem, RWSEM_WAKE_READ_OWNED); + sem = __rwsem_mark_wake(sem, RWSEM_WAKE_READ_OWNED, &wake_q); raw_spin_unlock_irqrestore(&sem->wait_lock, flags); + wake_up_q(&wake_q); return sem; } diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 2e853ad93a3a..45ba475d4be3 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -22,6 +22,7 @@ void __sched down_read(struct rw_semaphore *sem) rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_); LOCK_CONTENDED(sem, __down_read_trylock, __down_read); + rwsem_set_reader_owned(sem); } EXPORT_SYMBOL(down_read); @@ -33,8 +34,10 @@ int down_read_trylock(struct rw_semaphore *sem) { int ret = __down_read_trylock(sem); - if (ret == 1) + if (ret == 1) { rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_); + rwsem_set_reader_owned(sem); + } return ret; } @@ -124,7 +127,7 @@ void downgrade_write(struct rw_semaphore *sem) * lockdep: a downgraded write will live on as a write * dependency. */ - rwsem_clear_owner(sem); + rwsem_set_reader_owned(sem); __downgrade_write(sem); } @@ -138,6 +141,7 @@ void down_read_nested(struct rw_semaphore *sem, int subclass) rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_); LOCK_CONTENDED(sem, __down_read_trylock, __down_read); + rwsem_set_reader_owned(sem); } EXPORT_SYMBOL(down_read_nested); diff --git a/kernel/locking/rwsem.h b/kernel/locking/rwsem.h index 870ed9a5b426..a699f4048ba1 100644 --- a/kernel/locking/rwsem.h +++ b/kernel/locking/rwsem.h @@ -1,14 +1,58 @@ +/* + * The owner field of the rw_semaphore structure will be set to + * RWSEM_READ_OWNED when a reader grabs the lock. A writer will clear + * the owner field when it unlocks. A reader, on the other hand, will + * not touch the owner field when it unlocks. + * + * In essence, the owner field now has the following 3 states: + * 1) 0 + * - lock is free or the owner hasn't set the field yet + * 2) RWSEM_READER_OWNED + * - lock is currently or previously owned by readers (lock is free + * or not set by owner yet) + * 3) Other non-zero value + * - a writer owns the lock + */ +#define RWSEM_READER_OWNED ((struct task_struct *)1UL) + #ifdef CONFIG_RWSEM_SPIN_ON_OWNER +/* + * All writes to owner are protected by WRITE_ONCE() to make sure that + * store tearing can't happen as optimistic spinners may read and use + * the owner value concurrently without lock. Read from owner, however, + * may not need READ_ONCE() as long as the pointer value is only used + * for comparison and isn't being dereferenced. + */ static inline void rwsem_set_owner(struct rw_semaphore *sem) { - sem->owner = current; + WRITE_ONCE(sem->owner, current); } static inline void rwsem_clear_owner(struct rw_semaphore *sem) { - sem->owner = NULL; + WRITE_ONCE(sem->owner, NULL); +} + +static inline void rwsem_set_reader_owned(struct rw_semaphore *sem) +{ + /* + * We check the owner value first to make sure that we will only + * do a write to the rwsem cacheline when it is really necessary + * to minimize cacheline contention. + */ + if (sem->owner != RWSEM_READER_OWNED) + WRITE_ONCE(sem->owner, RWSEM_READER_OWNED); +} + +static inline bool rwsem_owner_is_writer(struct task_struct *owner) +{ + return owner && owner != RWSEM_READER_OWNED; } +static inline bool rwsem_owner_is_reader(struct task_struct *owner) +{ + return owner == RWSEM_READER_OWNED; +} #else static inline void rwsem_set_owner(struct rw_semaphore *sem) { @@ -17,4 +61,8 @@ static inline void rwsem_set_owner(struct rw_semaphore *sem) static inline void rwsem_clear_owner(struct rw_semaphore *sem) { } + +static inline void rwsem_set_reader_owned(struct rw_semaphore *sem) +{ +} #endif diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 0ee1df0a0bd6..a881c6a7ba74 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -1189,11 +1189,6 @@ static int __init nohibernate_setup(char *str) return 1; } -static int __init kaslr_nohibernate_setup(char *str) -{ - return nohibernate_setup(str); -} - static int __init page_poison_nohibernate_setup(char *str) { #ifdef CONFIG_PAGE_POISONING_ZERO @@ -1217,5 +1212,4 @@ __setup("hibernate=", hibernate_setup); __setup("resumewait", resumewait_setup); __setup("resumedelay=", resumedelay_setup); __setup("nohibernate", nohibernate_setup); -__setup("kaslr", kaslr_nohibernate_setup); __setup("page_poison=", page_poison_nohibernate_setup); diff --git a/kernel/power/swap.c b/kernel/power/swap.c index 51cef8432154..a3b1e617bcdc 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -261,7 +261,7 @@ static void hib_end_io(struct bio *bio) bio_put(bio); } -static int hib_submit_io(int rw, pgoff_t page_off, void *addr, +static int hib_submit_io(int op, int op_flags, pgoff_t page_off, void *addr, struct hib_bio_batch *hb) { struct page *page = virt_to_page(addr); @@ -271,6 +271,7 @@ static int hib_submit_io(int rw, pgoff_t page_off, void *addr, bio = bio_alloc(__GFP_RECLAIM | __GFP_HIGH, 1); bio->bi_iter.bi_sector = page_off * (PAGE_SIZE >> 9); bio->bi_bdev = hib_resume_bdev; + bio_set_op_attrs(bio, op, op_flags); if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) { printk(KERN_ERR "PM: Adding page to bio failed at %llu\n", @@ -283,9 +284,9 @@ static int hib_submit_io(int rw, pgoff_t page_off, void *addr, bio->bi_end_io = hib_end_io; bio->bi_private = hb; atomic_inc(&hb->count); - submit_bio(rw, bio); + submit_bio(bio); } else { - error = submit_bio_wait(rw, bio); + error = submit_bio_wait(bio); bio_put(bio); } @@ -306,7 +307,8 @@ static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags) { int error; - hib_submit_io(READ_SYNC, swsusp_resume_block, swsusp_header, NULL); + hib_submit_io(REQ_OP_READ, READ_SYNC, swsusp_resume_block, + swsusp_header, NULL); if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) || !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) { memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10); @@ -315,8 +317,8 @@ static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags) swsusp_header->flags = flags; if (flags & SF_CRC32_MODE) swsusp_header->crc32 = handle->crc32; - error = hib_submit_io(WRITE_SYNC, swsusp_resume_block, - swsusp_header, NULL); + error = hib_submit_io(REQ_OP_WRITE, WRITE_SYNC, + swsusp_resume_block, swsusp_header, NULL); } else { printk(KERN_ERR "PM: Swap header not found!\n"); error = -ENODEV; @@ -395,7 +397,7 @@ static int write_page(void *buf, sector_t offset, struct hib_bio_batch *hb) } else { src = buf; } - return hib_submit_io(WRITE_SYNC, offset, src, hb); + return hib_submit_io(REQ_OP_WRITE, WRITE_SYNC, offset, src, hb); } static void release_swap_writer(struct swap_map_handle *handle) @@ -998,7 +1000,8 @@ static int get_swap_reader(struct swap_map_handle *handle, return -ENOMEM; } - error = hib_submit_io(READ_SYNC, offset, tmp->map, NULL); + error = hib_submit_io(REQ_OP_READ, READ_SYNC, offset, + tmp->map, NULL); if (error) { release_swap_reader(handle); return error; @@ -1022,7 +1025,7 @@ static int swap_read_page(struct swap_map_handle *handle, void *buf, offset = handle->cur->entries[handle->k]; if (!offset) return -EFAULT; - error = hib_submit_io(READ_SYNC, offset, buf, hb); + error = hib_submit_io(REQ_OP_READ, READ_SYNC, offset, buf, hb); if (error) return error; if (++handle->k >= MAP_PAGE_ENTRIES) { @@ -1531,7 +1534,8 @@ int swsusp_check(void) if (!IS_ERR(hib_resume_bdev)) { set_blocksize(hib_resume_bdev, PAGE_SIZE); clear_page(swsusp_header); - error = hib_submit_io(READ_SYNC, swsusp_resume_block, + error = hib_submit_io(REQ_OP_READ, READ_SYNC, + swsusp_resume_block, swsusp_header, NULL); if (error) goto put; @@ -1539,7 +1543,8 @@ int swsusp_check(void) if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) { memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10); /* Reset swap signature now */ - error = hib_submit_io(WRITE_SYNC, swsusp_resume_block, + error = hib_submit_io(REQ_OP_WRITE, WRITE_SYNC, + swsusp_resume_block, swsusp_header, NULL); } else { error = -EINVAL; @@ -1583,10 +1588,12 @@ int swsusp_unmark(void) { int error; - hib_submit_io(READ_SYNC, swsusp_resume_block, swsusp_header, NULL); + hib_submit_io(REQ_OP_READ, READ_SYNC, swsusp_resume_block, + swsusp_header, NULL); if (!memcmp(HIBERNATE_SIG,swsusp_header->sig, 10)) { memcpy(swsusp_header->sig,swsusp_header->orig_sig, 10); - error = hib_submit_io(WRITE_SYNC, swsusp_resume_block, + error = hib_submit_io(REQ_OP_WRITE, WRITE_SYNC, + swsusp_resume_block, swsusp_header, NULL); } else { printk(KERN_ERR "PM: Cannot find swsusp signature!\n"); diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c index 3cee0d8393ed..d38ab08a3fe7 100644 --- a/kernel/rcu/rcuperf.c +++ b/kernel/rcu/rcuperf.c @@ -58,7 +58,7 @@ MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.vnet.ibm.com>"); #define VERBOSE_PERFOUT_ERRSTRING(s) \ do { if (verbose) pr_alert("%s" PERF_FLAG "!!! %s\n", perf_type, s); } while (0) -torture_param(bool, gp_exp, true, "Use expedited GP wait primitives"); +torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); torture_param(int, holdoff, 10, "Holdoff time before test start (s)"); torture_param(int, nreaders, -1, "Number of RCU reader threads"); torture_param(int, nwriters, -1, "Number of RCU updater threads"); @@ -96,12 +96,7 @@ static int rcu_perf_writer_state; #define MAX_MEAS 10000 #define MIN_MEAS 100 -#if defined(MODULE) || defined(CONFIG_RCU_PERF_TEST_RUNNABLE) -#define RCUPERF_RUNNABLE_INIT 1 -#else -#define RCUPERF_RUNNABLE_INIT 0 -#endif -static int perf_runnable = RCUPERF_RUNNABLE_INIT; +static int perf_runnable = IS_ENABLED(MODULE); module_param(perf_runnable, int, 0444); MODULE_PARM_DESC(perf_runnable, "Start rcuperf at boot"); @@ -363,8 +358,6 @@ rcu_perf_writer(void *arg) u64 *wdpp = writer_durations[me]; VERBOSE_PERFOUT_STRING("rcu_perf_writer task started"); - WARN_ON(rcu_gp_is_expedited() && !rcu_gp_is_normal() && !gp_exp); - WARN_ON(rcu_gp_is_normal() && gp_exp); WARN_ON(!wdpp); set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids)); sp.sched_priority = 1; @@ -631,12 +624,24 @@ rcu_perf_init(void) firsterr = -ENOMEM; goto unwind; } + if (rcu_gp_is_expedited() && !rcu_gp_is_normal() && !gp_exp) { + VERBOSE_PERFOUT_ERRSTRING("All grace periods expedited, no normal ones to measure!"); + firsterr = -EINVAL; + goto unwind; + } + if (rcu_gp_is_normal() && gp_exp) { + VERBOSE_PERFOUT_ERRSTRING("All grace periods normal, no expedited ones to measure!"); + firsterr = -EINVAL; + goto unwind; + } for (i = 0; i < nrealwriters; i++) { writer_durations[i] = kcalloc(MAX_MEAS, sizeof(*writer_durations[i]), GFP_KERNEL); - if (!writer_durations[i]) + if (!writer_durations[i]) { + firsterr = -ENOMEM; goto unwind; + } firsterr = torture_create_kthread(rcu_perf_writer, (void *)i, writer_tasks[i]); if (firsterr) diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 084a28a732eb..971e2b138063 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -182,12 +182,7 @@ static const char *rcu_torture_writer_state_getname(void) return rcu_torture_writer_state_names[i]; } -#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE) -#define RCUTORTURE_RUNNABLE_INIT 1 -#else -#define RCUTORTURE_RUNNABLE_INIT 0 -#endif -static int torture_runnable = RCUTORTURE_RUNNABLE_INIT; +static int torture_runnable = IS_ENABLED(MODULE); module_param(torture_runnable, int, 0444); MODULE_PARM_DESC(torture_runnable, "Start rcutorture at boot"); @@ -1476,7 +1471,7 @@ static int rcu_torture_barrier_cbs(void *arg) break; /* * The above smp_load_acquire() ensures barrier_phase load - * is ordered before the folloiwng ->call(). + * is ordered before the following ->call(). */ local_irq_disable(); /* Just to test no-irq call_rcu(). */ cur_ops->call(&rcu, rcu_torture_barrier_cbf); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index c7f1bc4f817c..f433959e9322 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -125,12 +125,14 @@ int rcu_num_lvls __read_mostly = RCU_NUM_LVLS; /* Number of rcu_nodes at specified level. */ static int num_rcu_lvl[] = NUM_RCU_LVL_INIT; int rcu_num_nodes __read_mostly = NUM_RCU_NODES; /* Total # rcu_nodes in use. */ +/* panic() on RCU Stall sysctl. */ +int sysctl_panic_on_rcu_stall __read_mostly; /* * The rcu_scheduler_active variable transitions from zero to one just * before the first task is spawned. So when this variable is zero, RCU * can assume that there is but one task, allowing RCU to (for example) - * optimize synchronize_sched() to a simple barrier(). When this variable + * optimize synchronize_rcu() to a simple barrier(). When this variable * is one, RCU must actually do all the hard work required to detect real * grace periods. This variable is also used to suppress boot-time false * positives from lockdep-RCU error checking. @@ -159,6 +161,7 @@ static void invoke_rcu_core(void); static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp); static void rcu_report_exp_rdp(struct rcu_state *rsp, struct rcu_data *rdp, bool wake); +static void sync_sched_exp_online_cleanup(int cpu); /* rcuc/rcub kthread realtime priority */ #ifdef CONFIG_RCU_KTHREAD_PRIO @@ -1284,9 +1287,9 @@ static void rcu_dump_cpu_stacks(struct rcu_state *rsp) rcu_for_each_leaf_node(rsp, rnp) { raw_spin_lock_irqsave_rcu_node(rnp, flags); if (rnp->qsmask != 0) { - for (cpu = 0; cpu <= rnp->grphi - rnp->grplo; cpu++) - if (rnp->qsmask & (1UL << cpu)) - dump_cpu_task(rnp->grplo + cpu); + for_each_leaf_node_possible_cpu(rnp, cpu) + if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) + dump_cpu_task(cpu); } raw_spin_unlock_irqrestore_rcu_node(rnp, flags); } @@ -1311,6 +1314,12 @@ static void rcu_stall_kick_kthreads(struct rcu_state *rsp) } } +static inline void panic_on_rcu_stall(void) +{ + if (sysctl_panic_on_rcu_stall) + panic("RCU Stall\n"); +} + static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum) { int cpu; @@ -1351,10 +1360,9 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum) raw_spin_lock_irqsave_rcu_node(rnp, flags); ndetected += rcu_print_task_stall(rnp); if (rnp->qsmask != 0) { - for (cpu = 0; cpu <= rnp->grphi - rnp->grplo; cpu++) - if (rnp->qsmask & (1UL << cpu)) { - print_cpu_stall_info(rsp, - rnp->grplo + cpu); + for_each_leaf_node_possible_cpu(rnp, cpu) + if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) { + print_cpu_stall_info(rsp, cpu); ndetected++; } } @@ -1390,6 +1398,8 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum) rcu_check_gp_kthread_starvation(rsp); + panic_on_rcu_stall(); + force_quiescent_state(rsp); /* Kick them all. */ } @@ -1430,6 +1440,8 @@ static void print_cpu_stall(struct rcu_state *rsp) jiffies + 3 * rcu_jiffies_till_stall_check() + 3); raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + panic_on_rcu_stall(); + /* * Attempt to revive the RCU machinery by forcing a context switch. * @@ -1989,8 +2001,7 @@ static bool rcu_gp_init(struct rcu_state *rsp) * of the tree within the rsp->node[] array. Note that other CPUs * will access only the leaves of the hierarchy, thus seeing that no * grace period is in progress, at least until the corresponding - * leaf node has been initialized. In addition, we have excluded - * CPU-hotplug operations. + * leaf node has been initialized. * * The grace period cannot complete until the initialization * process finishes, because this kthread handles both. @@ -2872,7 +2883,6 @@ static void force_qs_rnp(struct rcu_state *rsp, unsigned long *maxj), bool *isidle, unsigned long *maxj) { - unsigned long bit; int cpu; unsigned long flags; unsigned long mask; @@ -2907,9 +2917,8 @@ static void force_qs_rnp(struct rcu_state *rsp, continue; } } - cpu = rnp->grplo; - bit = 1; - for (; cpu <= rnp->grphi; cpu++, bit <<= 1) { + for_each_leaf_node_possible_cpu(rnp, cpu) { + unsigned long bit = leaf_node_cpu_bit(rnp, cpu); if ((rnp->qsmask & bit) != 0) { if (f(per_cpu_ptr(rsp->rda, cpu), isidle, maxj)) mask |= bit; @@ -3448,549 +3457,6 @@ static bool rcu_seq_done(unsigned long *sp, unsigned long s) return ULONG_CMP_GE(READ_ONCE(*sp), s); } -/* Wrapper functions for expedited grace periods. */ -static void rcu_exp_gp_seq_start(struct rcu_state *rsp) -{ - rcu_seq_start(&rsp->expedited_sequence); -} -static void rcu_exp_gp_seq_end(struct rcu_state *rsp) -{ - rcu_seq_end(&rsp->expedited_sequence); - smp_mb(); /* Ensure that consecutive grace periods serialize. */ -} -static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp) -{ - unsigned long s; - - smp_mb(); /* Caller's modifications seen first by other CPUs. */ - s = rcu_seq_snap(&rsp->expedited_sequence); - trace_rcu_exp_grace_period(rsp->name, s, TPS("snap")); - return s; -} -static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s) -{ - return rcu_seq_done(&rsp->expedited_sequence, s); -} - -/* - * Reset the ->expmaskinit values in the rcu_node tree to reflect any - * recent CPU-online activity. Note that these masks are not cleared - * when CPUs go offline, so they reflect the union of all CPUs that have - * ever been online. This means that this function normally takes its - * no-work-to-do fastpath. - */ -static void sync_exp_reset_tree_hotplug(struct rcu_state *rsp) -{ - bool done; - unsigned long flags; - unsigned long mask; - unsigned long oldmask; - int ncpus = READ_ONCE(rsp->ncpus); - struct rcu_node *rnp; - struct rcu_node *rnp_up; - - /* If no new CPUs onlined since last time, nothing to do. */ - if (likely(ncpus == rsp->ncpus_snap)) - return; - rsp->ncpus_snap = ncpus; - - /* - * Each pass through the following loop propagates newly onlined - * CPUs for the current rcu_node structure up the rcu_node tree. - */ - rcu_for_each_leaf_node(rsp, rnp) { - raw_spin_lock_irqsave_rcu_node(rnp, flags); - if (rnp->expmaskinit == rnp->expmaskinitnext) { - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - continue; /* No new CPUs, nothing to do. */ - } - - /* Update this node's mask, track old value for propagation. */ - oldmask = rnp->expmaskinit; - rnp->expmaskinit = rnp->expmaskinitnext; - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - - /* If was already nonzero, nothing to propagate. */ - if (oldmask) - continue; - - /* Propagate the new CPU up the tree. */ - mask = rnp->grpmask; - rnp_up = rnp->parent; - done = false; - while (rnp_up) { - raw_spin_lock_irqsave_rcu_node(rnp_up, flags); - if (rnp_up->expmaskinit) - done = true; - rnp_up->expmaskinit |= mask; - raw_spin_unlock_irqrestore_rcu_node(rnp_up, flags); - if (done) - break; - mask = rnp_up->grpmask; - rnp_up = rnp_up->parent; - } - } -} - -/* - * Reset the ->expmask values in the rcu_node tree in preparation for - * a new expedited grace period. - */ -static void __maybe_unused sync_exp_reset_tree(struct rcu_state *rsp) -{ - unsigned long flags; - struct rcu_node *rnp; - - sync_exp_reset_tree_hotplug(rsp); - rcu_for_each_node_breadth_first(rsp, rnp) { - raw_spin_lock_irqsave_rcu_node(rnp, flags); - WARN_ON_ONCE(rnp->expmask); - rnp->expmask = rnp->expmaskinit; - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - } -} - -/* - * Return non-zero if there is no RCU expedited grace period in progress - * for the specified rcu_node structure, in other words, if all CPUs and - * tasks covered by the specified rcu_node structure have done their bit - * for the current expedited grace period. Works only for preemptible - * RCU -- other RCU implementation use other means. - * - * Caller must hold the rcu_state's exp_mutex. - */ -static int sync_rcu_preempt_exp_done(struct rcu_node *rnp) -{ - return rnp->exp_tasks == NULL && - READ_ONCE(rnp->expmask) == 0; -} - -/* - * Report the exit from RCU read-side critical section for the last task - * that queued itself during or before the current expedited preemptible-RCU - * grace period. This event is reported either to the rcu_node structure on - * which the task was queued or to one of that rcu_node structure's ancestors, - * recursively up the tree. (Calm down, calm down, we do the recursion - * iteratively!) - * - * Caller must hold the rcu_state's exp_mutex and the specified rcu_node - * structure's ->lock. - */ -static void __rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp, - bool wake, unsigned long flags) - __releases(rnp->lock) -{ - unsigned long mask; - - for (;;) { - if (!sync_rcu_preempt_exp_done(rnp)) { - if (!rnp->expmask) - rcu_initiate_boost(rnp, flags); - else - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - break; - } - if (rnp->parent == NULL) { - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - if (wake) { - smp_mb(); /* EGP done before wake_up(). */ - swake_up(&rsp->expedited_wq); - } - break; - } - mask = rnp->grpmask; - raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled */ - rnp = rnp->parent; - raw_spin_lock_rcu_node(rnp); /* irqs already disabled */ - WARN_ON_ONCE(!(rnp->expmask & mask)); - rnp->expmask &= ~mask; - } -} - -/* - * Report expedited quiescent state for specified node. This is a - * lock-acquisition wrapper function for __rcu_report_exp_rnp(). - * - * Caller must hold the rcu_state's exp_mutex. - */ -static void __maybe_unused rcu_report_exp_rnp(struct rcu_state *rsp, - struct rcu_node *rnp, bool wake) -{ - unsigned long flags; - - raw_spin_lock_irqsave_rcu_node(rnp, flags); - __rcu_report_exp_rnp(rsp, rnp, wake, flags); -} - -/* - * Report expedited quiescent state for multiple CPUs, all covered by the - * specified leaf rcu_node structure. Caller must hold the rcu_state's - * exp_mutex. - */ -static void rcu_report_exp_cpu_mult(struct rcu_state *rsp, struct rcu_node *rnp, - unsigned long mask, bool wake) -{ - unsigned long flags; - - raw_spin_lock_irqsave_rcu_node(rnp, flags); - if (!(rnp->expmask & mask)) { - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - return; - } - rnp->expmask &= ~mask; - __rcu_report_exp_rnp(rsp, rnp, wake, flags); /* Releases rnp->lock. */ -} - -/* - * Report expedited quiescent state for specified rcu_data (CPU). - */ -static void rcu_report_exp_rdp(struct rcu_state *rsp, struct rcu_data *rdp, - bool wake) -{ - rcu_report_exp_cpu_mult(rsp, rdp->mynode, rdp->grpmask, wake); -} - -/* Common code for synchronize_{rcu,sched}_expedited() work-done checking. */ -static bool sync_exp_work_done(struct rcu_state *rsp, atomic_long_t *stat, - unsigned long s) -{ - if (rcu_exp_gp_seq_done(rsp, s)) { - trace_rcu_exp_grace_period(rsp->name, s, TPS("done")); - /* Ensure test happens before caller kfree(). */ - smp_mb__before_atomic(); /* ^^^ */ - atomic_long_inc(stat); - return true; - } - return false; -} - -/* - * Funnel-lock acquisition for expedited grace periods. Returns true - * if some other task completed an expedited grace period that this task - * can piggy-back on, and with no mutex held. Otherwise, returns false - * with the mutex held, indicating that the caller must actually do the - * expedited grace period. - */ -static bool exp_funnel_lock(struct rcu_state *rsp, unsigned long s) -{ - struct rcu_data *rdp = per_cpu_ptr(rsp->rda, raw_smp_processor_id()); - struct rcu_node *rnp = rdp->mynode; - struct rcu_node *rnp_root = rcu_get_root(rsp); - - /* Low-contention fastpath. */ - if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s) && - (rnp == rnp_root || - ULONG_CMP_LT(READ_ONCE(rnp_root->exp_seq_rq), s)) && - !mutex_is_locked(&rsp->exp_mutex) && - mutex_trylock(&rsp->exp_mutex)) - goto fastpath; - - /* - * Each pass through the following loop works its way up - * the rcu_node tree, returning if others have done the work or - * otherwise falls through to acquire rsp->exp_mutex. The mapping - * from CPU to rcu_node structure can be inexact, as it is just - * promoting locality and is not strictly needed for correctness. - */ - for (; rnp != NULL; rnp = rnp->parent) { - if (sync_exp_work_done(rsp, &rdp->exp_workdone1, s)) - return true; - - /* Work not done, either wait here or go up. */ - spin_lock(&rnp->exp_lock); - if (ULONG_CMP_GE(rnp->exp_seq_rq, s)) { - - /* Someone else doing GP, so wait for them. */ - spin_unlock(&rnp->exp_lock); - trace_rcu_exp_funnel_lock(rsp->name, rnp->level, - rnp->grplo, rnp->grphi, - TPS("wait")); - wait_event(rnp->exp_wq[(s >> 1) & 0x3], - sync_exp_work_done(rsp, - &rdp->exp_workdone2, s)); - return true; - } - rnp->exp_seq_rq = s; /* Followers can wait on us. */ - spin_unlock(&rnp->exp_lock); - trace_rcu_exp_funnel_lock(rsp->name, rnp->level, rnp->grplo, - rnp->grphi, TPS("nxtlvl")); - } - mutex_lock(&rsp->exp_mutex); -fastpath: - if (sync_exp_work_done(rsp, &rdp->exp_workdone3, s)) { - mutex_unlock(&rsp->exp_mutex); - return true; - } - rcu_exp_gp_seq_start(rsp); - trace_rcu_exp_grace_period(rsp->name, s, TPS("start")); - return false; -} - -/* Invoked on each online non-idle CPU for expedited quiescent state. */ -static void sync_sched_exp_handler(void *data) -{ - struct rcu_data *rdp; - struct rcu_node *rnp; - struct rcu_state *rsp = data; - - rdp = this_cpu_ptr(rsp->rda); - rnp = rdp->mynode; - if (!(READ_ONCE(rnp->expmask) & rdp->grpmask) || - __this_cpu_read(rcu_sched_data.cpu_no_qs.b.exp)) - return; - if (rcu_is_cpu_rrupt_from_idle()) { - rcu_report_exp_rdp(&rcu_sched_state, - this_cpu_ptr(&rcu_sched_data), true); - return; - } - __this_cpu_write(rcu_sched_data.cpu_no_qs.b.exp, true); - resched_cpu(smp_processor_id()); -} - -/* Send IPI for expedited cleanup if needed at end of CPU-hotplug operation. */ -static void sync_sched_exp_online_cleanup(int cpu) -{ - struct rcu_data *rdp; - int ret; - struct rcu_node *rnp; - struct rcu_state *rsp = &rcu_sched_state; - - rdp = per_cpu_ptr(rsp->rda, cpu); - rnp = rdp->mynode; - if (!(READ_ONCE(rnp->expmask) & rdp->grpmask)) - return; - ret = smp_call_function_single(cpu, sync_sched_exp_handler, rsp, 0); - WARN_ON_ONCE(ret); -} - -/* - * Select the nodes that the upcoming expedited grace period needs - * to wait for. - */ -static void sync_rcu_exp_select_cpus(struct rcu_state *rsp, - smp_call_func_t func) -{ - int cpu; - unsigned long flags; - unsigned long mask; - unsigned long mask_ofl_test; - unsigned long mask_ofl_ipi; - int ret; - struct rcu_node *rnp; - - sync_exp_reset_tree(rsp); - rcu_for_each_leaf_node(rsp, rnp) { - raw_spin_lock_irqsave_rcu_node(rnp, flags); - - /* Each pass checks a CPU for identity, offline, and idle. */ - mask_ofl_test = 0; - for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++) { - struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); - struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu); - - if (raw_smp_processor_id() == cpu || - !(atomic_add_return(0, &rdtp->dynticks) & 0x1)) - mask_ofl_test |= rdp->grpmask; - } - mask_ofl_ipi = rnp->expmask & ~mask_ofl_test; - - /* - * Need to wait for any blocked tasks as well. Note that - * additional blocking tasks will also block the expedited - * GP until such time as the ->expmask bits are cleared. - */ - if (rcu_preempt_has_tasks(rnp)) - rnp->exp_tasks = rnp->blkd_tasks.next; - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - - /* IPI the remaining CPUs for expedited quiescent state. */ - mask = 1; - for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask <<= 1) { - if (!(mask_ofl_ipi & mask)) - continue; -retry_ipi: - ret = smp_call_function_single(cpu, func, rsp, 0); - if (!ret) { - mask_ofl_ipi &= ~mask; - continue; - } - /* Failed, raced with offline. */ - raw_spin_lock_irqsave_rcu_node(rnp, flags); - if (cpu_online(cpu) && - (rnp->expmask & mask)) { - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - schedule_timeout_uninterruptible(1); - if (cpu_online(cpu) && - (rnp->expmask & mask)) - goto retry_ipi; - raw_spin_lock_irqsave_rcu_node(rnp, flags); - } - if (!(rnp->expmask & mask)) - mask_ofl_ipi &= ~mask; - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - } - /* Report quiescent states for those that went offline. */ - mask_ofl_test |= mask_ofl_ipi; - if (mask_ofl_test) - rcu_report_exp_cpu_mult(rsp, rnp, mask_ofl_test, false); - } -} - -static void synchronize_sched_expedited_wait(struct rcu_state *rsp) -{ - int cpu; - unsigned long jiffies_stall; - unsigned long jiffies_start; - unsigned long mask; - int ndetected; - struct rcu_node *rnp; - struct rcu_node *rnp_root = rcu_get_root(rsp); - int ret; - - jiffies_stall = rcu_jiffies_till_stall_check(); - jiffies_start = jiffies; - - for (;;) { - ret = swait_event_timeout( - rsp->expedited_wq, - sync_rcu_preempt_exp_done(rnp_root), - jiffies_stall); - if (ret > 0 || sync_rcu_preempt_exp_done(rnp_root)) - return; - if (ret < 0) { - /* Hit a signal, disable CPU stall warnings. */ - swait_event(rsp->expedited_wq, - sync_rcu_preempt_exp_done(rnp_root)); - return; - } - pr_err("INFO: %s detected expedited stalls on CPUs/tasks: {", - rsp->name); - ndetected = 0; - rcu_for_each_leaf_node(rsp, rnp) { - ndetected += rcu_print_task_exp_stall(rnp); - mask = 1; - for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask <<= 1) { - struct rcu_data *rdp; - - if (!(rnp->expmask & mask)) - continue; - ndetected++; - rdp = per_cpu_ptr(rsp->rda, cpu); - pr_cont(" %d-%c%c%c", cpu, - "O."[!!cpu_online(cpu)], - "o."[!!(rdp->grpmask & rnp->expmaskinit)], - "N."[!!(rdp->grpmask & rnp->expmaskinitnext)]); - } - mask <<= 1; - } - pr_cont(" } %lu jiffies s: %lu root: %#lx/%c\n", - jiffies - jiffies_start, rsp->expedited_sequence, - rnp_root->expmask, ".T"[!!rnp_root->exp_tasks]); - if (ndetected) { - pr_err("blocking rcu_node structures:"); - rcu_for_each_node_breadth_first(rsp, rnp) { - if (rnp == rnp_root) - continue; /* printed unconditionally */ - if (sync_rcu_preempt_exp_done(rnp)) - continue; - pr_cont(" l=%u:%d-%d:%#lx/%c", - rnp->level, rnp->grplo, rnp->grphi, - rnp->expmask, - ".T"[!!rnp->exp_tasks]); - } - pr_cont("\n"); - } - rcu_for_each_leaf_node(rsp, rnp) { - mask = 1; - for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask <<= 1) { - if (!(rnp->expmask & mask)) - continue; - dump_cpu_task(cpu); - } - } - jiffies_stall = 3 * rcu_jiffies_till_stall_check() + 3; - } -} - -/* - * Wait for the current expedited grace period to complete, and then - * wake up everyone who piggybacked on the just-completed expedited - * grace period. Also update all the ->exp_seq_rq counters as needed - * in order to avoid counter-wrap problems. - */ -static void rcu_exp_wait_wake(struct rcu_state *rsp, unsigned long s) -{ - struct rcu_node *rnp; - - synchronize_sched_expedited_wait(rsp); - rcu_exp_gp_seq_end(rsp); - trace_rcu_exp_grace_period(rsp->name, s, TPS("end")); - - /* - * Switch over to wakeup mode, allowing the next GP, but -only- the - * next GP, to proceed. - */ - mutex_lock(&rsp->exp_wake_mutex); - mutex_unlock(&rsp->exp_mutex); - - rcu_for_each_node_breadth_first(rsp, rnp) { - if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s)) { - spin_lock(&rnp->exp_lock); - /* Recheck, avoid hang in case someone just arrived. */ - if (ULONG_CMP_LT(rnp->exp_seq_rq, s)) - rnp->exp_seq_rq = s; - spin_unlock(&rnp->exp_lock); - } - wake_up_all(&rnp->exp_wq[(rsp->expedited_sequence >> 1) & 0x3]); - } - trace_rcu_exp_grace_period(rsp->name, s, TPS("endwake")); - mutex_unlock(&rsp->exp_wake_mutex); -} - -/** - * synchronize_sched_expedited - Brute-force RCU-sched grace period - * - * Wait for an RCU-sched grace period to elapse, but use a "big hammer" - * approach to force the grace period to end quickly. This consumes - * significant time on all CPUs and is unfriendly to real-time workloads, - * so is thus not recommended for any sort of common-case code. In fact, - * if you are using synchronize_sched_expedited() in a loop, please - * restructure your code to batch your updates, and then use a single - * synchronize_sched() instead. - * - * This implementation can be thought of as an application of sequence - * locking to expedited grace periods, but using the sequence counter to - * determine when someone else has already done the work instead of for - * retrying readers. - */ -void synchronize_sched_expedited(void) -{ - unsigned long s; - struct rcu_state *rsp = &rcu_sched_state; - - /* If only one CPU, this is automatically a grace period. */ - if (rcu_blocking_is_gp()) - return; - - /* If expedited grace periods are prohibited, fall back to normal. */ - if (rcu_gp_is_normal()) { - wait_rcu_gp(call_rcu_sched); - return; - } - - /* Take a snapshot of the sequence number. */ - s = rcu_exp_gp_seq_snap(rsp); - if (exp_funnel_lock(rsp, s)) - return; /* Someone else did our work for us. */ - - /* Initialize the rcu_node tree in preparation for the wait. */ - sync_rcu_exp_select_cpus(rsp, sync_sched_exp_handler); - - /* Wait and clean up, including waking everyone. */ - rcu_exp_wait_wake(rsp, s); -} -EXPORT_SYMBOL_GPL(synchronize_sched_expedited); - /* * Check to see if there is any immediate RCU-related work to be done * by the current CPU, for the specified type of RCU, returning 1 if so. @@ -4281,7 +3747,7 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp) /* Set up local state, ensuring consistent view of global state. */ raw_spin_lock_irqsave_rcu_node(rnp, flags); - rdp->grpmask = 1UL << (cpu - rdp->mynode->grplo); + rdp->grpmask = leaf_node_cpu_bit(rdp->mynode, cpu); rdp->dynticks = &per_cpu(rcu_dynticks, cpu); WARN_ON_ONCE(rdp->dynticks->dynticks_nesting != DYNTICK_TASK_EXIT_IDLE); WARN_ON_ONCE(atomic_read(&rdp->dynticks->dynticks) != 1); @@ -4364,9 +3830,6 @@ static void rcu_cleanup_dying_idle_cpu(int cpu, struct rcu_state *rsp) struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */ - if (!IS_ENABLED(CONFIG_HOTPLUG_CPU)) - return; - /* Remove outgoing CPU from mask in the leaf rcu_node structure. */ mask = rdp->grpmask; raw_spin_lock_irqsave_rcu_node(rnp, flags); /* Enforce GP memory-order guarantee. */ @@ -4751,4 +4214,5 @@ void __init rcu_init(void) rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)cpu); } +#include "tree_exp.h" #include "tree_plugin.h" diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index e3959f5e6ddf..f714f873bf9d 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -254,6 +254,13 @@ struct rcu_node { } ____cacheline_internodealigned_in_smp; /* + * Bitmasks in an rcu_node cover the interval [grplo, grphi] of CPU IDs, and + * are indexed relative to this interval rather than the global CPU ID space. + * This generates the bit for a CPU in node-local masks. + */ +#define leaf_node_cpu_bit(rnp, cpu) (1UL << ((cpu) - (rnp)->grplo)) + +/* * Do a full breadth-first scan of the rcu_node structures for the * specified rcu_state structure. */ @@ -281,6 +288,14 @@ struct rcu_node { (rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++) /* + * Iterate over all possible CPUs in a leaf RCU node. + */ +#define for_each_leaf_node_possible_cpu(rnp, cpu) \ + for ((cpu) = cpumask_next(rnp->grplo - 1, cpu_possible_mask); \ + cpu <= rnp->grphi; \ + cpu = cpumask_next((cpu), cpu_possible_mask)) + +/* * Union to allow "aggregate OR" operation on the need for a quiescent * state by the normal and expedited grace periods. */ diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h new file mode 100644 index 000000000000..6d86ab6ec2c9 --- /dev/null +++ b/kernel/rcu/tree_exp.h @@ -0,0 +1,655 @@ +/* + * RCU expedited grace periods + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, you can access it online at + * http://www.gnu.org/licenses/gpl-2.0.html. + * + * Copyright IBM Corporation, 2016 + * + * Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com> + */ + +/* Wrapper functions for expedited grace periods. */ +static void rcu_exp_gp_seq_start(struct rcu_state *rsp) +{ + rcu_seq_start(&rsp->expedited_sequence); +} +static void rcu_exp_gp_seq_end(struct rcu_state *rsp) +{ + rcu_seq_end(&rsp->expedited_sequence); + smp_mb(); /* Ensure that consecutive grace periods serialize. */ +} +static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp) +{ + unsigned long s; + + smp_mb(); /* Caller's modifications seen first by other CPUs. */ + s = rcu_seq_snap(&rsp->expedited_sequence); + trace_rcu_exp_grace_period(rsp->name, s, TPS("snap")); + return s; +} +static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s) +{ + return rcu_seq_done(&rsp->expedited_sequence, s); +} + +/* + * Reset the ->expmaskinit values in the rcu_node tree to reflect any + * recent CPU-online activity. Note that these masks are not cleared + * when CPUs go offline, so they reflect the union of all CPUs that have + * ever been online. This means that this function normally takes its + * no-work-to-do fastpath. + */ +static void sync_exp_reset_tree_hotplug(struct rcu_state *rsp) +{ + bool done; + unsigned long flags; + unsigned long mask; + unsigned long oldmask; + int ncpus = READ_ONCE(rsp->ncpus); + struct rcu_node *rnp; + struct rcu_node *rnp_up; + + /* If no new CPUs onlined since last time, nothing to do. */ + if (likely(ncpus == rsp->ncpus_snap)) + return; + rsp->ncpus_snap = ncpus; + + /* + * Each pass through the following loop propagates newly onlined + * CPUs for the current rcu_node structure up the rcu_node tree. + */ + rcu_for_each_leaf_node(rsp, rnp) { + raw_spin_lock_irqsave_rcu_node(rnp, flags); + if (rnp->expmaskinit == rnp->expmaskinitnext) { + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + continue; /* No new CPUs, nothing to do. */ + } + + /* Update this node's mask, track old value for propagation. */ + oldmask = rnp->expmaskinit; + rnp->expmaskinit = rnp->expmaskinitnext; + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + + /* If was already nonzero, nothing to propagate. */ + if (oldmask) + continue; + + /* Propagate the new CPU up the tree. */ + mask = rnp->grpmask; + rnp_up = rnp->parent; + done = false; + while (rnp_up) { + raw_spin_lock_irqsave_rcu_node(rnp_up, flags); + if (rnp_up->expmaskinit) + done = true; + rnp_up->expmaskinit |= mask; + raw_spin_unlock_irqrestore_rcu_node(rnp_up, flags); + if (done) + break; + mask = rnp_up->grpmask; + rnp_up = rnp_up->parent; + } + } +} + +/* + * Reset the ->expmask values in the rcu_node tree in preparation for + * a new expedited grace period. + */ +static void __maybe_unused sync_exp_reset_tree(struct rcu_state *rsp) +{ + unsigned long flags; + struct rcu_node *rnp; + + sync_exp_reset_tree_hotplug(rsp); + rcu_for_each_node_breadth_first(rsp, rnp) { + raw_spin_lock_irqsave_rcu_node(rnp, flags); + WARN_ON_ONCE(rnp->expmask); + rnp->expmask = rnp->expmaskinit; + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + } +} + +/* + * Return non-zero if there is no RCU expedited grace period in progress + * for the specified rcu_node structure, in other words, if all CPUs and + * tasks covered by the specified rcu_node structure have done their bit + * for the current expedited grace period. Works only for preemptible + * RCU -- other RCU implementation use other means. + * + * Caller must hold the rcu_state's exp_mutex. + */ +static int sync_rcu_preempt_exp_done(struct rcu_node *rnp) +{ + return rnp->exp_tasks == NULL && + READ_ONCE(rnp->expmask) == 0; +} + +/* + * Report the exit from RCU read-side critical section for the last task + * that queued itself during or before the current expedited preemptible-RCU + * grace period. This event is reported either to the rcu_node structure on + * which the task was queued or to one of that rcu_node structure's ancestors, + * recursively up the tree. (Calm down, calm down, we do the recursion + * iteratively!) + * + * Caller must hold the rcu_state's exp_mutex and the specified rcu_node + * structure's ->lock. + */ +static void __rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp, + bool wake, unsigned long flags) + __releases(rnp->lock) +{ + unsigned long mask; + + for (;;) { + if (!sync_rcu_preempt_exp_done(rnp)) { + if (!rnp->expmask) + rcu_initiate_boost(rnp, flags); + else + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + break; + } + if (rnp->parent == NULL) { + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + if (wake) { + smp_mb(); /* EGP done before wake_up(). */ + swake_up(&rsp->expedited_wq); + } + break; + } + mask = rnp->grpmask; + raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled */ + rnp = rnp->parent; + raw_spin_lock_rcu_node(rnp); /* irqs already disabled */ + WARN_ON_ONCE(!(rnp->expmask & mask)); + rnp->expmask &= ~mask; + } +} + +/* + * Report expedited quiescent state for specified node. This is a + * lock-acquisition wrapper function for __rcu_report_exp_rnp(). + * + * Caller must hold the rcu_state's exp_mutex. + */ +static void __maybe_unused rcu_report_exp_rnp(struct rcu_state *rsp, + struct rcu_node *rnp, bool wake) +{ + unsigned long flags; + + raw_spin_lock_irqsave_rcu_node(rnp, flags); + __rcu_report_exp_rnp(rsp, rnp, wake, flags); +} + +/* + * Report expedited quiescent state for multiple CPUs, all covered by the + * specified leaf rcu_node structure. Caller must hold the rcu_state's + * exp_mutex. + */ +static void rcu_report_exp_cpu_mult(struct rcu_state *rsp, struct rcu_node *rnp, + unsigned long mask, bool wake) +{ + unsigned long flags; + + raw_spin_lock_irqsave_rcu_node(rnp, flags); + if (!(rnp->expmask & mask)) { + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + return; + } + rnp->expmask &= ~mask; + __rcu_report_exp_rnp(rsp, rnp, wake, flags); /* Releases rnp->lock. */ +} + +/* + * Report expedited quiescent state for specified rcu_data (CPU). + */ +static void rcu_report_exp_rdp(struct rcu_state *rsp, struct rcu_data *rdp, + bool wake) +{ + rcu_report_exp_cpu_mult(rsp, rdp->mynode, rdp->grpmask, wake); +} + +/* Common code for synchronize_{rcu,sched}_expedited() work-done checking. */ +static bool sync_exp_work_done(struct rcu_state *rsp, atomic_long_t *stat, + unsigned long s) +{ + if (rcu_exp_gp_seq_done(rsp, s)) { + trace_rcu_exp_grace_period(rsp->name, s, TPS("done")); + /* Ensure test happens before caller kfree(). */ + smp_mb__before_atomic(); /* ^^^ */ + atomic_long_inc(stat); + return true; + } + return false; +} + +/* + * Funnel-lock acquisition for expedited grace periods. Returns true + * if some other task completed an expedited grace period that this task + * can piggy-back on, and with no mutex held. Otherwise, returns false + * with the mutex held, indicating that the caller must actually do the + * expedited grace period. + */ +static bool exp_funnel_lock(struct rcu_state *rsp, unsigned long s) +{ + struct rcu_data *rdp = per_cpu_ptr(rsp->rda, raw_smp_processor_id()); + struct rcu_node *rnp = rdp->mynode; + struct rcu_node *rnp_root = rcu_get_root(rsp); + + /* Low-contention fastpath. */ + if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s) && + (rnp == rnp_root || + ULONG_CMP_LT(READ_ONCE(rnp_root->exp_seq_rq), s)) && + mutex_trylock(&rsp->exp_mutex)) + goto fastpath; + + /* + * Each pass through the following loop works its way up + * the rcu_node tree, returning if others have done the work or + * otherwise falls through to acquire rsp->exp_mutex. The mapping + * from CPU to rcu_node structure can be inexact, as it is just + * promoting locality and is not strictly needed for correctness. + */ + for (; rnp != NULL; rnp = rnp->parent) { + if (sync_exp_work_done(rsp, &rdp->exp_workdone1, s)) + return true; + + /* Work not done, either wait here or go up. */ + spin_lock(&rnp->exp_lock); + if (ULONG_CMP_GE(rnp->exp_seq_rq, s)) { + + /* Someone else doing GP, so wait for them. */ + spin_unlock(&rnp->exp_lock); + trace_rcu_exp_funnel_lock(rsp->name, rnp->level, + rnp->grplo, rnp->grphi, + TPS("wait")); + wait_event(rnp->exp_wq[(s >> 1) & 0x3], + sync_exp_work_done(rsp, + &rdp->exp_workdone2, s)); + return true; + } + rnp->exp_seq_rq = s; /* Followers can wait on us. */ + spin_unlock(&rnp->exp_lock); + trace_rcu_exp_funnel_lock(rsp->name, rnp->level, rnp->grplo, + rnp->grphi, TPS("nxtlvl")); + } + mutex_lock(&rsp->exp_mutex); +fastpath: + if (sync_exp_work_done(rsp, &rdp->exp_workdone3, s)) { + mutex_unlock(&rsp->exp_mutex); + return true; + } + rcu_exp_gp_seq_start(rsp); + trace_rcu_exp_grace_period(rsp->name, s, TPS("start")); + return false; +} + +/* Invoked on each online non-idle CPU for expedited quiescent state. */ +static void sync_sched_exp_handler(void *data) +{ + struct rcu_data *rdp; + struct rcu_node *rnp; + struct rcu_state *rsp = data; + + rdp = this_cpu_ptr(rsp->rda); + rnp = rdp->mynode; + if (!(READ_ONCE(rnp->expmask) & rdp->grpmask) || + __this_cpu_read(rcu_sched_data.cpu_no_qs.b.exp)) + return; + if (rcu_is_cpu_rrupt_from_idle()) { + rcu_report_exp_rdp(&rcu_sched_state, + this_cpu_ptr(&rcu_sched_data), true); + return; + } + __this_cpu_write(rcu_sched_data.cpu_no_qs.b.exp, true); + resched_cpu(smp_processor_id()); +} + +/* Send IPI for expedited cleanup if needed at end of CPU-hotplug operation. */ +static void sync_sched_exp_online_cleanup(int cpu) +{ + struct rcu_data *rdp; + int ret; + struct rcu_node *rnp; + struct rcu_state *rsp = &rcu_sched_state; + + rdp = per_cpu_ptr(rsp->rda, cpu); + rnp = rdp->mynode; + if (!(READ_ONCE(rnp->expmask) & rdp->grpmask)) + return; + ret = smp_call_function_single(cpu, sync_sched_exp_handler, rsp, 0); + WARN_ON_ONCE(ret); +} + +/* + * Select the nodes that the upcoming expedited grace period needs + * to wait for. + */ +static void sync_rcu_exp_select_cpus(struct rcu_state *rsp, + smp_call_func_t func) +{ + int cpu; + unsigned long flags; + unsigned long mask_ofl_test; + unsigned long mask_ofl_ipi; + int ret; + struct rcu_node *rnp; + + sync_exp_reset_tree(rsp); + rcu_for_each_leaf_node(rsp, rnp) { + raw_spin_lock_irqsave_rcu_node(rnp, flags); + + /* Each pass checks a CPU for identity, offline, and idle. */ + mask_ofl_test = 0; + for_each_leaf_node_possible_cpu(rnp, cpu) { + struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); + struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu); + + if (raw_smp_processor_id() == cpu || + !(atomic_add_return(0, &rdtp->dynticks) & 0x1)) + mask_ofl_test |= rdp->grpmask; + } + mask_ofl_ipi = rnp->expmask & ~mask_ofl_test; + + /* + * Need to wait for any blocked tasks as well. Note that + * additional blocking tasks will also block the expedited + * GP until such time as the ->expmask bits are cleared. + */ + if (rcu_preempt_has_tasks(rnp)) + rnp->exp_tasks = rnp->blkd_tasks.next; + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + + /* IPI the remaining CPUs for expedited quiescent state. */ + for_each_leaf_node_possible_cpu(rnp, cpu) { + unsigned long mask = leaf_node_cpu_bit(rnp, cpu); + if (!(mask_ofl_ipi & mask)) + continue; +retry_ipi: + ret = smp_call_function_single(cpu, func, rsp, 0); + if (!ret) { + mask_ofl_ipi &= ~mask; + continue; + } + /* Failed, raced with offline. */ + raw_spin_lock_irqsave_rcu_node(rnp, flags); + if (cpu_online(cpu) && + (rnp->expmask & mask)) { + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + schedule_timeout_uninterruptible(1); + if (cpu_online(cpu) && + (rnp->expmask & mask)) + goto retry_ipi; + raw_spin_lock_irqsave_rcu_node(rnp, flags); + } + if (!(rnp->expmask & mask)) + mask_ofl_ipi &= ~mask; + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + } + /* Report quiescent states for those that went offline. */ + mask_ofl_test |= mask_ofl_ipi; + if (mask_ofl_test) + rcu_report_exp_cpu_mult(rsp, rnp, mask_ofl_test, false); + } +} + +static void synchronize_sched_expedited_wait(struct rcu_state *rsp) +{ + int cpu; + unsigned long jiffies_stall; + unsigned long jiffies_start; + unsigned long mask; + int ndetected; + struct rcu_node *rnp; + struct rcu_node *rnp_root = rcu_get_root(rsp); + int ret; + + jiffies_stall = rcu_jiffies_till_stall_check(); + jiffies_start = jiffies; + + for (;;) { + ret = swait_event_timeout( + rsp->expedited_wq, + sync_rcu_preempt_exp_done(rnp_root), + jiffies_stall); + if (ret > 0 || sync_rcu_preempt_exp_done(rnp_root)) + return; + if (ret < 0) { + /* Hit a signal, disable CPU stall warnings. */ + swait_event(rsp->expedited_wq, + sync_rcu_preempt_exp_done(rnp_root)); + return; + } + pr_err("INFO: %s detected expedited stalls on CPUs/tasks: {", + rsp->name); + ndetected = 0; + rcu_for_each_leaf_node(rsp, rnp) { + ndetected += rcu_print_task_exp_stall(rnp); + for_each_leaf_node_possible_cpu(rnp, cpu) { + struct rcu_data *rdp; + + mask = leaf_node_cpu_bit(rnp, cpu); + if (!(rnp->expmask & mask)) + continue; + ndetected++; + rdp = per_cpu_ptr(rsp->rda, cpu); + pr_cont(" %d-%c%c%c", cpu, + "O."[!!cpu_online(cpu)], + "o."[!!(rdp->grpmask & rnp->expmaskinit)], + "N."[!!(rdp->grpmask & rnp->expmaskinitnext)]); + } + } + pr_cont(" } %lu jiffies s: %lu root: %#lx/%c\n", + jiffies - jiffies_start, rsp->expedited_sequence, + rnp_root->expmask, ".T"[!!rnp_root->exp_tasks]); + if (ndetected) { + pr_err("blocking rcu_node structures:"); + rcu_for_each_node_breadth_first(rsp, rnp) { + if (rnp == rnp_root) + continue; /* printed unconditionally */ + if (sync_rcu_preempt_exp_done(rnp)) + continue; + pr_cont(" l=%u:%d-%d:%#lx/%c", + rnp->level, rnp->grplo, rnp->grphi, + rnp->expmask, + ".T"[!!rnp->exp_tasks]); + } + pr_cont("\n"); + } + rcu_for_each_leaf_node(rsp, rnp) { + for_each_leaf_node_possible_cpu(rnp, cpu) { + mask = leaf_node_cpu_bit(rnp, cpu); + if (!(rnp->expmask & mask)) + continue; + dump_cpu_task(cpu); + } + } + jiffies_stall = 3 * rcu_jiffies_till_stall_check() + 3; + } +} + +/* + * Wait for the current expedited grace period to complete, and then + * wake up everyone who piggybacked on the just-completed expedited + * grace period. Also update all the ->exp_seq_rq counters as needed + * in order to avoid counter-wrap problems. + */ +static void rcu_exp_wait_wake(struct rcu_state *rsp, unsigned long s) +{ + struct rcu_node *rnp; + + synchronize_sched_expedited_wait(rsp); + rcu_exp_gp_seq_end(rsp); + trace_rcu_exp_grace_period(rsp->name, s, TPS("end")); + + /* + * Switch over to wakeup mode, allowing the next GP, but -only- the + * next GP, to proceed. + */ + mutex_lock(&rsp->exp_wake_mutex); + mutex_unlock(&rsp->exp_mutex); + + rcu_for_each_node_breadth_first(rsp, rnp) { + if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s)) { + spin_lock(&rnp->exp_lock); + /* Recheck, avoid hang in case someone just arrived. */ + if (ULONG_CMP_LT(rnp->exp_seq_rq, s)) + rnp->exp_seq_rq = s; + spin_unlock(&rnp->exp_lock); + } + wake_up_all(&rnp->exp_wq[(rsp->expedited_sequence >> 1) & 0x3]); + } + trace_rcu_exp_grace_period(rsp->name, s, TPS("endwake")); + mutex_unlock(&rsp->exp_wake_mutex); +} + +/** + * synchronize_sched_expedited - Brute-force RCU-sched grace period + * + * Wait for an RCU-sched grace period to elapse, but use a "big hammer" + * approach to force the grace period to end quickly. This consumes + * significant time on all CPUs and is unfriendly to real-time workloads, + * so is thus not recommended for any sort of common-case code. In fact, + * if you are using synchronize_sched_expedited() in a loop, please + * restructure your code to batch your updates, and then use a single + * synchronize_sched() instead. + * + * This implementation can be thought of as an application of sequence + * locking to expedited grace periods, but using the sequence counter to + * determine when someone else has already done the work instead of for + * retrying readers. + */ +void synchronize_sched_expedited(void) +{ + unsigned long s; + struct rcu_state *rsp = &rcu_sched_state; + + /* If only one CPU, this is automatically a grace period. */ + if (rcu_blocking_is_gp()) + return; + + /* If expedited grace periods are prohibited, fall back to normal. */ + if (rcu_gp_is_normal()) { + wait_rcu_gp(call_rcu_sched); + return; + } + + /* Take a snapshot of the sequence number. */ + s = rcu_exp_gp_seq_snap(rsp); + if (exp_funnel_lock(rsp, s)) + return; /* Someone else did our work for us. */ + + /* Initialize the rcu_node tree in preparation for the wait. */ + sync_rcu_exp_select_cpus(rsp, sync_sched_exp_handler); + + /* Wait and clean up, including waking everyone. */ + rcu_exp_wait_wake(rsp, s); +} +EXPORT_SYMBOL_GPL(synchronize_sched_expedited); + +#ifdef CONFIG_PREEMPT_RCU + +/* + * Remote handler for smp_call_function_single(). If there is an + * RCU read-side critical section in effect, request that the + * next rcu_read_unlock() record the quiescent state up the + * ->expmask fields in the rcu_node tree. Otherwise, immediately + * report the quiescent state. + */ +static void sync_rcu_exp_handler(void *info) +{ + struct rcu_data *rdp; + struct rcu_state *rsp = info; + struct task_struct *t = current; + + /* + * Within an RCU read-side critical section, request that the next + * rcu_read_unlock() report. Unless this RCU read-side critical + * section has already blocked, in which case it is already set + * up for the expedited grace period to wait on it. + */ + if (t->rcu_read_lock_nesting > 0 && + !t->rcu_read_unlock_special.b.blocked) { + t->rcu_read_unlock_special.b.exp_need_qs = true; + return; + } + + /* + * We are either exiting an RCU read-side critical section (negative + * values of t->rcu_read_lock_nesting) or are not in one at all + * (zero value of t->rcu_read_lock_nesting). Or we are in an RCU + * read-side critical section that blocked before this expedited + * grace period started. Either way, we can immediately report + * the quiescent state. + */ + rdp = this_cpu_ptr(rsp->rda); + rcu_report_exp_rdp(rsp, rdp, true); +} + +/** + * synchronize_rcu_expedited - Brute-force RCU grace period + * + * Wait for an RCU-preempt grace period, but expedite it. The basic + * idea is to IPI all non-idle non-nohz online CPUs. The IPI handler + * checks whether the CPU is in an RCU-preempt critical section, and + * if so, it sets a flag that causes the outermost rcu_read_unlock() + * to report the quiescent state. On the other hand, if the CPU is + * not in an RCU read-side critical section, the IPI handler reports + * the quiescent state immediately. + * + * Although this is a greate improvement over previous expedited + * implementations, it is still unfriendly to real-time workloads, so is + * thus not recommended for any sort of common-case code. In fact, if + * you are using synchronize_rcu_expedited() in a loop, please restructure + * your code to batch your updates, and then Use a single synchronize_rcu() + * instead. + */ +void synchronize_rcu_expedited(void) +{ + struct rcu_state *rsp = rcu_state_p; + unsigned long s; + + /* If expedited grace periods are prohibited, fall back to normal. */ + if (rcu_gp_is_normal()) { + wait_rcu_gp(call_rcu); + return; + } + + s = rcu_exp_gp_seq_snap(rsp); + if (exp_funnel_lock(rsp, s)) + return; /* Someone else did our work for us. */ + + /* Initialize the rcu_node tree in preparation for the wait. */ + sync_rcu_exp_select_cpus(rsp, sync_rcu_exp_handler); + + /* Wait for ->blkd_tasks lists to drain, then wake everyone up. */ + rcu_exp_wait_wake(rsp, s); +} +EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); + +#else /* #ifdef CONFIG_PREEMPT_RCU */ + +/* + * Wait for an rcu-preempt grace period, but make it happen quickly. + * But because preemptible RCU does not exist, map to rcu-sched. + */ +void synchronize_rcu_expedited(void) +{ + synchronize_sched_expedited(); +} +EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); + +#endif /* #else #ifdef CONFIG_PREEMPT_RCU */ diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index ff1cd4e1188d..0082fce402a0 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -79,8 +79,6 @@ static void __init rcu_bootup_announce_oddness(void) pr_info("\tRCU dyntick-idle grace-period acceleration is enabled.\n"); if (IS_ENABLED(CONFIG_PROVE_RCU)) pr_info("\tRCU lockdep checking is enabled.\n"); - if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_RUNNABLE)) - pr_info("\tRCU torture testing starts during boot.\n"); if (RCU_NUM_LVLS >= 4) pr_info("\tFour(or more)-level hierarchy is enabled.\n"); if (RCU_FANOUT_LEAF != 16) @@ -681,84 +679,6 @@ void synchronize_rcu(void) } EXPORT_SYMBOL_GPL(synchronize_rcu); -/* - * Remote handler for smp_call_function_single(). If there is an - * RCU read-side critical section in effect, request that the - * next rcu_read_unlock() record the quiescent state up the - * ->expmask fields in the rcu_node tree. Otherwise, immediately - * report the quiescent state. - */ -static void sync_rcu_exp_handler(void *info) -{ - struct rcu_data *rdp; - struct rcu_state *rsp = info; - struct task_struct *t = current; - - /* - * Within an RCU read-side critical section, request that the next - * rcu_read_unlock() report. Unless this RCU read-side critical - * section has already blocked, in which case it is already set - * up for the expedited grace period to wait on it. - */ - if (t->rcu_read_lock_nesting > 0 && - !t->rcu_read_unlock_special.b.blocked) { - t->rcu_read_unlock_special.b.exp_need_qs = true; - return; - } - - /* - * We are either exiting an RCU read-side critical section (negative - * values of t->rcu_read_lock_nesting) or are not in one at all - * (zero value of t->rcu_read_lock_nesting). Or we are in an RCU - * read-side critical section that blocked before this expedited - * grace period started. Either way, we can immediately report - * the quiescent state. - */ - rdp = this_cpu_ptr(rsp->rda); - rcu_report_exp_rdp(rsp, rdp, true); -} - -/** - * synchronize_rcu_expedited - Brute-force RCU grace period - * - * Wait for an RCU-preempt grace period, but expedite it. The basic - * idea is to IPI all non-idle non-nohz online CPUs. The IPI handler - * checks whether the CPU is in an RCU-preempt critical section, and - * if so, it sets a flag that causes the outermost rcu_read_unlock() - * to report the quiescent state. On the other hand, if the CPU is - * not in an RCU read-side critical section, the IPI handler reports - * the quiescent state immediately. - * - * Although this is a greate improvement over previous expedited - * implementations, it is still unfriendly to real-time workloads, so is - * thus not recommended for any sort of common-case code. In fact, if - * you are using synchronize_rcu_expedited() in a loop, please restructure - * your code to batch your updates, and then Use a single synchronize_rcu() - * instead. - */ -void synchronize_rcu_expedited(void) -{ - struct rcu_state *rsp = rcu_state_p; - unsigned long s; - - /* If expedited grace periods are prohibited, fall back to normal. */ - if (rcu_gp_is_normal()) { - wait_rcu_gp(call_rcu); - return; - } - - s = rcu_exp_gp_seq_snap(rsp); - if (exp_funnel_lock(rsp, s)) - return; /* Someone else did our work for us. */ - - /* Initialize the rcu_node tree in preparation for the wait. */ - sync_rcu_exp_select_cpus(rsp, sync_rcu_exp_handler); - - /* Wait for ->blkd_tasks lists to drain, then wake everyone up. */ - rcu_exp_wait_wake(rsp, s); -} -EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); - /** * rcu_barrier - Wait until all in-flight call_rcu() callbacks complete. * @@ -883,16 +803,6 @@ static void rcu_preempt_check_callbacks(void) } /* - * Wait for an rcu-preempt grace period, but make it happen quickly. - * But because preemptible RCU does not exist, map to rcu-sched. - */ -void synchronize_rcu_expedited(void) -{ - synchronize_sched_expedited(); -} -EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); - -/* * Because preemptible RCU does not exist, rcu_barrier() is just * another name for rcu_barrier_sched(). */ @@ -1254,8 +1164,9 @@ static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu) return; if (!zalloc_cpumask_var(&cm, GFP_KERNEL)) return; - for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask >>= 1) - if ((mask & 0x1) && cpu != outgoingcpu) + for_each_leaf_node_possible_cpu(rnp, cpu) + if ((mask & leaf_node_cpu_bit(rnp, cpu)) && + cpu != outgoingcpu) cpumask_set_cpu(cpu, cm); if (cpumask_weight(cm) == 0) cpumask_setall(cm); diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index 3e888cd5a594..f0d8322bc3ec 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -528,6 +528,7 @@ static int rcu_task_stall_timeout __read_mostly = HZ * 60 * 10; module_param(rcu_task_stall_timeout, int, 0644); static void rcu_spawn_tasks_kthread(void); +static struct task_struct *rcu_tasks_kthread_ptr; /* * Post an RCU-tasks callback. First call must be from process context @@ -537,6 +538,7 @@ void call_rcu_tasks(struct rcu_head *rhp, rcu_callback_t func) { unsigned long flags; bool needwake; + bool havetask = READ_ONCE(rcu_tasks_kthread_ptr); rhp->next = NULL; rhp->func = func; @@ -545,7 +547,9 @@ void call_rcu_tasks(struct rcu_head *rhp, rcu_callback_t func) *rcu_tasks_cbs_tail = rhp; rcu_tasks_cbs_tail = &rhp->next; raw_spin_unlock_irqrestore(&rcu_tasks_cbs_lock, flags); - if (needwake) { + /* We can't create the thread unless interrupts are enabled. */ + if ((needwake && havetask) || + (!havetask && !irqs_disabled_flags(flags))) { rcu_spawn_tasks_kthread(); wake_up(&rcu_tasks_cbs_wq); } @@ -790,7 +794,6 @@ static int __noreturn rcu_tasks_kthread(void *arg) static void rcu_spawn_tasks_kthread(void) { static DEFINE_MUTEX(rcu_tasks_kthread_mutex); - static struct task_struct *rcu_tasks_kthread_ptr; struct task_struct *t; if (READ_ONCE(rcu_tasks_kthread_ptr)) { diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 97ee9ac7e97c..5c883fe8e440 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1937,7 +1937,7 @@ static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags) * chain to provide order. Instead we do: * * 1) smp_store_release(X->on_cpu, 0) - * 2) smp_cond_acquire(!X->on_cpu) + * 2) smp_cond_load_acquire(!X->on_cpu) * * Example: * @@ -1948,7 +1948,7 @@ static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags) * sched-out X * smp_store_release(X->on_cpu, 0); * - * smp_cond_acquire(!X->on_cpu); + * smp_cond_load_acquire(&X->on_cpu, !VAL); * X->state = WAKING * set_task_cpu(X,2) * @@ -1974,7 +1974,7 @@ static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags) * This means that any means of doing remote wakeups must order the CPU doing * the wakeup against the CPU the task is going to end up running on. This, * however, is already required for the regular Program-Order guarantee above, - * since the waking CPU is the one issueing the ACQUIRE (smp_cond_acquire). + * since the waking CPU is the one issueing the ACQUIRE (smp_cond_load_acquire). * */ @@ -2047,7 +2047,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) * This ensures that tasks getting woken will be fully ordered against * their previous state and preserve Program Order. */ - smp_cond_acquire(!p->on_cpu); + smp_cond_load_acquire(&p->on_cpu, !VAL); p->sched_contributes_to_load = !!task_contributes_to_load(p); p->state = TASK_WAKING; @@ -2342,11 +2342,11 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p) __sched_fork(clone_flags, p); /* - * We mark the process as running here. This guarantees that + * We mark the process as NEW here. This guarantees that * nobody will actually run it, and a signal or other external * event cannot wake it up and insert it on the runqueue either. */ - p->state = TASK_RUNNING; + p->state = TASK_NEW; /* * Make sure we do not leak PI boosting priority to the child. @@ -2383,8 +2383,7 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p) p->sched_class = &fair_sched_class; } - if (p->sched_class->task_fork) - p->sched_class->task_fork(p); + init_entity_runnable_average(&p->se); /* * The child is not yet in the pid-hash so no cgroup attach races, @@ -2394,7 +2393,13 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p) * Silence PROVE_RCU. */ raw_spin_lock_irqsave(&p->pi_lock, flags); - set_task_cpu(p, cpu); + /* + * We're setting the cpu for the first time, we don't migrate, + * so use __set_task_cpu(). + */ + __set_task_cpu(p, cpu); + if (p->sched_class->task_fork) + p->sched_class->task_fork(p); raw_spin_unlock_irqrestore(&p->pi_lock, flags); #ifdef CONFIG_SCHED_INFO @@ -2526,16 +2531,18 @@ void wake_up_new_task(struct task_struct *p) struct rq_flags rf; struct rq *rq; - /* Initialize new task's runnable average */ - init_entity_runnable_average(&p->se); raw_spin_lock_irqsave(&p->pi_lock, rf.flags); + p->state = TASK_RUNNING; #ifdef CONFIG_SMP /* * Fork balancing, do it here and not earlier because: * - cpus_allowed can change in the fork path * - any previously selected cpu might disappear through hotplug + * + * Use __set_task_cpu() to avoid calling sched_class::migrate_task_rq, + * as we're not fully set-up yet. */ - set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0)); + __set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0)); #endif rq = __task_rq_lock(p, &rf); post_init_entity_util_avg(&p->se); @@ -3161,6 +3168,9 @@ static noinline void __schedule_bug(struct task_struct *prev) pr_cont("\n"); } #endif + if (panic_on_warn) + panic("scheduling while atomic\n"); + dump_stack(); add_taint(TAINT_WARN, LOCKDEP_STILL_OK); } @@ -4752,7 +4762,8 @@ out_unlock: * @len: length in bytes of the bitmask pointed to by user_mask_ptr * @user_mask_ptr: user-space pointer to hold the current cpu mask * - * Return: 0 on success. An error code otherwise. + * Return: size of CPU mask copied to user_mask_ptr on success. An + * error code otherwise. */ SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, unsigned long __user *, user_mask_ptr) @@ -7233,7 +7244,6 @@ static void sched_rq_cpu_starting(unsigned int cpu) struct rq *rq = cpu_rq(cpu); rq->calc_load_update = calc_load_update; - account_reset_rq(rq); update_max_interval(); } @@ -7713,6 +7723,8 @@ void sched_online_group(struct task_group *tg, struct task_group *parent) INIT_LIST_HEAD(&tg->children); list_add_rcu(&tg->siblings, &parent->children); spin_unlock_irqrestore(&task_group_lock, flags); + + online_fair_sched_group(tg); } /* rcu callback to free various structures associated with a task group */ @@ -7741,27 +7753,9 @@ void sched_offline_group(struct task_group *tg) spin_unlock_irqrestore(&task_group_lock, flags); } -/* change task's runqueue when it moves between groups. - * The caller of this function should have put the task in its new group - * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to - * reflect its new group. - */ -void sched_move_task(struct task_struct *tsk) +static void sched_change_group(struct task_struct *tsk, int type) { struct task_group *tg; - int queued, running; - struct rq_flags rf; - struct rq *rq; - - rq = task_rq_lock(tsk, &rf); - - running = task_current(rq, tsk); - queued = task_on_rq_queued(tsk); - - if (queued) - dequeue_task(rq, tsk, DEQUEUE_SAVE | DEQUEUE_MOVE); - if (unlikely(running)) - put_prev_task(rq, tsk); /* * All callers are synchronized by task_rq_lock(); we do not use RCU @@ -7774,11 +7768,37 @@ void sched_move_task(struct task_struct *tsk) tsk->sched_task_group = tg; #ifdef CONFIG_FAIR_GROUP_SCHED - if (tsk->sched_class->task_move_group) - tsk->sched_class->task_move_group(tsk); + if (tsk->sched_class->task_change_group) + tsk->sched_class->task_change_group(tsk, type); else #endif set_task_rq(tsk, task_cpu(tsk)); +} + +/* + * Change task's runqueue when it moves between groups. + * + * The caller of this function should have put the task in its new group by + * now. This function just updates tsk->se.cfs_rq and tsk->se.parent to reflect + * its new group. + */ +void sched_move_task(struct task_struct *tsk) +{ + int queued, running; + struct rq_flags rf; + struct rq *rq; + + rq = task_rq_lock(tsk, &rf); + + running = task_current(rq, tsk); + queued = task_on_rq_queued(tsk); + + if (queued) + dequeue_task(rq, tsk, DEQUEUE_SAVE | DEQUEUE_MOVE); + if (unlikely(running)) + put_prev_task(rq, tsk); + + sched_change_group(tsk, TASK_MOVE_GROUP); if (unlikely(running)) tsk->sched_class->set_curr_task(rq); @@ -8206,15 +8226,27 @@ static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) sched_free_group(tg); } +/* + * This is called before wake_up_new_task(), therefore we really only + * have to set its group bits, all the other stuff does not apply. + */ static void cpu_cgroup_fork(struct task_struct *task) { - sched_move_task(task); + struct rq_flags rf; + struct rq *rq; + + rq = task_rq_lock(task, &rf); + + sched_change_group(task, TASK_SET_GROUP); + + task_rq_unlock(rq, task, &rf); } static int cpu_cgroup_can_attach(struct cgroup_taskset *tset) { struct task_struct *task; struct cgroup_subsys_state *css; + int ret = 0; cgroup_taskset_for_each(task, css, tset) { #ifdef CONFIG_RT_GROUP_SCHED @@ -8225,8 +8257,24 @@ static int cpu_cgroup_can_attach(struct cgroup_taskset *tset) if (task->sched_class != &fair_sched_class) return -EINVAL; #endif + /* + * Serialize against wake_up_new_task() such that if its + * running, we're sure to observe its full state. + */ + raw_spin_lock_irq(&task->pi_lock); + /* + * Avoid calling sched_move_task() before wake_up_new_task() + * has happened. This would lead to problems with PELT, due to + * move wanting to detach+attach while we're not attached yet. + */ + if (task->state == TASK_NEW) + ret = -EINVAL; + raw_spin_unlock_irq(&task->pi_lock); + + if (ret) + break; } - return 0; + return ret; } static void cpu_cgroup_attach(struct cgroup_taskset *tset) diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c index 41f85c4d0938..bc0b309c3f19 100644 --- a/kernel/sched/cpuacct.c +++ b/kernel/sched/cpuacct.c @@ -25,15 +25,13 @@ enum cpuacct_stat_index { CPUACCT_STAT_NSTATS, }; -enum cpuacct_usage_index { - CPUACCT_USAGE_USER, /* ... user mode */ - CPUACCT_USAGE_SYSTEM, /* ... kernel mode */ - - CPUACCT_USAGE_NRUSAGE, +static const char * const cpuacct_stat_desc[] = { + [CPUACCT_STAT_USER] = "user", + [CPUACCT_STAT_SYSTEM] = "system", }; struct cpuacct_usage { - u64 usages[CPUACCT_USAGE_NRUSAGE]; + u64 usages[CPUACCT_STAT_NSTATS]; }; /* track cpu usage of a group of tasks and its child groups */ @@ -108,16 +106,16 @@ static void cpuacct_css_free(struct cgroup_subsys_state *css) } static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu, - enum cpuacct_usage_index index) + enum cpuacct_stat_index index) { struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); u64 data; /* - * We allow index == CPUACCT_USAGE_NRUSAGE here to read + * We allow index == CPUACCT_STAT_NSTATS here to read * the sum of suages. */ - BUG_ON(index > CPUACCT_USAGE_NRUSAGE); + BUG_ON(index > CPUACCT_STAT_NSTATS); #ifndef CONFIG_64BIT /* @@ -126,11 +124,11 @@ static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu, raw_spin_lock_irq(&cpu_rq(cpu)->lock); #endif - if (index == CPUACCT_USAGE_NRUSAGE) { + if (index == CPUACCT_STAT_NSTATS) { int i = 0; data = 0; - for (i = 0; i < CPUACCT_USAGE_NRUSAGE; i++) + for (i = 0; i < CPUACCT_STAT_NSTATS; i++) data += cpuusage->usages[i]; } else { data = cpuusage->usages[index]; @@ -155,7 +153,7 @@ static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val) raw_spin_lock_irq(&cpu_rq(cpu)->lock); #endif - for (i = 0; i < CPUACCT_USAGE_NRUSAGE; i++) + for (i = 0; i < CPUACCT_STAT_NSTATS; i++) cpuusage->usages[i] = val; #ifndef CONFIG_64BIT @@ -165,7 +163,7 @@ static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val) /* return total cpu usage (in nanoseconds) of a group */ static u64 __cpuusage_read(struct cgroup_subsys_state *css, - enum cpuacct_usage_index index) + enum cpuacct_stat_index index) { struct cpuacct *ca = css_ca(css); u64 totalcpuusage = 0; @@ -180,18 +178,18 @@ static u64 __cpuusage_read(struct cgroup_subsys_state *css, static u64 cpuusage_user_read(struct cgroup_subsys_state *css, struct cftype *cft) { - return __cpuusage_read(css, CPUACCT_USAGE_USER); + return __cpuusage_read(css, CPUACCT_STAT_USER); } static u64 cpuusage_sys_read(struct cgroup_subsys_state *css, struct cftype *cft) { - return __cpuusage_read(css, CPUACCT_USAGE_SYSTEM); + return __cpuusage_read(css, CPUACCT_STAT_SYSTEM); } static u64 cpuusage_read(struct cgroup_subsys_state *css, struct cftype *cft) { - return __cpuusage_read(css, CPUACCT_USAGE_NRUSAGE); + return __cpuusage_read(css, CPUACCT_STAT_NSTATS); } static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft, @@ -213,7 +211,7 @@ static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft, } static int __cpuacct_percpu_seq_show(struct seq_file *m, - enum cpuacct_usage_index index) + enum cpuacct_stat_index index) { struct cpuacct *ca = css_ca(seq_css(m)); u64 percpu; @@ -229,48 +227,78 @@ static int __cpuacct_percpu_seq_show(struct seq_file *m, static int cpuacct_percpu_user_seq_show(struct seq_file *m, void *V) { - return __cpuacct_percpu_seq_show(m, CPUACCT_USAGE_USER); + return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_USER); } static int cpuacct_percpu_sys_seq_show(struct seq_file *m, void *V) { - return __cpuacct_percpu_seq_show(m, CPUACCT_USAGE_SYSTEM); + return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_SYSTEM); } static int cpuacct_percpu_seq_show(struct seq_file *m, void *V) { - return __cpuacct_percpu_seq_show(m, CPUACCT_USAGE_NRUSAGE); + return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_NSTATS); } -static const char * const cpuacct_stat_desc[] = { - [CPUACCT_STAT_USER] = "user", - [CPUACCT_STAT_SYSTEM] = "system", -}; +static int cpuacct_all_seq_show(struct seq_file *m, void *V) +{ + struct cpuacct *ca = css_ca(seq_css(m)); + int index; + int cpu; + + seq_puts(m, "cpu"); + for (index = 0; index < CPUACCT_STAT_NSTATS; index++) + seq_printf(m, " %s", cpuacct_stat_desc[index]); + seq_puts(m, "\n"); + + for_each_possible_cpu(cpu) { + struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); + + seq_printf(m, "%d", cpu); + + for (index = 0; index < CPUACCT_STAT_NSTATS; index++) { +#ifndef CONFIG_64BIT + /* + * Take rq->lock to make 64-bit read safe on 32-bit + * platforms. + */ + raw_spin_lock_irq(&cpu_rq(cpu)->lock); +#endif + + seq_printf(m, " %llu", cpuusage->usages[index]); + +#ifndef CONFIG_64BIT + raw_spin_unlock_irq(&cpu_rq(cpu)->lock); +#endif + } + seq_puts(m, "\n"); + } + return 0; +} static int cpuacct_stats_show(struct seq_file *sf, void *v) { struct cpuacct *ca = css_ca(seq_css(sf)); + s64 val[CPUACCT_STAT_NSTATS]; int cpu; - s64 val = 0; + int stat; + memset(val, 0, sizeof(val)); for_each_possible_cpu(cpu) { - struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu); - val += kcpustat->cpustat[CPUTIME_USER]; - val += kcpustat->cpustat[CPUTIME_NICE]; - } - val = cputime64_to_clock_t(val); - seq_printf(sf, "%s %lld\n", cpuacct_stat_desc[CPUACCT_STAT_USER], val); + u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat; - val = 0; - for_each_possible_cpu(cpu) { - struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu); - val += kcpustat->cpustat[CPUTIME_SYSTEM]; - val += kcpustat->cpustat[CPUTIME_IRQ]; - val += kcpustat->cpustat[CPUTIME_SOFTIRQ]; + val[CPUACCT_STAT_USER] += cpustat[CPUTIME_USER]; + val[CPUACCT_STAT_USER] += cpustat[CPUTIME_NICE]; + val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SYSTEM]; + val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_IRQ]; + val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SOFTIRQ]; } - val = cputime64_to_clock_t(val); - seq_printf(sf, "%s %lld\n", cpuacct_stat_desc[CPUACCT_STAT_SYSTEM], val); + for (stat = 0; stat < CPUACCT_STAT_NSTATS; stat++) { + seq_printf(sf, "%s %lld\n", + cpuacct_stat_desc[stat], + cputime64_to_clock_t(val[stat])); + } return 0; } @@ -302,6 +330,10 @@ static struct cftype files[] = { .seq_show = cpuacct_percpu_sys_seq_show, }, { + .name = "usage_all", + .seq_show = cpuacct_all_seq_show, + }, + { .name = "stat", .seq_show = cpuacct_stats_show, }, @@ -316,11 +348,11 @@ static struct cftype files[] = { void cpuacct_charge(struct task_struct *tsk, u64 cputime) { struct cpuacct *ca; - int index = CPUACCT_USAGE_SYSTEM; + int index = CPUACCT_STAT_SYSTEM; struct pt_regs *regs = task_pt_regs(tsk); if (regs && user_mode(regs)) - index = CPUACCT_USAGE_USER; + index = CPUACCT_STAT_USER; rcu_read_lock(); diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index 75f98c5498d5..ea0f6f31a244 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -49,15 +49,12 @@ DEFINE_PER_CPU(seqcount_t, irq_time_seq); */ void irqtime_account_irq(struct task_struct *curr) { - unsigned long flags; s64 delta; int cpu; if (!sched_clock_irqtime) return; - local_irq_save(flags); - cpu = smp_processor_id(); delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time); __this_cpu_add(irq_start_time, delta); @@ -75,44 +72,53 @@ void irqtime_account_irq(struct task_struct *curr) __this_cpu_add(cpu_softirq_time, delta); irq_time_write_end(); - local_irq_restore(flags); } EXPORT_SYMBOL_GPL(irqtime_account_irq); -static int irqtime_account_hi_update(void) +static cputime_t irqtime_account_hi_update(cputime_t maxtime) { u64 *cpustat = kcpustat_this_cpu->cpustat; unsigned long flags; - u64 latest_ns; - int ret = 0; + cputime_t irq_cputime; local_irq_save(flags); - latest_ns = this_cpu_read(cpu_hardirq_time); - if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_IRQ]) - ret = 1; + irq_cputime = nsecs_to_cputime64(this_cpu_read(cpu_hardirq_time)) - + cpustat[CPUTIME_IRQ]; + irq_cputime = min(irq_cputime, maxtime); + cpustat[CPUTIME_IRQ] += irq_cputime; local_irq_restore(flags); - return ret; + return irq_cputime; } -static int irqtime_account_si_update(void) +static cputime_t irqtime_account_si_update(cputime_t maxtime) { u64 *cpustat = kcpustat_this_cpu->cpustat; unsigned long flags; - u64 latest_ns; - int ret = 0; + cputime_t softirq_cputime; local_irq_save(flags); - latest_ns = this_cpu_read(cpu_softirq_time); - if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_SOFTIRQ]) - ret = 1; + softirq_cputime = nsecs_to_cputime64(this_cpu_read(cpu_softirq_time)) - + cpustat[CPUTIME_SOFTIRQ]; + softirq_cputime = min(softirq_cputime, maxtime); + cpustat[CPUTIME_SOFTIRQ] += softirq_cputime; local_irq_restore(flags); - return ret; + return softirq_cputime; } #else /* CONFIG_IRQ_TIME_ACCOUNTING */ #define sched_clock_irqtime (0) +static cputime_t irqtime_account_hi_update(cputime_t dummy) +{ + return 0; +} + +static cputime_t irqtime_account_si_update(cputime_t dummy) +{ + return 0; +} + #endif /* !CONFIG_IRQ_TIME_ACCOUNTING */ static inline void task_group_account_field(struct task_struct *p, int index, @@ -257,29 +263,42 @@ void account_idle_time(cputime_t cputime) cpustat[CPUTIME_IDLE] += (__force u64) cputime; } -static __always_inline bool steal_account_process_tick(void) +static __always_inline cputime_t steal_account_process_time(cputime_t maxtime) { #ifdef CONFIG_PARAVIRT if (static_key_false(¶virt_steal_enabled)) { + cputime_t steal_cputime; u64 steal; - unsigned long steal_jiffies; steal = paravirt_steal_clock(smp_processor_id()); steal -= this_rq()->prev_steal_time; - /* - * steal is in nsecs but our caller is expecting steal - * time in jiffies. Lets cast the result to jiffies - * granularity and account the rest on the next rounds. - */ - steal_jiffies = nsecs_to_jiffies(steal); - this_rq()->prev_steal_time += jiffies_to_nsecs(steal_jiffies); + steal_cputime = min(nsecs_to_cputime(steal), maxtime); + account_steal_time(steal_cputime); + this_rq()->prev_steal_time += cputime_to_nsecs(steal_cputime); - account_steal_time(jiffies_to_cputime(steal_jiffies)); - return steal_jiffies; + return steal_cputime; } #endif - return false; + return 0; +} + +/* + * Account how much elapsed time was spent in steal, irq, or softirq time. + */ +static inline cputime_t account_other_time(cputime_t max) +{ + cputime_t accounted; + + accounted = steal_account_process_time(max); + + if (accounted < max) + accounted += irqtime_account_hi_update(max - accounted); + + if (accounted < max) + accounted += irqtime_account_si_update(max - accounted); + + return accounted; } /* @@ -342,21 +361,23 @@ void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times) static void irqtime_account_process_tick(struct task_struct *p, int user_tick, struct rq *rq, int ticks) { - cputime_t scaled = cputime_to_scaled(cputime_one_jiffy); - u64 cputime = (__force u64) cputime_one_jiffy; - u64 *cpustat = kcpustat_this_cpu->cpustat; + u64 cputime = (__force u64) cputime_one_jiffy * ticks; + cputime_t scaled, other; - if (steal_account_process_tick()) + /* + * When returning from idle, many ticks can get accounted at + * once, including some ticks of steal, irq, and softirq time. + * Subtract those ticks from the amount of time accounted to + * idle, or potentially user or system time. Due to rounding, + * other time can exceed ticks occasionally. + */ + other = account_other_time(cputime); + if (other >= cputime) return; + cputime -= other; + scaled = cputime_to_scaled(cputime); - cputime *= ticks; - scaled *= ticks; - - if (irqtime_account_hi_update()) { - cpustat[CPUTIME_IRQ] += cputime; - } else if (irqtime_account_si_update()) { - cpustat[CPUTIME_SOFTIRQ] += cputime; - } else if (this_cpu_ksoftirqd() == p) { + if (this_cpu_ksoftirqd() == p) { /* * ksoftirqd time do not get accounted in cpu_softirq_time. * So, we have to handle it separately here. @@ -406,6 +427,10 @@ void vtime_common_task_switch(struct task_struct *prev) } #endif +#endif /* CONFIG_VIRT_CPU_ACCOUNTING */ + + +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE /* * Archs that account the whole time spent in the idle task * (outside irq) as idle time can rely on this and just implement @@ -415,33 +440,16 @@ void vtime_common_task_switch(struct task_struct *prev) * vtime_account(). */ #ifndef __ARCH_HAS_VTIME_ACCOUNT -void vtime_common_account_irq_enter(struct task_struct *tsk) +void vtime_account_irq_enter(struct task_struct *tsk) { - if (!in_interrupt()) { - /* - * If we interrupted user, context_tracking_in_user() - * is 1 because the context tracking don't hook - * on irq entry/exit. This way we know if - * we need to flush user time on kernel entry. - */ - if (context_tracking_in_user()) { - vtime_account_user(tsk); - return; - } - - if (is_idle_task(tsk)) { - vtime_account_idle(tsk); - return; - } - } - vtime_account_system(tsk); + if (!in_interrupt() && is_idle_task(tsk)) + vtime_account_idle(tsk); + else + vtime_account_system(tsk); } -EXPORT_SYMBOL_GPL(vtime_common_account_irq_enter); +EXPORT_SYMBOL_GPL(vtime_account_irq_enter); #endif /* __ARCH_HAS_VTIME_ACCOUNT */ -#endif /* CONFIG_VIRT_CPU_ACCOUNTING */ - -#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st) { *ut = p->utime; @@ -466,7 +474,7 @@ void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime */ void account_process_tick(struct task_struct *p, int user_tick) { - cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); + cputime_t cputime, scaled, steal; struct rq *rq = this_rq(); if (vtime_accounting_cpu_enabled()) @@ -477,16 +485,21 @@ void account_process_tick(struct task_struct *p, int user_tick) return; } - if (steal_account_process_tick()) + cputime = cputime_one_jiffy; + steal = steal_account_process_time(cputime); + + if (steal >= cputime) return; + cputime -= steal; + scaled = cputime_to_scaled(cputime); + if (user_tick) - account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); + account_user_time(p, cputime, scaled); else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET)) - account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy, - one_jiffy_scaled); + account_system_time(p, HARDIRQ_OFFSET, cputime, scaled); else - account_idle_time(cputime_one_jiffy); + account_idle_time(cputime); } /* @@ -681,12 +694,14 @@ static cputime_t vtime_delta(struct task_struct *tsk) static cputime_t get_vtime_delta(struct task_struct *tsk) { unsigned long now = READ_ONCE(jiffies); - unsigned long delta = now - tsk->vtime_snap; + cputime_t delta, other; + delta = jiffies_to_cputime(now - tsk->vtime_snap); + other = account_other_time(delta); WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_INACTIVE); tsk->vtime_snap = now; - return jiffies_to_cputime(delta); + return delta - other; } static void __vtime_account_system(struct task_struct *tsk) @@ -706,16 +721,6 @@ void vtime_account_system(struct task_struct *tsk) write_seqcount_end(&tsk->vtime_seqcount); } -void vtime_gen_account_irq_exit(struct task_struct *tsk) -{ - write_seqcount_begin(&tsk->vtime_seqcount); - if (vtime_delta(tsk)) - __vtime_account_system(tsk); - if (context_tracking_in_user()) - tsk->vtime_snap_whence = VTIME_USER; - write_seqcount_end(&tsk->vtime_seqcount); -} - void vtime_account_user(struct task_struct *tsk) { cputime_t delta_cpu; diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 0368c393a336..2a0a9995256d 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -879,9 +879,9 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m) nr_switches = p->nvcsw + p->nivcsw; -#ifdef CONFIG_SCHEDSTATS P(se.nr_migrations); +#ifdef CONFIG_SCHEDSTATS if (schedstat_enabled()) { u64 avg_atom, avg_per_cpu; diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c8c5d2d48424..4088eedea763 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -690,6 +690,11 @@ void init_entity_runnable_average(struct sched_entity *se) /* when this task enqueue'ed, it will contribute to its cfs_rq's load_avg */ } +static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq); +static int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq); +static void update_tg_load_avg(struct cfs_rq *cfs_rq, int force); +static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se); + /* * With new tasks being created, their initial util_avgs are extrapolated * based on the cfs_rq's current util_avg: @@ -720,6 +725,8 @@ void post_init_entity_util_avg(struct sched_entity *se) struct cfs_rq *cfs_rq = cfs_rq_of(se); struct sched_avg *sa = &se->avg; long cap = (long)(SCHED_CAPACITY_SCALE - cfs_rq->avg.util_avg) / 2; + u64 now = cfs_rq_clock_task(cfs_rq); + int tg_update; if (cap > 0) { if (cfs_rq->avg.util_avg != 0) { @@ -733,16 +740,42 @@ void post_init_entity_util_avg(struct sched_entity *se) } sa->util_sum = sa->util_avg * LOAD_AVG_MAX; } + + if (entity_is_task(se)) { + struct task_struct *p = task_of(se); + if (p->sched_class != &fair_sched_class) { + /* + * For !fair tasks do: + * + update_cfs_rq_load_avg(now, cfs_rq, false); + attach_entity_load_avg(cfs_rq, se); + switched_from_fair(rq, p); + * + * such that the next switched_to_fair() has the + * expected state. + */ + se->avg.last_update_time = now; + return; + } + } + + tg_update = update_cfs_rq_load_avg(now, cfs_rq, false); + attach_entity_load_avg(cfs_rq, se); + if (tg_update) + update_tg_load_avg(cfs_rq, false); } -#else +#else /* !CONFIG_SMP */ void init_entity_runnable_average(struct sched_entity *se) { } void post_init_entity_util_avg(struct sched_entity *se) { } -#endif +static void update_tg_load_avg(struct cfs_rq *cfs_rq, int force) +{ +} +#endif /* CONFIG_SMP */ /* * Update the current task's runtime statistics. @@ -1303,6 +1336,8 @@ static void task_numa_assign(struct task_numa_env *env, { if (env->best_task) put_task_struct(env->best_task); + if (p) + get_task_struct(p); env->best_task = p; env->best_imp = imp; @@ -1370,31 +1405,11 @@ static void task_numa_compare(struct task_numa_env *env, long imp = env->p->numa_group ? groupimp : taskimp; long moveimp = imp; int dist = env->dist; - bool assigned = false; rcu_read_lock(); - - raw_spin_lock_irq(&dst_rq->lock); - cur = dst_rq->curr; - /* - * No need to move the exiting task or idle task. - */ - if ((cur->flags & PF_EXITING) || is_idle_task(cur)) + cur = task_rcu_dereference(&dst_rq->curr); + if (cur && ((cur->flags & PF_EXITING) || is_idle_task(cur))) cur = NULL; - else { - /* - * The task_struct must be protected here to protect the - * p->numa_faults access in the task_weight since the - * numa_faults could already be freed in the following path: - * finish_task_switch() - * --> put_task_struct() - * --> __put_task_struct() - * --> task_numa_free() - */ - get_task_struct(cur); - } - - raw_spin_unlock_irq(&dst_rq->lock); /* * Because we have preemption enabled we can get migrated around and @@ -1477,7 +1492,6 @@ balance: */ if (!load_too_imbalanced(src_load, dst_load, env)) { imp = moveimp - 1; - put_task_struct(cur); cur = NULL; goto assign; } @@ -1503,16 +1517,9 @@ balance: env->dst_cpu = select_idle_sibling(env->p, env->dst_cpu); assign: - assigned = true; task_numa_assign(env, cur, imp); unlock: rcu_read_unlock(); - /* - * The dst_rq->curr isn't assigned. The protection for task_struct is - * finished. - */ - if (cur && !assigned) - put_task_struct(cur); } static void task_numa_find_cpu(struct task_numa_env *env, @@ -2866,8 +2873,6 @@ void set_task_rq_fair(struct sched_entity *se, static inline void update_tg_load_avg(struct cfs_rq *cfs_rq, int force) {} #endif /* CONFIG_FAIR_GROUP_SCHED */ -static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq); - static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq) { struct rq *rq = rq_of(cfs_rq); @@ -2914,7 +2919,23 @@ static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq) WRITE_ONCE(*ptr, res); \ } while (0) -/* Group cfs_rq's load_avg is used for task_h_load and update_cfs_share */ +/** + * update_cfs_rq_load_avg - update the cfs_rq's load/util averages + * @now: current time, as per cfs_rq_clock_task() + * @cfs_rq: cfs_rq to update + * @update_freq: should we call cfs_rq_util_change() or will the call do so + * + * The cfs_rq avg is the direct sum of all its entities (blocked and runnable) + * avg. The immediate corollary is that all (fair) tasks must be attached, see + * post_init_entity_util_avg(). + * + * cfs_rq->avg is used for task_h_load() and update_cfs_share() for example. + * + * Returns true if the load decayed or we removed utilization. It is expected + * that one calls update_tg_load_avg() on this condition, but after you've + * modified the cfs_rq avg (attach/detach), such that we propagate the new + * avg up. + */ static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq) { @@ -2969,6 +2990,14 @@ static inline void update_load_avg(struct sched_entity *se, int update_tg) update_tg_load_avg(cfs_rq, 0); } +/** + * attach_entity_load_avg - attach this entity to its cfs_rq load avg + * @cfs_rq: cfs_rq to attach to + * @se: sched_entity to attach + * + * Must call update_cfs_rq_load_avg() before this, since we rely on + * cfs_rq->avg.last_update_time being current. + */ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { if (!sched_feat(ATTACH_AGE_LOAD)) @@ -2977,6 +3006,8 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s /* * If we got migrated (either between CPUs or between cgroups) we'll * have aged the average right before clearing @last_update_time. + * + * Or we're fresh through post_init_entity_util_avg(). */ if (se->avg.last_update_time) { __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)), @@ -2998,6 +3029,14 @@ skip_aging: cfs_rq_util_change(cfs_rq); } +/** + * detach_entity_load_avg - detach this entity from its cfs_rq load avg + * @cfs_rq: cfs_rq to detach from + * @se: sched_entity to detach + * + * Must call update_cfs_rq_load_avg() before this, since we rely on + * cfs_rq->avg.last_update_time being current. + */ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)), @@ -3082,11 +3121,14 @@ void remove_entity_load_avg(struct sched_entity *se) u64 last_update_time; /* - * Newly created task or never used group entity should not be removed - * from its (source) cfs_rq + * tasks cannot exit without having gone through wake_up_new_task() -> + * post_init_entity_util_avg() which will have added things to the + * cfs_rq, so we can remove unconditionally. + * + * Similarly for groups, they will have passed through + * post_init_entity_util_avg() before unregister_sched_fair_group() + * calls this. */ - if (se->avg.last_update_time == 0) - return; last_update_time = cfs_rq_last_update_time(cfs_rq); @@ -3109,6 +3151,12 @@ static int idle_balance(struct rq *this_rq); #else /* CONFIG_SMP */ +static inline int +update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq) +{ + return 0; +} + static inline void update_load_avg(struct sched_entity *se, int not_used) { struct cfs_rq *cfs_rq = cfs_rq_of(se); @@ -3698,7 +3746,7 @@ static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg) static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq) { if (unlikely(cfs_rq->throttle_count)) - return cfs_rq->throttled_clock_task; + return cfs_rq->throttled_clock_task - cfs_rq->throttled_clock_task_time; return rq_clock_task(rq_of(cfs_rq)) - cfs_rq->throttled_clock_task_time; } @@ -3836,13 +3884,11 @@ static int tg_unthrottle_up(struct task_group *tg, void *data) struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; cfs_rq->throttle_count--; -#ifdef CONFIG_SMP if (!cfs_rq->throttle_count) { /* adjust cfs_rq_clock_task() */ cfs_rq->throttled_clock_task_time += rq_clock_task(rq) - cfs_rq->throttled_clock_task; } -#endif return 0; } @@ -4195,26 +4241,6 @@ static void check_enqueue_throttle(struct cfs_rq *cfs_rq) if (!cfs_bandwidth_used()) return; - /* Synchronize hierarchical throttle counter: */ - if (unlikely(!cfs_rq->throttle_uptodate)) { - struct rq *rq = rq_of(cfs_rq); - struct cfs_rq *pcfs_rq; - struct task_group *tg; - - cfs_rq->throttle_uptodate = 1; - - /* Get closest up-to-date node, because leaves go first: */ - for (tg = cfs_rq->tg->parent; tg; tg = tg->parent) { - pcfs_rq = tg->cfs_rq[cpu_of(rq)]; - if (pcfs_rq->throttle_uptodate) - break; - } - if (tg) { - cfs_rq->throttle_count = pcfs_rq->throttle_count; - cfs_rq->throttled_clock_task = rq_clock_task(rq); - } - } - /* an active group must be handled by the update_curr()->put() path */ if (!cfs_rq->runtime_enabled || cfs_rq->curr) return; @@ -4229,6 +4255,23 @@ static void check_enqueue_throttle(struct cfs_rq *cfs_rq) throttle_cfs_rq(cfs_rq); } +static void sync_throttle(struct task_group *tg, int cpu) +{ + struct cfs_rq *pcfs_rq, *cfs_rq; + + if (!cfs_bandwidth_used()) + return; + + if (!tg->parent) + return; + + cfs_rq = tg->cfs_rq[cpu]; + pcfs_rq = tg->parent->cfs_rq[cpu]; + + cfs_rq->throttle_count = pcfs_rq->throttle_count; + pcfs_rq->throttled_clock_task = rq_clock_task(cpu_rq(cpu)); +} + /* conditionally throttle active cfs_rq's from put_prev_entity() */ static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq) { @@ -4368,6 +4411,7 @@ static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq) static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) {} static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq) { return false; } static void check_enqueue_throttle(struct cfs_rq *cfs_rq) {} +static inline void sync_throttle(struct task_group *tg, int cpu) {} static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) {} static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq) @@ -4476,7 +4520,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) * * note: in the case of encountering a throttled cfs_rq we will * post the final h_nr_running increment below. - */ + */ if (cfs_rq_throttled(cfs_rq)) break; cfs_rq->h_nr_running++; @@ -8317,31 +8361,17 @@ static void task_fork_fair(struct task_struct *p) { struct cfs_rq *cfs_rq; struct sched_entity *se = &p->se, *curr; - int this_cpu = smp_processor_id(); struct rq *rq = this_rq(); - unsigned long flags; - - raw_spin_lock_irqsave(&rq->lock, flags); + raw_spin_lock(&rq->lock); update_rq_clock(rq); cfs_rq = task_cfs_rq(current); curr = cfs_rq->curr; - - /* - * Not only the cpu but also the task_group of the parent might have - * been changed after parent->se.parent,cfs_rq were copied to - * child->se.parent,cfs_rq. So call __set_task_cpu() to make those - * of child point to valid ones. - */ - rcu_read_lock(); - __set_task_cpu(p, this_cpu); - rcu_read_unlock(); - - update_curr(cfs_rq); - - if (curr) + if (curr) { + update_curr(cfs_rq); se->vruntime = curr->vruntime; + } place_entity(cfs_rq, se, 1); if (sysctl_sched_child_runs_first && curr && entity_before(curr, se)) { @@ -8354,8 +8384,7 @@ static void task_fork_fair(struct task_struct *p) } se->vruntime -= cfs_rq->min_vruntime; - - raw_spin_unlock_irqrestore(&rq->lock, flags); + raw_spin_unlock(&rq->lock); } /* @@ -8411,6 +8440,8 @@ static void detach_task_cfs_rq(struct task_struct *p) { struct sched_entity *se = &p->se; struct cfs_rq *cfs_rq = cfs_rq_of(se); + u64 now = cfs_rq_clock_task(cfs_rq); + int tg_update; if (!vruntime_normalized(p)) { /* @@ -8422,13 +8453,18 @@ static void detach_task_cfs_rq(struct task_struct *p) } /* Catch up with the cfs_rq and remove our load when we leave */ + tg_update = update_cfs_rq_load_avg(now, cfs_rq, false); detach_entity_load_avg(cfs_rq, se); + if (tg_update) + update_tg_load_avg(cfs_rq, false); } static void attach_task_cfs_rq(struct task_struct *p) { struct sched_entity *se = &p->se; struct cfs_rq *cfs_rq = cfs_rq_of(se); + u64 now = cfs_rq_clock_task(cfs_rq); + int tg_update; #ifdef CONFIG_FAIR_GROUP_SCHED /* @@ -8439,7 +8475,10 @@ static void attach_task_cfs_rq(struct task_struct *p) #endif /* Synchronize task with its cfs_rq */ + tg_update = update_cfs_rq_load_avg(now, cfs_rq, false); attach_entity_load_avg(cfs_rq, se); + if (tg_update) + update_tg_load_avg(cfs_rq, false); if (!vruntime_normalized(p)) se->vruntime += cfs_rq->min_vruntime; @@ -8499,6 +8538,14 @@ void init_cfs_rq(struct cfs_rq *cfs_rq) } #ifdef CONFIG_FAIR_GROUP_SCHED +static void task_set_group_fair(struct task_struct *p) +{ + struct sched_entity *se = &p->se; + + set_task_rq(p, task_cpu(p)); + se->depth = se->parent ? se->parent->depth + 1 : 0; +} + static void task_move_group_fair(struct task_struct *p) { detach_task_cfs_rq(p); @@ -8511,6 +8558,19 @@ static void task_move_group_fair(struct task_struct *p) attach_task_cfs_rq(p); } +static void task_change_group_fair(struct task_struct *p, int type) +{ + switch (type) { + case TASK_SET_GROUP: + task_set_group_fair(p); + break; + + case TASK_MOVE_GROUP: + task_move_group_fair(p); + break; + } +} + void free_fair_sched_group(struct task_group *tg) { int i; @@ -8562,10 +8622,6 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) init_cfs_rq(cfs_rq); init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]); init_entity_runnable_average(se); - - raw_spin_lock_irq(&rq->lock); - post_init_entity_util_avg(se); - raw_spin_unlock_irq(&rq->lock); } return 1; @@ -8576,6 +8632,23 @@ err: return 0; } +void online_fair_sched_group(struct task_group *tg) +{ + struct sched_entity *se; + struct rq *rq; + int i; + + for_each_possible_cpu(i) { + rq = cpu_rq(i); + se = tg->se[i]; + + raw_spin_lock_irq(&rq->lock); + post_init_entity_util_avg(se); + sync_throttle(tg, i); + raw_spin_unlock_irq(&rq->lock); + } +} + void unregister_fair_sched_group(struct task_group *tg) { unsigned long flags; @@ -8680,6 +8753,8 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) return 1; } +void online_fair_sched_group(struct task_group *tg) { } + void unregister_fair_sched_group(struct task_group *tg) { } #endif /* CONFIG_FAIR_GROUP_SCHED */ @@ -8739,7 +8814,7 @@ const struct sched_class fair_sched_class = { .update_curr = update_curr_fair, #ifdef CONFIG_FAIR_GROUP_SCHED - .task_move_group = task_move_group_fair, + .task_change_group = task_change_group_fair, #endif }; diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index c5aeedf4e93a..9fb873cfc75c 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -201,6 +201,8 @@ exit_idle: */ static void cpu_idle_loop(void) { + int cpu = smp_processor_id(); + while (1) { /* * If the arch has a polling bit, we maintain an invariant: @@ -219,7 +221,7 @@ static void cpu_idle_loop(void) check_pgt_cache(); rmb(); - if (cpu_is_offline(smp_processor_id())) { + if (cpu_is_offline(cpu)) { cpuhp_report_idle_dead(); arch_cpu_idle_dead(); } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 898c0d2f18fe..c64fc5114004 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -321,6 +321,7 @@ extern int tg_nop(struct task_group *tg, void *data); extern void free_fair_sched_group(struct task_group *tg); extern int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent); +extern void online_fair_sched_group(struct task_group *tg); extern void unregister_fair_sched_group(struct task_group *tg); extern void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq, struct sched_entity *se, int cpu, @@ -437,7 +438,7 @@ struct cfs_rq { u64 throttled_clock, throttled_clock_task; u64 throttled_clock_task_time; - int throttled, throttle_count, throttle_uptodate; + int throttled, throttle_count; struct list_head throttled_list; #endif /* CONFIG_CFS_BANDWIDTH */ #endif /* CONFIG_FAIR_GROUP_SCHED */ @@ -1113,7 +1114,7 @@ static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) * In particular, the load of prev->state in finish_task_switch() must * happen before this. * - * Pairs with the smp_cond_acquire() in try_to_wake_up(). + * Pairs with the smp_cond_load_acquire() in try_to_wake_up(). */ smp_store_release(&prev->on_cpu, 0); #endif @@ -1246,8 +1247,11 @@ struct sched_class { void (*update_curr) (struct rq *rq); +#define TASK_SET_GROUP 0 +#define TASK_MOVE_GROUP 1 + #ifdef CONFIG_FAIR_GROUP_SCHED - void (*task_move_group) (struct task_struct *p); + void (*task_change_group) (struct task_struct *p, int type); #endif }; @@ -1809,16 +1813,3 @@ static inline void cpufreq_trigger_update(u64 time) {} #else /* arch_scale_freq_capacity */ #define arch_scale_freq_invariant() (false) #endif - -static inline void account_reset_rq(struct rq *rq) -{ -#ifdef CONFIG_IRQ_TIME_ACCOUNTING - rq->prev_irq_time = 0; -#endif -#ifdef CONFIG_PARAVIRT - rq->prev_steal_time = 0; -#endif -#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING - rq->prev_steal_time_rq = 0; -#endif -} diff --git a/kernel/signal.c b/kernel/signal.c index 96e9bc40667f..af21afc00d08 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2751,23 +2751,18 @@ int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from) * @ts: upper bound on process time suspension */ int do_sigtimedwait(const sigset_t *which, siginfo_t *info, - const struct timespec *ts) + const struct timespec *ts) { + ktime_t *to = NULL, timeout = { .tv64 = KTIME_MAX }; struct task_struct *tsk = current; - long timeout = MAX_SCHEDULE_TIMEOUT; sigset_t mask = *which; - int sig; + int sig, ret = 0; if (ts) { if (!timespec_valid(ts)) return -EINVAL; - timeout = timespec_to_jiffies(ts); - /* - * We can be close to the next tick, add another one - * to ensure we will wait at least the time asked for. - */ - if (ts->tv_sec || ts->tv_nsec) - timeout++; + timeout = timespec_to_ktime(*ts); + to = &timeout; } /* @@ -2778,7 +2773,7 @@ int do_sigtimedwait(const sigset_t *which, siginfo_t *info, spin_lock_irq(&tsk->sighand->siglock); sig = dequeue_signal(tsk, &mask, info); - if (!sig && timeout) { + if (!sig && timeout.tv64) { /* * None ready, temporarily unblock those we're interested * while we are sleeping in so that we'll be awakened when @@ -2790,8 +2785,9 @@ int do_sigtimedwait(const sigset_t *which, siginfo_t *info, recalc_sigpending(); spin_unlock_irq(&tsk->sighand->siglock); - timeout = freezable_schedule_timeout_interruptible(timeout); - + __set_current_state(TASK_INTERRUPTIBLE); + ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns, + HRTIMER_MODE_REL); spin_lock_irq(&tsk->sighand->siglock); __set_task_blocked(tsk, &tsk->real_blocked); sigemptyset(&tsk->real_blocked); @@ -2801,7 +2797,7 @@ int do_sigtimedwait(const sigset_t *which, siginfo_t *info, if (sig) return sig; - return timeout ? -EINTR : -EAGAIN; + return ret ? -EINTR : -EAGAIN; } /** diff --git a/kernel/smp.c b/kernel/smp.c index 74165443c240..36552beed397 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -107,7 +107,7 @@ void __init call_function_init(void) */ static __always_inline void csd_lock_wait(struct call_single_data *csd) { - smp_cond_acquire(!(csd->flags & CSD_FLAG_LOCK)); + smp_cond_load_acquire(&csd->flags, !(VAL & CSD_FLAG_LOCK)); } static __always_inline void csd_lock(struct call_single_data *csd) diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 87b2fc38398b..35f0dcb1cb4f 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1205,6 +1205,17 @@ static struct ctl_table kern_table[] = { .extra2 = &one, }, #endif +#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU) + { + .procname = "panic_on_rcu_stall", + .data = &sysctl_panic_on_rcu_stall, + .maxlen = sizeof(sysctl_panic_on_rcu_stall), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &one, + }, +#endif { } }; diff --git a/kernel/task_work.c b/kernel/task_work.c index 53fa971d000d..6ab4842b00e8 100644 --- a/kernel/task_work.c +++ b/kernel/task_work.c @@ -108,7 +108,6 @@ void task_work_run(void) * fail, but it can play with *work and other entries. */ raw_spin_unlock_wait(&task->pi_lock); - smp_mb(); do { next = work->next; diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index e840ed867a5d..c3aad685bbc0 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -30,7 +30,6 @@ * struct alarm_base - Alarm timer bases * @lock: Lock for syncrhonized access to the base * @timerqueue: Timerqueue head managing the list of events - * @timer: hrtimer used to schedule events while running * @gettime: Function to read the time correlating to the base * @base_clockid: clockid for the base */ diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index a9b76a40319e..2c5bc77c0bb0 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -645,7 +645,7 @@ void tick_cleanup_dead_cpu(int cpu) #endif #ifdef CONFIG_SYSFS -struct bus_type clockevents_subsys = { +static struct bus_type clockevents_subsys = { .name = "clockevents", .dev_name = "clockevent", }; diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 56ece145a814..6a5a310a1a53 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -669,10 +669,12 @@ static void clocksource_enqueue(struct clocksource *cs) struct list_head *entry = &clocksource_list; struct clocksource *tmp; - list_for_each_entry(tmp, &clocksource_list, list) + list_for_each_entry(tmp, &clocksource_list, list) { /* Keep track of the place, where to insert */ - if (tmp->rating >= cs->rating) - entry = &tmp->list; + if (tmp->rating < cs->rating) + break; + entry = &tmp->list; + } list_add(&cs->list, entry); } diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index e99df0ff1d42..d13c9aebf7a3 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -177,7 +177,7 @@ hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base) #endif } -#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON) +#ifdef CONFIG_NO_HZ_COMMON static inline struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base, int pinned) diff --git a/kernel/time/test_udelay.c b/kernel/time/test_udelay.c index e622ba365a13..b0928ab3270f 100644 --- a/kernel/time/test_udelay.c +++ b/kernel/time/test_udelay.c @@ -43,13 +43,13 @@ static int udelay_test_single(struct seq_file *s, int usecs, uint32_t iters) int allowed_error_ns = usecs * 5; for (i = 0; i < iters; ++i) { - struct timespec ts1, ts2; + s64 kt1, kt2; int time_passed; - ktime_get_ts(&ts1); + kt1 = ktime_get_ns(); udelay(usecs); - ktime_get_ts(&ts2); - time_passed = timespec_to_ns(&ts2) - timespec_to_ns(&ts1); + kt2 = ktime_get_ns(); + time_passed = kt2 - kt1; if (i == 0 || time_passed < min) min = time_passed; @@ -87,11 +87,11 @@ static int udelay_test_show(struct seq_file *s, void *v) if (usecs > 0 && iters > 0) { return udelay_test_single(s, usecs, iters); } else if (usecs == 0) { - struct timespec ts; + struct timespec64 ts; - ktime_get_ts(&ts); - seq_printf(s, "udelay() test (lpj=%ld kt=%ld.%09ld)\n", - loops_per_jiffy, ts.tv_sec, ts.tv_nsec); + ktime_get_ts64(&ts); + seq_printf(s, "udelay() test (lpj=%ld kt=%lld.%09ld)\n", + loops_per_jiffy, (s64)ts.tv_sec, ts.tv_nsec); seq_puts(s, "usage:\n"); seq_puts(s, "echo USECS [ITERS] > " DEBUGFS_FILENAME "\n"); seq_puts(s, "cat " DEBUGFS_FILENAME "\n"); diff --git a/kernel/time/tick-broadcast-hrtimer.c b/kernel/time/tick-broadcast-hrtimer.c index 53d7184da0be..690b797f522e 100644 --- a/kernel/time/tick-broadcast-hrtimer.c +++ b/kernel/time/tick-broadcast-hrtimer.c @@ -75,6 +75,7 @@ static int bc_set_next(ktime_t expires, struct clock_event_device *bc) } static struct clock_event_device ce_broadcast_hrtimer = { + .name = "bc_hrtimer", .set_state_shutdown = bc_shutdown, .set_next_ktime = bc_set_next, .features = CLOCK_EVT_FEAT_ONESHOT | diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h index 966a5a6fdd0a..f738251000fe 100644 --- a/kernel/time/tick-internal.h +++ b/kernel/time/tick-internal.h @@ -164,3 +164,4 @@ static inline void timers_update_migration(bool update_nohz) { } DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases); extern u64 get_next_timer_interrupt(unsigned long basej, u64 basem); +void timer_clear_idle(void); diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 536ada80f6dd..204fdc86863d 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -31,7 +31,7 @@ #include <trace/events/timer.h> /* - * Per cpu nohz control structure + * Per-CPU nohz control structure */ static DEFINE_PER_CPU(struct tick_sched, tick_cpu_sched); @@ -61,7 +61,7 @@ static void tick_do_update_jiffies64(ktime_t now) if (delta.tv64 < tick_period.tv64) return; - /* Reevalute with jiffies_lock held */ + /* Reevaluate with jiffies_lock held */ write_seqlock(&jiffies_lock); delta = ktime_sub(now, last_jiffies_update); @@ -116,8 +116,8 @@ static void tick_sched_do_timer(ktime_t now) #ifdef CONFIG_NO_HZ_COMMON /* * Check if the do_timer duty was dropped. We don't care about - * concurrency: This happens only when the cpu in charge went - * into a long sleep. If two cpus happen to assign themself to + * concurrency: This happens only when the CPU in charge went + * into a long sleep. If two CPUs happen to assign themselves to * this duty, then the jiffies update is still serialized by * jiffies_lock. */ @@ -349,7 +349,7 @@ void tick_nohz_dep_clear_signal(struct signal_struct *sig, enum tick_dep_bits bi /* * Re-evaluate the need for the tick as we switch the current task. * It might need the tick due to per task/process properties: - * perf events, posix cpu timers, ... + * perf events, posix CPU timers, ... */ void __tick_nohz_task_switch(void) { @@ -509,8 +509,8 @@ int tick_nohz_tick_stopped(void) * * In case the sched_tick was stopped on this CPU, we have to check if jiffies * must be updated. Otherwise an interrupt handler could use a stale jiffy - * value. We do this unconditionally on any cpu, as we don't know whether the - * cpu, which has the update task assigned is in a long sleep. + * value. We do this unconditionally on any CPU, as we don't know whether the + * CPU, which has the update task assigned is in a long sleep. */ static void tick_nohz_update_jiffies(ktime_t now) { @@ -526,7 +526,7 @@ static void tick_nohz_update_jiffies(ktime_t now) } /* - * Updates the per cpu time idle statistics counters + * Updates the per-CPU time idle statistics counters */ static void update_ts_time_stats(int cpu, struct tick_sched *ts, ktime_t now, u64 *last_update_time) @@ -566,12 +566,12 @@ static ktime_t tick_nohz_start_idle(struct tick_sched *ts) } /** - * get_cpu_idle_time_us - get the total idle time of a cpu + * get_cpu_idle_time_us - get the total idle time of a CPU * @cpu: CPU number to query * @last_update_time: variable to store update time in. Do not update * counters if NULL. * - * Return the cummulative idle time (since boot) for a given + * Return the cumulative idle time (since boot) for a given * CPU, in microseconds. * * This time is measured via accounting rather than sampling, @@ -607,12 +607,12 @@ u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time) EXPORT_SYMBOL_GPL(get_cpu_idle_time_us); /** - * get_cpu_iowait_time_us - get the total iowait time of a cpu + * get_cpu_iowait_time_us - get the total iowait time of a CPU * @cpu: CPU number to query * @last_update_time: variable to store update time in. Do not update * counters if NULL. * - * Return the cummulative iowait time (since boot) for a given + * Return the cumulative iowait time (since boot) for a given * CPU, in microseconds. * * This time is measured via accounting rather than sampling, @@ -700,6 +700,12 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts, delta = next_tick - basemono; if (delta <= (u64)TICK_NSEC) { tick.tv64 = 0; + + /* + * Tell the timer code that the base is not idle, i.e. undo + * the effect of get_next_timer_interrupt(): + */ + timer_clear_idle(); /* * We've not stopped the tick yet, and there's a timer in the * next period, so no point in stopping it either, bail. @@ -726,14 +732,14 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts, } /* - * If this cpu is the one which updates jiffies, then give up - * the assignment and let it be taken by the cpu which runs - * the tick timer next, which might be this cpu as well. If we + * If this CPU is the one which updates jiffies, then give up + * the assignment and let it be taken by the CPU which runs + * the tick timer next, which might be this CPU as well. If we * don't drop this here the jiffies might be stale and * do_timer() never invoked. Keep track of the fact that it - * was the one which had the do_timer() duty last. If this cpu + * was the one which had the do_timer() duty last. If this CPU * is the one which had the do_timer() duty last, we limit the - * sleep time to the timekeeping max_deferement value. + * sleep time to the timekeeping max_deferment value. * Otherwise we can sleep as long as we want. */ delta = timekeeping_max_deferment(); @@ -809,6 +815,12 @@ static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now) tick_do_update_jiffies64(now); cpu_load_update_nohz_stop(); + /* + * Clear the timer idle flag, so we avoid IPIs on remote queueing and + * the clock forward checks in the enqueue path: + */ + timer_clear_idle(); + calc_load_exit_idle(); touch_softlockup_watchdog_sched(); /* @@ -841,9 +853,9 @@ static void tick_nohz_full_update_tick(struct tick_sched *ts) static bool can_stop_idle_tick(int cpu, struct tick_sched *ts) { /* - * If this cpu is offline and it is the one which updates + * If this CPU is offline and it is the one which updates * jiffies, then give up the assignment and let it be taken by - * the cpu which runs the tick timer next. If we don't drop + * the CPU which runs the tick timer next. If we don't drop * this here the jiffies might be stale and do_timer() never * invoked. */ @@ -896,11 +908,10 @@ static void __tick_nohz_idle_enter(struct tick_sched *ts) ktime_t now, expires; int cpu = smp_processor_id(); - now = tick_nohz_start_idle(ts); - if (can_stop_idle_tick(cpu, ts)) { int was_stopped = ts->tick_stopped; + now = tick_nohz_start_idle(ts); ts->idle_calls++; expires = tick_nohz_stop_sched_tick(ts, now, cpu); @@ -933,11 +944,11 @@ void tick_nohz_idle_enter(void) WARN_ON_ONCE(irqs_disabled()); /* - * Update the idle state in the scheduler domain hierarchy - * when tick_nohz_stop_sched_tick() is called from the idle loop. - * State will be updated to busy during the first busy tick after - * exiting idle. - */ + * Update the idle state in the scheduler domain hierarchy + * when tick_nohz_stop_sched_tick() is called from the idle loop. + * State will be updated to busy during the first busy tick after + * exiting idle. + */ set_cpu_sd_state_idle(); local_irq_disable(); @@ -1092,35 +1103,6 @@ static void tick_nohz_switch_to_nohz(void) tick_nohz_activate(ts, NOHZ_MODE_LOWRES); } -/* - * When NOHZ is enabled and the tick is stopped, we need to kick the - * tick timer from irq_enter() so that the jiffies update is kept - * alive during long running softirqs. That's ugly as hell, but - * correctness is key even if we need to fix the offending softirq in - * the first place. - * - * Note, this is different to tick_nohz_restart. We just kick the - * timer and do not touch the other magic bits which need to be done - * when idle is left. - */ -static void tick_nohz_kick_tick(struct tick_sched *ts, ktime_t now) -{ -#if 0 - /* Switch back to 2.6.27 behaviour */ - ktime_t delta; - - /* - * Do not touch the tick device, when the next expiry is either - * already reached or less/equal than the tick period. - */ - delta = ktime_sub(hrtimer_get_expires(&ts->sched_timer), now); - if (delta.tv64 <= tick_period.tv64) - return; - - tick_nohz_restart(ts, now); -#endif -} - static inline void tick_nohz_irq_enter(void) { struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched); @@ -1131,10 +1113,8 @@ static inline void tick_nohz_irq_enter(void) now = ktime_get(); if (ts->idle_active) tick_nohz_stop_idle(ts, now); - if (ts->tick_stopped) { + if (ts->tick_stopped) tick_nohz_update_jiffies(now); - tick_nohz_kick_tick(ts, now); - } } #else @@ -1211,7 +1191,7 @@ void tick_setup_sched_timer(void) hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); ts->sched_timer.function = tick_sched_timer; - /* Get the next period (per cpu) */ + /* Get the next period (per-CPU) */ hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update()); /* Offset the tick to avert jiffies_lock contention. */ diff --git a/kernel/time/timeconv.c b/kernel/time/timeconv.c index 86628e755f38..7142580ad94f 100644 --- a/kernel/time/timeconv.c +++ b/kernel/time/timeconv.c @@ -67,20 +67,21 @@ static const unsigned short __mon_yday[2][13] = { #define SECS_PER_DAY (SECS_PER_HOUR * 24) /** - * time_to_tm - converts the calendar time to local broken-down time + * time64_to_tm - converts the calendar time to local broken-down time * * @totalsecs the number of seconds elapsed since 00:00:00 on January 1, 1970, * Coordinated Universal Time (UTC). * @offset offset seconds adding to totalsecs. * @result pointer to struct tm variable to receive broken-down time */ -void time_to_tm(time_t totalsecs, int offset, struct tm *result) +void time64_to_tm(time64_t totalsecs, int offset, struct tm *result) { long days, rem, y; + int remainder; const unsigned short *ip; - days = totalsecs / SECS_PER_DAY; - rem = totalsecs % SECS_PER_DAY; + days = div_s64_rem(totalsecs, SECS_PER_DAY, &remainder); + rem = remainder; rem += offset; while (rem < 0) { rem += SECS_PER_DAY; @@ -124,4 +125,4 @@ void time_to_tm(time_t totalsecs, int offset, struct tm *result) result->tm_mon = y; result->tm_mday = days + 1; } -EXPORT_SYMBOL(time_to_tm); +EXPORT_SYMBOL(time64_to_tm); diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 479d25cd3d4f..3b65746c7f15 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -480,10 +480,12 @@ static inline void old_vsyscall_fixup(struct timekeeper *tk) * users are removed, this can be killed. */ remainder = tk->tkr_mono.xtime_nsec & ((1ULL << tk->tkr_mono.shift) - 1); - tk->tkr_mono.xtime_nsec -= remainder; - tk->tkr_mono.xtime_nsec += 1ULL << tk->tkr_mono.shift; - tk->ntp_error += remainder << tk->ntp_error_shift; - tk->ntp_error -= (1ULL << tk->tkr_mono.shift) << tk->ntp_error_shift; + if (remainder != 0) { + tk->tkr_mono.xtime_nsec -= remainder; + tk->tkr_mono.xtime_nsec += 1ULL << tk->tkr_mono.shift; + tk->ntp_error += remainder << tk->ntp_error_shift; + tk->ntp_error -= (1ULL << tk->tkr_mono.shift) << tk->ntp_error_shift; + } } #else #define old_vsyscall_fixup(tk) @@ -2186,6 +2188,7 @@ struct timespec64 get_monotonic_coarse64(void) return now; } +EXPORT_SYMBOL(get_monotonic_coarse64); /* * Must hold jiffies_lock diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 3a95f9728778..cb9ab401e2d9 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -59,43 +59,153 @@ __visible u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES; EXPORT_SYMBOL(jiffies_64); /* - * per-CPU timer vector definitions: + * The timer wheel has LVL_DEPTH array levels. Each level provides an array of + * LVL_SIZE buckets. Each level is driven by its own clock and therefor each + * level has a different granularity. + * + * The level granularity is: LVL_CLK_DIV ^ lvl + * The level clock frequency is: HZ / (LVL_CLK_DIV ^ level) + * + * The array level of a newly armed timer depends on the relative expiry + * time. The farther the expiry time is away the higher the array level and + * therefor the granularity becomes. + * + * Contrary to the original timer wheel implementation, which aims for 'exact' + * expiry of the timers, this implementation removes the need for recascading + * the timers into the lower array levels. The previous 'classic' timer wheel + * implementation of the kernel already violated the 'exact' expiry by adding + * slack to the expiry time to provide batched expiration. The granularity + * levels provide implicit batching. + * + * This is an optimization of the original timer wheel implementation for the + * majority of the timer wheel use cases: timeouts. The vast majority of + * timeout timers (networking, disk I/O ...) are canceled before expiry. If + * the timeout expires it indicates that normal operation is disturbed, so it + * does not matter much whether the timeout comes with a slight delay. + * + * The only exception to this are networking timers with a small expiry + * time. They rely on the granularity. Those fit into the first wheel level, + * which has HZ granularity. + * + * We don't have cascading anymore. timers with a expiry time above the + * capacity of the last wheel level are force expired at the maximum timeout + * value of the last wheel level. From data sampling we know that the maximum + * value observed is 5 days (network connection tracking), so this should not + * be an issue. + * + * The currently chosen array constants values are a good compromise between + * array size and granularity. + * + * This results in the following granularity and range levels: + * + * HZ 1000 steps + * Level Offset Granularity Range + * 0 0 1 ms 0 ms - 63 ms + * 1 64 8 ms 64 ms - 511 ms + * 2 128 64 ms 512 ms - 4095 ms (512ms - ~4s) + * 3 192 512 ms 4096 ms - 32767 ms (~4s - ~32s) + * 4 256 4096 ms (~4s) 32768 ms - 262143 ms (~32s - ~4m) + * 5 320 32768 ms (~32s) 262144 ms - 2097151 ms (~4m - ~34m) + * 6 384 262144 ms (~4m) 2097152 ms - 16777215 ms (~34m - ~4h) + * 7 448 2097152 ms (~34m) 16777216 ms - 134217727 ms (~4h - ~1d) + * 8 512 16777216 ms (~4h) 134217728 ms - 1073741822 ms (~1d - ~12d) + * + * HZ 300 + * Level Offset Granularity Range + * 0 0 3 ms 0 ms - 210 ms + * 1 64 26 ms 213 ms - 1703 ms (213ms - ~1s) + * 2 128 213 ms 1706 ms - 13650 ms (~1s - ~13s) + * 3 192 1706 ms (~1s) 13653 ms - 109223 ms (~13s - ~1m) + * 4 256 13653 ms (~13s) 109226 ms - 873810 ms (~1m - ~14m) + * 5 320 109226 ms (~1m) 873813 ms - 6990503 ms (~14m - ~1h) + * 6 384 873813 ms (~14m) 6990506 ms - 55924050 ms (~1h - ~15h) + * 7 448 6990506 ms (~1h) 55924053 ms - 447392423 ms (~15h - ~5d) + * 8 512 55924053 ms (~15h) 447392426 ms - 3579139406 ms (~5d - ~41d) + * + * HZ 250 + * Level Offset Granularity Range + * 0 0 4 ms 0 ms - 255 ms + * 1 64 32 ms 256 ms - 2047 ms (256ms - ~2s) + * 2 128 256 ms 2048 ms - 16383 ms (~2s - ~16s) + * 3 192 2048 ms (~2s) 16384 ms - 131071 ms (~16s - ~2m) + * 4 256 16384 ms (~16s) 131072 ms - 1048575 ms (~2m - ~17m) + * 5 320 131072 ms (~2m) 1048576 ms - 8388607 ms (~17m - ~2h) + * 6 384 1048576 ms (~17m) 8388608 ms - 67108863 ms (~2h - ~18h) + * 7 448 8388608 ms (~2h) 67108864 ms - 536870911 ms (~18h - ~6d) + * 8 512 67108864 ms (~18h) 536870912 ms - 4294967288 ms (~6d - ~49d) + * + * HZ 100 + * Level Offset Granularity Range + * 0 0 10 ms 0 ms - 630 ms + * 1 64 80 ms 640 ms - 5110 ms (640ms - ~5s) + * 2 128 640 ms 5120 ms - 40950 ms (~5s - ~40s) + * 3 192 5120 ms (~5s) 40960 ms - 327670 ms (~40s - ~5m) + * 4 256 40960 ms (~40s) 327680 ms - 2621430 ms (~5m - ~43m) + * 5 320 327680 ms (~5m) 2621440 ms - 20971510 ms (~43m - ~5h) + * 6 384 2621440 ms (~43m) 20971520 ms - 167772150 ms (~5h - ~1d) + * 7 448 20971520 ms (~5h) 167772160 ms - 1342177270 ms (~1d - ~15d) */ -#define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6) -#define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8) -#define TVN_SIZE (1 << TVN_BITS) -#define TVR_SIZE (1 << TVR_BITS) -#define TVN_MASK (TVN_SIZE - 1) -#define TVR_MASK (TVR_SIZE - 1) -#define MAX_TVAL ((unsigned long)((1ULL << (TVR_BITS + 4*TVN_BITS)) - 1)) - -struct tvec { - struct hlist_head vec[TVN_SIZE]; -}; -struct tvec_root { - struct hlist_head vec[TVR_SIZE]; -}; +/* Clock divisor for the next level */ +#define LVL_CLK_SHIFT 3 +#define LVL_CLK_DIV (1UL << LVL_CLK_SHIFT) +#define LVL_CLK_MASK (LVL_CLK_DIV - 1) +#define LVL_SHIFT(n) ((n) * LVL_CLK_SHIFT) +#define LVL_GRAN(n) (1UL << LVL_SHIFT(n)) -struct tvec_base { - spinlock_t lock; - struct timer_list *running_timer; - unsigned long timer_jiffies; - unsigned long next_timer; - unsigned long active_timers; - unsigned long all_timers; - int cpu; - bool migration_enabled; - bool nohz_active; - struct tvec_root tv1; - struct tvec tv2; - struct tvec tv3; - struct tvec tv4; - struct tvec tv5; -} ____cacheline_aligned; +/* + * The time start value for each level to select the bucket at enqueue + * time. + */ +#define LVL_START(n) ((LVL_SIZE - 1) << (((n) - 1) * LVL_CLK_SHIFT)) + +/* Size of each clock level */ +#define LVL_BITS 6 +#define LVL_SIZE (1UL << LVL_BITS) +#define LVL_MASK (LVL_SIZE - 1) +#define LVL_OFFS(n) ((n) * LVL_SIZE) + +/* Level depth */ +#if HZ > 100 +# define LVL_DEPTH 9 +# else +# define LVL_DEPTH 8 +#endif + +/* The cutoff (max. capacity of the wheel) */ +#define WHEEL_TIMEOUT_CUTOFF (LVL_START(LVL_DEPTH)) +#define WHEEL_TIMEOUT_MAX (WHEEL_TIMEOUT_CUTOFF - LVL_GRAN(LVL_DEPTH - 1)) + +/* + * The resulting wheel size. If NOHZ is configured we allocate two + * wheels so we have a separate storage for the deferrable timers. + */ +#define WHEEL_SIZE (LVL_SIZE * LVL_DEPTH) + +#ifdef CONFIG_NO_HZ_COMMON +# define NR_BASES 2 +# define BASE_STD 0 +# define BASE_DEF 1 +#else +# define NR_BASES 1 +# define BASE_STD 0 +# define BASE_DEF 0 +#endif +struct timer_base { + spinlock_t lock; + struct timer_list *running_timer; + unsigned long clk; + unsigned long next_expiry; + unsigned int cpu; + bool migration_enabled; + bool nohz_active; + bool is_idle; + DECLARE_BITMAP(pending_map, WHEEL_SIZE); + struct hlist_head vectors[WHEEL_SIZE]; +} ____cacheline_aligned; -static DEFINE_PER_CPU(struct tvec_base, tvec_bases); +static DEFINE_PER_CPU(struct timer_base, timer_bases[NR_BASES]); #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON) unsigned int sysctl_timer_migration = 1; @@ -106,15 +216,17 @@ void timers_update_migration(bool update_nohz) unsigned int cpu; /* Avoid the loop, if nothing to update */ - if (this_cpu_read(tvec_bases.migration_enabled) == on) + if (this_cpu_read(timer_bases[BASE_STD].migration_enabled) == on) return; for_each_possible_cpu(cpu) { - per_cpu(tvec_bases.migration_enabled, cpu) = on; + per_cpu(timer_bases[BASE_STD].migration_enabled, cpu) = on; + per_cpu(timer_bases[BASE_DEF].migration_enabled, cpu) = on; per_cpu(hrtimer_bases.migration_enabled, cpu) = on; if (!update_nohz) continue; - per_cpu(tvec_bases.nohz_active, cpu) = true; + per_cpu(timer_bases[BASE_STD].nohz_active, cpu) = true; + per_cpu(timer_bases[BASE_DEF].nohz_active, cpu) = true; per_cpu(hrtimer_bases.nohz_active, cpu) = true; } } @@ -133,20 +245,6 @@ int timer_migration_handler(struct ctl_table *table, int write, mutex_unlock(&mutex); return ret; } - -static inline struct tvec_base *get_target_base(struct tvec_base *base, - int pinned) -{ - if (pinned || !base->migration_enabled) - return this_cpu_ptr(&tvec_bases); - return per_cpu_ptr(&tvec_bases, get_nohz_timer_target()); -} -#else -static inline struct tvec_base *get_target_base(struct tvec_base *base, - int pinned) -{ - return this_cpu_ptr(&tvec_bases); -} #endif static unsigned long round_jiffies_common(unsigned long j, int cpu, @@ -351,101 +449,126 @@ unsigned long round_jiffies_up_relative(unsigned long j) } EXPORT_SYMBOL_GPL(round_jiffies_up_relative); -/** - * set_timer_slack - set the allowed slack for a timer - * @timer: the timer to be modified - * @slack_hz: the amount of time (in jiffies) allowed for rounding - * - * Set the amount of time, in jiffies, that a certain timer has - * in terms of slack. By setting this value, the timer subsystem - * will schedule the actual timer somewhere between - * the time mod_timer() asks for, and that time plus the slack. - * - * By setting the slack to -1, a percentage of the delay is used - * instead. - */ -void set_timer_slack(struct timer_list *timer, int slack_hz) + +static inline unsigned int timer_get_idx(struct timer_list *timer) { - timer->slack = slack_hz; + return (timer->flags & TIMER_ARRAYMASK) >> TIMER_ARRAYSHIFT; } -EXPORT_SYMBOL_GPL(set_timer_slack); -static void -__internal_add_timer(struct tvec_base *base, struct timer_list *timer) +static inline void timer_set_idx(struct timer_list *timer, unsigned int idx) { - unsigned long expires = timer->expires; - unsigned long idx = expires - base->timer_jiffies; - struct hlist_head *vec; + timer->flags = (timer->flags & ~TIMER_ARRAYMASK) | + idx << TIMER_ARRAYSHIFT; +} - if (idx < TVR_SIZE) { - int i = expires & TVR_MASK; - vec = base->tv1.vec + i; - } else if (idx < 1 << (TVR_BITS + TVN_BITS)) { - int i = (expires >> TVR_BITS) & TVN_MASK; - vec = base->tv2.vec + i; - } else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) { - int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK; - vec = base->tv3.vec + i; - } else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) { - int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK; - vec = base->tv4.vec + i; - } else if ((signed long) idx < 0) { - /* - * Can happen if you add a timer with expires == jiffies, - * or you set a timer to go off in the past - */ - vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK); +/* + * Helper function to calculate the array index for a given expiry + * time. + */ +static inline unsigned calc_index(unsigned expires, unsigned lvl) +{ + expires = (expires + LVL_GRAN(lvl)) >> LVL_SHIFT(lvl); + return LVL_OFFS(lvl) + (expires & LVL_MASK); +} + +static int calc_wheel_index(unsigned long expires, unsigned long clk) +{ + unsigned long delta = expires - clk; + unsigned int idx; + + if (delta < LVL_START(1)) { + idx = calc_index(expires, 0); + } else if (delta < LVL_START(2)) { + idx = calc_index(expires, 1); + } else if (delta < LVL_START(3)) { + idx = calc_index(expires, 2); + } else if (delta < LVL_START(4)) { + idx = calc_index(expires, 3); + } else if (delta < LVL_START(5)) { + idx = calc_index(expires, 4); + } else if (delta < LVL_START(6)) { + idx = calc_index(expires, 5); + } else if (delta < LVL_START(7)) { + idx = calc_index(expires, 6); + } else if (LVL_DEPTH > 8 && delta < LVL_START(8)) { + idx = calc_index(expires, 7); + } else if ((long) delta < 0) { + idx = clk & LVL_MASK; } else { - int i; - /* If the timeout is larger than MAX_TVAL (on 64-bit - * architectures or with CONFIG_BASE_SMALL=1) then we - * use the maximum timeout. + /* + * Force expire obscene large timeouts to expire at the + * capacity limit of the wheel. */ - if (idx > MAX_TVAL) { - idx = MAX_TVAL; - expires = idx + base->timer_jiffies; - } - i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK; - vec = base->tv5.vec + i; + if (expires >= WHEEL_TIMEOUT_CUTOFF) + expires = WHEEL_TIMEOUT_MAX; + + idx = calc_index(expires, LVL_DEPTH - 1); } + return idx; +} - hlist_add_head(&timer->entry, vec); +/* + * Enqueue the timer into the hash bucket, mark it pending in + * the bitmap and store the index in the timer flags. + */ +static void enqueue_timer(struct timer_base *base, struct timer_list *timer, + unsigned int idx) +{ + hlist_add_head(&timer->entry, base->vectors + idx); + __set_bit(idx, base->pending_map); + timer_set_idx(timer, idx); } -static void internal_add_timer(struct tvec_base *base, struct timer_list *timer) +static void +__internal_add_timer(struct timer_base *base, struct timer_list *timer) { - /* Advance base->jiffies, if the base is empty */ - if (!base->all_timers++) - base->timer_jiffies = jiffies; + unsigned int idx; + + idx = calc_wheel_index(timer->expires, base->clk); + enqueue_timer(base, timer, idx); +} + +static void +trigger_dyntick_cpu(struct timer_base *base, struct timer_list *timer) +{ + if (!IS_ENABLED(CONFIG_NO_HZ_COMMON) || !base->nohz_active) + return; - __internal_add_timer(base, timer); /* - * Update base->active_timers and base->next_timer + * TODO: This wants some optimizing similar to the code below, but we + * will do that when we switch from push to pull for deferrable timers. */ - if (!(timer->flags & TIMER_DEFERRABLE)) { - if (!base->active_timers++ || - time_before(timer->expires, base->next_timer)) - base->next_timer = timer->expires; + if (timer->flags & TIMER_DEFERRABLE) { + if (tick_nohz_full_cpu(base->cpu)) + wake_up_nohz_cpu(base->cpu); + return; } /* - * Check whether the other CPU is in dynticks mode and needs - * to be triggered to reevaluate the timer wheel. - * We are protected against the other CPU fiddling - * with the timer by holding the timer base lock. This also - * makes sure that a CPU on the way to stop its tick can not - * evaluate the timer wheel. - * - * Spare the IPI for deferrable timers on idle targets though. - * The next busy ticks will take care of it. Except full dynticks - * require special care against races with idle_cpu(), lets deal - * with that later. + * We might have to IPI the remote CPU if the base is idle and the + * timer is not deferrable. If the other CPU is on the way to idle + * then it can't set base->is_idle as we hold the base lock: */ - if (base->nohz_active) { - if (!(timer->flags & TIMER_DEFERRABLE) || - tick_nohz_full_cpu(base->cpu)) - wake_up_nohz_cpu(base->cpu); - } + if (!base->is_idle) + return; + + /* Check whether this is the new first expiring timer: */ + if (time_after_eq(timer->expires, base->next_expiry)) + return; + + /* + * Set the next expiry time and kick the CPU so it can reevaluate the + * wheel: + */ + base->next_expiry = timer->expires; + wake_up_nohz_cpu(base->cpu); +} + +static void +internal_add_timer(struct timer_base *base, struct timer_list *timer) +{ + __internal_add_timer(base, timer); + trigger_dyntick_cpu(base, timer); } #ifdef CONFIG_TIMER_STATS @@ -666,7 +789,6 @@ static void do_init_timer(struct timer_list *timer, unsigned int flags, { timer->entry.pprev = NULL; timer->flags = flags | raw_smp_processor_id(); - timer->slack = -1; #ifdef CONFIG_TIMER_STATS timer->start_site = NULL; timer->start_pid = -1; @@ -706,54 +828,125 @@ static inline void detach_timer(struct timer_list *timer, bool clear_pending) entry->next = LIST_POISON2; } -static inline void -detach_expired_timer(struct timer_list *timer, struct tvec_base *base) -{ - detach_timer(timer, true); - if (!(timer->flags & TIMER_DEFERRABLE)) - base->active_timers--; - base->all_timers--; -} - -static int detach_if_pending(struct timer_list *timer, struct tvec_base *base, +static int detach_if_pending(struct timer_list *timer, struct timer_base *base, bool clear_pending) { + unsigned idx = timer_get_idx(timer); + if (!timer_pending(timer)) return 0; + if (hlist_is_singular_node(&timer->entry, base->vectors + idx)) + __clear_bit(idx, base->pending_map); + detach_timer(timer, clear_pending); - if (!(timer->flags & TIMER_DEFERRABLE)) { - base->active_timers--; - if (timer->expires == base->next_timer) - base->next_timer = base->timer_jiffies; - } - /* If this was the last timer, advance base->jiffies */ - if (!--base->all_timers) - base->timer_jiffies = jiffies; return 1; } +static inline struct timer_base *get_timer_cpu_base(u32 tflags, u32 cpu) +{ + struct timer_base *base = per_cpu_ptr(&timer_bases[BASE_STD], cpu); + + /* + * If the timer is deferrable and nohz is active then we need to use + * the deferrable base. + */ + if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active && + (tflags & TIMER_DEFERRABLE)) + base = per_cpu_ptr(&timer_bases[BASE_DEF], cpu); + return base; +} + +static inline struct timer_base *get_timer_this_cpu_base(u32 tflags) +{ + struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); + + /* + * If the timer is deferrable and nohz is active then we need to use + * the deferrable base. + */ + if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active && + (tflags & TIMER_DEFERRABLE)) + base = this_cpu_ptr(&timer_bases[BASE_DEF]); + return base; +} + +static inline struct timer_base *get_timer_base(u32 tflags) +{ + return get_timer_cpu_base(tflags, tflags & TIMER_CPUMASK); +} + +#ifdef CONFIG_NO_HZ_COMMON +static inline struct timer_base * +__get_target_base(struct timer_base *base, unsigned tflags) +{ +#ifdef CONFIG_SMP + if ((tflags & TIMER_PINNED) || !base->migration_enabled) + return get_timer_this_cpu_base(tflags); + return get_timer_cpu_base(tflags, get_nohz_timer_target()); +#else + return get_timer_this_cpu_base(tflags); +#endif +} + +static inline void forward_timer_base(struct timer_base *base) +{ + /* + * We only forward the base when it's idle and we have a delta between + * base clock and jiffies. + */ + if (!base->is_idle || (long) (jiffies - base->clk) < 2) + return; + + /* + * If the next expiry value is > jiffies, then we fast forward to + * jiffies otherwise we forward to the next expiry value. + */ + if (time_after(base->next_expiry, jiffies)) + base->clk = jiffies; + else + base->clk = base->next_expiry; +} +#else +static inline struct timer_base * +__get_target_base(struct timer_base *base, unsigned tflags) +{ + return get_timer_this_cpu_base(tflags); +} + +static inline void forward_timer_base(struct timer_base *base) { } +#endif + +static inline struct timer_base * +get_target_base(struct timer_base *base, unsigned tflags) +{ + struct timer_base *target = __get_target_base(base, tflags); + + forward_timer_base(target); + return target; +} + /* - * We are using hashed locking: holding per_cpu(tvec_bases).lock - * means that all timers which are tied to this base via timer->base are - * locked, and the base itself is locked too. + * We are using hashed locking: Holding per_cpu(timer_bases[x]).lock means + * that all timers which are tied to this base are locked, and the base itself + * is locked too. * * So __run_timers/migrate_timers can safely modify all timers which could - * be found on ->tvX lists. + * be found in the base->vectors array. * - * When the timer's base is locked and removed from the list, the - * TIMER_MIGRATING flag is set, FIXME + * When a timer is migrating then the TIMER_MIGRATING flag is set and we need + * to wait until the migration is done. */ -static struct tvec_base *lock_timer_base(struct timer_list *timer, - unsigned long *flags) +static struct timer_base *lock_timer_base(struct timer_list *timer, + unsigned long *flags) __acquires(timer->base->lock) { for (;;) { + struct timer_base *base; u32 tf = timer->flags; - struct tvec_base *base; if (!(tf & TIMER_MIGRATING)) { - base = per_cpu_ptr(&tvec_bases, tf & TIMER_CPUMASK); + base = get_timer_base(tf); spin_lock_irqsave(&base->lock, *flags); if (timer->flags == tf) return base; @@ -764,13 +957,41 @@ static struct tvec_base *lock_timer_base(struct timer_list *timer, } static inline int -__mod_timer(struct timer_list *timer, unsigned long expires, - bool pending_only, int pinned) +__mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only) { - struct tvec_base *base, *new_base; - unsigned long flags; + struct timer_base *base, *new_base; + unsigned int idx = UINT_MAX; + unsigned long clk = 0, flags; int ret = 0; + /* + * This is a common optimization triggered by the networking code - if + * the timer is re-modified to have the same timeout or ends up in the + * same array bucket then just return: + */ + if (timer_pending(timer)) { + if (timer->expires == expires) + return 1; + /* + * Take the current timer_jiffies of base, but without holding + * the lock! + */ + base = get_timer_base(timer->flags); + clk = base->clk; + + idx = calc_wheel_index(expires, clk); + + /* + * Retrieve and compare the array index of the pending + * timer. If it matches set the expiry to the new value so a + * subsequent call will exit in the expires check above. + */ + if (idx == timer_get_idx(timer)) { + timer->expires = expires; + return 1; + } + } + timer_stats_timer_set_start_info(timer); BUG_ON(!timer->function); @@ -782,15 +1003,15 @@ __mod_timer(struct timer_list *timer, unsigned long expires, debug_activate(timer, expires); - new_base = get_target_base(base, pinned); + new_base = get_target_base(base, timer->flags); if (base != new_base) { /* - * We are trying to schedule the timer on the local CPU. + * We are trying to schedule the timer on the new base. * However we can't change timer's base while it is running, * otherwise del_timer_sync() can't detect that the timer's - * handler yet has not finished. This also guarantees that - * the timer is serialized wrt itself. + * handler yet has not finished. This also guarantees that the + * timer is serialized wrt itself. */ if (likely(base->running_timer != timer)) { /* See the comment in lock_timer_base() */ @@ -805,7 +1026,18 @@ __mod_timer(struct timer_list *timer, unsigned long expires, } timer->expires = expires; - internal_add_timer(base, timer); + /* + * If 'idx' was calculated above and the base time did not advance + * between calculating 'idx' and taking the lock, only enqueue_timer() + * and trigger_dyntick_cpu() is required. Otherwise we need to + * (re)calculate the wheel index via internal_add_timer(). + */ + if (idx != UINT_MAX && clk == base->clk) { + enqueue_timer(base, timer, idx); + trigger_dyntick_cpu(base, timer); + } else { + internal_add_timer(base, timer); + } out_unlock: spin_unlock_irqrestore(&base->lock, flags); @@ -825,49 +1057,10 @@ out_unlock: */ int mod_timer_pending(struct timer_list *timer, unsigned long expires) { - return __mod_timer(timer, expires, true, TIMER_NOT_PINNED); + return __mod_timer(timer, expires, true); } EXPORT_SYMBOL(mod_timer_pending); -/* - * Decide where to put the timer while taking the slack into account - * - * Algorithm: - * 1) calculate the maximum (absolute) time - * 2) calculate the highest bit where the expires and new max are different - * 3) use this bit to make a mask - * 4) use the bitmask to round down the maximum time, so that all last - * bits are zeros - */ -static inline -unsigned long apply_slack(struct timer_list *timer, unsigned long expires) -{ - unsigned long expires_limit, mask; - int bit; - - if (timer->slack >= 0) { - expires_limit = expires + timer->slack; - } else { - long delta = expires - jiffies; - - if (delta < 256) - return expires; - - expires_limit = expires + delta / 256; - } - mask = expires ^ expires_limit; - if (mask == 0) - return expires; - - bit = __fls(mask); - - mask = (1UL << bit) - 1; - - expires_limit = expires_limit & ~(mask); - - return expires_limit; -} - /** * mod_timer - modify a timer's timeout * @timer: the timer to be modified @@ -890,49 +1083,11 @@ unsigned long apply_slack(struct timer_list *timer, unsigned long expires) */ int mod_timer(struct timer_list *timer, unsigned long expires) { - expires = apply_slack(timer, expires); - - /* - * This is a common optimization triggered by the - * networking code - if the timer is re-modified - * to be the same thing then just return: - */ - if (timer_pending(timer) && timer->expires == expires) - return 1; - - return __mod_timer(timer, expires, false, TIMER_NOT_PINNED); + return __mod_timer(timer, expires, false); } EXPORT_SYMBOL(mod_timer); /** - * mod_timer_pinned - modify a timer's timeout - * @timer: the timer to be modified - * @expires: new timeout in jiffies - * - * mod_timer_pinned() is a way to update the expire field of an - * active timer (if the timer is inactive it will be activated) - * and to ensure that the timer is scheduled on the current CPU. - * - * Note that this does not prevent the timer from being migrated - * when the current CPU goes offline. If this is a problem for - * you, use CPU-hotplug notifiers to handle it correctly, for - * example, cancelling the timer when the corresponding CPU goes - * offline. - * - * mod_timer_pinned(timer, expires) is equivalent to: - * - * del_timer(timer); timer->expires = expires; add_timer(timer); - */ -int mod_timer_pinned(struct timer_list *timer, unsigned long expires) -{ - if (timer->expires == expires && timer_pending(timer)) - return 1; - - return __mod_timer(timer, expires, false, TIMER_PINNED); -} -EXPORT_SYMBOL(mod_timer_pinned); - -/** * add_timer - start a timer * @timer: the timer to be added * @@ -962,13 +1117,14 @@ EXPORT_SYMBOL(add_timer); */ void add_timer_on(struct timer_list *timer, int cpu) { - struct tvec_base *new_base = per_cpu_ptr(&tvec_bases, cpu); - struct tvec_base *base; + struct timer_base *new_base, *base; unsigned long flags; timer_stats_timer_set_start_info(timer); BUG_ON(timer_pending(timer) || !timer->function); + new_base = get_timer_cpu_base(timer->flags, cpu); + /* * If @timer was on a different CPU, it should be migrated with the * old base locked to prevent other operations proceeding with the @@ -1004,7 +1160,7 @@ EXPORT_SYMBOL_GPL(add_timer_on); */ int del_timer(struct timer_list *timer) { - struct tvec_base *base; + struct timer_base *base; unsigned long flags; int ret = 0; @@ -1030,7 +1186,7 @@ EXPORT_SYMBOL(del_timer); */ int try_to_del_timer_sync(struct timer_list *timer) { - struct tvec_base *base; + struct timer_base *base; unsigned long flags; int ret = -1; @@ -1114,27 +1270,6 @@ int del_timer_sync(struct timer_list *timer) EXPORT_SYMBOL(del_timer_sync); #endif -static int cascade(struct tvec_base *base, struct tvec *tv, int index) -{ - /* cascade all the timers from tv up one level */ - struct timer_list *timer; - struct hlist_node *tmp; - struct hlist_head tv_list; - - hlist_move_list(tv->vec + index, &tv_list); - - /* - * We are removing _all_ timers from the list, so we - * don't have to detach them individually. - */ - hlist_for_each_entry_safe(timer, tmp, &tv_list, entry) { - /* No accounting, while moving them */ - __internal_add_timer(base, timer); - } - - return index; -} - static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long), unsigned long data) { @@ -1178,147 +1313,141 @@ static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long), } } -#define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK) - -/** - * __run_timers - run all expired timers (if any) on this CPU. - * @base: the timer vector to be processed. - * - * This function cascades all vectors and executes all expired timer - * vectors. - */ -static inline void __run_timers(struct tvec_base *base) +static void expire_timers(struct timer_base *base, struct hlist_head *head) { - struct timer_list *timer; + while (!hlist_empty(head)) { + struct timer_list *timer; + void (*fn)(unsigned long); + unsigned long data; - spin_lock_irq(&base->lock); + timer = hlist_entry(head->first, struct timer_list, entry); + timer_stats_account_timer(timer); - while (time_after_eq(jiffies, base->timer_jiffies)) { - struct hlist_head work_list; - struct hlist_head *head = &work_list; - int index; + base->running_timer = timer; + detach_timer(timer, true); - if (!base->all_timers) { - base->timer_jiffies = jiffies; - break; + fn = timer->function; + data = timer->data; + + if (timer->flags & TIMER_IRQSAFE) { + spin_unlock(&base->lock); + call_timer_fn(timer, fn, data); + spin_lock(&base->lock); + } else { + spin_unlock_irq(&base->lock); + call_timer_fn(timer, fn, data); + spin_lock_irq(&base->lock); } + } +} - index = base->timer_jiffies & TVR_MASK; +static int __collect_expired_timers(struct timer_base *base, + struct hlist_head *heads) +{ + unsigned long clk = base->clk; + struct hlist_head *vec; + int i, levels = 0; + unsigned int idx; - /* - * Cascade timers: - */ - if (!index && - (!cascade(base, &base->tv2, INDEX(0))) && - (!cascade(base, &base->tv3, INDEX(1))) && - !cascade(base, &base->tv4, INDEX(2))) - cascade(base, &base->tv5, INDEX(3)); - ++base->timer_jiffies; - hlist_move_list(base->tv1.vec + index, head); - while (!hlist_empty(head)) { - void (*fn)(unsigned long); - unsigned long data; - bool irqsafe; - - timer = hlist_entry(head->first, struct timer_list, entry); - fn = timer->function; - data = timer->data; - irqsafe = timer->flags & TIMER_IRQSAFE; - - timer_stats_account_timer(timer); - - base->running_timer = timer; - detach_expired_timer(timer, base); - - if (irqsafe) { - spin_unlock(&base->lock); - call_timer_fn(timer, fn, data); - spin_lock(&base->lock); - } else { - spin_unlock_irq(&base->lock); - call_timer_fn(timer, fn, data); - spin_lock_irq(&base->lock); - } + for (i = 0; i < LVL_DEPTH; i++) { + idx = (clk & LVL_MASK) + i * LVL_SIZE; + + if (__test_and_clear_bit(idx, base->pending_map)) { + vec = base->vectors + idx; + hlist_move_list(vec, heads++); + levels++; } + /* Is it time to look at the next level? */ + if (clk & LVL_CLK_MASK) + break; + /* Shift clock for the next level granularity */ + clk >>= LVL_CLK_SHIFT; } - base->running_timer = NULL; - spin_unlock_irq(&base->lock); + return levels; } #ifdef CONFIG_NO_HZ_COMMON /* - * Find out when the next timer event is due to happen. This - * is used on S/390 to stop all activity when a CPU is idle. - * This function needs to be called with interrupts disabled. + * Find the next pending bucket of a level. Search from level start (@offset) + * + @clk upwards and if nothing there, search from start of the level + * (@offset) up to @offset + clk. */ -static unsigned long __next_timer_interrupt(struct tvec_base *base) -{ - unsigned long timer_jiffies = base->timer_jiffies; - unsigned long expires = timer_jiffies + NEXT_TIMER_MAX_DELTA; - int index, slot, array, found = 0; - struct timer_list *nte; - struct tvec *varray[4]; - - /* Look for timer events in tv1. */ - index = slot = timer_jiffies & TVR_MASK; - do { - hlist_for_each_entry(nte, base->tv1.vec + slot, entry) { - if (nte->flags & TIMER_DEFERRABLE) - continue; - - found = 1; - expires = nte->expires; - /* Look at the cascade bucket(s)? */ - if (!index || slot < index) - goto cascade; - return expires; +static int next_pending_bucket(struct timer_base *base, unsigned offset, + unsigned clk) +{ + unsigned pos, start = offset + clk; + unsigned end = offset + LVL_SIZE; + + pos = find_next_bit(base->pending_map, end, start); + if (pos < end) + return pos - start; + + pos = find_next_bit(base->pending_map, start, offset); + return pos < start ? pos + LVL_SIZE - start : -1; +} + +/* + * Search the first expiring timer in the various clock levels. Caller must + * hold base->lock. + */ +static unsigned long __next_timer_interrupt(struct timer_base *base) +{ + unsigned long clk, next, adj; + unsigned lvl, offset = 0; + + next = base->clk + NEXT_TIMER_MAX_DELTA; + clk = base->clk; + for (lvl = 0; lvl < LVL_DEPTH; lvl++, offset += LVL_SIZE) { + int pos = next_pending_bucket(base, offset, clk & LVL_MASK); + + if (pos >= 0) { + unsigned long tmp = clk + (unsigned long) pos; + + tmp <<= LVL_SHIFT(lvl); + if (time_before(tmp, next)) + next = tmp; } - slot = (slot + 1) & TVR_MASK; - } while (slot != index); - -cascade: - /* Calculate the next cascade event */ - if (index) - timer_jiffies += TVR_SIZE - index; - timer_jiffies >>= TVR_BITS; - - /* Check tv2-tv5. */ - varray[0] = &base->tv2; - varray[1] = &base->tv3; - varray[2] = &base->tv4; - varray[3] = &base->tv5; - - for (array = 0; array < 4; array++) { - struct tvec *varp = varray[array]; - - index = slot = timer_jiffies & TVN_MASK; - do { - hlist_for_each_entry(nte, varp->vec + slot, entry) { - if (nte->flags & TIMER_DEFERRABLE) - continue; - - found = 1; - if (time_before(nte->expires, expires)) - expires = nte->expires; - } - /* - * Do we still search for the first timer or are - * we looking up the cascade buckets ? - */ - if (found) { - /* Look at the cascade bucket(s)? */ - if (!index || slot < index) - break; - return expires; - } - slot = (slot + 1) & TVN_MASK; - } while (slot != index); - - if (index) - timer_jiffies += TVN_SIZE - index; - timer_jiffies >>= TVN_BITS; + /* + * Clock for the next level. If the current level clock lower + * bits are zero, we look at the next level as is. If not we + * need to advance it by one because that's going to be the + * next expiring bucket in that level. base->clk is the next + * expiring jiffie. So in case of: + * + * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0 + * 0 0 0 0 0 0 + * + * we have to look at all levels @index 0. With + * + * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0 + * 0 0 0 0 0 2 + * + * LVL0 has the next expiring bucket @index 2. The upper + * levels have the next expiring bucket @index 1. + * + * In case that the propagation wraps the next level the same + * rules apply: + * + * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0 + * 0 0 0 0 F 2 + * + * So after looking at LVL0 we get: + * + * LVL5 LVL4 LVL3 LVL2 LVL1 + * 0 0 0 1 0 + * + * So no propagation from LVL1 to LVL2 because that happened + * with the add already, but then we need to propagate further + * from LVL2 to LVL3. + * + * So the simple check whether the lower bits of the current + * level are 0 or not is sufficient for all cases. + */ + adj = clk & LVL_CLK_MASK ? 1 : 0; + clk >>= LVL_CLK_SHIFT; + clk += adj; } - return expires; + return next; } /* @@ -1364,7 +1493,7 @@ static u64 cmp_next_hrtimer_event(u64 basem, u64 expires) */ u64 get_next_timer_interrupt(unsigned long basej, u64 basem) { - struct tvec_base *base = this_cpu_ptr(&tvec_bases); + struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); u64 expires = KTIME_MAX; unsigned long nextevt; @@ -1376,19 +1505,80 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem) return expires; spin_lock(&base->lock); - if (base->active_timers) { - if (time_before_eq(base->next_timer, base->timer_jiffies)) - base->next_timer = __next_timer_interrupt(base); - nextevt = base->next_timer; - if (time_before_eq(nextevt, basej)) - expires = basem; - else - expires = basem + (nextevt - basej) * TICK_NSEC; + nextevt = __next_timer_interrupt(base); + base->next_expiry = nextevt; + /* + * We have a fresh next event. Check whether we can forward the base: + */ + if (time_after(nextevt, jiffies)) + base->clk = jiffies; + else if (time_after(nextevt, base->clk)) + base->clk = nextevt; + + if (time_before_eq(nextevt, basej)) { + expires = basem; + base->is_idle = false; + } else { + expires = basem + (nextevt - basej) * TICK_NSEC; + /* + * If we expect to sleep more than a tick, mark the base idle: + */ + if ((expires - basem) > TICK_NSEC) + base->is_idle = true; } spin_unlock(&base->lock); return cmp_next_hrtimer_event(basem, expires); } + +/** + * timer_clear_idle - Clear the idle state of the timer base + * + * Called with interrupts disabled + */ +void timer_clear_idle(void) +{ + struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); + + /* + * We do this unlocked. The worst outcome is a remote enqueue sending + * a pointless IPI, but taking the lock would just make the window for + * sending the IPI a few instructions smaller for the cost of taking + * the lock in the exit from idle path. + */ + base->is_idle = false; +} + +static int collect_expired_timers(struct timer_base *base, + struct hlist_head *heads) +{ + /* + * NOHZ optimization. After a long idle sleep we need to forward the + * base to current jiffies. Avoid a loop by searching the bitfield for + * the next expiring timer. + */ + if ((long)(jiffies - base->clk) > 2) { + unsigned long next = __next_timer_interrupt(base); + + /* + * If the next timer is ahead of time forward to current + * jiffies, otherwise forward to the next expiry time: + */ + if (time_after(next, jiffies)) { + /* The call site will increment clock! */ + base->clk = jiffies - 1; + return 0; + } + base->clk = next; + } + return __collect_expired_timers(base, heads); +} +#else +static inline int collect_expired_timers(struct timer_base *base, + struct hlist_head *heads) +{ + return __collect_expired_timers(base, heads); +} #endif /* @@ -1411,15 +1601,42 @@ void update_process_times(int user_tick) run_posix_cpu_timers(p); } +/** + * __run_timers - run all expired timers (if any) on this CPU. + * @base: the timer vector to be processed. + */ +static inline void __run_timers(struct timer_base *base) +{ + struct hlist_head heads[LVL_DEPTH]; + int levels; + + if (!time_after_eq(jiffies, base->clk)) + return; + + spin_lock_irq(&base->lock); + + while (time_after_eq(jiffies, base->clk)) { + + levels = collect_expired_timers(base, heads); + base->clk++; + + while (levels--) + expire_timers(base, heads + levels); + } + base->running_timer = NULL; + spin_unlock_irq(&base->lock); +} + /* * This function runs timers and the timer-tq in bottom half context. */ static void run_timer_softirq(struct softirq_action *h) { - struct tvec_base *base = this_cpu_ptr(&tvec_bases); + struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); - if (time_after_eq(jiffies, base->timer_jiffies)) - __run_timers(base); + __run_timers(base); + if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active) + __run_timers(this_cpu_ptr(&timer_bases[BASE_DEF])); } /* @@ -1427,7 +1644,18 @@ static void run_timer_softirq(struct softirq_action *h) */ void run_local_timers(void) { + struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); + hrtimer_run_queues(); + /* Raise the softirq only if required. */ + if (time_before(jiffies, base->clk)) { + if (!IS_ENABLED(CONFIG_NO_HZ_COMMON) || !base->nohz_active) + return; + /* CPU is awake, so check the deferrable base. */ + base++; + if (time_before(jiffies, base->clk)) + return; + } raise_softirq(TIMER_SOFTIRQ); } @@ -1512,7 +1740,7 @@ signed long __sched schedule_timeout(signed long timeout) expire = timeout + jiffies; setup_timer_on_stack(&timer, process_timeout, (unsigned long)current); - __mod_timer(&timer, expire, false, TIMER_NOT_PINNED); + __mod_timer(&timer, expire, false); schedule(); del_singleshot_timer_sync(&timer); @@ -1563,14 +1791,13 @@ signed long __sched schedule_timeout_idle(signed long timeout) EXPORT_SYMBOL(schedule_timeout_idle); #ifdef CONFIG_HOTPLUG_CPU -static void migrate_timer_list(struct tvec_base *new_base, struct hlist_head *head) +static void migrate_timer_list(struct timer_base *new_base, struct hlist_head *head) { struct timer_list *timer; int cpu = new_base->cpu; while (!hlist_empty(head)) { timer = hlist_entry(head->first, struct timer_list, entry); - /* We ignore the accounting on the dying cpu */ detach_timer(timer, false); timer->flags = (timer->flags & ~TIMER_BASEMASK) | cpu; internal_add_timer(new_base, timer); @@ -1579,37 +1806,31 @@ static void migrate_timer_list(struct tvec_base *new_base, struct hlist_head *he static void migrate_timers(int cpu) { - struct tvec_base *old_base; - struct tvec_base *new_base; - int i; + struct timer_base *old_base; + struct timer_base *new_base; + int b, i; BUG_ON(cpu_online(cpu)); - old_base = per_cpu_ptr(&tvec_bases, cpu); - new_base = get_cpu_ptr(&tvec_bases); - /* - * The caller is globally serialized and nobody else - * takes two locks at once, deadlock is not possible. - */ - spin_lock_irq(&new_base->lock); - spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING); - - BUG_ON(old_base->running_timer); - - for (i = 0; i < TVR_SIZE; i++) - migrate_timer_list(new_base, old_base->tv1.vec + i); - for (i = 0; i < TVN_SIZE; i++) { - migrate_timer_list(new_base, old_base->tv2.vec + i); - migrate_timer_list(new_base, old_base->tv3.vec + i); - migrate_timer_list(new_base, old_base->tv4.vec + i); - migrate_timer_list(new_base, old_base->tv5.vec + i); - } - old_base->active_timers = 0; - old_base->all_timers = 0; + for (b = 0; b < NR_BASES; b++) { + old_base = per_cpu_ptr(&timer_bases[b], cpu); + new_base = get_cpu_ptr(&timer_bases[b]); + /* + * The caller is globally serialized and nobody else + * takes two locks at once, deadlock is not possible. + */ + spin_lock_irq(&new_base->lock); + spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING); + + BUG_ON(old_base->running_timer); - spin_unlock(&old_base->lock); - spin_unlock_irq(&new_base->lock); - put_cpu_ptr(&tvec_bases); + for (i = 0; i < WHEEL_SIZE; i++) + migrate_timer_list(new_base, old_base->vectors + i); + + spin_unlock(&old_base->lock); + spin_unlock_irq(&new_base->lock); + put_cpu_ptr(&timer_bases); + } } static int timer_cpu_notify(struct notifier_block *self, @@ -1637,13 +1858,15 @@ static inline void timer_register_cpu_notifier(void) { } static void __init init_timer_cpu(int cpu) { - struct tvec_base *base = per_cpu_ptr(&tvec_bases, cpu); - - base->cpu = cpu; - spin_lock_init(&base->lock); + struct timer_base *base; + int i; - base->timer_jiffies = jiffies; - base->next_timer = base->timer_jiffies; + for (i = 0; i < NR_BASES; i++) { + base = per_cpu_ptr(&timer_bases[i], cpu); + base->cpu = cpu; + spin_lock_init(&base->lock); + base->clk = jiffies; + } } static void __init init_timer_cpus(void) @@ -1702,9 +1925,15 @@ static void __sched do_usleep_range(unsigned long min, unsigned long max) } /** - * usleep_range - Drop in replacement for udelay where wakeup is flexible + * usleep_range - Sleep for an approximate time * @min: Minimum time in usecs to sleep * @max: Maximum time in usecs to sleep + * + * In non-atomic context where the exact wakeup time is flexible, use + * usleep_range() instead of udelay(). The sleep improves responsiveness + * by avoiding the CPU-hogging busy-wait of udelay(), and the range reduces + * power usage by allowing hrtimers to take advantage of an already- + * scheduled interrupt instead of scheduling a new one just for this sleep. */ void __sched usleep_range(unsigned long min, unsigned long max) { diff --git a/kernel/time/timer_stats.c b/kernel/time/timer_stats.c index 1adecb4b87c8..087204c733eb 100644 --- a/kernel/time/timer_stats.c +++ b/kernel/time/timer_stats.c @@ -279,7 +279,7 @@ static void print_name_offset(struct seq_file *m, unsigned long addr) static int tstats_show(struct seq_file *m, void *v) { - struct timespec period; + struct timespec64 period; struct entry *entry; unsigned long ms; long events = 0; @@ -295,11 +295,11 @@ static int tstats_show(struct seq_file *m, void *v) time = ktime_sub(time_stop, time_start); - period = ktime_to_timespec(time); + period = ktime_to_timespec64(time); ms = period.tv_nsec / 1000000; seq_puts(m, "Timer Stats Version: v0.3\n"); - seq_printf(m, "Sample period: %ld.%03ld s\n", period.tv_sec, ms); + seq_printf(m, "Sample period: %ld.%03ld s\n", (long)period.tv_sec, ms); if (atomic_read(&overflow_count)) seq_printf(m, "Overflow: %d entries\n", atomic_read(&overflow_count)); seq_printf(m, "Collection: %s\n", timer_stats_active ? "active" : "inactive"); diff --git a/kernel/torture.c b/kernel/torture.c index fa0bdeee17ac..75961b3decfe 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -82,6 +82,104 @@ static int min_online = -1; static int max_online; /* + * Attempt to take a CPU offline. Return false if the CPU is already + * offline or if it is not subject to CPU-hotplug operations. The + * caller can detect other failures by looking at the statistics. + */ +bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes, + unsigned long *sum_offl, int *min_offl, int *max_offl) +{ + unsigned long delta; + int ret; + unsigned long starttime; + + if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu)) + return false; + + if (verbose) + pr_alert("%s" TORTURE_FLAG + "torture_onoff task: offlining %d\n", + torture_type, cpu); + starttime = jiffies; + (*n_offl_attempts)++; + ret = cpu_down(cpu); + if (ret) { + if (verbose) + pr_alert("%s" TORTURE_FLAG + "torture_onoff task: offline %d failed: errno %d\n", + torture_type, cpu, ret); + } else { + if (verbose) + pr_alert("%s" TORTURE_FLAG + "torture_onoff task: offlined %d\n", + torture_type, cpu); + (*n_offl_successes)++; + delta = jiffies - starttime; + sum_offl += delta; + if (*min_offl < 0) { + *min_offl = delta; + *max_offl = delta; + } + if (*min_offl > delta) + *min_offl = delta; + if (*max_offl < delta) + *max_offl = delta; + } + + return true; +} +EXPORT_SYMBOL_GPL(torture_offline); + +/* + * Attempt to bring a CPU online. Return false if the CPU is already + * online or if it is not subject to CPU-hotplug operations. The + * caller can detect other failures by looking at the statistics. + */ +bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes, + unsigned long *sum_onl, int *min_onl, int *max_onl) +{ + unsigned long delta; + int ret; + unsigned long starttime; + + if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu)) + return false; + + if (verbose) + pr_alert("%s" TORTURE_FLAG + "torture_onoff task: onlining %d\n", + torture_type, cpu); + starttime = jiffies; + (*n_onl_attempts)++; + ret = cpu_up(cpu); + if (ret) { + if (verbose) + pr_alert("%s" TORTURE_FLAG + "torture_onoff task: online %d failed: errno %d\n", + torture_type, cpu, ret); + } else { + if (verbose) + pr_alert("%s" TORTURE_FLAG + "torture_onoff task: onlined %d\n", + torture_type, cpu); + (*n_onl_successes)++; + delta = jiffies - starttime; + *sum_onl += delta; + if (*min_onl < 0) { + *min_onl = delta; + *max_onl = delta; + } + if (*min_onl > delta) + *min_onl = delta; + if (*max_onl < delta) + *max_onl = delta; + } + + return true; +} +EXPORT_SYMBOL_GPL(torture_online); + +/* * Execute random CPU-hotplug operations at the interval specified * by the onoff_interval. */ @@ -89,16 +187,19 @@ static int torture_onoff(void *arg) { int cpu; - unsigned long delta; int maxcpu = -1; DEFINE_TORTURE_RANDOM(rand); - int ret; - unsigned long starttime; VERBOSE_TOROUT_STRING("torture_onoff task started"); for_each_online_cpu(cpu) maxcpu = cpu; WARN_ON(maxcpu < 0); + + if (maxcpu == 0) { + VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled"); + goto stop; + } + if (onoff_holdoff > 0) { VERBOSE_TOROUT_STRING("torture_onoff begin holdoff"); schedule_timeout_interruptible(onoff_holdoff); @@ -106,69 +207,16 @@ torture_onoff(void *arg) } while (!torture_must_stop()) { cpu = (torture_random(&rand) >> 4) % (maxcpu + 1); - if (cpu_online(cpu) && cpu_is_hotpluggable(cpu)) { - if (verbose) - pr_alert("%s" TORTURE_FLAG - "torture_onoff task: offlining %d\n", - torture_type, cpu); - starttime = jiffies; - n_offline_attempts++; - ret = cpu_down(cpu); - if (ret) { - if (verbose) - pr_alert("%s" TORTURE_FLAG - "torture_onoff task: offline %d failed: errno %d\n", - torture_type, cpu, ret); - } else { - if (verbose) - pr_alert("%s" TORTURE_FLAG - "torture_onoff task: offlined %d\n", - torture_type, cpu); - n_offline_successes++; - delta = jiffies - starttime; - sum_offline += delta; - if (min_offline < 0) { - min_offline = delta; - max_offline = delta; - } - if (min_offline > delta) - min_offline = delta; - if (max_offline < delta) - max_offline = delta; - } - } else if (cpu_is_hotpluggable(cpu)) { - if (verbose) - pr_alert("%s" TORTURE_FLAG - "torture_onoff task: onlining %d\n", - torture_type, cpu); - starttime = jiffies; - n_online_attempts++; - ret = cpu_up(cpu); - if (ret) { - if (verbose) - pr_alert("%s" TORTURE_FLAG - "torture_onoff task: online %d failed: errno %d\n", - torture_type, cpu, ret); - } else { - if (verbose) - pr_alert("%s" TORTURE_FLAG - "torture_onoff task: onlined %d\n", - torture_type, cpu); - n_online_successes++; - delta = jiffies - starttime; - sum_online += delta; - if (min_online < 0) { - min_online = delta; - max_online = delta; - } - if (min_online > delta) - min_online = delta; - if (max_online < delta) - max_online = delta; - } - } + if (!torture_offline(cpu, + &n_offline_attempts, &n_offline_successes, + &sum_offline, &min_offline, &max_offline)) + torture_online(cpu, + &n_online_attempts, &n_online_successes, + &sum_online, &min_online, &max_online); schedule_timeout_interruptible(onoff_interval); } + +stop: torture_kthread_stopping("torture_onoff"); return 0; } diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 9aef8654e90d..fb345cd11883 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -127,12 +127,13 @@ static void trace_note_tsk(struct task_struct *tsk) static void trace_note_time(struct blk_trace *bt) { - struct timespec now; + struct timespec64 now; unsigned long flags; u32 words[2]; - getnstimeofday(&now); - words[0] = now.tv_sec; + /* need to check user space to see if this breaks in y2038 or y2106 */ + ktime_get_real_ts64(&now); + words[0] = (u32)now.tv_sec; words[1] = now.tv_nsec; local_irq_save(flags); @@ -189,6 +190,7 @@ static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), BLK_TC_ACT(BLK_TC_WRITE) }; #define BLK_TC_RAHEAD BLK_TC_AHEAD +#define BLK_TC_PREFLUSH BLK_TC_FLUSH /* The ilog2() calls fall out because they're constant */ #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \ @@ -199,7 +201,8 @@ static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), * blk_io_trace structure and places it in a per-cpu subbuffer. */ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, - int rw, u32 what, int error, int pdu_len, void *pdu_data) + int op, int op_flags, u32 what, int error, int pdu_len, + void *pdu_data) { struct task_struct *tsk = current; struct ring_buffer_event *event = NULL; @@ -214,13 +217,16 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) return; - what |= ddir_act[rw & WRITE]; - what |= MASK_TC_BIT(rw, SYNC); - what |= MASK_TC_BIT(rw, RAHEAD); - what |= MASK_TC_BIT(rw, META); - what |= MASK_TC_BIT(rw, DISCARD); - what |= MASK_TC_BIT(rw, FLUSH); - what |= MASK_TC_BIT(rw, FUA); + what |= ddir_act[op_is_write(op) ? WRITE : READ]; + what |= MASK_TC_BIT(op_flags, SYNC); + what |= MASK_TC_BIT(op_flags, RAHEAD); + what |= MASK_TC_BIT(op_flags, META); + what |= MASK_TC_BIT(op_flags, PREFLUSH); + what |= MASK_TC_BIT(op_flags, FUA); + if (op == REQ_OP_DISCARD) + what |= BLK_TC_ACT(BLK_TC_DISCARD); + if (op == REQ_OP_FLUSH) + what |= BLK_TC_ACT(BLK_TC_FLUSH); pid = tsk->pid; if (act_log_check(bt, what, sector, pid)) @@ -708,11 +714,11 @@ static void blk_add_trace_rq(struct request_queue *q, struct request *rq, if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { what |= BLK_TC_ACT(BLK_TC_PC); - __blk_add_trace(bt, 0, nr_bytes, rq->cmd_flags, + __blk_add_trace(bt, 0, nr_bytes, req_op(rq), rq->cmd_flags, what, rq->errors, rq->cmd_len, rq->cmd); } else { what |= BLK_TC_ACT(BLK_TC_FS); - __blk_add_trace(bt, blk_rq_pos(rq), nr_bytes, + __blk_add_trace(bt, blk_rq_pos(rq), nr_bytes, req_op(rq), rq->cmd_flags, what, rq->errors, 0, NULL); } } @@ -770,7 +776,7 @@ static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, return; __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, - bio->bi_rw, what, error, 0, NULL); + bio_op(bio), bio->bi_rw, what, error, 0, NULL); } static void blk_add_trace_bio_bounce(void *ignore, @@ -818,7 +824,8 @@ static void blk_add_trace_getrq(void *ignore, struct blk_trace *bt = q->blk_trace; if (bt) - __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL); + __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0, + NULL); } } @@ -833,7 +840,7 @@ static void blk_add_trace_sleeprq(void *ignore, struct blk_trace *bt = q->blk_trace; if (bt) - __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, + __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ, 0, 0, NULL); } } @@ -843,7 +850,7 @@ static void blk_add_trace_plug(void *ignore, struct request_queue *q) struct blk_trace *bt = q->blk_trace; if (bt) - __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); + __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); } static void blk_add_trace_unplug(void *ignore, struct request_queue *q, @@ -860,7 +867,7 @@ static void blk_add_trace_unplug(void *ignore, struct request_queue *q, else what = BLK_TA_UNPLUG_TIMER; - __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu); + __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu); } } @@ -874,8 +881,9 @@ static void blk_add_trace_split(void *ignore, __be64 rpdu = cpu_to_be64(pdu); __blk_add_trace(bt, bio->bi_iter.bi_sector, - bio->bi_iter.bi_size, bio->bi_rw, BLK_TA_SPLIT, - bio->bi_error, sizeof(rpdu), &rpdu); + bio->bi_iter.bi_size, bio_op(bio), bio->bi_rw, + BLK_TA_SPLIT, bio->bi_error, sizeof(rpdu), + &rpdu); } } @@ -907,7 +915,7 @@ static void blk_add_trace_bio_remap(void *ignore, r.sector_from = cpu_to_be64(from); __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, - bio->bi_rw, BLK_TA_REMAP, bio->bi_error, + bio_op(bio), bio->bi_rw, BLK_TA_REMAP, bio->bi_error, sizeof(r), &r); } @@ -940,7 +948,7 @@ static void blk_add_trace_rq_remap(void *ignore, r.sector_from = cpu_to_be64(from); __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), - rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors, + rq_data_dir(rq), 0, BLK_TA_REMAP, !!rq->errors, sizeof(r), &r); } @@ -965,10 +973,10 @@ void blk_add_driver_data(struct request_queue *q, return; if (rq->cmd_type == REQ_TYPE_BLOCK_PC) - __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, + __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 0, BLK_TA_DRV_DATA, rq->errors, len, data); else - __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, + __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 0, BLK_TA_DRV_DATA, rq->errors, len, data); } EXPORT_SYMBOL_GPL(blk_add_driver_data); @@ -1769,21 +1777,34 @@ void blk_dump_cmd(char *buf, struct request *rq) } } -void blk_fill_rwbs(char *rwbs, u32 rw, int bytes) +void blk_fill_rwbs(char *rwbs, int op, u32 rw, int bytes) { int i = 0; - if (rw & REQ_FLUSH) + if (rw & REQ_PREFLUSH) rwbs[i++] = 'F'; - if (rw & WRITE) + switch (op) { + case REQ_OP_WRITE: + case REQ_OP_WRITE_SAME: rwbs[i++] = 'W'; - else if (rw & REQ_DISCARD) + break; + case REQ_OP_DISCARD: + rwbs[i++] = 'D'; + break; + case REQ_OP_SECURE_ERASE: rwbs[i++] = 'D'; - else if (bytes) + rwbs[i++] = 'E'; + break; + case REQ_OP_FLUSH: + rwbs[i++] = 'F'; + break; + case REQ_OP_READ: rwbs[i++] = 'R'; - else + break; + default: rwbs[i++] = 'N'; + } if (rw & REQ_FUA) rwbs[i++] = 'F'; @@ -1793,8 +1814,6 @@ void blk_fill_rwbs(char *rwbs, u32 rw, int bytes) rwbs[i++] = 'S'; if (rw & REQ_META) rwbs[i++] = 'M'; - if (rw & REQ_SECURE) - rwbs[i++] = 'E'; rwbs[i] = '\0'; } |