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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-09 10:52:16 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-09 10:52:16 -0700 |
commit | 4fde846ac0f019b7c877da35e1c1517d79e17ffc (patch) | |
tree | ee94559d13406f2ba29819fd3d0e6c4cc85ac174 | |
parent | c3931a87db9e840dc20f3b962668d477eaeb2f75 (diff) | |
parent | 242fc35290bd8cf0effc6e3474e3a417985de2f3 (diff) | |
download | linux-4fde846ac0f019b7c877da35e1c1517d79e17ffc.tar.bz2 |
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Thomas Gleixner:
"This scheduler update provides:
- The (hopefully) final fix for the vtime accounting issues which
were around for quite some time
- Use types known to user space in UAPI headers to unbreak user space
builds
- Make load balancing respect the current scheduling domain again
instead of evaluating unrelated CPUs"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/headers/uapi: Fix linux/sched/types.h userspace compilation errors
sched/fair: Fix load_balance() affinity redo path
sched/cputime: Accumulate vtime on top of nsec clocksource
sched/cputime: Move the vtime task fields to their own struct
sched/cputime: Rename vtime fields
sched/cputime: Always set tsk->vtime_snap_whence after accounting vtime
vtime, sched/cputime: Remove vtime_account_user()
Revert "sched/cputime: Refactor the cputime_adjust() code"
-rw-r--r-- | include/linux/init_task.h | 6 | ||||
-rw-r--r-- | include/linux/sched.h | 29 | ||||
-rw-r--r-- | include/linux/vtime.h | 9 | ||||
-rw-r--r-- | include/uapi/linux/sched/types.h | 16 | ||||
-rw-r--r-- | kernel/fork.c | 6 | ||||
-rw-r--r-- | kernel/sched/cputime.c | 180 | ||||
-rw-r--r-- | kernel/sched/fair.c | 32 |
7 files changed, 165 insertions, 113 deletions
diff --git a/include/linux/init_task.h b/include/linux/init_task.h index e049526bc188..a2f6707e9fc0 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -170,9 +170,9 @@ extern struct cred init_cred; #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN # define INIT_VTIME(tsk) \ - .vtime_seqcount = SEQCNT_ZERO(tsk.vtime_seqcount), \ - .vtime_snap = 0, \ - .vtime_snap_whence = VTIME_SYS, + .vtime.seqcount = SEQCNT_ZERO(tsk.vtime.seqcount), \ + .vtime.starttime = 0, \ + .vtime.state = VTIME_SYS, #else # define INIT_VTIME(tsk) #endif diff --git a/include/linux/sched.h b/include/linux/sched.h index 5e8759b1b428..20814b7d7d70 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -223,6 +223,24 @@ struct task_cputime { #define prof_exp stime #define sched_exp sum_exec_runtime +enum vtime_state { + /* Task is sleeping or running in a CPU with VTIME inactive: */ + VTIME_INACTIVE = 0, + /* Task runs in userspace in a CPU with VTIME active: */ + VTIME_USER, + /* Task runs in kernelspace in a CPU with VTIME active: */ + VTIME_SYS, +}; + +struct vtime { + seqcount_t seqcount; + unsigned long long starttime; + enum vtime_state state; + u64 utime; + u64 stime; + u64 gtime; +}; + struct sched_info { #ifdef CONFIG_SCHED_INFO /* Cumulative counters: */ @@ -688,16 +706,7 @@ struct task_struct { u64 gtime; struct prev_cputime prev_cputime; #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN - seqcount_t vtime_seqcount; - unsigned long long vtime_snap; - enum { - /* Task is sleeping or running in a CPU with VTIME inactive: */ - VTIME_INACTIVE = 0, - /* Task runs in userspace in a CPU with VTIME active: */ - VTIME_USER, - /* Task runs in kernelspace in a CPU with VTIME active: */ - VTIME_SYS, - } vtime_snap_whence; + struct vtime vtime; #endif #ifdef CONFIG_NO_HZ_FULL diff --git a/include/linux/vtime.h b/include/linux/vtime.h index 0681fe25abeb..18b405e3cd93 100644 --- a/include/linux/vtime.h +++ b/include/linux/vtime.h @@ -67,19 +67,12 @@ static inline void vtime_account_system(struct task_struct *tsk) { } #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN extern void arch_vtime_task_switch(struct task_struct *tsk); -extern void vtime_account_user(struct task_struct *tsk); extern void vtime_user_enter(struct task_struct *tsk); - -static inline void vtime_user_exit(struct task_struct *tsk) -{ - vtime_account_user(tsk); -} - +extern void vtime_user_exit(struct task_struct *tsk); extern void vtime_guest_enter(struct task_struct *tsk); extern void vtime_guest_exit(struct task_struct *tsk); extern void vtime_init_idle(struct task_struct *tsk, int cpu); #else /* !CONFIG_VIRT_CPU_ACCOUNTING_GEN */ -static inline void vtime_account_user(struct task_struct *tsk) { } static inline void vtime_user_enter(struct task_struct *tsk) { } static inline void vtime_user_exit(struct task_struct *tsk) { } static inline void vtime_guest_enter(struct task_struct *tsk) { } diff --git a/include/uapi/linux/sched/types.h b/include/uapi/linux/sched/types.h index 307acbc82d80..34b81aa1a2f7 100644 --- a/include/uapi/linux/sched/types.h +++ b/include/uapi/linux/sched/types.h @@ -54,21 +54,21 @@ struct sched_param { * available in the scheduling class file or in Documentation/. */ struct sched_attr { - u32 size; + __u32 size; - u32 sched_policy; - u64 sched_flags; + __u32 sched_policy; + __u64 sched_flags; /* SCHED_NORMAL, SCHED_BATCH */ - s32 sched_nice; + __s32 sched_nice; /* SCHED_FIFO, SCHED_RR */ - u32 sched_priority; + __u32 sched_priority; /* SCHED_DEADLINE */ - u64 sched_runtime; - u64 sched_deadline; - u64 sched_period; + __u64 sched_runtime; + __u64 sched_deadline; + __u64 sched_period; }; #endif /* _UAPI_LINUX_SCHED_TYPES_H */ diff --git a/kernel/fork.c b/kernel/fork.c index aa01b810c0bd..0f69a3e5281e 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1637,9 +1637,9 @@ static __latent_entropy struct task_struct *copy_process( prev_cputime_init(&p->prev_cputime); #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN - seqcount_init(&p->vtime_seqcount); - p->vtime_snap = 0; - p->vtime_snap_whence = VTIME_INACTIVE; + seqcount_init(&p->vtime.seqcount); + p->vtime.starttime = 0; + p->vtime.state = VTIME_INACTIVE; #endif #if defined(SPLIT_RSS_COUNTING) diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index 67c70e287647..6e3ea4ac1bda 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -611,17 +611,23 @@ static void cputime_adjust(struct task_cputime *curr, utime = curr->utime; /* - * If either stime or both stime and utime are 0, assume all runtime is - * userspace. Once a task gets some ticks, the monotonicy code at - * 'update' will ensure things converge to the observed ratio. + * If either stime or utime are 0, assume all runtime is userspace. + * Once a task gets some ticks, the monotonicy code at 'update:' + * will ensure things converge to the observed ratio. */ - if (stime != 0) { - if (utime == 0) - stime = rtime; - else - stime = scale_stime(stime, rtime, stime + utime); + if (stime == 0) { + utime = rtime; + goto update; } + if (utime == 0) { + stime = rtime; + goto update; + } + + stime = scale_stime(stime, rtime, stime + utime); + +update: /* * Make sure stime doesn't go backwards; this preserves monotonicity * for utime because rtime is monotonic. @@ -673,20 +679,21 @@ void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st) #endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN -static u64 vtime_delta(struct task_struct *tsk) +static u64 vtime_delta(struct vtime *vtime) { - unsigned long now = READ_ONCE(jiffies); + unsigned long long clock; - if (time_before(now, (unsigned long)tsk->vtime_snap)) + clock = sched_clock_cpu(smp_processor_id()); + if (clock < vtime->starttime) return 0; - return jiffies_to_nsecs(now - tsk->vtime_snap); + return clock - vtime->starttime; } -static u64 get_vtime_delta(struct task_struct *tsk) +static u64 get_vtime_delta(struct vtime *vtime) { - unsigned long now = READ_ONCE(jiffies); - u64 delta, other; + u64 delta = vtime_delta(vtime); + u64 other; /* * Unlike tick based timing, vtime based timing never has lost @@ -695,104 +702,138 @@ static u64 get_vtime_delta(struct task_struct *tsk) * elapsed time. Limit account_other_time to prevent rounding * errors from causing elapsed vtime to go negative. */ - delta = jiffies_to_nsecs(now - tsk->vtime_snap); other = account_other_time(delta); - WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_INACTIVE); - tsk->vtime_snap = now; + WARN_ON_ONCE(vtime->state == VTIME_INACTIVE); + vtime->starttime += delta; return delta - other; } -static void __vtime_account_system(struct task_struct *tsk) +static void __vtime_account_system(struct task_struct *tsk, + struct vtime *vtime) +{ + vtime->stime += get_vtime_delta(vtime); + if (vtime->stime >= TICK_NSEC) { + account_system_time(tsk, irq_count(), vtime->stime); + vtime->stime = 0; + } +} + +static void vtime_account_guest(struct task_struct *tsk, + struct vtime *vtime) { - account_system_time(tsk, irq_count(), get_vtime_delta(tsk)); + vtime->gtime += get_vtime_delta(vtime); + if (vtime->gtime >= TICK_NSEC) { + account_guest_time(tsk, vtime->gtime); + vtime->gtime = 0; + } } void vtime_account_system(struct task_struct *tsk) { - if (!vtime_delta(tsk)) + struct vtime *vtime = &tsk->vtime; + + if (!vtime_delta(vtime)) return; - write_seqcount_begin(&tsk->vtime_seqcount); - __vtime_account_system(tsk); - write_seqcount_end(&tsk->vtime_seqcount); + write_seqcount_begin(&vtime->seqcount); + /* We might have scheduled out from guest path */ + if (current->flags & PF_VCPU) + vtime_account_guest(tsk, vtime); + else + __vtime_account_system(tsk, vtime); + write_seqcount_end(&vtime->seqcount); } -void vtime_account_user(struct task_struct *tsk) +void vtime_user_enter(struct task_struct *tsk) { - write_seqcount_begin(&tsk->vtime_seqcount); - tsk->vtime_snap_whence = VTIME_SYS; - if (vtime_delta(tsk)) - account_user_time(tsk, get_vtime_delta(tsk)); - write_seqcount_end(&tsk->vtime_seqcount); + struct vtime *vtime = &tsk->vtime; + + write_seqcount_begin(&vtime->seqcount); + __vtime_account_system(tsk, vtime); + vtime->state = VTIME_USER; + write_seqcount_end(&vtime->seqcount); } -void vtime_user_enter(struct task_struct *tsk) +void vtime_user_exit(struct task_struct *tsk) { - write_seqcount_begin(&tsk->vtime_seqcount); - if (vtime_delta(tsk)) - __vtime_account_system(tsk); - tsk->vtime_snap_whence = VTIME_USER; - write_seqcount_end(&tsk->vtime_seqcount); + struct vtime *vtime = &tsk->vtime; + + write_seqcount_begin(&vtime->seqcount); + vtime->utime += get_vtime_delta(vtime); + if (vtime->utime >= TICK_NSEC) { + account_user_time(tsk, vtime->utime); + vtime->utime = 0; + } + vtime->state = VTIME_SYS; + write_seqcount_end(&vtime->seqcount); } void vtime_guest_enter(struct task_struct *tsk) { + struct vtime *vtime = &tsk->vtime; /* * The flags must be updated under the lock with - * the vtime_snap flush and update. + * the vtime_starttime flush and update. * That enforces a right ordering and update sequence * synchronization against the reader (task_gtime()) * that can thus safely catch up with a tickless delta. */ - write_seqcount_begin(&tsk->vtime_seqcount); - if (vtime_delta(tsk)) - __vtime_account_system(tsk); + write_seqcount_begin(&vtime->seqcount); + __vtime_account_system(tsk, vtime); current->flags |= PF_VCPU; - write_seqcount_end(&tsk->vtime_seqcount); + write_seqcount_end(&vtime->seqcount); } EXPORT_SYMBOL_GPL(vtime_guest_enter); void vtime_guest_exit(struct task_struct *tsk) { - write_seqcount_begin(&tsk->vtime_seqcount); - __vtime_account_system(tsk); + struct vtime *vtime = &tsk->vtime; + + write_seqcount_begin(&vtime->seqcount); + vtime_account_guest(tsk, vtime); current->flags &= ~PF_VCPU; - write_seqcount_end(&tsk->vtime_seqcount); + write_seqcount_end(&vtime->seqcount); } EXPORT_SYMBOL_GPL(vtime_guest_exit); void vtime_account_idle(struct task_struct *tsk) { - account_idle_time(get_vtime_delta(tsk)); + account_idle_time(get_vtime_delta(&tsk->vtime)); } void arch_vtime_task_switch(struct task_struct *prev) { - write_seqcount_begin(&prev->vtime_seqcount); - prev->vtime_snap_whence = VTIME_INACTIVE; - write_seqcount_end(&prev->vtime_seqcount); + struct vtime *vtime = &prev->vtime; + + write_seqcount_begin(&vtime->seqcount); + vtime->state = VTIME_INACTIVE; + write_seqcount_end(&vtime->seqcount); + + vtime = ¤t->vtime; - write_seqcount_begin(¤t->vtime_seqcount); - current->vtime_snap_whence = VTIME_SYS; - current->vtime_snap = jiffies; - write_seqcount_end(¤t->vtime_seqcount); + write_seqcount_begin(&vtime->seqcount); + vtime->state = VTIME_SYS; + vtime->starttime = sched_clock_cpu(smp_processor_id()); + write_seqcount_end(&vtime->seqcount); } void vtime_init_idle(struct task_struct *t, int cpu) { + struct vtime *vtime = &t->vtime; unsigned long flags; local_irq_save(flags); - write_seqcount_begin(&t->vtime_seqcount); - t->vtime_snap_whence = VTIME_SYS; - t->vtime_snap = jiffies; - write_seqcount_end(&t->vtime_seqcount); + write_seqcount_begin(&vtime->seqcount); + vtime->state = VTIME_SYS; + vtime->starttime = sched_clock_cpu(cpu); + write_seqcount_end(&vtime->seqcount); local_irq_restore(flags); } u64 task_gtime(struct task_struct *t) { + struct vtime *vtime = &t->vtime; unsigned int seq; u64 gtime; @@ -800,13 +841,13 @@ u64 task_gtime(struct task_struct *t) return t->gtime; do { - seq = read_seqcount_begin(&t->vtime_seqcount); + seq = read_seqcount_begin(&vtime->seqcount); gtime = t->gtime; - if (t->vtime_snap_whence == VTIME_SYS && t->flags & PF_VCPU) - gtime += vtime_delta(t); + if (vtime->state == VTIME_SYS && t->flags & PF_VCPU) + gtime += vtime->gtime + vtime_delta(vtime); - } while (read_seqcount_retry(&t->vtime_seqcount, seq)); + } while (read_seqcount_retry(&vtime->seqcount, seq)); return gtime; } @@ -818,8 +859,9 @@ u64 task_gtime(struct task_struct *t) */ void task_cputime(struct task_struct *t, u64 *utime, u64 *stime) { - u64 delta; + struct vtime *vtime = &t->vtime; unsigned int seq; + u64 delta; if (!vtime_accounting_enabled()) { *utime = t->utime; @@ -828,25 +870,25 @@ void task_cputime(struct task_struct *t, u64 *utime, u64 *stime) } do { - seq = read_seqcount_begin(&t->vtime_seqcount); + seq = read_seqcount_begin(&vtime->seqcount); *utime = t->utime; *stime = t->stime; /* Task is sleeping, nothing to add */ - if (t->vtime_snap_whence == VTIME_INACTIVE || is_idle_task(t)) + if (vtime->state == VTIME_INACTIVE || is_idle_task(t)) continue; - delta = vtime_delta(t); + delta = vtime_delta(vtime); /* * Task runs either in user or kernel space, add pending nohz time to * the right place. */ - if (t->vtime_snap_whence == VTIME_USER || t->flags & PF_VCPU) - *utime += delta; - else if (t->vtime_snap_whence == VTIME_SYS) - *stime += delta; - } while (read_seqcount_retry(&t->vtime_seqcount, seq)); + if (vtime->state == VTIME_USER || t->flags & PF_VCPU) + *utime += vtime->utime + delta; + else if (vtime->state == VTIME_SYS) + *stime += vtime->stime + delta; + } while (read_seqcount_retry(&vtime->seqcount, seq)); } #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 008c514dc241..c95880e216f6 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6646,10 +6646,10 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env) * our sched_group. We may want to revisit it if we couldn't * meet load balance goals by pulling other tasks on src_cpu. * - * Also avoid computing new_dst_cpu if we have already computed - * one in current iteration. + * Avoid computing new_dst_cpu for NEWLY_IDLE or if we have + * already computed one in current iteration. */ - if (!env->dst_grpmask || (env->flags & LBF_DST_PINNED)) + if (env->idle == CPU_NEWLY_IDLE || (env->flags & LBF_DST_PINNED)) return 0; /* Prevent to re-select dst_cpu via env's cpus */ @@ -8022,14 +8022,7 @@ static int load_balance(int this_cpu, struct rq *this_rq, .tasks = LIST_HEAD_INIT(env.tasks), }; - /* - * For NEWLY_IDLE load_balancing, we don't need to consider - * other cpus in our group - */ - if (idle == CPU_NEWLY_IDLE) - env.dst_grpmask = NULL; - - cpumask_copy(cpus, cpu_active_mask); + cpumask_and(cpus, sched_domain_span(sd), cpu_active_mask); schedstat_inc(sd->lb_count[idle]); @@ -8151,7 +8144,15 @@ more_balance: /* All tasks on this runqueue were pinned by CPU affinity */ if (unlikely(env.flags & LBF_ALL_PINNED)) { cpumask_clear_cpu(cpu_of(busiest), cpus); - if (!cpumask_empty(cpus)) { + /* + * Attempting to continue load balancing at the current + * sched_domain level only makes sense if there are + * active CPUs remaining as possible busiest CPUs to + * pull load from which are not contained within the + * destination group that is receiving any migrated + * load. + */ + if (!cpumask_subset(cpus, env.dst_grpmask)) { env.loop = 0; env.loop_break = sched_nr_migrate_break; goto redo; @@ -8447,6 +8448,13 @@ static int active_load_balance_cpu_stop(void *data) .src_cpu = busiest_rq->cpu, .src_rq = busiest_rq, .idle = CPU_IDLE, + /* + * can_migrate_task() doesn't need to compute new_dst_cpu + * for active balancing. Since we have CPU_IDLE, but no + * @dst_grpmask we need to make that test go away with lying + * about DST_PINNED. + */ + .flags = LBF_DST_PINNED, }; schedstat_inc(sd->alb_count); |