diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cpu.c | 15 | ||||
| -rw-r--r-- | kernel/ptrace.c | 10 | ||||
| -rw-r--r-- | kernel/sched/core.c | 19 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 4 |
4 files changed, 21 insertions, 27 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 3c7f3b4c453c..91d5c38eb7e5 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -10,6 +10,7 @@ #include <linux/sched/signal.h> #include <linux/sched/hotplug.h> #include <linux/sched/task.h> +#include <linux/sched/smt.h> #include <linux/unistd.h> #include <linux/cpu.h> #include <linux/oom.h> @@ -367,6 +368,12 @@ static void lockdep_release_cpus_lock(void) #endif /* CONFIG_HOTPLUG_CPU */ +/* + * Architectures that need SMT-specific errata handling during SMT hotplug + * should override this. + */ +void __weak arch_smt_update(void) { } + #ifdef CONFIG_HOTPLUG_SMT enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; EXPORT_SYMBOL_GPL(cpu_smt_control); @@ -1011,6 +1018,7 @@ out: * concurrent CPU hotplug via cpu_add_remove_lock. */ lockup_detector_cleanup(); + arch_smt_update(); return ret; } @@ -1139,6 +1147,7 @@ static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) ret = cpuhp_up_callbacks(cpu, st, target); out: cpus_write_unlock(); + arch_smt_update(); return ret; } @@ -2055,12 +2064,6 @@ static void cpuhp_online_cpu_device(unsigned int cpu) kobject_uevent(&dev->kobj, KOBJ_ONLINE); } -/* - * Architectures that need SMT-specific errata handling during SMT hotplug - * should override this. - */ -void __weak arch_smt_update(void) { }; - static int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) { int cpu, ret = 0; diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 80b34dffdfb9..c2cee9db5204 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -261,9 +261,6 @@ static int ptrace_check_attach(struct task_struct *child, bool ignore_state) static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode) { - if (mode & PTRACE_MODE_SCHED) - return false; - if (mode & PTRACE_MODE_NOAUDIT) return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE); else @@ -331,16 +328,9 @@ ok: !ptrace_has_cap(mm->user_ns, mode))) return -EPERM; - if (mode & PTRACE_MODE_SCHED) - return 0; return security_ptrace_access_check(task, mode); } -bool ptrace_may_access_sched(struct task_struct *task, unsigned int mode) -{ - return __ptrace_may_access(task, mode | PTRACE_MODE_SCHED); -} - bool ptrace_may_access(struct task_struct *task, unsigned int mode) { int err; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 091e089063be..6fedf3a98581 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5738,15 +5738,10 @@ int sched_cpu_activate(unsigned int cpu) #ifdef CONFIG_SCHED_SMT /* - * The sched_smt_present static key needs to be evaluated on every - * hotplug event because at boot time SMT might be disabled when - * the number of booted CPUs is limited. - * - * If then later a sibling gets hotplugged, then the key would stay - * off and SMT scheduling would never be functional. + * When going up, increment the number of cores with SMT present. */ - if (cpumask_weight(cpu_smt_mask(cpu)) > 1) - static_branch_enable_cpuslocked(&sched_smt_present); + if (cpumask_weight(cpu_smt_mask(cpu)) == 2) + static_branch_inc_cpuslocked(&sched_smt_present); #endif set_cpu_active(cpu, true); @@ -5790,6 +5785,14 @@ int sched_cpu_deactivate(unsigned int cpu) */ synchronize_rcu_mult(call_rcu, call_rcu_sched); +#ifdef CONFIG_SCHED_SMT + /* + * When going down, decrement the number of cores with SMT present. + */ + if (cpumask_weight(cpu_smt_mask(cpu)) == 2) + static_branch_dec_cpuslocked(&sched_smt_present); +#endif + if (!sched_smp_initialized) return 0; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 618577fc9aa8..4e524ab589c9 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -23,6 +23,7 @@ #include <linux/sched/prio.h> #include <linux/sched/rt.h> #include <linux/sched/signal.h> +#include <linux/sched/smt.h> #include <linux/sched/stat.h> #include <linux/sched/sysctl.h> #include <linux/sched/task.h> @@ -936,9 +937,6 @@ static inline int cpu_of(struct rq *rq) #ifdef CONFIG_SCHED_SMT - -extern struct static_key_false sched_smt_present; - extern void __update_idle_core(struct rq *rq); static inline void update_idle_core(struct rq *rq) |