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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-25 17:11:43 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-25 17:11:43 -0700 |
| commit | f89eae4ee7e075e576bd4b4d2db901023421a3be (patch) | |
| tree | 8dbd69cdc48c15f6b623e882b31092b7c451803f | |
| parent | bdc6b758e443c21c39a14c075e5b7e01f095b37b (diff) | |
| parent | b7e7ade34e6188bee2e3b0d42b51d25137d9e2a5 (diff) | |
| download | lwn-f89eae4ee7e075e576bd4b4d2db901023421a3be.tar.gz lwn-f89eae4ee7e075e576bd4b4d2db901023421a3be.zip | |
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"Two fixes: one for a lost wakeup, the other to fix the compiler
optimizing out preempt operations on ARM64 (and possibly other non-x86
architectures)"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/core: Fix remote wakeups
sched/preempt: Fix preempt_count manipulations
| -rw-r--r-- | include/asm-generic/preempt.h | 4 | ||||
| -rw-r--r-- | include/linux/sched.h | 1 | ||||
| -rw-r--r-- | kernel/sched/core.c | 18 |
3 files changed, 14 insertions, 9 deletions
diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h index 5d8ffa3e6f8c..c1cde3577551 100644 --- a/include/asm-generic/preempt.h +++ b/include/asm-generic/preempt.h @@ -7,10 +7,10 @@ static __always_inline int preempt_count(void) { - return current_thread_info()->preempt_count; + return READ_ONCE(current_thread_info()->preempt_count); } -static __always_inline int *preempt_count_ptr(void) +static __always_inline volatile int *preempt_count_ptr(void) { return ¤t_thread_info()->preempt_count; } diff --git a/include/linux/sched.h b/include/linux/sched.h index 21c26e78aec5..23e075dcdfe4 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1539,6 +1539,7 @@ struct task_struct { unsigned sched_reset_on_fork:1; unsigned sched_contributes_to_load:1; unsigned sched_migrated:1; + unsigned sched_remote_wakeup:1; unsigned :0; /* force alignment to the next boundary */ /* unserialized, strictly 'current' */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 404c0784b1fc..7f2cae4620c7 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1768,13 +1768,15 @@ void sched_ttwu_pending(void) cookie = lockdep_pin_lock(&rq->lock); while (llist) { + int wake_flags = 0; + p = llist_entry(llist, struct task_struct, wake_entry); llist = llist_next(llist); - /* - * See ttwu_queue(); we only call ttwu_queue_remote() when - * its a x-cpu wakeup. - */ - ttwu_do_activate(rq, p, WF_MIGRATED, cookie); + + if (p->sched_remote_wakeup) + wake_flags = WF_MIGRATED; + + ttwu_do_activate(rq, p, wake_flags, cookie); } lockdep_unpin_lock(&rq->lock, cookie); @@ -1819,10 +1821,12 @@ void scheduler_ipi(void) irq_exit(); } -static void ttwu_queue_remote(struct task_struct *p, int cpu) +static void ttwu_queue_remote(struct task_struct *p, int cpu, int wake_flags) { struct rq *rq = cpu_rq(cpu); + p->sched_remote_wakeup = !!(wake_flags & WF_MIGRATED); + if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) { if (!set_nr_if_polling(rq->idle)) smp_send_reschedule(cpu); @@ -1869,7 +1873,7 @@ static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags) #if defined(CONFIG_SMP) if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { sched_clock_cpu(cpu); /* sync clocks x-cpu */ - ttwu_queue_remote(p, cpu); + ttwu_queue_remote(p, cpu, wake_flags); return; } #endif |