The patch titled
wait_task_inactive: "improve" the returned value for ->nvcsw == 0
has been added to the -mm tree. Its filename is
wait_task_inactive-improve-the-returned-value-for-nvcsw-==-0.patch
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------------------------------------------------------
Subject: wait_task_inactive: "improve" the returned value for ->nvcsw == 0
From: Oleg Nesterov <oleg@xxxxxxxxxx>
wait_task_inactive() returns 1 when p->nvcsw == 0 || p->nvcsw == 1. This
means that two subsequent calls can return the same number while the task
was scheduled in between.
Change the code to return "nvcsw | LONG_MIN" instead of "nvcsw ?: 1", now
the overlap always needs LONG_MAX schedules.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Acked-by: Roland McGrath <roland@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/sched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN kernel/sched.c~wait_task_inactive-improve-the-returned-value-for-nvcsw-==-0 kernel/sched.c
--- a/kernel/sched.c~wait_task_inactive-improve-the-returned-value-for-nvcsw-==-0
+++ a/kernel/sched.c
@@ -1923,7 +1923,7 @@ unsigned long wait_task_inactive(struct
on_rq = p->se.on_rq;
ncsw = 0;
if (!match_state || p->state == match_state)
- ncsw = p->nvcsw ?: 1;
+ ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
task_rq_unlock(rq, &flags);
/*
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
semaphore-__down_common-use-signal_pending_state.patch
proc-fix-warnings.patch
linux-next.patch
migrate_timers-add-comment-use-spinlock_irq.patch
sched-do_wait_for_common-use-signal_pending_state.patch
wait_task_inactive-dont-consider-task-nivcsw.patch
wait_task_inactive-improve-the-returned-value-for-nvcsw-==-0.patch
posix-timers-fix-posix_timer_event-vs-dequeue_signal-race.patch
posix-timers-do_schedule_next_timer-fix-the-setting-of-si_overrun.patch
posix-timers-dont-switch-to-group_leader-if-it_process-dies.patch
posix-timers-always-do-get_task_structtimer-it_process.patch
posix-timers-sys_timer_create-remove-the-buggy-pf_exiting-check.patch
posix-timers-sys_timer_create-simplify-and-s-tasklist-rcu.patch
posix-timers-move-the-initialization-of-timer-sigq-from-send-to-create-path.patch
posix-timers-sys_timer_create-cleanup-the-error-handling.patch
posix-timers-kill-it_sigev_signo-and-it_sigev_value.patch
posix-timers-lock_timer-kill-the-bogus-it_id-check.patch
posix-timers-lock_timer-make-it-readable.patch
coredump-format_corename-dont-append-%pid-if-multi-threaded.patch
kthread_bind-use-wait_task_inactivetask_uninterruptible.patch
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