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| author | Oleg Nesterov <oleg@tv-sign.ru> | 2008-08-20 16:54:44 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-08-22 15:17:31 +0200 |
| commit | 93dcf55f828b035fc93fc19eb03c1390e1e6d570 (patch) | |
| tree | 8a5b2ee5c5bb664ff856483244cec1f249a129a3 /kernel/sched.c | |
| parent | f31e11d87a5d7601636710195891ba462ad99f11 (diff) | |
| download | lwn-93dcf55f828b035fc93fc19eb03c1390e1e6d570.tar.gz lwn-93dcf55f828b035fc93fc19eb03c1390e1e6d570.zip | |
wait_task_inactive: "improve" the returned value for ->nvcsw == 0
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@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 908670aa215a..6a43c8942b05 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1922,7 +1922,7 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state) 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); /* |