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kfence: use TASK_IDLE when awaiting allocation

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Since wait_event() uses TASK_UNINTERRUPTIBLE by default, waiting for an
allocation counts towards load.  However, for KFENCE, this does not make
any sense, since there is no busy work we're awaiting.

Instead, use TASK_IDLE via wait_event_idle() to not count towards load.

BugLink: https://bugzilla.suse.com/show_bug.cgi?id=1185565
Link: https://lkml.kernel.org/r/20210521083209.3740269-1-elver@google.com
Fixes: 407f1d8c1b5f ("kfence: await for allocation using wait_event")
Signed-off-by: Marco Elver <elver@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Hillf Danton <hdanton@sina.com>
Cc: <stable@vger.kernel.org>	[5.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Marco Elver 2021-06-04 20:01:11 -07:00 committed by Linus Torvalds
parent 50c25ee97c
commit 8fd0e995cc
1 changed files with 3 additions and 3 deletions
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6
mm/kfence/core.c
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@ -627,10 +627,10 @@ static void toggle_allocation_gate(struct work_struct *work)
* During low activity with no allocations we might wait a
* while; let's avoid the hung task warning.
*/
wait_event_timeout(allocation_wait, atomic_read(&kfence_allocation_gate),
sysctl_hung_task_timeout_secs * HZ / 2);
wait_event_idle_timeout(allocation_wait, atomic_read(&kfence_allocation_gate),
sysctl_hung_task_timeout_secs * HZ / 2);
} else {
wait_event(allocation_wait, atomic_read(&kfence_allocation_gate));
wait_event_idle(allocation_wait, atomic_read(&kfence_allocation_gate));
}
/* Disable static key and reset timer. */