UPSTREAM: kfence: use TASK_IDLE when awaiting allocation

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>
(cherry picked from commit 8fd0e995cc7b6a7a8a40bc03d52a2cd445beeff4)
Bug: 187129171
Signed-off-by: Connor O'Brien <connoro@google.com>
Change-Id: I837f80e59c11d0322063bac0b2873c25ff528ab6
This commit is contained in:
Marco Elver
2021-06-04 20:01:11 -07:00
committed by Connor O'Brien
parent 1ea718cd9e
commit 71710d40d9

View File

@@ -627,10 +627,10 @@ static void toggle_allocation_gate(struct work_struct *work)
* During low activity with no allocations we might wait a * During low activity with no allocations we might wait a
* while; let's avoid the hung task warning. * while; let's avoid the hung task warning.
*/ */
wait_event_timeout(allocation_wait, atomic_read(&kfence_allocation_gate), wait_event_idle_timeout(allocation_wait, atomic_read(&kfence_allocation_gate),
sysctl_hung_task_timeout_secs * HZ / 2); sysctl_hung_task_timeout_secs * HZ / 2);
} else { } 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. */ /* Disable static key and reset timer. */