The patch titled
Subject: kfence: use TASK_IDLE when awaiting allocation
has been added to the -mm tree. Its filename is
kfence-use-task_idle-when-awaiting-allocation.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kfence-use-task_idle-when-awaiting-allocation.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kfence-use-task_idle-when-awaiting-allocation.patch
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------------------------------------------------------
From: Marco Elver <elver@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx
Fixes: 407f1d8c1b5f ("kfence: await for allocation using wait_event")
Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: David Laight <David.Laight@xxxxxxxxxx>
Cc: Hillf Danton <hdanton@xxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [5.12+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/kfence/core.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/mm/kfence/core.c~kfence-use-task_idle-when-awaiting-allocation
+++ a/mm/kfence/core.c
@@ -627,10 +627,10 @@ static void toggle_allocation_gate(struc
* 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. */
_
Patches currently in -mm which might be from elver@xxxxxxxxxx are
kfence-use-task_idle-when-awaiting-allocation.patch
mm-slub-change-run-time-assertion-in-kmalloc_index-to-compile-time-fix.patch
printk-introduce-dump_stack_lvl-fix.patch
kfence-unconditionally-use-unbound-work-queue.patch
