From: akpm@linux-foundation.org
To: dvyukov@google.com, elver@google.com, glider@google.com,
hdanton@sina.com, jannh@google.com, mark.rutland@arm.com,
mm-commits@vger.kernel.org
Subject: + kfence-maximize-allocation-wait-timeout-duration.patch added to -mm tree
Date: Tue, 20 Apr 2021 19:46:15 -0700 [thread overview]
Message-ID: <20210421024615.a-S0Fzotk%akpm@linux-foundation.org> (raw)
The patch titled
Subject: kfence: maximize allocation wait timeout duration
has been added to the -mm tree. Its filename is
kfence-maximize-allocation-wait-timeout-duration.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kfence-maximize-allocation-wait-timeout-duration.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kfence-maximize-allocation-wait-timeout-duration.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Marco Elver <elver@google.com>
Subject: kfence: maximize allocation wait timeout duration
The allocation wait timeout was initially added because of warnings due to
CONFIG_DETECT_HUNG_TASK=y [1]. While the 1 sec timeout is sufficient to
resolve the warnings (given the hung task timeout must be 1 sec or larger)
it may cause unnecessary wake-ups if the system is idle. [1]
https://lkml.kernel.org/r/CADYN=9J0DQhizAGB0-jz4HOBBh+05kMBXb4c0cXMS7Qi5NAJiw@mail.gmail.com
Fix it by computing the timeout duration in terms of the current
sysctl_hung_task_timeout_secs value.
Link: https://lkml.kernel.org/r/20210419085027.761150-3-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jann Horn <jannh@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/kfence/core.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
--- a/mm/kfence/core.c~kfence-maximize-allocation-wait-timeout-duration
+++ a/mm/kfence/core.c
@@ -20,6 +20,7 @@
#include <linux/moduleparam.h>
#include <linux/random.h>
#include <linux/rcupdate.h>
+#include <linux/sched/sysctl.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
@@ -626,7 +627,16 @@ static void toggle_allocation_gate(struc
WRITE_ONCE(kfence_timer_waiting, true);
smp_mb(); /* See comment in __kfence_alloc(). */
- wait_event_timeout(allocation_wait, atomic_read(&kfence_allocation_gate), HZ);
+ if (sysctl_hung_task_timeout_secs) {
+ /*
+ * 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);
+ } else {
+ wait_event(allocation_wait, atomic_read(&kfence_allocation_gate));
+ }
smp_store_release(&kfence_timer_waiting, false); /* Order after wait_event(). */
/* Disable static key and reset timer. */
_
Patches currently in -mm which might be from elver@google.com are
kfence-zero-guard-page-after-out-of-bounds-access.patch
kfence-await-for-allocation-using-wait_event.patch
kfence-maximize-allocation-wait-timeout-duration.patch
kfence-use-power-efficient-work-queue-to-run-delayed-work.patch
next reply other threads:[~2021-04-21 2:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-21 2:46 akpm [this message]
2021-04-22 4:17 + kfence-maximize-allocation-wait-timeout-duration.patch added to -mm tree akpm
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