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| author | Marco Elver <elver@google.com> | 2021-05-04 18:40:24 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-06-10 13:41:45 +0200 |
| commit | 18071d618c1a09e751af193b0888cc4753ec47e3 (patch) | |
| tree | 958494c34c507ddc1296db44779fd6e1d734e216 /mm | |
| parent | 08ec01b5318a65abdef9f5ab88ceb0f4fc0b19e2 (diff) | |
| download | linux-18071d618c1a09e751af193b0888cc4753ec47e3.tar.gz linux-18071d618c1a09e751af193b0888cc4753ec47e3.tar.bz2 linux-18071d618c1a09e751af193b0888cc4753ec47e3.zip | |
kfence: maximize allocation wait timeout duration
commit 37c9284f6932b915043717703d6496dfd59c85f5 upstream.
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:
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/20210421105132.3965998-3-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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/kfence/core.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/mm/kfence/core.c b/mm/kfence/core.c index f0be2c5038b5..bedc0910f0da 100644 --- a/mm/kfence/core.c +++ b/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> @@ -620,7 +621,16 @@ static void toggle_allocation_gate(struct work_struct *work) /* Enable static key, and await allocation to happen. */ static_branch_enable(&kfence_allocation_key); - 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)); + } /* Disable static key and reset timer. */ static_branch_disable(&kfence_allocation_key); |