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| author | Vlastimil Babka <vbabka@suse.cz> | 2018-04-13 15:35:38 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-13 17:10:27 -0700 |
| commit | a9f2a846f0503e7d729f552e3ccfe2279010fe94 (patch) | |
| tree | 488d32afd2afdda8666a8f2df04b488ead551cdc /mm/slab.c | |
| parent | 1cbf29da3628b661379acba7b08a07ef1e5da3b5 (diff) | |
| download | lwn-a9f2a846f0503e7d729f552e3ccfe2279010fe94.tar.gz lwn-a9f2a846f0503e7d729f552e3ccfe2279010fe94.zip | |
mm, slab: reschedule cache_reap() on the same CPU
cache_reap() is initially scheduled in start_cpu_timer() via
schedule_delayed_work_on(). But then the next iterations are scheduled
via schedule_delayed_work(), i.e. using WORK_CPU_UNBOUND.
Thus since commit ef557180447f ("workqueue: schedule WORK_CPU_UNBOUND
work on wq_unbound_cpumask CPUs") there is no guarantee the future
iterations will run on the originally intended cpu, although it's still
preferred. I was able to demonstrate this with
/sys/module/workqueue/parameters/debug_force_rr_cpu. IIUC, it may also
happen due to migrating timers in nohz context. As a result, some cpu's
would be calling cache_reap() more frequently and others never.
This patch uses schedule_delayed_work_on() with the current cpu when
scheduling the next iteration.
Link: http://lkml.kernel.org/r/20180411070007.32225-1-vbabka@suse.cz
Fixes: ef557180447f ("workqueue: schedule WORK_CPU_UNBOUND work on wq_unbound_cpumask CPUs")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Pekka Enberg <penberg@kernel.org>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slab.c')
| -rw-r--r-- | mm/slab.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/slab.c b/mm/slab.c index e3a9b8e23306..2f308253c3d7 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -4086,7 +4086,8 @@ next: next_reap_node(); out: /* Set up the next iteration */ - schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_AC)); + schedule_delayed_work_on(smp_processor_id(), work, + round_jiffies_relative(REAPTIMEOUT_AC)); } void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo) |