Commit a9f2a846 authored by Vlastimil Babka's avatar Vlastimil Babka Committed by Linus Torvalds

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 ef557180 ("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.

Fixes: ef557180 ("workqueue: schedule WORK_CPU_UNBOUND work on wq_unbound_cpumask CPUs")
Signed-off-by: default avatarVlastimil Babka <>
Acked-by: default avatarPekka Enberg <>
Acked-by: default avatarChristoph Lameter <>
Cc: Joonsoo Kim <>
Cc: David Rientjes <>
Cc: Tejun Heo <>
Cc: Lai Jiangshan <>
Cc: John Stultz <>
Cc: Thomas Gleixner <>
Cc: Stephen Boyd <>
Cc: <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 1cbf29da
......@@ -4086,7 +4086,8 @@ static void cache_reap(struct work_struct *w)
/* Set up the next iteration */
schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_AC));
schedule_delayed_work_on(smp_processor_id(), work,
void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo)
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment