Re: [PATCH] mm, slab: Extend slab/shrink to shrink all the memcg caches

Roman Gushchin
2019-07-02T19:31:43Z

On Tue, Jul 02, 2019 at 02:37:30PM -0400, Waiman Long wrote:
> Currently, a value of '1" is written to /sys/kernel/slab/<slab>/shrink
> file to shrink the slab by flushing all the per-cpu slabs and free
> slabs in partial lists. This applies only to the root caches, though.
>
> Extends this capability by shrinking all the child memcg caches and
> the root cache when a value of '2' is written to the shrink sysfs file.
>
> On a 4-socket 112-core 224-thread x86-64 system after a parallel kernel
> build, the the amount of memory occupied by slabs before shrinking
> slabs were:
>
> # grep task_struct /proc/slabinfo
> task_struct 7114 7296 7744 4 8 : tunables 0 0
> 0 : slabdata 1824 1824 0
> # grep "^S[lRU]" /proc/meminfo
> Slab: 1310444 kB
> SReclaimable: 377604 kB
> SUnreclaim: 932840 kB
>
> After shrinking slabs:
>
> # grep "^S[lRU]" /proc/meminfo
> Slab: 695652 kB
> SReclaimable: 322796 kB
> SUnreclaim: 372856 kB
> # grep task_struct /proc/slabinfo
> task_struct 2262 2572 7744 4 8 : tunables 0 0
> 0 : slabdata 643 643 0
>
> Signed-off-by: Waiman Long <longman@redhat.com>

Acked-by: Roman Gushchin <guro@fb.com>

Thanks, Waiman!