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

[Roman Gushchin]

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@xxxxxxxxxx>

Acked-by: Roman Gushchin <guro@xxxxxx>

Thanks, Waiman!