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From:   Roman Gushchin <guro@fb.com>
To:     Waiman Long <longman@redhat.com>
CC:     Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
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Subject: Re: [PATCH] mm, slab: Extend slab/shrink to shrink all the memcg
 caches
Thread-Topic: [PATCH] mm, slab: Extend slab/shrink to shrink all the memcg
 caches
Thread-Index: AQHVMQU0aiPYUCU7kUq+agLP0TSFvKa3tzYA
Date:   Tue, 2 Jul 2019 19:30:44 +0000
Message-ID: <20190702193038.GA9224@tower.DHCP.thefacebook.com>
References: <20190702183730.14461-1-longman@redhat.com>
In-Reply-To: <20190702183730.14461-1-longman@redhat.com>
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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.
>=20
> 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.
>=20
> 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:
>=20
>  # 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
>=20
> After shrinking slabs:
>=20
>  # 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
>=20
> Signed-off-by: Waiman Long <longman@redhat.com>

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

Thanks, Waiman!