linux-kernel - Re: [PATCH RFC 1/2] mm: kmem: optimize get_obj_cgroup_from

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Date:   Tue, 20 Dec 2022 11:55:34 -0800
From:   Shakeel Butt <shakeelb@...gle.com>
To:     Roman Gushchin <roman.gushchin@...ux.dev>
Cc:     linux-mm@...ck.org, cgroups@...r.kernel.org,
        linux-kernel@...r.kernel.org, Johannes Weiner <hannes@...xchg.org>,
        Michal Hocko <mhocko@...nel.org>,
        Muchun Song <muchun.song@...ux.dev>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH RFC 1/2] mm: kmem: optimize get_obj_cgroup_from_current()

On Tue, Dec 20, 2022 at 10:28 AM Roman Gushchin
<roman.gushchin@...ux.dev> wrote:
>
> Manually inline memcg_kmem_bypass() and active_memcg() to speed up
> get_obj_cgroup_from_current() by avoiding duplicate in_task() checks
> and active_memcg() readings.
>
> Also add a likely() macro to __get_obj_cgroup_from_memcg():
> obj_cgroup_tryget() should succeed at almost all times except
> a very unlikely race with the memcg deletion path.
>
> Signed-off-by: Roman Gushchin <roman.gushchin@...ux.dev>

Can you please add your performance experiment setup and result of
this patch in the commit description of this patch as well?

Acked-by: Shakeel Butt <shakeelb@...gle.com>