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Date:   Wed, 11 Oct 2023 19:51:02 +0000
In-Reply-To: <20231010000929.450702-4-roman.gushchin@linux.dev>
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References: <20231010000929.450702-1-roman.gushchin@linux.dev> <20231010000929.450702-4-roman.gushchin@linux.dev>
Message-ID: <20231011195102.mym2mrgqyavp3n6r@google.com>
Subject: Re: [PATCH v2 3/5] mm: kmem: make memcg keep a reference to the
 original objcg
From:   Shakeel Butt <shakeelb@google.com>
To:     Roman Gushchin <roman.gushchin@linux.dev>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        cgroups@vger.kernel.org, Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Muchun Song <muchun.song@linux.dev>,
        Dennis Zhou <dennis@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        David Rientjes <rientjes@google.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Naresh Kamboju <naresh.kamboju@linaro.org>
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On Mon, Oct 09, 2023 at 05:09:27PM -0700, Roman Gushchin wrote:
> Keep a reference to the original objcg object for the entire life
> of a memcg structure.
> 
> This allows to simplify the synchronization on the kernel memory
> allocation paths: pinning a (live) memcg will also pin the
> corresponding objcg.
> 
> The memory overhead of this change is minimal because object cgroups
> usually outlive their corresponding memory cgroups even without this
> change, so it's only an additional pointer per memcg.
> 
> Signed-off-by: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>

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