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bh=wbKYjA9SVhaxm7sXHvounFWAXV9u7juv1r8koG8xUvc=; b=1xM8cFvEFiF65OuR9V/ekQ71vCryl2riVCfFmRM1/x9EKQIe2mYdSLpR/ODzlVpW/9uEeu QsIVvhyCldUpI/YDPtTx8qnzQ0U2fpN9JLoPXmPpfQ6d5Jca/VpP+jZzf0vrCx5Q32voIU UdsA2dCvkQREGaxDQh8OJ4AuAYiG6uUoiMaBg4XG7oy9vw8kGGNZmSlosJ5Eyi0X7KLHB1 dbonBDZnxZiClHm+vZ0A5uxYDsSiKmboAZ9Kpcn9htr0W3VtGJauwPRiYvhKZLJ/+GsixP apm4oeRDseB7/dEP8hm82XeOc3yicvCCA/odquVHkz8VXYhvzS0Sy7wlPHRFtw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1741951588; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=wbKYjA9SVhaxm7sXHvounFWAXV9u7juv1r8koG8xUvc=; b=5i0oLDcPq477lNZkULp774DDX1tbW5zxOX5PMAwhAdu+Gn8h1h97wkXmG84JkaoHRtJZ8s 8d4uRk3HmUnBfnAQ== From: Sebastian Andrzej Siewior To: Shakeel Butt Cc: Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Vlastimil Babka , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Meta kernel team Subject: Re: [RFC PATCH 05/10] memcg: no refilling stock from obj_cgroup_release Message-ID: <20250314112627.dPKeawXj@linutronix.de> References: <20250314061511.1308152-1-shakeel.butt@linux.dev> <20250314061511.1308152-6-shakeel.butt@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250314061511.1308152-6-shakeel.butt@linux.dev> X-Rspam-User: X-Rspamd-Queue-Id: D866212000D X-Rspamd-Server: rspam08 X-Stat-Signature: znpecwqryqrzycwat1pjzn1k6fep5uzd X-HE-Tag: 1741951590-619327 X-HE-Meta: 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 rZy0ELWp XjXhDysjYPbmahD5y47Cip5V0jIdadQHCi4ZHATPhVg4PFyTEAfw8dWhiwy5B+hU6vY3s6ox/ze6OCX7WHh+pC1s1YFW69qgRJpfEqvkY9WJnYgJhNtXA8LAptVbDWtqBXKfzJ6eXpclSpbX30FFfKNt9w/CyVjAH+BcSgkamnjhRZzSTuwZuJt6xKXoHL4eM22sttNxVhJQq/+nB08z7jdrNWnbgMPEYl98PZU2EOQ6SudI= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000002, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2025-03-13 23:15:06 [-0700], Shakeel Butt wrote: > obj_cgroup_release is called when all the references to the objcg has "references to the objcg have" > been released i.e. no more memory objects are pointing to it. Most > probably objcg->memcg will be pointing to some ancestor memcg and at the > moment, in obj_cgroup_release, the kernel call > obj_cgroup_uncharge_pages() to uncharge last remaining memory. This sounds somehow funny. I think the point is to uncharge the pages without tampering memcg_stock because it is unnecessary. > However obj_cgroup_uncharge_pages() refills the local stock. There is > no need to refill the local stock with some ancestor memcg and flush the > local stock. In addition this removes the requirement to only call > obj_cgroup_put() outside of local_lock. > > Signed-off-by: Shakeel Butt Sebastian