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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1762887714; 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=X3p0OHTe0vlUjyhDWhZhm6oTZ1C1L+keJX+PJWob0hk=; b=Zg6iOzgwfbrFafmG6DBIIvIS6DBeLRm6Sopz75Lft2XojfXoTDjLb5lA4KUWmxyE+akzZq L3lqa9rGljR2bmGx6tMT30TfUHA7vjS3K2hsIgOxPH/lQ0f2S+Cqb4t4w5E9tZZz4qX8le gnjpDmDj0GMG5gDFQ0SkqBFkI7O/HRw= From: Roman Gushchin To: Shakeel Butt Cc: Andrew Morton , Johannes Weiner , Michal Hocko , Muchun Song , Harry Yoo , Qi Zheng , Vlastimil Babka , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Meta kernel team Subject: Re: [PATCH 0/4] memcg: cleanup the memcg stats interfaces In-Reply-To: <20251110232008.1352063-1-shakeel.butt@linux.dev> (Shakeel Butt's message of "Mon, 10 Nov 2025 15:20:04 -0800") References: <20251110232008.1352063-1-shakeel.butt@linux.dev> Date: Tue, 11 Nov 2025 11:01:47 -0800 Message-ID: <87pl9oqtpg.fsf@linux.dev> MIME-Version: 1.0 Content-Type: text/plain X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: AF73D140018 X-Stat-Signature: 3kqqd1khj6skpwf4bj3bia3txx98a6zq X-Rspam-User: X-HE-Tag: 1762887715-103040 X-HE-Meta: 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 l/FWhwqC UmjZI+t441H62hOIn25e6Mu/qDsKl+uNbofcPvn8lVRku63xYnmVz+s/q6qn7UInXEqxuTj4PVXrGhzntkcATxQeqHBV518wzcOo7sgAb4/yTnPCNn5yK/R/1gw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Shakeel Butt writes: > The memcg stats are safe against irq (and nmi) context and thus does not > require disabling irqs. However for some stats which are also maintained > at node level, it is using irq unsafe interface and thus requiring the > users to still disables irqs or use interfaces which explicitly disables > irqs. Let's move memcg code to use irq safe node level stats function > which is already optimized for architectures with HAVE_CMPXCHG_LOCAL > (all major ones), so there will not be any performance penalty for its > usage. Do you have any production data for this or it's theory-based? In general I feel we need a benchmark focused on memcg stats: there was a number of performance improvements and regressions in this code over last years, so a dedicated benchmark can help with measuring them. Nice cleanup btw, thanks!