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AJvYcCXqyieOj3eSIJ8Fn6zZcal7JyVMCkapHUJRNx6kq3XyglnKMXs8EnS2e1TcVdYP4rjTRE5l9GnC@vger.kernel.org X-Gm-Message-State: AOJu0YwAp9XtUODW/PpXFnqgVBRKgxtj+wNecClOKw1RcnA1li7Fo8Lo Z3G4Ij1JYWnUx6ZI+iMLjChxYuWg7tMrbnc9EShJfQEBbohMJNX9cmqlvLjmre9WVxnqsPAe4fe B X-Google-Smtp-Source: AGHT+IGls0KX1bRa/5udb60IOUG7S3+RObbDPF9EP/nc4moCuctIsvmDxZp8/MHeexJO2YJQ3fajDQ== X-Received: by 2002:a05:6214:300a:b0:6cb:55e4:54d5 with SMTP id 6a1803df08f44-6cbe5239cc6mr302364356d6.10.1728910819640; Mon, 14 Oct 2024 06:00:19 -0700 (PDT) Received: from localhost ([2603:7000:c01:2716:da5e:d3ff:fee7:26e7]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6cbe85a5d49sm44835096d6.29.2024.10.14.06.00.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Oct 2024 06:00:18 -0700 (PDT) Date: Mon, 14 Oct 2024 09:00:17 -0400 From: Johannes Weiner To: Ryan Roberts Cc: Andrew Morton , Anshuman Khandual , Ard Biesheuvel , Catalin Marinas , David Hildenbrand , Greg Marsden , Ivan Ivanov , Kalesh Singh , Marc Zyngier , Mark Rutland , Matthias Brugger , Michal Hocko , Miroslav Benes , Roman Gushchin , Shakeel Butt , Will Deacon , cgroups@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC PATCH v1 03/57] mm/memcontrol: Fix seq_buf size to save memory when PAGE_SIZE is large Message-ID: <20241014130017.GA1021@cmpxchg.org> References: <20241014105514.3206191-1-ryan.roberts@arm.com> <20241014105912.3207374-1-ryan.roberts@arm.com> <20241014105912.3207374-3-ryan.roberts@arm.com> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241014105912.3207374-3-ryan.roberts@arm.com> On Mon, Oct 14, 2024 at 11:58:10AM +0100, Ryan Roberts wrote: > Previously the seq_buf used for accumulating the memory.stat output was > sized at PAGE_SIZE. But the amount of output is invariant to PAGE_SIZE; > If 4K is enough on a 4K page system, then it should also be enough on a > 64K page system, so we can save 60K om the static buffer used in > mem_cgroup_print_oom_meminfo(). Let's make it so. > > This also has the beneficial side effect of removing a place in the code > that assumed PAGE_SIZE is a compile-time constant. So this helps our > quest towards supporting boot-time page size selection. > > Signed-off-by: Ryan Roberts Acked-by: Johannes Weiner