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Thu, 17 Oct 2024 05:21:26 -0700 (PDT) Received: from localhost ([193.86.92.181]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5c98d5077e6sm2733482a12.48.2024.10.17.05.21.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Oct 2024 05:21:25 -0700 (PDT) Date: Thu, 17 Oct 2024 14:21:25 +0200 From: Michal Hocko To: Ryan Roberts Cc: Shakeel Butt , Andrew Morton , Anshuman Khandual , Ard Biesheuvel , Catalin Marinas , David Hildenbrand , Greg Marsden , Ivan Ivanov , Johannes Weiner , Kalesh Singh , Marc Zyngier , Mark Rutland , Matthias Brugger , Miroslav Benes , Roman Gushchin , 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: References: <20241014105514.3206191-1-ryan.roberts@arm.com> <20241014105912.3207374-1-ryan.roberts@arm.com> <20241014105912.3207374-3-ryan.roberts@arm.com> <315d4258-ea96-4008-8781-9205f41cec6c@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <315d4258-ea96-4008-8781-9205f41cec6c@arm.com> X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: ACE0A10001C X-Stat-Signature: jkc9ozwrbbrqudr4fbchf45463zadc4u X-HE-Tag: 1729167676-740902 X-HE-Meta: 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 L6Q/zAlA y3EPkdUMy0Rm1eRo9CJqRMAHWh2Ln/4Wlxi/8Dugdvy3en4HVkx65YPz92z/+pe44KuR4i3LDG+cZQjvpLeVb3WCJliLTkDaDt4Ms+I3vPPwgV6Gok6FMPqcPWv0G9QkouYP9fKCHuIksHQ2CtjgmWUNbYLEHNO372xARiZ0rDB5T2UntbtmsD90wPwzjT9i/zTlfWNU4eRFg8ZEPr8G8BGfMCSh9hZPAeOnDFrPyWtG30OrSowySW8qBK4vI8EvZovFr4fPsCwZe4IQ6jbZ4xqcj39hTQL2iloD5vUgyjQ0jYdZkHDf/cRQMvSFdrlK8QbgDUjSbIoNKKnNwOGTsYOub1K03FwFyyKDh3fv/KUfnDH5QJJrEdQOks9bbQ6mzW9QMdm6rbnxOv1/IufXL50TzCvUABa8UCUZhlaO08l1AZ6Fm/t+m1BRmRpSOcYt06dPuBtAv03Upo2m1AJUxWVwRc/wXYXHJc62I 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: On Tue 15-10-24 11:55:26, Ryan Roberts wrote: > On 14/10/2024 20:59, Shakeel Butt wrote: > > On Mon, Oct 14, 2024 at 11:58:10AM GMT, 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: Shakeel Butt > > Thanks Shakeel and Johannes, for the acks. Given this patch is totally > independent, I'll plan to resubmit it on its own and hopefully we can get it in > independently of the rest of the series. Yes, this makes sense independent on the whole series. Acked-by: Michal Hocko Thanks! -- Michal Hocko SUSE Labs