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bh=/wdeyyx7dv1HsPlpNEj9Dj0LTQdnHO4YhWLcKbfowbU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=yvkJo8w5JRqMbsDaKL0WE+RV+xa72xSSyH3AtInII8c9HGUqW8Bw/v5EspEjXw/yi Nzx07fMbxXI9usH5NoJlJ5iYqax54AtHi/KMi/JEsUSGjoXYIBHEs3TpRjmZ7pnSIQ kLYH8XJzneET2Y/jBw+pS3ytqmsllwmKZK8xWz8E= Date: Tue, 11 Apr 2023 13:48:01 -0700 From: Andrew Morton To: wenyang.linux@foxmail.com Cc: Mel Gorman , Oscar Salvador , William Lam , Fu Wei , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: compaction: optimize compact_memory to comply with the admin-guide Message-Id: <20230411134801.a4aadef5aba0f51e0d44bb7a@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: DFB8740010 X-Stat-Signature: 8618r84s5a16gozg3bjad4i65z5knrbd X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1681246083-356740 X-HE-Meta: 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 QLkG6/N5 HtXGUAyjTWUiho1elkJxa1+A0Mcb4zpHlJKI82S84oI2gZ8C4jz5AdIFBUySxzEzH4tTGj15rzc6bGaWCHDu3vAufiIV0aAu24/imRmynbwVOmO+5a3glm+ichMQVOzClFFKffF2TjM0ua2wBAr6ZCLN/T6c0NF4TkvLp053sAoTpFUS30OgRPHRVvjbTV73vU8tVm7icK2NebTn/qD3/PrN4Rb1ZgPOxPgqCnQ2HpqhK6lVvwZyISX4XXhnjmJGYqVjKxf10k8y+xQAsJ4tRdX1nbOp+b48FdYjIV7aRHLiGHyuWKCkA6iWRF1gweP2yQqaZgJjf5t0I5i4GoHdLRqD3b94xHt5afz6spirDOksiN9raS2LP+VQx0Z8I0Wyl8G8tURfs98+1kx03eAfp3HRaE17EWLsUF2r1QhGS/WGGWyjsc7lesW3cJBva0OcfhE4Z X-Bogosity: Ham, tests=bogofilter, spamicity=0.000262, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 12 Apr 2023 02:24:26 +0800 wenyang.linux@foxmail.com wrote: > For the /proc/sys/vm/compact_memory file, the admin-guide states: > When 1 is written to the file, all zones are compacted such that free > memory is available in contiguous blocks where possible. This can be > important for example in the allocation of huge pages although processes > will also directly compact memory as required > > But it was not strictly followed, writing any value would cause all > zones to be compacted. In some critical scenarios, some applications > operating it, such as echo 0, have caused serious problems. Really? You mean someone actually did this and didn't observe the effect during their testing? > It has been slightly optimized to comply with the admin-guide.