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b=Q6judB9iBxgyeVnV6AglZMnfWJRVmqj8bnQ3XfIfutH/CFnB0Ytq8OpY7yrzsITKw 4w/+++NZ37QXH+vjnvQSmXgEwJhIVcBj0ybcoyzIP4CsyvWVxBRBvZkQNLaqhNMdsM pUGB/jlrsiEUm2QvwVqg3T24lA2+RmYfMW2t4CuziLLZGZlVFng9wXtN2mAtht8YiN 1SXnunl7LsIb2Z0DXfYxveTP5KVIZ7aP3FJ6WhCjDbTIuKhkThrzfsG44ceJhInObq EhzMCOtrq9tWwM5X7YVSciVszwjhHTUy/UiYYC+1tNTXOa1oxSEhpM0twVP2Qjomh1 zgdNJ91cFcnoQ== From: SeongJae Park To: SeongJae Park Cc: Baolin Wang , akpm@linux-foundation.org, david@redhat.com, shakeelb@google.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] mm: fix the inaccurate memory statistics issue for users Date: Fri, 23 May 2025 10:23:05 -0700 Message-Id: <20250523172305.57843-1-sj@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250523172029.57745-1-sj@kernel.org> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 6C8762000E X-Stat-Signature: yx7i4r447mrqoyhu7eyyo8gm3bttwyuw X-Rspam-User: X-HE-Tag: 1748020989-94730 X-HE-Meta: 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 l84c0iZu 6G7hEnI3KCj7KEkFB2tNVZPuaR1MS7OAyBABEPLFjPPFx33StDvaAM6VsCYjbfS1wthfGZMY+fIzhKmJVGhXXvRxXkwxAXnCceG79VFWsYFQULTZd9YxG78eeJ3CyQ/2kt6OkciG52SitN+vufUqZHEf4OUaLqlMem5+0mdC/OnLjnJnUNizqdsRHScdrCxDxXrq4keXhoDFwZldPCokxDiSCHKrmsXRp2dwPO5M7K/TlkZF24mI5GiOgqbicdzsL4KH3 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 Fri, 23 May 2025 10:20:29 -0700 SeongJae Park wrote: > On Fri, 23 May 2025 11:16:13 +0800 Baolin Wang wrote: > > > On some large machines with a high number of CPUs running a 64K kernel, > > What does 64K kernel means? > > > we found that the 'RES' field is always 0 displayed by the top command > > for some processes, which will cause a lot of confusion for users. > > > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > > 875525 root 20 0 12480 0 0 R 0.3 0.0 0:00.08 top > > 1 root 20 0 172800 0 0 S 0.0 0.0 0:04.52 systemd > > > > The main reason is that the batch size of the percpu counter is quite large > > on these machines, caching a significant percpu value, since converting mm's > > rss stats into percpu_counter by commit f1a7941243c1 ("mm: convert mm's rss > > stats into percpu_counter"). Forgot asking this, sorry. Should we add Fixes: tag and Cc stable@? Thanks, SJ [...]