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Sat, 14 Nov 2026 11:56:35 -0800 (PST) Received: from [172.22.0.2] ([64.16.22.130]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3b197d35525sm14940403a91.16.2026.11.14.11.56.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 14 Nov 2026 11:56:35 -0800 (PST) Date: Sat, 14 Nov 2026 11:56:30 -0800 From: Chris Down To: "Lorenzo Stoakes (ARM)" Cc: David Hildenbrand , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , David Rientjes , Shakeel Butt , Andrew Morton , Jann Horn , Pedro Falcato , "Matthew Wilcox (Oracle)" , Jan Kara , Nhat Pham , Johannes Weiner , Zi Yan , Matthew Brost , Joshua Hahn , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Usama Arif , Kairui Song , Balbir Singh , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Kiryl Shutsemau , Yu-cheng Yu , Dave Hansen , Dennis Zhou , Tejun Heo , Christoph Lameter , Peng Fan , Josef Bacik , Chris Mason , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, "Borislav Petkov (AMD)" , Mark Brown , "Dennis Zhou (Facebook)" , Rick Edgecombe , stable@vger.kernel.org Subject: Re: [PATCH v2 01/13] mm/mmap: free gathered pages before MMF_OOM_SKIP In-Reply-To: <20261113-mason-migrate-et-al-fixes-v2-1-50a2ed382b61@kernel.org> References: <20261113-mason-migrate-et-al-fixes-v2-0-50a2ed382b61@kernel.org> <20261113-mason-migrate-et-al-fixes-v2-1-50a2ed382b61@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Message-ID: <20261114115630.0b75d0b49869d4fa@chrisdown.name> User-Agent: Mutt/2.4.3 (cc9e3943) (2026-10-09) X-Spam-Status: No, score=-12.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 71D3240005 X-Stat-Signature: itzuwas1qqfbh661m73ppcx9euqy1di8 X-Rspam-User: X-HE-Tag: 1794686197-361708 X-HE-Meta: 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 TR1hAjam 7Xo78WrG+iuLjwI/Kahr5/1U1UFjsrb6s4GEaom+azFfPZSfIGTvLQkdKg5bVAU4EzhBw6HvTKcjl7FPm8kjgJIr87Ug+wXFE03uXAdjZQcg3EBNHS6zvgt3U7e4mIorQP2f56RBW+aH3V8AatYpNL3x6BSLJcfoRAFtoADDB67jaK4KewrAi4GiwoJ32+yJRR/jWUQ6kcWjcqpU2lekOA6Gp/wl3u2CvS+Tb8TmyxU63v/KsEeiNsGQ2MAaM/JN2OfbTxPrTQNmu/0gbLS4NPoMum9jDiDSITMdQQVbgONJ7+j3FwtiUTu7zfbLwakj4kz3amWv5tpytixPPakTmO9s74e5uo2CRvshQCi/aLnYgnmOyKg6CNoNz4ZXF+zP045fp37Deq3+TPP2+lpTt+Ew2Xm/zflgNBsOJtL0u9E8cKucCW/+GTfNHvKU1QOA4MdB+rSKcxKGMTvPYovy5khAxkljQmK8nw3bGoFqY+QtpP7GVuOqqEoKaqnVk7t5G/S/x/Qj+s4AbquD6HVOvUvoYjy6pQqXi7gIlJ79MwDLgz4ppMjqrMjVrjk7b6y/oyHjeABl0ZDvhFFgny9z+FeN6IQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Hi Lorenzo, Thanks! I've tested this with memcg OOMs where one kill is enough to get back under the limit, and with it the second kill is gone. It's probably worth knowing that for a memcg OOM this also needs my css_task_iter fix [1], which is in mm-hotfixes-unstable. Without it the memcg task scan stops seeing the victim once its last thread starts to exit, so oom_evaluate_task() never gets as far as checking MMF_OOM_SKIP for it. The test I used for this has a 48M memcg with a 30M task and a 1M task in it, and then a third task in there faults in 26M, so one kill should be enough. Out of 300 rounds of that, I got a second kill in 299 with neither patch, 277 with only this one, 147 with only that one, and none with both. [1] https://lore.kernel.org/r/avA1wXhTMs9eY2NF@chrisdown.name Reviewed-by: Chris Down Tested-by: Chris Down Chris