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[109.81.32.81]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48e71b8a7d1sm23718452f8f.38.2026.11.03.00.34.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Nov 2026 00:34:34 -0800 (PST) Date: Tue, 3 Nov 2026 09:34:33 +0100 From: Michal Hocko To: Shakeel Butt Cc: Andrew Morton , Johannes Weiner , Roman Gushchin , Muchun Song , Tejun Heo , Harry Yoo , Meta kernel team , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/5] memcg: force charges from reclaim before trying the limits Message-ID: References: <20261030205418.341214-1-shakeel.butt@linux.dev> <20261030205418.341214-3-shakeel.butt@linux.dev> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: zbs34578u6jx7sr1pzre834uaqta5k4z X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 37B5E20005 X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-HE-Tag: 1793694876-760991 X-HE-Meta: U2FsdGVkX183oOs6dWlq1jjtpg+qYoHmFE+GV2LtLGMcs2pjjdtvuDtTaVewjND+EsTgamZw7h6ykYDtfoQCixzK3wZNu29+eM4svztJGVYdxMuYhen4IuMnBhI1QRDilEUjNrfjS7iVs2URYm66Bq8k2eFhMs+vQhBB/AnshOVvB2VvsquZZePLZINLq3MvNuwhvpFZXSNBssV+q2cy6KjqXWbkmbHqHAZwi1EDeX0Gvx+JmIhb88M9MR2aKq/Yp03BIvS01PucHnaTh26vwcaWmcEqcUEzlwd525StwCP8atCXmJkSVrHchhV9ZvaASypRs9R/2DpUDp+/1VMi0nf+jCrXAJCvGB/eCU3w1Mv9QEq5a9ziY999ooUmrivxo76CVeQVPESaHBpN825RCVLyLoFQsbL6C+pb2Xq8FccABnP+RTibok1pdBAepOgdQeD7sgWqJ7QVK4gw4X41qjV9XXL4bBoizfJikhGq/kXmrkg7h/VVTtSCGl2a/lztML5KBXODOC3eiZY6ikWt65NEXdnZbec3dScx6SlxGr6jgfC3JhePcwPt00X/thZxlqTClg8w2ZqrFGz3EQ4x5hzrXJp2GENDa1x3kQIHRuTft774EpB6aYXsra/7c/ns167CxLVEDqzVxVjF7jvl9wpBSy7wooEjol6RHBErY9iFnQj2XPsj2XkT4rvIzTUkLVzz+To8kJ9dsJLeoqeG5gbe5u1xr5rkL2YKLCVuPBwz2thn21dR0uSiecNGSMPrbPZxzyyoM/8353X2mkLC9BSjvJIfwvXa9IZ+eMr2kStLqVFSEEQB06s8AFLq6FLDCYZhz04msvlEvS5UjpS/npIkwtBMj6f9we7Z8W8eBPct5MBBND0TPgAY2PYajncWOZEIzM6J6r1LbBKqng0anFT2WGxbwkBbOiCKJB7G4BhQsmUqbZf5UEETxIYLeo4uKLPccS3E84QnEUDSxkJ 0exOxO14 nmSbe+VBLiaKhF9X6pE2HGeOdCjfECulMOvYGoZcOJNGGKsdwkUxGH6Uqz6b4b5aO/gSJA/sd5J/DlVOUCYA41/OLuy7vr+dygJLToycusffpiBZsMO40eW/2Fup7oIxFklLes3YEI+LReCPiQlavmMJeO+IMddICZmD68O1RAEOsUDhpar/TaluUWdCUrD00Ggw0EjfWC8xgcG+quYb/H1uI9Co24DSzykecYoUDaVc37C5uVEonphpNZtG2lvtA4hMCcqS7/glJ/yb61ajineKNR8ip8cAAyeE90J623gU2/JyKWZR7GkBvpfn5F9C1j5yqCPMbe0bw20ceHKtLqI2Xi8EH6/3xTPRDrggYVEfxdpkKsiak2ZI1tyXkW6r6xQokE7ojXvouR5SWBrs/E3OfEbWMyVX2rkXD 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 On Mon 02-11-26 20:34:40, Shakeel Butt wrote: > On Mon, Nov 02, 2026 at 09:46:38AM +0100, Michal Hocko wrote: [...] > > @@ -2789,6 +2779,15 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask, > > if (do_memsw_account()) > > page_counter_charge(&memcg->memsw, nr_pages); > > > > + /* > > + * If the allocation has to be enforced, don't forget to raise > > + * a MEMCG_MAX event. > > + */ > > + for (mem_over_limit = memcg; mem_over_limit; > > + mem_over_limit = parent_mem_cgroup(mem_over_limit)) > > + if (!mem_cgroup_margin(mem_over_limit)) > > Second, !mem_cgroup_margin() is true at usage == max, so a charge that fits > exactly raises an event (unlike today). True > > > + __memcg_memory_event(mem_over_limit, MEMCG_MAX, allow_spinning); > > Third, we definitely need a break here otherwise every ancestor at its limit gets > an event which does not happen today. This is a separate thing but shouldn't we actually raise the event on all levels that are over? > I want to keep my current version. OK, fair enough. My intention was to have those two parts closer together but this is not something I would insist. Acked-by: Michal Hocko Thanks! -- Michal Hocko SUSE Labs