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[109.81.86.177]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48a7c1d0228sm83315235e9.2.2026.04.29.07.44.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Apr 2026 07:44:17 -0700 (PDT) Date: Wed, 29 Apr 2026 16:44:16 +0200 From: Michal Hocko To: "David Hildenbrand (Arm)" Cc: Minchan Kim , Suren Baghdasaryan , akpm@linux-foundation.org, hca@linux.ibm.com, linux-s390@vger.kernel.org, brauner@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, timmurray@google.com, "Liam R. Howlett" Subject: Re: [PATCH v1 2/3] mm: process_mrelease: skip LRU movement for exclusive file folios Message-ID: References: <7f98f461-62a7-455d-a7a8-cb8928465946@kernel.org> <4a612d63-2838-40f5-ab67-79bf35dd3a56@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4a612d63-2838-40f5-ab67-79bf35dd3a56@kernel.org> X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: A300E140005 X-Stat-Signature: 14hn9m1u9bdrbbizuu668c8adai53jbs X-HE-Tag: 1777473859-136778 X-HE-Meta: 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 53iP6y5H xBD5LDT216rfulYEIhvWJ6p0Rfg3ZeOMwJqx5IVlQudPvU4Qbiyr6o5lQ2UBzIJZRsvdj53KC2741dfPVChzcsphEE5e5WKz4y+pjJPZKSOMFzlIviAKGRiUQgsb4pwMiiEhtEnRe/D7KmX6hbKNNYEtyms+9FjTlSeFeBPj1tiB9tgsKS8xzHS8GcSp94YPPkQrKKLLW/Ns5+7VNx/2Ud5IS+3uVFIY2/aCyd2Q3ZLda8IRX2MMrwiEnCADdqMM62bjUFhbBKU+F3Geuz8FmoW26+DZBPYBnddJrt7C/xc0UIHcLvc0JoWSFkaIdiUHtOEcblxR87gVIbMpX5WCScBRxIZl7xJfXFKsQbyinQl+Yl46ecQile5EtHmFfh7VvYvBw2RQMZ2Ne/2/tPcfvd4AEJtQWRbkKf2OCaRfzzEy5fNJKI6QZ8vpEsiKmL+FXEGqnebF+Q9dgBTnGP3pCrVyfCD9c0pGF1PQxtys+4aPQFW4= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed 29-04-26 15:07:04, David Hildenbrand wrote: > On 4/29/26 12:33, Michal Hocko wrote: > > On Wed 29-04-26 11:09:55, David Hildenbrand wrote: > >> Unrelated stupid question: would things be clearer if we could rename > >> MMF_UNSTABLE to MMF_OOM_REAPING once figure out whether aborting fork() still > >> really needs it? > > > > While the oom is the only current kernel user of MMF_UNSTABLE (in a > > sense it sets the flag) the flag should denote that any page faults are > > reliable because it might fault in a fresh memory and user would lose > > the previous content without knowing that. Not sure MMF_OOM_REAPING > > would reflect that reality better. > > We use it for failed fork() as well, but that's slightly different semantics (no > real page faults ever made sense). The bottom line is the same. Make sure PF fails rather than silently provide potentially corrupted data. > Looking at the original patch here, using MMF_OOM_REAPING to modify zapping > behavior would be clearer than MMF_UNSTABLE, I guess. Ohh, you mean to add a new flag, right? -- Michal Hocko SUSE Labs