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Fri, 27 Mar 2026 09:20:19 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id L7TvBdNLxmkhFgAAD6G6ig (envelope-from ); Fri, 27 Mar 2026 09:20:19 +0000 Date: Fri, 27 Mar 2026 09:20:17 +0000 From: Pedro Falcato To: "Lorenzo Stoakes (Oracle)" Cc: Andrew Morton , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jann Horn , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jianzhou Zhao , Oscar Salvador Subject: Re: [PATCH 2/3] mm: abstract reading sysctl_max_map_count, and READ_ONCE() Message-ID: <357u5es4z7jjnpkyefubvlygpkcinqomnyg233ra6geeamq35y@fuor6y4es3cp> References: <0715259eb37cbdfde4f9e5db92a20ec7110a1ce5.1773249037.git.ljs@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0715259eb37cbdfde4f9e5db92a20ec7110a1ce5.1773249037.git.ljs@kernel.org> X-Rspamd-Action: no action X-Rspamd-Queue-Id: 700A920003 X-Stat-Signature: do55tn9o71nqb8uueuf6roimgisq368n X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1774603221-239707 X-HE-Meta: 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 RORz6LDY OXyz0wVZpkeS9O1JB5xxs8Jxm01c8lhWTIKL1L7E1oyIQejMUl7RXRL0O6HereUJl38Ad0+FcXBlK/a2JEYSW/40Md6qKoc8Gt3myNUEVbKexg9pvmszHqqNr5yab+HUsaBKB08UMIJdHkE2aYJQV9F1UkQBPi0LRQZKNzSGGlLSrPjtjhaEuJg8F0wzISsofEQXq+XvzfFRmmEk0pRgNqhNU74EwoS7UAheH0kWui0M5Ll8tTZtqEkj18ddF/ksl1FqSGU+AjqW7kUmfP74lo/9BP/aFZNyuBPsLz9Xyr7sggqJhas9S/Yl26hCnDiMBLNpqHB0ZNQjREYbuSlZB3kPBevn4ueVwgBQskW68FJTJxiK3QUbJcf8fmodcNK/UTEvWvl4D0x6U/1GnWDLsBiHdHg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Mar 11, 2026 at 05:24:37PM +0000, Lorenzo Stoakes (Oracle) wrote: > Concurrent reads and writes of sysctl_max_map_count are possible, so we > should READ_ONCE() and WRITE_ONCE(). > > The sysctl procfs logic already enforces WRITE_ONCE(), so abstract the read > side with get_sysctl_max_map_count(). > > While we're here, also move the field to mm/internal.h and add the getter > there since only mm interacts with it, there's no need for anybody else to > have access. > > Finally, update the VMA userland tests to reflect the change. > > Signed-off-by: Lorenzo Stoakes (Oracle) Reviewed-by: Pedro Falcato -- Pedro