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bh=c4jFt5CSjdtnMDLvsXCu/fyC50qdW3CP98LJCVII0A8=; b=d5MjKKHwyjWRuUoQdFCQiQaKS/JlY/J94I3M2WBvbAmveiTWcDYJRvgsQn3QP1DbIS8h86 2MLS3tC4LCpGJZ/GhBlu/WwSnutZqfichRjG6EWfHMez2Ot67t008SDi5qbZV1Wnj5Iuop QqMNgkJvwaIxblG6TubYXrpPvSmURnY= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 7B41A139D2; Wed, 18 Jan 2023 09:23:38 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id EA6cHZq6x2NjNQAAMHmgww (envelope-from ); Wed, 18 Jan 2023 09:23:38 +0000 Date: Wed, 18 Jan 2023 10:23:34 +0100 From: Michal Hocko To: Suren Baghdasaryan Cc: akpm@linux-foundation.org, michel@lespinasse.org, jglisse@google.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, ldufour@linux.ibm.com, laurent.dufour@fr.ibm.com, paulmck@kernel.org, luto@kernel.org, songliubraving@fb.com, peterx@redhat.com, david@redhat.com, dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev, punit.agrawal@bytedance.com, lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, hughlynch@google.com, leewalsh@google.com, posk@google.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH 17/41] mm/mmap: move VMA locking before anon_vma_lock_write call Message-ID: References: <20230109205336.3665937-1-surenb@google.com> <20230109205336.3665937-18-surenb@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230118_012342_614670_58905612 X-CRM114-Status: GOOD ( 13.64 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue 17-01-23 18:01:01, Suren Baghdasaryan wrote: > On Tue, Jan 17, 2023 at 7:16 AM Michal Hocko wrote: > > > > On Mon 09-01-23 12:53:12, Suren Baghdasaryan wrote: > > > Move VMA flag modification (which now implies VMA locking) before > > > anon_vma_lock_write to match the locking order of page fault handler. > > > > Does this changelog assumes per vma locking in the #PF? > > Hmm, you are right. Page fault handlers do not use per-vma locks yet > but the changelog already talks about that. Maybe I should change it > to simply: > ``` > Move VMA flag modification (which now implies VMA locking) before > vma_adjust_trans_huge() to ensure the modifications are done after VMA > has been locked. Because .... Withtout that additional reasonaning it is not really clear why that is needed and seems arbitrary. -- Michal Hocko SUSE Labs _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel