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c=relaxed/relaxed; d=suse.com; s=susede1; t=1674077620; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=7pZDwwkHXBi6TQs0bTATnlfLJxHePp59pNH6+hjByaY=; b=aqxWcXoZK36abrfVw7/RkaFoV9G5OwXVTbqZF7541hZRkh7wmcDUyaoUWMfXpa+rggoIxC dRlAnEppanHYrid8nc5falTWzW0Gs2cXsJVfhMTekptUZAvCgqM51Iw8aO90Z6AjGMVYGw DhRk/TYvEFKgz8v3Mm2mvdGScingIXA= 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 1A054139D2; Wed, 18 Jan 2023 21:33:40 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id ByrZBbRlyGN5OgAAMHmgww (envelope-from ); Wed, 18 Jan 2023 21:33:40 +0000 Date: Wed, 18 Jan 2023 22:33:39 +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-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Queue-Id: 88EC8A0007 X-Rspamd-Server: rspam01 X-Stat-Signature: r7f5xxt7qw8ksfwyb9t4k9yjq5i6d44u X-HE-Tag: 1674077621-256118 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed 18-01-23 10:09:29, Suren Baghdasaryan wrote: > On Wed, Jan 18, 2023 at 1:23 AM Michal Hocko wrote: > > > > 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 .... > > because vma_adjust_trans_huge() modifies the VMA and such > modifications should be done under VMA write-lock protection. So it will become: 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 vma_adjust_trans_huge() modifies the VMA and such modifications should be done under VMA write-lock protection. which is effectivelly saying vma_adjust_trans_huge() modifies the VMA and such modifications should be done under VMA write-lock protection so move VMA flag modifications before so all of them are covered by the same write protection. right? -- Michal Hocko SUSE Labs