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bh=g2TS0UNExVN4AiesqATrfgArdGM2yjQzXweTQoVYk+4=; b=Yn8hj86p+46x9S4HNw1QqQPot25eIVF1vtcZdtFRgk6ea828Wen47zYGgYSAcxDnOc2BCo GyFUYYhexK1ScR3aPadwjYicNXlzB4Hka9Z5g14S1Ik/dyJIDxBDrr9kbBG4qEtMqm+oqK 4L+petp0kIaDXCYVHSD4mgnMFCh4D58= 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 37AEA13591; Wed, 11 Jan 2023 17:37:06 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 2TGRDcLzvmMkdwAAMHmgww (envelope-from ); Wed, 11 Jan 2023 17:37:06 +0000 Date: Wed, 11 Jan 2023 18:37:05 +0100 From: Michal Hocko To: Suren Baghdasaryan Cc: David Laight , Ingo Molnar , "michel@lespinasse.org" , "joelaf@google.com" , "songliubraving@fb.com" , "leewalsh@google.com" , "david@redhat.com" , "peterz@infradead.org" , "bigeasy@linutronix.de" , "peterx@redhat.com" , "dhowells@redhat.com" , "linux-mm@kvack.org" , "edumazet@google.com" , "jglisse@google.com" , "punit.agrawal@bytedance.com" , "arjunroy@google.com" , "minchan@google.com" , "x86@kernel.org" , "hughd@google.com" , "willy@infradead.org" , "gurua@google.com" , "laurent.dufour@fr.ibm.com" , "linux-arm-kernel@lists.infradead.org" , "rientjes@google.com" , "axelrasmussen@google.com" , "kernel-team@android.com" , "soheil@google.com" , "paulmck@kernel.org" , "jannh@google.com" , "liam.howlett@oracle.com" , "shakeelb@google.com" , "luto@kernel.org" , "gthelen@google.com" , "ldufour@linux.ibm.com" , "vbabka@suse.cz" , "posk@google.com" , "lstoakes@gmail.com" , "peterjung1337@gmail.com" , "linuxppc-dev@lists.ozlabs.org" , "kent.overstreet@linux.dev" , "hughlynch@google.com" , "linux-kernel@vger.kernel.org" , "hannes@cmpxchg.org" , "akpm@linux-foundation.org" , "tatashin@google.com" Subject: Re: [PATCH 08/41] mm: introduce CONFIG_PER_VMA_LOCK Message-ID: References: <20230109205336.3665937-1-surenb@google.com> <20230109205336.3665937-9-surenb@google.com> <20230111001331.cxdeh52vvta6ok2p@offworld> <6be809f5554a4faaa22c287ba4224bd0@AcuMS.aculab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: 6ytcb9o75phuyiweypztbhimrwwf1sak X-Rspam-User: X-Rspamd-Queue-Id: 4A01940004 X-Rspamd-Server: rspam06 X-HE-Tag: 1673458628-30258 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 11-01-23 09:04:41, Suren Baghdasaryan wrote: > On Wed, Jan 11, 2023 at 8:44 AM Michal Hocko wrote: > > > > On Wed 11-01-23 08:28:49, Suren Baghdasaryan wrote: > > [...] > > > Anyhow. Sounds like the overhead of the current design is small enough > > > to remove CONFIG_PER_VMA_LOCK and let it depend only on architecture > > > support? > > > > Yes. Further optimizations can be done on top. Let's not over optimize > > at this stage. > > Sure, I won't optimize any further. > Just to expand on your question. Original design would be problematic > for embedded systems like Android. It notoriously has a high number of > VMAs due to anonymous VMAs being named, which prevents them from > merging. What is the usual number of VMAs in that environment? -- Michal Hocko SUSE Labs