From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CAA43C5479D for ; Wed, 11 Jan 2023 17:42:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235327AbjAKRmo (ORCPT ); Wed, 11 Jan 2023 12:42:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36814 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239175AbjAKRiV (ORCPT ); Wed, 11 Jan 2023 12:38:21 -0500 Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2001:67c:2178:6::1d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6296121AE for ; Wed, 11 Jan 2023 09:37:19 -0800 (PST) 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 smtp-out2.suse.de (Postfix) with ESMTPS id 627A44F8A; Wed, 11 Jan 2023 17:37:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1673458626; 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=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: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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