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 612FDC5479D for ; Wed, 11 Jan 2023 17:07:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233197AbjAKRHQ (ORCPT ); Wed, 11 Jan 2023 12:07:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239078AbjAKRGk (ORCPT ); Wed, 11 Jan 2023 12:06:40 -0500 Received: from mail-yb1-xb2b.google.com (mail-yb1-xb2b.google.com [IPv6:2607:f8b0:4864:20::b2b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A884321B9 for ; Wed, 11 Jan 2023 09:04:53 -0800 (PST) Received: by mail-yb1-xb2b.google.com with SMTP id c82so8412232ybf.6 for ; Wed, 11 Jan 2023 09:04:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=LTJYmIxK7HXmivC0K3EGms7i6vie+YSU0ogRPhLAOWY=; b=mNAGtaf8jUOcbLC2GpY2IoOKVHZsaeSbuTMqB0BfbfYLRyVOF36Ix55jRi6VXABc2C TxHjeefcMzNJWY/YYv6W5ahFqaQmr9lvf1jGIqiEx8ySeybJFbSXh7kyg0REyOpFJ3nH qgVT4D8lYYrgosLusEdUk6v9fL81IeduQoDY1CoEHY7D6fZ1FTpu9HfIbpxV9/ZgBpjb lhCOVJRxYZXXqUPheviOgPqcc0ccJ7ZE+SCJKJc9myn5grFAs5xj6zbeWKyRGyMjbouQ FlOSd3pY+1imiSyJ1udW76G4nfJkk9sYWezx9f2BI+FYnk36Etq0x095sJRpXZCAhe9E wTIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=LTJYmIxK7HXmivC0K3EGms7i6vie+YSU0ogRPhLAOWY=; b=LA1YIVwsiGtkxg4j8M1vkg+/L7BfT0TSfP8FRS42K2nxNAKOem2YdLiyNTNT+oQkV9 DPNH003oceTl5QG+wdDmqU6a2Q/qlsNeSJCTBZP33t/71yvMnBaGWhrgZD78aLuaL47K 75QZ5CPmU1dWHCGky4V49K1PTRzDbu1yGtKFzlJ70pXmm8cqYsZeEDFwNtctMcjXwqVk C5YgIuAOe8xsoVLytOnIm5K8lKqCQyYVlmpCSAJgFI3WfeydtGW3jLHckzmJEjxpVNJi EMVgdkc3p75+idje7KnHjNVvMzEZfVWgA9UiYKZQWLm9YnQgpj0sBkOHbQ3HkJ/huBMG 7BOw== X-Gm-Message-State: AFqh2kpaiJoKw9cmQ336oX+cdyeBV+kzaBN2/YTIHNETJSF7IEt6GETv XwpvpeNx1Cl+1WU08qTXgK7lp3GU+uGCmyW/ShCCGQ== X-Google-Smtp-Source: AMrXdXuT2tWUr2Hd/aaxX3TJlatyg89hpnEY3Qn0fpRBzhAdGcwVITlGCP7wKe7gcAbYlKYD+1hcbSYSMwXYBplkZ8k= X-Received: by 2002:a25:1388:0:b0:7b8:6d00:ef23 with SMTP id 130-20020a251388000000b007b86d00ef23mr2129455ybt.119.1673456692551; Wed, 11 Jan 2023 09:04:52 -0800 (PST) MIME-Version: 1.0 References: <20230109205336.3665937-1-surenb@google.com> <20230109205336.3665937-9-surenb@google.com> <20230111001331.cxdeh52vvta6ok2p@offworld> <6be809f5554a4faaa22c287ba4224bd0@AcuMS.aculab.com> In-Reply-To: From: Suren Baghdasaryan Date: Wed, 11 Jan 2023 09:04:41 -0800 Message-ID: Subject: Re: [PATCH 08/41] mm: introduce CONFIG_PER_VMA_LOCK To: Michal Hocko 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" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. 2M per process increase would raise questions, therefore I felt the need for optimizing the memory overhead which is done in the last patch. Thanks for the feedback! > -- > Michal Hocko > SUSE Labs