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 69FE9C38147 for ; Wed, 18 Jan 2023 21:48:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231279AbjARVse (ORCPT ); Wed, 18 Jan 2023 16:48:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43146 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231235AbjARVs0 (ORCPT ); Wed, 18 Jan 2023 16:48:26 -0500 Received: from mail-yw1-x112d.google.com (mail-yw1-x112d.google.com [IPv6:2607:f8b0:4864:20::112d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C39715D7C2 for ; Wed, 18 Jan 2023 13:48:25 -0800 (PST) Received: by mail-yw1-x112d.google.com with SMTP id 00721157ae682-4a263c4ddbaso940517b3.0 for ; Wed, 18 Jan 2023 13:48:25 -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=uzT4Y+nMi8LDe2iEcfC4M3fZx7ZCs1usjL+yZe3S9Zg=; b=RhZ9zpDQ2tbO3UOHyEZ6OxL8Q7pdjhMsOsRzcBfXmJ1imO6bs0aWmPetPNnitsYH+4 yQWRmYHt2rKWbnkEeTpp25/fOxiz+AGY7oBG31Xmes7A5Qp0wmVarh3YODCj2ag0d8fg tgiL3bgnzTnuW3HtHK2HGsWiA6sXHkspotz9jEzegBpQjXvCzUYviYMY7Btlwb64jgpZ 1CfmWkYqIsrPfulP9bqiXjA9LRrqDcL4EL8jfUvE4QVAIsAUVHfRqoUyDl7UgAYSUQZr VHSCaH4Nwq0dwyL5OOw0Y1tLnRNlqc0xAhHDD3tgXrprsFOPPJspfcHjrNSfyj05EOod zvjA== 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=uzT4Y+nMi8LDe2iEcfC4M3fZx7ZCs1usjL+yZe3S9Zg=; b=V71glxTtNhBdFR4wtZ9UWU2qS/aws3ZSColpUJWqeyMFz8MXycs92Bd0zLK7ecWqSQ AdsoeXTp/X3D2uO1p+qVEaNpMkec7/7jhtcsUr1/RKK53EstJHpcz+QmqcyINqHy1AaZ Wh9MMN9fQcGN/k7aplf1w648Cbf6NhoSyiJ/wq0fQAKZTgjKNHFS1z9GtqCsS0DEq4jm nHyxXccTbyqaQlKOd+AJ9dABO4/PH/XVB9WpiV7QG2F7v8fCZ0KZVlQhT9s4MEZ77RIw x6AA+zWpvlJZR8uozBHgU4PhzUiV/JaYro1dfmkC/colaKyz1mXQLuTjMfv7xPm5dJd/ bW/g== X-Gm-Message-State: AFqh2kr5FwLwU21hpN/Dk/HycBOJUu3rviaIK/JAb46tqO4sTY2T9tWn Tr+jTZHlIUe/qvYF/BLov5SHmJ/b9PPWfsZgY85/5A== X-Google-Smtp-Source: AMrXdXvjDsaTscQe0ZYEXddn6BYHX+/MM+QlKzksu62WfW6oaplhyuT1n5g7GuUEaFRAGRMX9y3muPFlrpfKM7HD/Po= X-Received: by 2002:a81:6d8d:0:b0:490:89c3:21b0 with SMTP id i135-20020a816d8d000000b0049089c321b0mr1111410ywc.132.1674078504732; Wed, 18 Jan 2023 13:48:24 -0800 (PST) MIME-Version: 1.0 References: <20230109205336.3665937-1-surenb@google.com> <20230109205336.3665937-18-surenb@google.com> In-Reply-To: From: Suren Baghdasaryan Date: Wed, 18 Jan 2023 13:48:13 -0800 Message-ID: Subject: Re: [PATCH 17/41] mm/mmap: move VMA locking before anon_vma_lock_write call To: Michal Hocko 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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 18, 2023 at 1:33 PM Michal Hocko wrote: > > 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? Yes, and the wording in the latter version is simpler to understand IMO, so I would like to adopt it. Do you agree? > -- > Michal Hocko > SUSE Labs