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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4640C54EE9 for ; Fri, 9 Sep 2022 00:15:44 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D18C08D0003; Thu, 8 Sep 2022 20:15:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CA0548D0001; Thu, 8 Sep 2022 20:15:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B19EA8D0003; Thu, 8 Sep 2022 20:15:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 9D8B08D0001 for ; Thu, 8 Sep 2022 20:15:43 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 63928160217 for ; Fri, 9 Sep 2022 00:15:43 +0000 (UTC) X-FDA: 79890628566.30.545D7F0 Received: from mail-yw1-f172.google.com (mail-yw1-f172.google.com [209.85.128.172]) by imf01.hostedemail.com (Postfix) with ESMTP id 21D4640078 for ; Fri, 9 Sep 2022 00:15:42 +0000 (UTC) Received: by mail-yw1-f172.google.com with SMTP id 00721157ae682-3452214cec6so2148667b3.1 for ; Thu, 08 Sep 2022 17:15:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date; bh=hqY5A7Q3sRIg+0suDoUYAY9ycBZxq0iP/o3p4lTPQtw=; b=oBDufWXfW+Av/lwxqv0a/EmqwgX3S9/bXbt6VPEO7NL873V6R8oQZDcLwtycRTOpXd ETEjULXGw4a08PRJMrQ0Nm5rozdANb4QWO+80W8Mflqxsz2iKlb84+RJB/TmEhy3p43o p4R41uJlGA49hCYO16U/nbK5AfKp/LocXCNl5xvBp0ILImSEpasSy1IvxO6+UJaGSIcl YLsP7TlWAHeAYCI4A+RRC+n1yvSdbLnsaNWmEhuIXbEMmMGUmPmSZZTRN+8g19QX4YyS aYOqOsPfivibr4WSH7pE+0/NSWF4MCgHB5gjaRwq/g7jkpOCAn94Vsh+Zd8qJFI5KMqh TLLQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date; bh=hqY5A7Q3sRIg+0suDoUYAY9ycBZxq0iP/o3p4lTPQtw=; b=ijggOr6LFFxD9w8PGxZ3wNwmolMWkxPb6el4hdL3eodkR+mz1spjGvTX2YjqFRz5yl opXJ4coeNO+Qax8cVtNPwXkgjOvzEGNIUHg79omjsXXzOzfsjGbZ9ZW28YEo87EQfO5T XUPJqsw6GDvJdd69652dRvOU5G+caICd6axCjHJfz1cbIc51nYPpQDhQlPwC6f8KpzMl 6EkzFFSQ5nGsavkf93KXBMX1hRnSoGWMuknlkCccwhHdn4ggcv+5vTRHoX/tuOeITfxE Nt6RT9x+BiO1IhZJPxLLavTOiBeYXGKJa6uoKfwevz3cbahKH7EaBQvobKgoK2WJKzbw Pn0w== X-Gm-Message-State: ACgBeo3BzhN6W+OGx9sdsFmFv3I+dbZ2xhdc2AKWS5YKZdfTEAFfHpJK fYfpTyRVYLN8uoZAS8uAapEcdqogGFuVgFzD1dqSvw== X-Google-Smtp-Source: AA6agR62K1l39S/fz8ik5C68GuNknlfDBZR1zBzGcquAcYVnBiWDcbx92wi2JBC2nOolf2zZJxL60pxpYTaDIxhQc9o= X-Received: by 2002:a81:a002:0:b0:345:55c5:9c6e with SMTP id x2-20020a81a002000000b0034555c59c6emr9844670ywg.218.1662682542238; Thu, 08 Sep 2022 17:15:42 -0700 (PDT) MIME-Version: 1.0 References: <20220901173516.702122-1-surenb@google.com> <20220901173516.702122-9-surenb@google.com> In-Reply-To: From: Suren Baghdasaryan Date: Thu, 8 Sep 2022 17:15:31 -0700 Message-ID: Subject: Re: [RFC PATCH RESEND 08/28] mm/khugepaged: mark VMA as locked while collapsing a hugepage To: Laurent Dufour Cc: akpm@linux-foundation.org, michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@suse.de, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, 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, rientjes@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, kernel-team@android.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662682543; a=rsa-sha256; cv=none; b=LaeUBC+qPqefYdza0yIsM2zTyhJovq6cGhMnuaQ+W89MOM8kLj3/xRbw2KIj3LvpVkz7Qu YBGF8EOo4zWPV/FGs3C5D1iyZ3aYa+4buv1MWToSPbRCHgZyecOHmBTyu96PB5C5yEE9ts 1w1paX3Z07s8U003H4+Aw2+9kImxPRw= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=oBDufWXf; spf=pass (imf01.hostedemail.com: domain of surenb@google.com designates 209.85.128.172 as permitted sender) smtp.mailfrom=surenb@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662682543; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=hqY5A7Q3sRIg+0suDoUYAY9ycBZxq0iP/o3p4lTPQtw=; b=lDEnYP69JhBM5f4xgTi0SzUB5nNZhA22y4Emmid5/zmQzDM/7e5fKZXtNou9MyMJuZbu/D SkMH9/QcOmUjwyFiZ52PQSDGuSmdrVklx2OXkDgu75k0vN5kaqoLclrALxMm6LS/xw724w BjMGU7gdI0I+Atgopqc96UVAY/lydK4= Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=oBDufWXf; spf=pass (imf01.hostedemail.com: domain of surenb@google.com designates 209.85.128.172 as permitted sender) smtp.mailfrom=surenb@google.com; dmarc=pass (policy=reject) header.from=google.com X-Stat-Signature: wafr35ehfaa5u46dba64p81pm5kfuigf X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 21D4640078 X-HE-Tag: 1662682542-26027 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 Tue, Sep 6, 2022 at 7:43 AM Laurent Dufour wrote= : > > Le 01/09/2022 =C3=A0 19:34, Suren Baghdasaryan a =C3=A9crit : > > Protect VMA from concurrent page fault handler while modifying it in > > collapse_huge_page. > > Is the goal to protect changes in the anon_vma structure? > > AFAICS, the vma it self is not impacted here, only the anon_vma and the > PMD/PTE are touched, and they have their own protection mechanism, isn't = it? Yes, I think you are right about not needing to lock VMA here as all modified components are already protected. Thanks! > > > > > Signed-off-by: Suren Baghdasaryan > > --- > > mm/khugepaged.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > > index 01f71786d530..030680633989 100644 > > --- a/mm/khugepaged.c > > +++ b/mm/khugepaged.c > > @@ -1072,6 +1072,7 @@ static void collapse_huge_page(struct mm_struct *= mm, > > if (mm_find_pmd(mm, address) !=3D pmd) > > goto out_up_write; > > > > + vma_mark_locked(vma); > > anon_vma_lock_write(vma->anon_vma); > > > > mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm, >