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 9B717C636CC for ; Wed, 1 Feb 2023 00:01:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231431AbjBAABi (ORCPT ); Tue, 31 Jan 2023 19:01:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48956 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231469AbjBAABd (ORCPT ); Tue, 31 Jan 2023 19:01:33 -0500 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0155C1024B for ; Tue, 31 Jan 2023 16:01:28 -0800 (PST) Received: by mail-yb1-xb4a.google.com with SMTP id p19-20020a25d813000000b0080b78270db5so17980762ybg.15 for ; Tue, 31 Jan 2023 16:01:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=bxtFPzszSwirgU1/0J+PiMZRXMSQgSBrsapRb9QUY2A=; b=Rk9+8STvrqcbQlKiAZtMBFXlHokjI0hFJPEVyGKrBrbMfUwZG8qeTJEuvgsTMPrddh QBvNTohEnVdpbnlrXIgz3Ikz6D2cz4x6un8ohdjcDpAfu7gZ17WU+drJlhJu9Qtc4X1w EN1waKUDwB0WD09JdlRGgqA2ctv2OIzWCDINQo+peotxUMRoWPkFgEen/RotX4SxEykY LuacT9neZvFmURFR16w8DaONfwFwVOcr03mG+PjT2JsZXXZmxD4X3lmTqKTBd5FY/kIG JWR8f0Sx+Z/NFa0Ne873ZtAwDgad97njkhjjwAf7i14upKxsl5EruUIt4SUZYeig/N3q ro2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=bxtFPzszSwirgU1/0J+PiMZRXMSQgSBrsapRb9QUY2A=; b=PdKlbWUtySgUlFUD5NLTVWV+CVlrUxDHqqp5Axz7XLxIeZDGH7g88Vpnev+bGAFrCz dkXO1zQxd6Qc3ixW+PmrD/IQXm8jKtZDyOpCmxWM4Vp7WMEqgdJTi2p68XdobtUdVy1m cn50C4eTc+dBl5utO/9QN0ligiPXU/Hoqt0pSVzBeMN+OHjCJLLcMUEQdLxjXASkES2T vl7KOlyGSLFlg1N2ux3zUIc7Jl/+2nCbp86YJ9aqFKmjDg2k8hxDI3nOFpkpVuzM9hzX o9lgpeBQyayHDLzsBfFtJdWIs/RTo5kndRveBPzlwUjAE9Jk6Pc7xYgtsZZ2yUNyRCoY k8gg== X-Gm-Message-State: AO0yUKULE6yk9dU1rbiKC/kpJb0IXVI65lB3jZTyyAA6fQpqwaUS3XIf Ow2z0C1TXKoK/1okyCdYZ0dtDRPNX/o= X-Google-Smtp-Source: AK7set8qCAXBbF1QMD7keC0/SZMMktYNysM7vnt2K6tJydZhJP2e/r9qdYRWK1+YTYhm0sm9RG76XRb3Zl4= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:200:3d02:e79b:d9e3:ddd3]) (user=surenb job=sendgmr) by 2002:a81:204:0:b0:4db:df79:a7c7 with SMTP id 4-20020a810204000000b004dbdf79a7c7mr21711ywc.515.1675209688185; Tue, 31 Jan 2023 16:01:28 -0800 (PST) Date: Tue, 31 Jan 2023 16:01:16 -0800 Mime-Version: 1.0 X-Mailer: git-send-email 2.39.1.456.gfc5497dd1b-goog Message-ID: <20230201000116.1333160-1-surenb@google.com> Subject: [PATCH 1/1] mm: introduce vm_flags_reset_once to replace WRITE_ONCE vm_flags updates From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: michel@lespinasse.org, jglisse@google.com, mhocko@suse.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, paulmck@kernel.org, mingo@redhat.com, will@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, rppt@kernel.org, 42.hyeyoo@gmail.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, 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, surenb@google.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Provide vm_flags_reset_once() and replace the vm_flags updates which used WRITE_ONCE() to prevent compiler optimizations. Fixes: 0cce31a0aa0e ("mm: replace vma->vm_flags direct modifications with modifier calls") Reported-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Suren Baghdasaryan --- Notes: - The patch applies cleanly over mm-unstable - The SHA in Fixes: line is from mm-unstable, so is... unstable include/linux/mm.h | 7 +++++++ mm/mlock.c | 4 ++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 5bf0ad48faaa..23ce04f6e91e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -648,6 +648,13 @@ static inline void vm_flags_reset(struct vm_area_struct *vma, vm_flags_init(vma, flags); } +static inline void vm_flags_reset_once(struct vm_area_struct *vma, + vm_flags_t flags) +{ + mmap_assert_write_locked(vma->vm_mm); + WRITE_ONCE(ACCESS_PRIVATE(vma, __vm_flags), flags); +} + static inline void vm_flags_set(struct vm_area_struct *vma, vm_flags_t flags) { diff --git a/mm/mlock.c b/mm/mlock.c index ed49459e343e..617469fce96d 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -380,7 +380,7 @@ static void mlock_vma_pages_range(struct vm_area_struct *vma, */ if (newflags & VM_LOCKED) newflags |= VM_IO; - vm_flags_reset(vma, newflags); + vm_flags_reset_once(vma, newflags); lru_add_drain(); walk_page_range(vma->vm_mm, start, end, &mlock_walk_ops, NULL); @@ -388,7 +388,7 @@ static void mlock_vma_pages_range(struct vm_area_struct *vma, if (newflags & VM_IO) { newflags &= ~VM_IO; - vm_flags_reset(vma, newflags); + vm_flags_reset_once(vma, newflags); } } -- 2.39.1.456.gfc5497dd1b-goog