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 4C3D0C433EF for ; Sun, 24 Apr 2022 07:45:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4D7E66B0074; Sun, 24 Apr 2022 03:45:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 45F1E6B0075; Sun, 24 Apr 2022 03:45:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3003D6B0078; Sun, 24 Apr 2022 03:45:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.28]) by kanga.kvack.org (Postfix) with ESMTP id 19EAF6B0074 for ; Sun, 24 Apr 2022 03:45:09 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay11.hostedemail.com (Postfix) with ESMTP id D8B4B8239F for ; Sun, 24 Apr 2022 07:45:08 +0000 (UTC) X-FDA: 79390986696.14.01EAF02 Received: from mail-pl1-f181.google.com (mail-pl1-f181.google.com [209.85.214.181]) by imf22.hostedemail.com (Postfix) with ESMTP id 2EE51C002C for ; Sun, 24 Apr 2022 07:45:07 +0000 (UTC) Received: by mail-pl1-f181.google.com with SMTP id s17so20314186plg.9 for ; Sun, 24 Apr 2022 00:45:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=gL5y2sIiW+TivQxmc7o7gDDW8gSuHpLVd5lzE9Konhw=; b=1RAraEJ5xHCWBlEGPQxmAthJmBsHyzOu5gUwW01HfgrGFQh9okpsjSVgMY4NjovnTP iq0XKKwHFzBsjTnUb4OsU95p1LFYOJXTZxLQSWEwFORB2lfQidbaq1bf1XBcRwxooxak WLhgJGwmqbHhOAFgmTRW1H6mzl4VRPmWBik58M8/RUzqgDNlcKkdUMBrbtiRoCAVmTwh UWuqDjER+dQCGfziwjpLytGqu94eu33fLE8cIJsSbC7pfkNs2/AOcRraKkhR7LtqpJD6 tVxV96yuAiq81Em8tBFaoSj3TNR6yqLWmBpUwDBq3Mc0r4YMEkpRGJZSvzF9e0tAGqT0 XejQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=gL5y2sIiW+TivQxmc7o7gDDW8gSuHpLVd5lzE9Konhw=; b=Av2Rh7A3iCcNXsYHYNw51dtmJ3DOWN1ozJO0bfyT2Vp1r0mBuSHbKy2XEK9lh2/Ybp 25SUStCH8zVb3tGxXSnGPl8fDejDQxj+7g0pqKqCBuwfENVlBXnEzBCbSir/XdoRTk7v cIIQH7UyPKX0qh388lwnJKDZD5CZ2G22/ZYf+5E0+MK3z8KaSj6CPeH/dzSjlsT44rjc aasuzENCVxQ3GHoLFWVvQAlxOOU5kE0z2mmfGTlBbSIiwExvP7i0ILnmPkCEojj5ccJG RzJKSn70s+f/O7HWpdHqmrngPVHlss0o7qWBznDw26SKlMtQLJaUUIZVjCkSF0UjKDeE RhDw== X-Gm-Message-State: AOAM531DtLZM3Ytf5pKT+FC9PvtFNShWD7bpFPQ/LYqdEUjme4ENDnZ3 lscoEKLYGpwE7XcybLCKidMFxg== X-Google-Smtp-Source: ABdhPJwElLASkEbwdc2PbXhRzXiLtCOhbVZusYiyzt+/WxR/g+yEiPugE6kKCb6sdYGH6W+viCwPog== X-Received: by 2002:a17:90a:aa92:b0:1d9:5223:489b with SMTP id l18-20020a17090aaa9200b001d95223489bmr3188503pjq.60.1650786306412; Sun, 24 Apr 2022 00:45:06 -0700 (PDT) Received: from localhost ([139.177.225.239]) by smtp.gmail.com with ESMTPSA id 123-20020a620681000000b004fa7c20d732sm7402721pfg.133.2022.04.24.00.45.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 24 Apr 2022 00:45:06 -0700 (PDT) Date: Sun, 24 Apr 2022 15:45:02 +0800 From: Muchun Song To: Baolin Wang Cc: akpm@linux-foundation.org, mike.kravetz@oracle.com, peterx@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: hugetlb: Add missing cache flushing in hugetlb_unshare_all_pmds() Message-ID: References: <419b0e777c9e6d1454dcd906e0f5b752a736d335.1650781755.git.baolin.wang@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <419b0e777c9e6d1454dcd906e0f5b752a736d335.1650781755.git.baolin.wang@linux.alibaba.com> X-Stat-Signature: ocn16r1f3rw77fmrenfss1qrqionzczh Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=bytedance-com.20210112.gappssmtp.com header.s=20210112 header.b=1RAraEJ5; spf=pass (imf22.hostedemail.com: domain of songmuchun@bytedance.com designates 209.85.214.181 as permitted sender) smtp.mailfrom=songmuchun@bytedance.com; dmarc=pass (policy=none) header.from=bytedance.com X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 2EE51C002C X-HE-Tag: 1650786307-254245 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 Sun, Apr 24, 2022 at 02:33:19PM +0800, Baolin Wang wrote: > Missed calling flush_cache_range() before removing the sharing PMD entrires, > otherwise data consistence issue may be occurred on some architectures whose > caches are strict and require a virtual–>physical translation to exist for > a virtual address. Thus add it. > > Fixes: 6dfeaff93be1 ("hugetlb/userfaultfd: unshare all pmds for hugetlbfs when register wp") > Signed-off-by: Baolin Wang CONFIG_ARCH_WANT_HUGE_PMD_SHARE is only definded on riscv, arm64 and x86. All of them do not have a VIVT cache. In others words, flush_cache_range() is null on those architectures. So I suspect in practice this does not cause any issue. It is better to clarify this in commit log. Anyway: Reviewed-by: Muchun Song Thanks.