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 18E77C433F5 for ; Thu, 10 Mar 2022 00:06:19 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9D12B8D0002; Wed, 9 Mar 2022 19:06:18 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 980FD8D0001; Wed, 9 Mar 2022 19:06:18 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 86FC88D0002; Wed, 9 Mar 2022 19:06:18 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0002.hostedemail.com [216.40.44.2]) by kanga.kvack.org (Postfix) with ESMTP id 790908D0001 for ; Wed, 9 Mar 2022 19:06:18 -0500 (EST) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 376D6181CAC51 for ; Thu, 10 Mar 2022 00:06:18 +0000 (UTC) X-FDA: 79226534436.31.B279183 Received: from mail-pj1-f48.google.com (mail-pj1-f48.google.com [209.85.216.48]) by imf20.hostedemail.com (Postfix) with ESMTP id 9F8E51C0015 for ; Thu, 10 Mar 2022 00:06:17 +0000 (UTC) Received: by mail-pj1-f48.google.com with SMTP id mr24-20020a17090b239800b001bf0a375440so6736701pjb.4 for ; Wed, 09 Mar 2022 16:06:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=IQJaIhmi/QzFmALiltJXNjf6ckrS2EgY1Uh0aPn7MYs=; b=gHn6uRZhcwc/1/iluj+hvVI/tjLthpe0Akd+MQKuvfdxMcu9PCDly6aCrg472eEh3m TjX0NOdopbKbRdKaTnbzERgZdM/mueEx2YG8+M+5257GEhp393PupeQgUlkt7oFEvDNE 3oK0YaD8xaVKZQHhdXj8we5uTjgvoB98hHYuntfbhhJEs/08fC7MpT6rEISUbYY/ic66 WSvO3h2xy30LL3YTP0oNjR8eybS0lFiAfsfYGA4HOD3rEng97uK2wZ6VlssMAfKNTXSz EKoRjaRuHELjmnQMxekNcgSoQf+ZMttBSndyI4apgf7t9m0BmZJQgb+1OpttRu0tnJ2D 9JGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=IQJaIhmi/QzFmALiltJXNjf6ckrS2EgY1Uh0aPn7MYs=; b=eP2ezDQzGEfVVXRZR3bNjFT0y8qENA3xOkFEYYi6EQ6LyZSA0b73XOGdUmbuYEAulz ePfQQ9+4KIY6/K3z5IUbpdSsdlerhUyjp8XViAnU7xOz74ZCaVDqZuIN8mtNPkVI1Vg1 WXPxSf6qrEQo/oZr0KlR4IfPq+ivLMjI6FU5nVbKH3j7v4rM7UP4rVv1FH03GQmp8+IO lFTNlSAjpQY+XkMe5gr+Klm0eKZc7nkcrwU9y+aicPUpEvoANzkRo8PFpzbCAPa01Ilw KJIuox1FktP2evykJwiey0nCLoAPLTG/u6pZyOQKd6q4LNFbuDBGNArsJc2zBn7MYo9S DpsQ== X-Gm-Message-State: AOAM531VP1AyUDZ4FmEXOfN05hljlGr+n5scHsAAcNOsdjLO67cJJL8X cNz5/j2PF+ZnC6EYyaRIwOsVIfUpXAmY4s0rRiEIKg== X-Google-Smtp-Source: ABdhPJwb9kJQ7QI7FmWPhygsP7CpEdP0qVgYwpDcpFWyZG/Qf8Jpi7IliqWagwPdOiBZnW2yD9cno3XpwTf/bXrgthc= X-Received: by 2002:a17:902:7296:b0:14b:4bc6:e81 with SMTP id d22-20020a170902729600b0014b4bc60e81mr2305234pll.132.1646870776595; Wed, 09 Mar 2022 16:06:16 -0800 (PST) MIME-Version: 1.0 References: <20220302082718.32268-1-songmuchun@bytedance.com> <20220302082718.32268-3-songmuchun@bytedance.com> In-Reply-To: <20220302082718.32268-3-songmuchun@bytedance.com> From: Dan Williams Date: Wed, 9 Mar 2022 16:06:05 -0800 Message-ID: Subject: Re: [PATCH v4 2/6] dax: fix cache flush on PMD-mapped pages To: Muchun Song Cc: Matthew Wilcox , Jan Kara , Al Viro , Andrew Morton , Alistair Popple , Yang Shi , Ralph Campbell , Hugh Dickins , xiyuyang19@fudan.edu.cn, "Kirill A. Shutemov" , Ross Zwisler , Christoph Hellwig , linux-fsdevel , Linux NVDIMM , Linux Kernel Mailing List , Linux MM , duanxiongchun@bytedance.com, Muchun Song Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 9F8E51C0015 X-Stat-Signature: pnjixdtz3erqxe9uwoj4uhjhyj6yc5n8 X-Rspam-User: Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=intel-com.20210112.gappssmtp.com header.s=20210112 header.b=gHn6uRZh; dmarc=fail reason="No valid SPF, DKIM not aligned (relaxed)" header.from=intel.com (policy=none); spf=none (imf20.hostedemail.com: domain of dan.j.williams@intel.com has no SPF policy when checking 209.85.216.48) smtp.mailfrom=dan.j.williams@intel.com X-Rspamd-Server: rspam03 X-HE-Tag: 1646870777-218816 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 Wed, Mar 2, 2022 at 12:29 AM Muchun Song wrote: > > The flush_cache_page() only remove a PAGE_SIZE sized range from the cache. > However, it does not cover the full pages in a THP except a head page. > Replace it with flush_cache_range() to fix this issue. This needs to clarify that this is just a documentation issue with the respect to properly documenting the expected usage of cache flushing before modifying the pmd. However, in practice this is not a problem due to the fact that DAX is not available on architectures with virtually indexed caches per: d92576f1167c dax: does not work correctly with virtual aliasing caches Otherwise, you can add: Reviewed-by: Dan Williams