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[70.27.3.10]) by smtp.gmail.com with ESMTPSA id q15-20020ac8450f000000b0034303785596sm2723182qtn.34.2022.08.09.10.59.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Aug 2022 10:59:50 -0700 (PDT) Date: Tue, 9 Aug 2022 13:59:48 -0400 From: Peter Xu To: "Huang, Ying" Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrea Arcangeli , David Hildenbrand , Minchan Kim , Andrew Morton , Vlastimil Babka , Nadav Amit , Hugh Dickins , Andi Kleen , "Kirill A . Shutemov" Subject: Re: [PATCH v2 2/2] mm: Remember young/dirty bit for page migrations Message-ID: References: <20220804203952.53665-1-peterx@redhat.com> <20220804203952.53665-3-peterx@redhat.com> <877d3hhksz.fsf@yhuang6-desk2.ccr.corp.intel.com> MIME-Version: 1.0 In-Reply-To: <877d3hhksz.fsf@yhuang6-desk2.ccr.corp.intel.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1660067993; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=AfxVZADNWEfFzXttPFva+96zrEVI5cpqVt6HGbyuOxU=; b=WW5XnBUTL7ATdoVR2375Nqf0jhVsLK7cJm6h5+B0JpBNyoCSNDHecZH6eo5AXCQI9FxVSL +KSUOmgVbsFIxbuaDG0ML2vk8mlsRP3SKngQTQSvbxXVlot3zwkmHj/2bKAVtzUMmdXrjY /rohzJpyh02NdaAQqjQVrIflui615ZA= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=GYaVOhn+; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf11.hostedemail.com: domain of peterx@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=peterx@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1660067993; a=rsa-sha256; cv=none; b=LH8+NGLkatQsxknvJGs6jtCUg0OiI7K3PiWItw5mFdfJZFM/fAwCpYm0nHCMlqgaoT2gcx 2laPWuc+Ga4igh9HzGPElbE1whRWA8yvZtTO9EdrCSCYBQKADFrpcH3FtZqSSfdjOBMb89 q34KpHcD8hCN0A0Xiu/IGD6Pp1pgWDA= X-Rspamd-Queue-Id: 100654019C Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=GYaVOhn+; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf11.hostedemail.com: domain of peterx@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=peterx@redhat.com X-Rspam-User: X-Rspamd-Server: rspam07 X-Stat-Signature: 4gwgobo6wmxjzj6x4q3tpz9iswnstymb X-HE-Tag: 1660067992-492135 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, Aug 09, 2022 at 04:40:12PM +0800, Huang, Ying wrote: > > @@ -2160,6 +2167,12 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, > > entry = pte_wrprotect(entry); > > if (!young) > > entry = pte_mkold(entry); > > + if (dirty) > > + /* > > + * NOTE: this may contains setting soft > > + * dirty too on some archs like x86. > > + */ > > Personally, I prefer to put comments above "if (dirty)". But you can > choose your favorite way unless it violates coding style. Sure. > > > + entry = pte_mkdirty(entry); > > We don't track dirty flag even for normal PTE before. So I think we > should separate the dirty flag tracking for normal PTE in a separate > patch. It's kinda convenient to touch that up, but for sure I can split that into a tiny but separate patch too. [...] > I don't find pte_dirty() is synced to PageDirty() as in > try_to_migrate_one(). Is it a issue in the original code? I think it has? There is: /* Set the dirty flag on the folio now the pte is gone. */ if (pte_dirty(pteval)) folio_mark_dirty(folio); ? Thanks, -- Peter Xu