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[2607:7c80:54:e::133]) by mx.google.com with ESMTPS id j21si18862570pll.271.2019.03.27.04.50.14 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 27 Mar 2019 04:50:14 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) client-ip=2607:7c80:54:e::133; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=oD1tLB1L; spf=pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=willy@infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=2JzlpAdmBNeKMsGiSD5xhZyfgPsLZPvBX1ubCGB+Vp4=; b=oD1tLB1LI3PFhkaSfE94lSSu2 XTkPysAFfESqqcrrs2InrIzcIc7i/4K1M/op6bcQ+UwM0qEqs/td4nlDx/qSxbzTfD/oruxX6T2Bw F6vw+B2osm0M00olhuxJCpPiSx1bbrJT2XC1phaZmisSugXDub4Imf8+bgKqNZgN5sHRGnisdGSUE nAHn70Tf+8N0OdP1HKovK04T34W6LBfbMt4Knx2hhmuoWsyBVXhKYGhmr3L8MQ9u1MPs0y/i9iZeE VS9XbSCxSjMe4cNhqyr3CrAJrG2VdcjPlIqZnnHgcl/nwIBVmuW2rPw56Mi7lpAP1kZtvS/+GA8KY p4HXvFMcA==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1h974M-0000Lc-OB; Wed, 27 Mar 2019 11:50:10 +0000 Date: Wed, 27 Mar 2019 04:50:10 -0700 From: Matthew Wilcox To: William Kucharski Cc: Qian Cai , Huang Ying , linux-mm@kvack.org Subject: Re: page cache: Store only head pages in i_pages Message-ID: <20190327115010.GQ10344@bombadil.infradead.org> References: <1553285568.26196.24.camel@lca.pw> <20190323033852.GC10344@bombadil.infradead.org> <20190324020614.GD10344@bombadil.infradead.org> <897cfdda-7686-3794-571a-ecb8b9f6101f@lca.pw> <20190324030422.GE10344@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.2 (2017-12-15) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000308, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Mar 27, 2019 at 04:48:42AM -0600, William Kucharski wrote: > > On Mar 23, 2019, at 9:04 PM, Matthew Wilcox wrote: > > static inline struct page *find_subpage(struct page *page, pgoff_t offset) > > { > > + unsigned long index = page_index(page); > > + > > VM_BUG_ON_PAGE(PageTail(page), page); > > - VM_BUG_ON_PAGE(page->index > offset, page); > > - VM_BUG_ON_PAGE(page->index + (1 << compound_order(page)) <= offset, > > - page); > > - return page - page->index + offset; > > + VM_BUG_ON_PAGE(index > offset, page); > > + VM_BUG_ON_PAGE(index + (1 << compound_order(page)) <= offset, page); > > + return page - index + offset; > > } > > > > > >> [ 56.915812] page dumped because: VM_BUG_ON_PAGE(index + compound_order(page) > >> <= offset) > > Is a V5 patch coming incorporating these? No; Andrew prefers to accumulate fixes as separate patches, so that's what I sent on March 24th; Andrew added it to -mm yesterday.