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[2607:7c80:54:e::133]) by mx.google.com with ESMTPS id q23si8306662pgq.246.2019.05.10.09.52.14 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 10 May 2019 09:52:14 -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=MRHCCiJ+; 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-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To: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=hkMgP0pxOFd4HXfh4zG7QpG6/qI5aXSYBZKtEO3EEOI=; b=MRHCCiJ+3KeZif+1OowuNRo8gx rw7Pi279ZHHTn8y+BPlMF+KGvPAKwTr37z9Le5nCCU1xz0k7mZTBVhCYs+rrX1T4qSXTySjZOVkgi FBkfp8faCE6Yp6LnvgcG3RoGA3/Q4LrApYMwdTfaWfeoBJIh3f9bdUwV4LpCNcqccpSO9e5SzeC55 bwjPm+PaV0By4jwPQ29iFDXr0OACaYxAJJILFO4Gni3WsTwj68bWAnoSyx3FpWLgXcaFSd6ZirxlU 0IGUnh+W3pbx1E1b1A5SgRfD666iyufVPJKb++1gBE6nHF68XkZ6DP/SWIcLissANZMhMeybeCplc PoVJlybA==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1hP8kh-00045a-F2; Fri, 10 May 2019 16:52:07 +0000 Date: Fri, 10 May 2019 09:52:07 -0700 From: Matthew Wilcox To: Yang Shi Cc: "Huang, Ying" , hannes@cmpxchg.org, mhocko@suse.com, mgorman@techsingularity.net, kirill.shutemov@linux.intel.com, hughd@google.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: vmscan: correct nr_reclaimed for THP Message-ID: <20190510165207.GB3162@bombadil.infradead.org> References: <1557447392-61607-1-git-send-email-yang.shi@linux.alibaba.com> <87y33fjbvr.fsf@yhuang-dev.intel.com> <20190510163612.GA23417@bombadil.infradead.org> <3a919cba-fefe-d78e-313a-8f0d81a4a75d@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <3a919cba-fefe-d78e-313a-8f0d81a4a75d@linux.alibaba.com> User-Agent: Mutt/1.9.2 (2017-12-15) 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 Fri, May 10, 2019 at 09:50:04AM -0700, Yang Shi wrote: > On 5/10/19 9:36 AM, Matthew Wilcox wrote: > > On Fri, May 10, 2019 at 10:12:40AM +0800, Huang, Ying wrote: > > > > + nr_reclaimed += (1 << compound_order(page)); > > > How about to change this to > > > > > > nr_reclaimed += hpage_nr_pages(page); > > Please don't. That embeds the knowledge that we can only swap out either > > normal pages or THP sized pages. I'm trying to make the VM capable of > > supporting arbitrary-order pages, and this would be just one more place > > to fix. > > > > I'm sympathetic to the "self documenting" argument. My current tree has > > a patch in it: > > > > mm: Introduce compound_nr > > Replace 1 << compound_order(page) with compound_nr(page). Minor > > improvements in readability. > > > > It goes along with this patch: > > > > mm: Introduce page_size() > > > > It's unnecessarily hard to find out the size of a potentially huge page. > > Replace 'PAGE_SIZE << compound_order(page)' with page_size(page). > > So you prefer keeping using  "1 << compound_order" as v1 did? Then you will > convert all "1 << compound_order" to compound_nr? Yes. Please, let's merge v1 and ignore v2.