From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f175.google.com (mail-wi0-f175.google.com [209.85.212.175]) by kanga.kvack.org (Postfix) with ESMTP id 24F886B006E for ; Fri, 15 May 2015 07:33:36 -0400 (EDT) Received: by wicmc15 with SMTP id mc15so36730952wic.1 for ; Fri, 15 May 2015 04:33:35 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id j8si3245249wia.40.2015.05.15.04.33.34 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 15 May 2015 04:33:34 -0700 (PDT) Message-ID: <5555D98B.7010900@suse.cz> Date: Fri, 15 May 2015 13:33:31 +0200 From: Vlastimil Babka MIME-Version: 1.0 Subject: Re: [PATCHv5 01/28] mm, proc: adjust PSS calculation References: <1429823043-157133-1-git-send-email-kirill.shutemov@linux.intel.com> <1429823043-157133-2-git-send-email-kirill.shutemov@linux.intel.com> <5554AD4D.9040000@suse.cz> <20150515105621.GA6250@node.dhcp.inet.fi> In-Reply-To: <20150515105621.GA6250@node.dhcp.inet.fi> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: "Kirill A. Shutemov" , Andrew Morton , Andrea Arcangeli , Hugh Dickins , Dave Hansen , Mel Gorman , Rik van Riel , Christoph Lameter , Naoya Horiguchi , Steve Capper , "Aneesh Kumar K.V" , Johannes Weiner , Michal Hocko , Jerome Marchand , Sasha Levin , linux-kernel@vger.kernel.org, linux-mm@kvack.org On 05/15/2015 12:56 PM, Kirill A. Shutemov wrote: > On Thu, May 14, 2015 at 04:12:29PM +0200, Vlastimil Babka wrote: >> On 04/23/2015 11:03 PM, Kirill A. Shutemov wrote: >>> With new refcounting all subpages of the compound page are not nessessary >>> have the same mapcount. We need to take into account mapcount of every >>> sub-page. >>> >>> Signed-off-by: Kirill A. Shutemov >>> Tested-by: Sasha Levin >> >> Acked-by: Vlastimil Babka >> >> (some nitpicks below) >> >>> --- >>> fs/proc/task_mmu.c | 43 ++++++++++++++++++++++--------------------- >>> 1 file changed, 22 insertions(+), 21 deletions(-) >>> >>> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c >>> index 956b75d61809..95bc384ee3f7 100644 >>> --- a/fs/proc/task_mmu.c >>> +++ b/fs/proc/task_mmu.c >>> @@ -449,9 +449,10 @@ struct mem_size_stats { >>> }; >>> >>> static void smaps_account(struct mem_size_stats *mss, struct page *page, >>> - unsigned long size, bool young, bool dirty) >>> + bool compound, bool young, bool dirty) >>> { >>> - int mapcount; >>> + int i, nr = compound ? hpage_nr_pages(page) : 1; >> >> Why not just HPAGE_PMD_NR instead of hpage_nr_pages(page)? > > Okay, makes sense. Compiler is smart enough to optimize away HPAGE_PMD_NR > for THP=n. (HPAGE_PMD_NR is BUILD_BUG() for THP=n) Ah, BUILD_BUG()... I'm not sure we can rely on optimization to avoid BUILD_BUG(), what if somebody compiles with all optimizations off? So why not replace BUILD_BUG() with "1", or create a variant of HPAGE_PMD_NR that does that, for this case and patch 3. Seems better than testing PageTransHuge everywhere... -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org