From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932646AbcBDX36 (ORCPT ); Thu, 4 Feb 2016 18:29:58 -0500 Received: from TYO202.gate.nec.co.jp ([210.143.35.52]:63466 "EHLO tyo202.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750744AbcBDX35 convert rfc822-to-8bit (ORCPT ); Thu, 4 Feb 2016 18:29:57 -0500 From: Naoya Horiguchi To: Vladimir Davydov CC: Andrew Morton , Konstantin Khlebnikov , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "Naoya Horiguchi" Subject: Re: [PATCH v1 1/3] /proc/kpageflags: return KPF_BUDDY for "tail" buddy pages Thread-Topic: [PATCH v1 1/3] /proc/kpageflags: return KPF_BUDDY for "tail" buddy pages Thread-Index: AQHRXxrp4MhWnfrwk0aTxzR7XviAqp8bgPkAgABxpgA= Date: Thu, 4 Feb 2016 23:29:13 +0000 Message-ID: <20160204232912.GA29354@hori1.linux.bs1.fc.nec.co.jp> References: <1454569683-17918-1-git-send-email-n-horiguchi@ah.jp.nec.com> <20160204164226.GA16895@esperanza> In-Reply-To: <20160204164226.GA16895@esperanza> Accept-Language: ja-JP, en-US Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.128.101.1] Content-Type: text/plain; charset="iso-2022-jp" Content-ID: <3508D0569BA5574F8ED5E88765E9A2F1@gisp.nec.co.jp> Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 04, 2016 at 07:42:26PM +0300, Vladimir Davydov wrote: > On Thu, Feb 04, 2016 at 04:08:01PM +0900, Naoya Horiguchi wrote: > > Currently /proc/kpageflags returns nothing for "tail" buddy pages, which > > is inconvenient when grasping how free pages are distributed. This patch > > sets KPF_BUDDY for such pages. > > Looks reasonable to me, > > Reviewed-by: Vladimir Davydov Thank you. > > > > With this patch: > > > > $ grep MemFree /proc/meminfo ; tools/vm/page-types -b buddy > > MemFree: 3134992 kB > > flags page-count MB symbolic-flags long-symbolic-flags > > 0x0000000000000400 779272 3044 __________B_______________________________ buddy > > 0x0000000000000c00 4385 17 __________BM______________________________ buddy,mmap > > total 783657 3061 > > Why are buddy pages reported as mmapped? That looks weird. Shouldn't we > fix it? Something like this, may be? > > -- > From: Vladimir Davydov > Subject: [PATCH] proc: kpageflags: do not report buddy and balloon pages as > mapped > > PageBuddy and PageBalloon are not usual page flags - they are identified > by a special negative (so as not to confuse with mapped pages) value of > page->_mapcount. Since /proc/kpageflags uses page_mapcount helper to > check if a page is mapped, it reports pages of these kinds as being > mapped, which is confusing. Fix that by replacing page_mapcount with > page_mapped. > > Signed-off-by: Vladimir Davydov > > diff --git a/fs/proc/page.c b/fs/proc/page.c > index b2855eea5405..332450d87ea4 100644 > --- a/fs/proc/page.c > +++ b/fs/proc/page.c > @@ -105,7 +105,7 @@ u64 stable_page_flags(struct page *page) > * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the > * simple test in page_mapcount() is not enough. We can do s/page_mapcount/page_mapped/ for this line too. > */ > - if (!PageSlab(page) && page_mapcount(page)) > + if (!PageSlab(page) && page_mapped(page)) Look good to me. Acked-by: Naoya Horiguchi > u |= 1 << KPF_MMAP; > if (PageAnon(page)) > u |= 1 << KPF_ANON; From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f41.google.com (mail-pa0-f41.google.com [209.85.220.41]) by kanga.kvack.org (Postfix) with ESMTP id 1EE724403D8 for ; Thu, 4 Feb 2016 18:29:56 -0500 (EST) Received: by mail-pa0-f41.google.com with SMTP id cy9so23372619pac.0 for ; Thu, 04 Feb 2016 15:29:56 -0800 (PST) Received: from tyo202.gate.nec.co.jp (TYO202.gate.nec.co.jp. [210.143.35.52]) by mx.google.com with ESMTPS id sj10si19572095pab.65.2016.02.04.15.29.54 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 04 Feb 2016 15:29:55 -0800 (PST) From: Naoya Horiguchi Subject: Re: [PATCH v1 1/3] /proc/kpageflags: return KPF_BUDDY for "tail" buddy pages Date: Thu, 4 Feb 2016 23:29:13 +0000 Message-ID: <20160204232912.GA29354@hori1.linux.bs1.fc.nec.co.jp> References: <1454569683-17918-1-git-send-email-n-horiguchi@ah.jp.nec.com> <20160204164226.GA16895@esperanza> In-Reply-To: <20160204164226.GA16895@esperanza> Content-Language: ja-JP Content-Type: text/plain; charset="iso-2022-jp" Content-ID: <3508D0569BA5574F8ED5E88765E9A2F1@gisp.nec.co.jp> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Vladimir Davydov Cc: Andrew Morton , Konstantin Khlebnikov , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Naoya Horiguchi On Thu, Feb 04, 2016 at 07:42:26PM +0300, Vladimir Davydov wrote: > On Thu, Feb 04, 2016 at 04:08:01PM +0900, Naoya Horiguchi wrote: > > Currently /proc/kpageflags returns nothing for "tail" buddy pages, whic= h > > is inconvenient when grasping how free pages are distributed. This patc= h > > sets KPF_BUDDY for such pages. >=20 > Looks reasonable to me, >=20 > Reviewed-by: Vladimir Davydov Thank you. > >=20 > > With this patch: > >=20 > > $ grep MemFree /proc/meminfo ; tools/vm/page-types -b buddy > > MemFree: 3134992 kB > > flags page-count MB symbolic-flags = long-symbolic-flags > > 0x0000000000000400 779272 3044 __________B_____________= __________________ buddy > > 0x0000000000000c00 4385 17 __________BM____________= __________________ buddy,mmap > > total 783657 3061 >=20 > Why are buddy pages reported as mmapped? That looks weird. Shouldn't we > fix it? Something like this, may be? >=20 > -- > From: Vladimir Davydov > Subject: [PATCH] proc: kpageflags: do not report buddy and balloon pages = as > mapped >=20 > PageBuddy and PageBalloon are not usual page flags - they are identified > by a special negative (so as not to confuse with mapped pages) value of > page->_mapcount. Since /proc/kpageflags uses page_mapcount helper to > check if a page is mapped, it reports pages of these kinds as being > mapped, which is confusing. Fix that by replacing page_mapcount with > page_mapped. >=20 > Signed-off-by: Vladimir Davydov >=20 > diff --git a/fs/proc/page.c b/fs/proc/page.c > index b2855eea5405..332450d87ea4 100644 > --- a/fs/proc/page.c > +++ b/fs/proc/page.c > @@ -105,7 +105,7 @@ u64 stable_page_flags(struct page *page) > * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the > * simple test in page_mapcount() is not enough. We can do s/page_mapcount/page_mapped/ for this line too. > */ > - if (!PageSlab(page) && page_mapcount(page)) > + if (!PageSlab(page) && page_mapped(page)) Look good to me. Acked-by: Naoya Horiguchi > u |=3D 1 << KPF_MMAP; > if (PageAnon(page)) > u |=3D 1 << KPF_ANON;= -- 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/ . 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