From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id C29126B0038 for ; Wed, 9 Nov 2016 18:53:43 -0500 (EST) Received: by mail-pf0-f197.google.com with SMTP id 83so97324536pfx.1 for ; Wed, 09 Nov 2016 15:53:43 -0800 (PST) Received: from tyo201.gate.nec.co.jp (TYO201.gate.nec.co.jp. [210.143.35.51]) by mx.google.com with ESMTPS id g68si1691728pfe.278.2016.11.09.15.53.42 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 09 Nov 2016 15:53:42 -0800 (PST) From: Naoya Horiguchi Subject: Re: [PATCH v2 00/12] mm: page migration enhancement for thp Date: Wed, 9 Nov 2016 23:52:25 +0000 Message-ID: <20161109235223.GA31285@hori1.linux.bs1.fc.nec.co.jp> References: <1478561517-4317-1-git-send-email-n-horiguchi@ah.jp.nec.com> <5822FB60.5040905@linux.vnet.ibm.com> In-Reply-To: <5822FB60.5040905@linux.vnet.ibm.com> Content-Language: ja-JP Content-Type: text/plain; charset="iso-2022-jp" Content-ID: <8D6B989798C35F4BA47BC60D561EFF77@gisp.nec.co.jp> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Anshuman Khandual Cc: "linux-mm@kvack.org" , "Kirill A. Shutemov" , Hugh Dickins , Andrew Morton , Dave Hansen , Andrea Arcangeli , Mel Gorman , Michal Hocko , Vlastimil Babka , Pavel Emelyanov , Zi Yan , Balbir Singh , "linux-kernel@vger.kernel.org" , Naoya Horiguchi Hi Anshuman, On Wed, Nov 09, 2016 at 04:03:04PM +0530, Anshuman Khandual wrote: > On 11/08/2016 05:01 AM, Naoya Horiguchi wrote: > > Hi everyone, > >=20 > > I've updated thp migration patches for v4.9-rc2-mmotm-2016-10-27-18-27 > > with feedbacks for ver.1. > >=20 > > General description (no change since ver.1) > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > >=20 > > This patchset enhances page migration functionality to handle thp migra= tion > > for various page migration's callers: > > - mbind(2) > > - move_pages(2) > > - migrate_pages(2) > > - cgroup/cpuset migration > > - memory hotremove > > - soft offline > >=20 > > The main benefit is that we can avoid unnecessary thp splits, which hel= ps us > > avoid performance decrease when your applications handles NUMA optimiza= tion on > > their own. > >=20 > > The implementation is similar to that of normal page migration, the key= point > > is that we modify a pmd to a pmd migration entry in swap-entry like for= mat. >=20 > Will it be better to have new THP_MIGRATE_SUCCESS and THP_MIGRATE_FAIL > VM events to capture how many times the migration worked without first > splitting the huge page and how many time it did not work ? Thank you for the suggestion. I think that's helpful, so will try it in next version. > Also do you > have a test case which demonstrates this THP migration and kind of shows > its better than the present split and move method ? I don't have test cases which compare thp migration and split-then-migratio= n with some numbers. Maybe measuring/comparing the overhead of migration is a good start point, although I think the real benefit of thp migration come= s from workload "after migration" by avoiding thp split. Thanks, Naoya Horiguchi= -- 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