From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751454AbeDER6r (ORCPT ); Thu, 5 Apr 2018 13:58:47 -0400 Received: from out5-smtp.messagingengine.com ([66.111.4.29]:55221 "EHLO out5-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751285AbeDER6p (ORCPT ); Thu, 5 Apr 2018 13:58:45 -0400 X-ME-Sender: From: "Zi Yan" To: "Michal Hocko" Cc: "Kirill A. Shutemov" , "Naoya Horiguchi" , linux-mm@kvack.org, "Andrew Morton" , "Vlastimil Babka" , linux-kernel@vger.kernel.org Subject: Re: [PATCH v1] mm: consider non-anonymous thp as unmovable page Date: Thu, 05 Apr 2018 13:58:43 -0400 X-Mailer: MailMate (2.0BETAr6106) Message-ID: <7C2DE363-E113-4284-B94F-814F386743DF@sent.com> In-Reply-To: <20180405160317.GP6312@dhcp22.suse.cz> References: <20180403075928.GC5501@dhcp22.suse.cz> <20180403082405.GA23809@hori1.linux.bs1.fc.nec.co.jp> <20180403083451.GG5501@dhcp22.suse.cz> <20180403105411.hknofkbn6rzs26oz@node.shutemov.name> <20180405085927.GC6312@dhcp22.suse.cz> <20180405122838.6a6b35psizem4tcy@node.shutemov.name> <20180405124830.GJ6312@dhcp22.suse.cz> <20180405134045.7axuun6d7ufobzj4@node.shutemov.name> <20180405150547.GN6312@dhcp22.suse.cz> <20180405155551.wchleyaf4rxooj6m@node.shutemov.name> <20180405160317.GP6312@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=_MailMate_59658812-A57F-4162-ADE9-D428C633317B_="; micalg=pgp-sha512; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 3156 and 4880). --=_MailMate_59658812-A57F-4162-ADE9-D428C633317B_= Content-Type: text/plain On 5 Apr 2018, at 12:03, Michal Hocko wrote: > On Thu 05-04-18 18:55:51, Kirill A. Shutemov wrote: >> On Thu, Apr 05, 2018 at 05:05:47PM +0200, Michal Hocko wrote: >>> On Thu 05-04-18 16:40:45, Kirill A. Shutemov wrote: >>>> On Thu, Apr 05, 2018 at 02:48:30PM +0200, Michal Hocko wrote: >>> [...] >>>>> RIght, I confused the two. What is the proper layer to fix that then? >>>>> rmap_walk_file? >>>> >>>> Maybe something like this? Totally untested. >>> >>> This looks way too complex. Why cannot we simply split THP page cache >>> during migration? >> >> This way we unify the codepath for archictures that don't support THP >> migration and shmem THP. > > But why? There shouldn't be really nothing to prevent THP (anon or > shemem) to be migratable. If we cannot migrate it at once we can always > split it. So why should we add another thp specific handling all over > the place? Then, it would be much easier if your "unclutter thp migration" patches is merged, plus the patch below: diff --git a/mm/migrate.c b/mm/migrate.c index 60531108021a..b4087aa890f5 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1138,7 +1138,9 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page, int rc = MIGRATEPAGE_SUCCESS; struct page *newpage; - if (!thp_migration_supported() && PageTransHuge(page)) + if ((!thp_migration_supported() || + (thp_migration_supported() && !PageAnon(page))) && + PageTransHuge(page)) return -ENOMEM; newpage = get_new_page(page, private) -- Best Regards Yan Zi --=_MailMate_59658812-A57F-4162-ADE9-D428C633317B_= Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQEcBAEBCgAGBQJaxmPTAAoJEEGLLxGcTqbMGgAIAKnOSuGNcjeF+rn47lUvbr7J lUFh+Q4lkvFFXajiO1H+A69eU/ZUmhHhkBEDHGFb4cR+Zbp6eHZ/5HAFVQcU+ftG UsaEZ/IEXFmSxevG3Z6h3Uo/84eNhs+QpnrjClf5Jp3tZhODlPHBfLAwcG0H1oef x1oj3fx4ShI6/9/28JpozBLDBCgs2ZMHKxY709PVhICAzjY3gc1vdrfCfXb3UqiP LWJw1PzPBg+FyjKA9oi9lFA/mYTQs2GfmIiGFXKLONaN8r7wtZ7kLauL9h2+vaZX be313lynxDNyZlsmLAFEnG1wIUvSfgY9nLcXJJidV0L7EEeHcS4VX+8bgLvQZVs= =rWLp -----END PGP SIGNATURE----- --=_MailMate_59658812-A57F-4162-ADE9-D428C633317B_=--