From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756393AbaEIPoR (ORCPT ); Fri, 9 May 2014 11:44:17 -0400 Received: from mail-pa0-f47.google.com ([209.85.220.47]:53397 "EHLO mail-pa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751748AbaEIPoP (ORCPT ); Fri, 9 May 2014 11:44:15 -0400 From: Michal Nazarewicz To: Joonsoo Kim , Andrew Morton Cc: Rik van Riel , Johannes Weiner , Mel Gorman , Joonsoo Kim , Laura Abbott , Minchan Kim , Heesub Shin , Marek Szyprowski , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 1/3] CMA: remove redundant retrying code in __alloc_contig_migrate_range In-Reply-To: <1399509144-8898-2-git-send-email-iamjoonsoo.kim@lge.com> Organization: http://mina86.com/ References: <1399509144-8898-1-git-send-email-iamjoonsoo.kim@lge.com> <1399509144-8898-2-git-send-email-iamjoonsoo.kim@lge.com> User-Agent: Notmuch/0.17+15~gb65ca8e (http://notmuchmail.org) Emacs/24.3.50.1 (x86_64-unknown-linux-gnu) X-Face: PbkBB1w#)bOqd`iCe"Ds{e+!C7`pkC9a|f)Qo^BMQvy\q5x3?vDQJeN(DS?|-^$uMti[3D*#^_Ts"pU$jBQLq~Ud6iNwAw_r_o_4]|JO?]}P_}Nc&"p#D(ZgUb4uCNPe7~a[DbPG0T~!&c.y$Ur,=N4RT>]dNpd;KFrfMCylc}gc??'U2j,!8%xdD Face: 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 X-PGP: 50751FF4 X-PGP-FP: AC1F 5F5C D418 88F8 CC84 5858 2060 4012 5075 1FF4 X-Hashcash: 1:20:140509:iamjoonsoo.kim@lge.com::TESFHnDQVc6ItF7n:0000000000000000000000000000000000000000dZy X-Hashcash: 1:20:140509:hannes@cmpxchg.org::gvLdQCyuEuYycmaz:00000000000000000000000000000000000000000000gQa X-Hashcash: 1:20:140509:iamjoonsoo.kim@lge.com::xLrSo7AUpGIExFcb:0000000000000000000000000000000000000000S7H X-Hashcash: 1:20:140509:m.szyprowski@samsung.com::BOOx9wCDJ98d7kky:000000000000000000000000000000000000015gF X-Hashcash: 1:20:140509:riel@redhat.com::/jx7R2FDMgRaVIlv:002Hgm X-Hashcash: 1:20:140509:linux-kernel@vger.kernel.org::EKY3qKinWEKGWGd4:0000000000000000000000000000000001/Vu X-Hashcash: 1:20:140509:akpm@linux-foundation.org::ObeCDMIbIv3XQox6:00000000000000000000000000000000000025mA X-Hashcash: 1:20:140509:mgorman@suse.de::H7HpknEYyVRBs4s2:002X9/ X-Hashcash: 1:20:140509:minchan@kernel.org::QpasDFc4iNPaqoer:00000000000000000000000000000000000000000002JPd X-Hashcash: 1:20:140509:lauraa@codeaurora.org::eElI9U0wf/zVdS9w:00000000000000000000000000000000000000003S6g X-Hashcash: 1:20:140509:heesub.shin@samsung.com::UOJ6jEmDigYNx2O4:0000000000000000000000000000000000000035Hd X-Hashcash: 1:20:140509:linux-mm@kvack.org::sPXPBazAcS3zu/Mk:00000000000000000000000000000000000000000002wyc Date: Fri, 09 May 2014 08:44:06 -0700 Message-ID: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="=-=-=" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-=-= Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Wed, May 07 2014, Joonsoo Kim wrote: > We already have retry logic in migrate_pages(). It does retry 10 times. > So if we keep this retrying code in __alloc_contig_migrate_range(), we > would try to migrate some unmigratable page in 50 times. There is just one > small difference in -ENOMEM case. migrate_pages() don't do retry > in this case, however, current __alloc_contig_migrate_range() does. But, > I think that this isn't problem, because in this case, we may fail again > with same reason. > > Signed-off-by: Joonsoo Kim I think there was a reason for the retries in __alloc_contig_migrate_range but perhaps those are no longer valid. Acked-by: Michal Nazarewicz > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 5dba293..674ade7 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -6185,7 +6185,6 @@ static int __alloc_contig_migrate_range(struct comp= act_control *cc, > /* This function is based on compact_zone() from compaction.c. */ > unsigned long nr_reclaimed; > unsigned long pfn =3D start; > - unsigned int tries =3D 0; > int ret =3D 0; >=20=20 > migrate_prep(); > @@ -6204,10 +6203,6 @@ static int __alloc_contig_migrate_range(struct com= pact_control *cc, > ret =3D -EINTR; > break; > } > - tries =3D 0; > - } else if (++tries =3D=3D 5) { > - ret =3D ret < 0 ? ret : -EBUSY; > - break; > } >=20=20 > nr_reclaimed =3D reclaim_clean_pages_from_list(cc->zone, > @@ -6216,6 +6211,10 @@ static int __alloc_contig_migrate_range(struct com= pact_control *cc, >=20=20 > ret =3D migrate_pages(&cc->migratepages, alloc_migrate_target, > 0, MIGRATE_SYNC, MR_CMA); > + if (ret) { > + ret =3D ret < 0 ? ret : -EBUSY; > + break; > + } > } > if (ret < 0) { > putback_movable_pages(&cc->migratepages); --=20 Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=3D./ `o ..o | Computer Science, Micha=C5=82 =E2=80=9Cmina86=E2=80=9D Nazarewicz = (o o) ooo +------ooO--(_)--Ooo-- --=-=-= Content-Type: multipart/signed; boundary="==-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" --==-=-= Content-Type: text/plain --==-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAEBAgAGBQJTbPfGAAoJECBgQBJQdR/0nJQP/0htX/xZxE1ePn5SBbCWts+2 Zx9ESFvp1aZEQKrPQ/u692Imj99GtbUntwK4NPH9ponpK9ErSFoONK8h1FP2hgLG KF8IhmKSy3D2J37r/kLLmmSHJqw52uqIu1UefbUv3fDgHvULd9kKz0eRPNn4dJTv 9+Vv7AbW69v39Owwp2R84y7t5SrPGN/SlqABzii296zmGkXQrWkDwRFk17FJ/KqA RkmMSzkR+hMmAfefd2WcFeUASJDqTDMTxBKiUmEs9/WKSbkTRVa+Z+MRvpnKBTDs Ra6Ya13fbFDKAVXivZiU+fIJkxnCQmPUfbjoZQn6T9FwkC89aVZKnLyPldKcPKg5 BjtoX7/HWrK3ERrV+n3CjqwITZZ4kMWbY8O81PgmM0HFZKdunEdqZCj07O0og7G3 xW/zGGlpXRBeDQa6xAm08ZInl3PTt5yq89Sl6vrNmOsubjrNiP4HNfR5dSHk08Ly 69Cs3SpCrNp64IzISO8QjabCw7oGzZoMrl6bnWaHSmNllOZwkAPTGQjq4kS8kcH5 KAqtF0tgQZcqLRh8dnQI7/WS6r5ClcHnuKQpN+4XXXo6B00Dc0B7ypBMRlPYgKJ8 FoxIMP6HyFTxxEtrndpfC4q6jcleoBRSWXkOYFArFu6az9egW3wlIYCYUpGprDZh Gt6W2uDFcn0rHqEJoXGl =+M2V -----END PGP SIGNATURE----- --==-=-=-- --=-=-=--