From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx186.postini.com [74.125.245.186]) by kanga.kvack.org (Postfix) with SMTP id 1F3C96B004A for ; Tue, 10 Apr 2012 11:00:50 -0400 (EDT) Received: by vbbey12 with SMTP id ey12so4231310vbb.14 for ; Tue, 10 Apr 2012 08:00:49 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1334000524-23972-1-git-send-email-yinghan@google.com> References: <1334000524-23972-1-git-send-email-yinghan@google.com> Date: Tue, 10 Apr 2012 23:00:48 +0800 Message-ID: Subject: Re: [PATCH] Revert "mm: vmscan: fix misused nr_reclaimed in shrink_mem_cgroup_zone()" From: Hillf Danton Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Ying Han Cc: Andrew Morton , Rik van Riel , Hugh Dickins , linux-mm@kvack.org On Tue, Apr 10, 2012 at 3:42 AM, Ying Han wrote: > This reverts commit c38446cc65e1f2b3eb8630c53943b94c4f65f670. > > Before the commit, the code makes senses to me but not after the commit. = The > "nr_reclaimed" is the number of pages reclaimed by scanning through the m= emcg's > lru lists. The "nr_to_reclaim" is the target value for the whole function= . For > example, we like to early break the reclaim if reclaimed 32 pages under d= irect > reclaim (not DEF_PRIORITY). > > After the reverted commit, the target "nr_to_reclaim" is decremented each= time > by "nr_reclaimed" but we still use it to compare the "nr_reclaimed". It j= ust > doesn't make sense to me... > I downloaded mm/vmscan.c from the next tree a couple minutes ago, and see .nr_to_reclaim =3D SWAP_CLUSTER_MAX, and nr_reclaimed =3D do_try_to_free_pages(zonelist, &sc, &shrink); in try_to_free_pages(). I also see total_scanned +=3D sc->nr_scanned; if (sc->nr_reclaimed >=3D sc->nr_to_reclaim) goto out; in do_try_to_free_pages(), then would you please say a few words about the sense of the check of nr_to_reclaim? > Signed-off-by: Ying Han > --- > =C2=A0mm/vmscan.c | =C2=A0 =C2=A07 +------ > =C2=A01 files changed, 1 insertions(+), 6 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 33c332b..1a51868 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -2107,12 +2107,7 @@ restart: > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 * with multiple p= rocesses reclaiming pages, the total > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 * freeing target = can get unreasonably large. > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 */ > - =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 if (nr_reclaimed >=3D = nr_to_reclaim) > - =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 nr_to_reclaim =3D 0; > - =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 else > - =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 nr_to_reclaim -=3D nr_reclaimed; > - > - =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 if (!nr_to_reclaim && = priority < DEF_PRIORITY) > + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 if (nr_reclaimed >=3D = nr_to_reclaim && priority < DEF_PRIORITY) > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0break; > =C2=A0 =C2=A0 =C2=A0 =C2=A0} > =C2=A0 =C2=A0 =C2=A0 =C2=A0blk_finish_plug(&plug); > -- > 1.7.7.3 > -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org