From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751837Ab2G1FCm (ORCPT ); Sat, 28 Jul 2012 01:02:42 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:44604 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751198Ab2G1FCk (ORCPT ); Sat, 28 Jul 2012 01:02:40 -0400 Date: Sat, 28 Jul 2012 02:02:31 -0300 From: Herton Ronaldo Krzesinski To: Greg Kroah-Hartman Cc: Mel Gorman , linux-kernel@vger.kernel.org, stable@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Miao Xie , David Rientjes , Peter Zijlstra , Christoph Lameter Subject: Re: [ 39/40] cpuset: mm: reduce large amounts of memory barrier related damage v3 Message-ID: <20120728050230.GA9155@herton-Z68MA-D2H-B3> References: <20120726211424.GA7709@kroah.com> <20120726211411.164006056@linuxfoundation.org> <20120726211414.752069185@linuxfoundation.org> <20120727150823.GD3033@herton-Z68MA-D2H-B3> <20120727152347.GG612@suse.de> <20120727190116.GA29646@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120727190116.GA29646@kroah.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 27, 2012 at 12:01:16PM -0700, Greg Kroah-Hartman wrote: > On Fri, Jul 27, 2012 at 04:23:47PM +0100, Mel Gorman wrote: > > > > --- a/mm/slub.c > > > > +++ b/mm/slub.c > > > > @@ -1457,6 +1457,7 @@ static struct page *get_any_partial(stru > > > > struct zone *zone; > > > > enum zone_type high_zoneidx = gfp_zone(flags); > > > > struct page *page; > > > > + unsigned int cpuset_mems_cookie; > > > > > > > > /* > > > > * The defrag ratio allows a configuration of the tradeoffs between > > > > @@ -1480,22 +1481,32 @@ static struct page *get_any_partial(stru > > > > get_cycles() % 1024 > s->remote_node_defrag_ratio) > > > > return NULL; > > > > > > > > - get_mems_allowed(); > > > > - zonelist = node_zonelist(slab_node(current->mempolicy), flags); > > > > - for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { > > > > - struct kmem_cache_node *n; > > > > + do { > > > > + cpuset_mems_cookie = get_mems_allowed(); > > > > + zonelist = node_zonelist(slab_node(current->mempolicy), flags); > > > > + for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { > > > > + struct kmem_cache_node *n; > > > > > > > > - n = get_node(s, zone_to_nid(zone)); > > > > + n = get_node(s, zone_to_nid(zone)); > > > > > > > > - if (n && cpuset_zone_allowed_hardwall(zone, flags) && > > > > - n->nr_partial > s->min_partial) { > > > > - page = get_partial_node(n); > > > > - if (page) { > > > > - put_mems_allowed(); > > > > - return page; > > > > + if (n && cpuset_zone_allowed_hardwall(zone, flags) && > > > > + n->nr_partial > s->min_partial) { > > > > + page = get_partial_node(n); > > > > + if (page) { > > > > + /* > > > > + * Return the object even if > > > > + * put_mems_allowed indicated that > > > > + * the cpuset mems_allowed was > > > > + * updated in parallel. It's a > > > > + * harmless race between the alloc > > > > + * and the cpuset update. > > > > + */ > > > > + put_mems_allowed(cpuset_mems_cookie); > > > > + return page; > > > > + } > > > > } > > > > } > > > > - } > > > > + } while (!put_mems_allowed(cpuset_mems_cookie)); > > > > put_mems_allowed(); > > > > > > This doesn't build on 3.0, the backport left the stray put_mems_allowed > > > above: > > > > > > linux-stable/mm/slub.c: In function 'get_any_partial': > > > linux-stable/mm/slub.c:1510:2: error: too few arguments to function 'put_mems_allowed' > > > linux-stable/include/linux/cpuset.h:108:20: note: declared here > > > > > > > That line should have been deleted and tests were based on slab. My > > apologies. > > > > ---8<--- > > cpuset: mm: Reduce large amounts of memory barrier related damage fix > > > > linux-stable/mm/slub.c: In function 'get_any_partial': > > linux-stable/mm/slub.c:1510:2: error: too few arguments to function 'put_mems_allowed' > > linux-stable/include/linux/cpuset.h:108:20: note: declared here > > > > Reported-by: Herton Ronaldo Krzesinski > > Signed-off-by: Mel Gorman > > > > diff --git a/mm/slub.c b/mm/slub.c > > index 00ccf2c..ae6e80e 100644 > > --- a/mm/slub.c > > +++ b/mm/slub.c > > @@ -1507,7 +1507,6 @@ static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags) > > } > > } > > } while (!put_mems_allowed(cpuset_mems_cookie)); > > - put_mems_allowed(); > > #endif > > return NULL; > > } > > Thanks, I've merged this with the "original" in the tree, so all should > be good now. Thanks. I saw what seems another issue now on the patch too, sorry for not noticing earlier: this backport is lacking the write_seqcount_{begin,end} on set_mems_allowed for the case with CONFIG_CPUSETS, like in the original patch: static inline void set_mems_allowed(nodemask_t nodemask) { task_lock(current); + write_seqcount_begin(¤t->mems_allowed_seq); current->mems_allowed = nodemask; + write_seqcount_end(¤t->mems_allowed_seq); task_unlock(current); } > > greg k-h > -- > To unsubscribe from this list: send the line "unsubscribe stable" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- []'s Herton