From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751375Ab2JATBA (ORCPT ); Mon, 1 Oct 2012 15:01:00 -0400 Received: from zene.cmpxchg.org ([85.214.230.12]:58589 "EHLO zene.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750927Ab2JATA6 (ORCPT ); Mon, 1 Oct 2012 15:00:58 -0400 Date: Mon, 1 Oct 2012 15:00:48 -0400 From: Johannes Weiner To: Glauber Costa Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, kamezawa.hiroyu@jp.fujitsu.com, devel@openvz.org, Tejun Heo , linux-mm@kvack.org, Suleiman Souhlal , Frederic Weisbecker , Mel Gorman , David Rientjes Subject: Re: [PATCH v3 02/13] memcg: Reclaim when more than one page needed. Message-ID: <20121001190048.GC23734@cmpxchg.org> References: <1347977050-29476-1-git-send-email-glommer@parallels.com> <1347977050-29476-3-git-send-email-glommer@parallels.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1347977050-29476-3-git-send-email-glommer@parallels.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 18, 2012 at 06:03:59PM +0400, Glauber Costa wrote: > From: Suleiman Souhlal > > mem_cgroup_do_charge() was written before kmem accounting, and expects > three cases: being called for 1 page, being called for a stock of 32 > pages, or being called for a hugepage. If we call for 2 or 3 pages (and > both the stack and several slabs used in process creation are such, at > least with the debug options I had), it assumed it's being called for > stock and just retried without reclaiming. > > Fix that by passing down a minsize argument in addition to the csize. > > And what to do about that (csize == PAGE_SIZE && ret) retry? If it's Wow, that patch set has been around for a while. It's been nr_pages == 1 for a while now :-) > needed at all (and presumably is since it's there, perhaps to handle > races), then it should be extended to more than PAGE_SIZE, yet how far? > And should there be a retry count limit, of what? For now retry up to > COSTLY_ORDER (as page_alloc.c does) and make sure not to do it if > __GFP_NORETRY. > > [v4: fixed nr pages calculation pointed out by Christoph Lameter ] > > Signed-off-by: Suleiman Souhlal > Signed-off-by: Glauber Costa > Reviewed-by: Kamezawa Hiroyuki > Acked-by: Michal Hocko > --- > mm/memcontrol.c | 16 +++++++++------- > 1 file changed, 9 insertions(+), 7 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 9d3bc72..b12121b 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2232,7 +2232,8 @@ enum { > }; > > static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, > - unsigned int nr_pages, bool oom_check) > + unsigned int nr_pages, unsigned int min_pages, > + bool oom_check) I'm not a big fan of the parameter names. Can we make this function officially aware of batching and name the parameters like the arguments that are passed in? I.e. @batch and @nr_pages? > { > unsigned long csize = nr_pages * PAGE_SIZE; > struct mem_cgroup *mem_over_limit; > @@ -2255,18 +2256,18 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, > } else > mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); > /* > - * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch > - * of regular pages (CHARGE_BATCH), or a single regular page (1). > - * > * Never reclaim on behalf of optional batching, retry with a > * single page instead. "[...] with the amount of actually required pages instead." > */ > - if (nr_pages == CHARGE_BATCH) > + if (nr_pages > min_pages) > return CHARGE_RETRY; if (batch > nr_pages) return CHARGE_RETRY; But that is all just nitpicking. Functionally, it looks sane, so: Acked-by: Johannes Weiner From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Weiner Subject: Re: [PATCH v3 02/13] memcg: Reclaim when more than one page needed. Date: Mon, 1 Oct 2012 15:00:48 -0400 Message-ID: <20121001190048.GC23734@cmpxchg.org> References: <1347977050-29476-1-git-send-email-glommer@parallels.com> <1347977050-29476-3-git-send-email-glommer@parallels.com> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <1347977050-29476-3-git-send-email-glommer@parallels.com> Sender: owner-linux-mm@kvack.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Glauber Costa Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, kamezawa.hiroyu@jp.fujitsu.com, devel@openvz.org, Tejun Heo , linux-mm@kvack.org, Suleiman Souhlal , Frederic Weisbecker , Mel Gorman , David Rientjes On Tue, Sep 18, 2012 at 06:03:59PM +0400, Glauber Costa wrote: > From: Suleiman Souhlal > > mem_cgroup_do_charge() was written before kmem accounting, and expects > three cases: being called for 1 page, being called for a stock of 32 > pages, or being called for a hugepage. If we call for 2 or 3 pages (and > both the stack and several slabs used in process creation are such, at > least with the debug options I had), it assumed it's being called for > stock and just retried without reclaiming. > > Fix that by passing down a minsize argument in addition to the csize. > > And what to do about that (csize == PAGE_SIZE && ret) retry? If it's Wow, that patch set has been around for a while. It's been nr_pages == 1 for a while now :-) > needed at all (and presumably is since it's there, perhaps to handle > races), then it should be extended to more than PAGE_SIZE, yet how far? > And should there be a retry count limit, of what? For now retry up to > COSTLY_ORDER (as page_alloc.c does) and make sure not to do it if > __GFP_NORETRY. > > [v4: fixed nr pages calculation pointed out by Christoph Lameter ] > > Signed-off-by: Suleiman Souhlal > Signed-off-by: Glauber Costa > Reviewed-by: Kamezawa Hiroyuki > Acked-by: Michal Hocko > --- > mm/memcontrol.c | 16 +++++++++------- > 1 file changed, 9 insertions(+), 7 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 9d3bc72..b12121b 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2232,7 +2232,8 @@ enum { > }; > > static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, > - unsigned int nr_pages, bool oom_check) > + unsigned int nr_pages, unsigned int min_pages, > + bool oom_check) I'm not a big fan of the parameter names. Can we make this function officially aware of batching and name the parameters like the arguments that are passed in? I.e. @batch and @nr_pages? > { > unsigned long csize = nr_pages * PAGE_SIZE; > struct mem_cgroup *mem_over_limit; > @@ -2255,18 +2256,18 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, > } else > mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); > /* > - * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch > - * of regular pages (CHARGE_BATCH), or a single regular page (1). > - * > * Never reclaim on behalf of optional batching, retry with a > * single page instead. "[...] with the amount of actually required pages instead." > */ > - if (nr_pages == CHARGE_BATCH) > + if (nr_pages > min_pages) > return CHARGE_RETRY; if (batch > nr_pages) return CHARGE_RETRY; But that is all just nitpicking. Functionally, it looks sane, so: Acked-by: Johannes Weiner -- 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