From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753242Ab1L2Kmi (ORCPT ); Thu, 29 Dec 2011 05:42:38 -0500 Received: from cantor2.suse.de ([195.135.220.15]:49351 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752618Ab1L2Kmg (ORCPT ); Thu, 29 Dec 2011 05:42:36 -0500 Date: Thu, 29 Dec 2011 11:42:30 +0100 From: Michal Hocko To: "Kirill A. Shutemov" Cc: linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, KAMEZAWA Hiroyuki , Balbir Singh , Johannes Weiner , Michal Marek , linux-kbuild@vger.kernel.org Subject: Re: [PATCH] Makefiles: Disable unused-variable warning (was: Re: [PATCH 1/6] memcg: fix unused variable warning) Message-ID: <20111229104230.GA20854@tiehlicka.suse.cz> References: <1324695619-5537-1-git-send-email-kirill@shutemov.name> <20111227135752.GK5344@tiehlicka.suse.cz> <20111227182613.GA21840@shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20111227182613.GA21840@shutemov.name> 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 Tue 27-12-11 20:26:13, Kirill A. Shutemov wrote: > On Tue, Dec 27, 2011 at 02:57:52PM +0100, Michal Hocko wrote: > > On Sat 24-12-11 05:00:14, Kirill A. Shutemov wrote: > > > From: "Kirill A. Shutemov" > > > > > > mm/memcontrol.c: In function ‘memcg_check_events’: > > > mm/memcontrol.c:784:22: warning: unused variable ‘do_numainfo’ [-Wunused-variable] > > > > > > Signed-off-by: Kirill A. Shutemov > > > --- > > > mm/memcontrol.c | 7 ++++--- > > > 1 files changed, 4 insertions(+), 3 deletions(-) > > > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > > index d643bd6..a5e92bd 100644 > > > --- a/mm/memcontrol.c > > > +++ b/mm/memcontrol.c > > > @@ -781,14 +781,15 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) > > > /* threshold event is triggered in finer grain than soft limit */ > > > if (unlikely(mem_cgroup_event_ratelimit(memcg, > > > MEM_CGROUP_TARGET_THRESH))) { > > > - bool do_softlimit, do_numainfo; > > > + bool do_softlimit; > > > > > > - do_softlimit = mem_cgroup_event_ratelimit(memcg, > > > - MEM_CGROUP_TARGET_SOFTLIMIT); > > > #if MAX_NUMNODES > 1 > > > + bool do_numainfo; > > > do_numainfo = mem_cgroup_event_ratelimit(memcg, > > > MEM_CGROUP_TARGET_NUMAINFO); > > > #endif > > > + do_softlimit = mem_cgroup_event_ratelimit(memcg, > > > + MEM_CGROUP_TARGET_SOFTLIMIT); > > > > I don't like this very much. Maybe we should get rid of both do_* and > > do it with flags? But maybe it is not worth the additional code at > > all... > > Something like this (untested): > ==== > From f57e1a2e1aaaa167c75b963d5bf12fcbdd3331b8 Mon Sep 17 00:00:00 2001 > From: "Kirill A. Shutemov" > Date: Tue, 27 Dec 2011 20:17:13 +0200 > Subject: [PATCH] memcg: cleanup memcg_check_events() > > Signed-off-by: Kirill A. Shutemov The patch looks correct but I am still not sure this is worth fixing in the code rather than disabling Wunused-variable. > --- > mm/memcontrol.c | 42 ++++++++++++++++++++++++------------------ > 1 files changed, 24 insertions(+), 18 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index d643bd6..40c2236 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -108,11 +108,12 @@ enum mem_cgroup_events_index { > * than using jiffies etc. to handle periodic memcg event. > */ > enum mem_cgroup_events_target { > - MEM_CGROUP_TARGET_THRESH, > - MEM_CGROUP_TARGET_SOFTLIMIT, > - MEM_CGROUP_TARGET_NUMAINFO, > - MEM_CGROUP_NTARGETS, > + MEM_CGROUP_TARGET_THRESH = BIT(1), > + MEM_CGROUP_TARGET_SOFTLIMIT = BIT(2), > + MEM_CGROUP_TARGET_NUMAINFO = BIT(3), > }; > +#define MEM_CGROUP_NTARGETS 3 > + > #define THRESHOLDS_EVENTS_TARGET (128) > #define SOFTLIMIT_EVENTS_TARGET (1024) > #define NUMAINFO_EVENTS_TARGET (1024) > @@ -743,7 +744,7 @@ static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg, > return total; > } > > -static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, > +static int mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, > enum mem_cgroup_events_target target) > { > unsigned long val, next; > @@ -766,9 +767,9 @@ static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, > break; > } > __this_cpu_write(memcg->stat->targets[target], next); > - return true; > + return target; > } > - return false; > + return 0; > } > > /* > @@ -777,29 +778,34 @@ static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, > */ > static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) > { > + int flags; > + > preempt_disable(); > - /* threshold event is triggered in finer grain than soft limit */ > - if (unlikely(mem_cgroup_event_ratelimit(memcg, > - MEM_CGROUP_TARGET_THRESH))) { > - bool do_softlimit, do_numainfo; > + flags = mem_cgroup_event_ratelimit(memcg, MEM_CGROUP_TARGET_THRESH); > > - do_softlimit = mem_cgroup_event_ratelimit(memcg, > + /* > + * Threshold event is triggered in finer grain than soft limit > + * and numainfo > + */ > + if (unlikely(flags)) { > + flags |= mem_cgroup_event_ratelimit(memcg, > MEM_CGROUP_TARGET_SOFTLIMIT); > #if MAX_NUMNODES > 1 > - do_numainfo = mem_cgroup_event_ratelimit(memcg, > + flags |= mem_cgroup_event_ratelimit(memcg, > MEM_CGROUP_TARGET_NUMAINFO); > #endif > - preempt_enable(); > + } > + preempt_enable(); > > + if (unlikely(flags)) { > mem_cgroup_threshold(memcg); > - if (unlikely(do_softlimit)) > + if (unlikely(flags & MEM_CGROUP_TARGET_SOFTLIMIT)) > mem_cgroup_update_tree(memcg, page); > #if MAX_NUMNODES > 1 > - if (unlikely(do_numainfo)) > + if (unlikely(flags & MEM_CGROUP_TARGET_NUMAINFO)) > atomic_inc(&memcg->numainfo_events); > #endif > - } else > - preempt_enable(); > + } > } > > struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) > -- > 1.7.7.3 -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic