From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f70.google.com (mail-wm0-f70.google.com [74.125.82.70]) by kanga.kvack.org (Postfix) with ESMTP id 985E66B053F for ; Fri, 28 Jul 2017 09:05:31 -0400 (EDT) Received: by mail-wm0-f70.google.com with SMTP id o201so14079937wmg.3 for ; Fri, 28 Jul 2017 06:05:31 -0700 (PDT) Received: from gum.cmpxchg.org (gum.cmpxchg.org. [85.214.110.215]) by mx.google.com with ESMTPS id e30si1078364eda.29.2017.07.28.06.05.30 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 28 Jul 2017 06:05:30 -0700 (PDT) Date: Fri, 28 Jul 2017 09:05:17 -0400 From: Johannes Weiner Subject: Re: [4.13-rc1] /proc/meminfo reports that Slab: is little used. Message-ID: <20170728130517.GA16849@cmpxchg.org> References: <201707260628.v6Q6SmaS030814@www262.sakura.ne.jp> <20170727162355.GA23896@cmpxchg.org> <20170728090750.GH2274@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170728090750.GH2274@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Tetsuo Handa , Josef Bacik , Vladimir Davydov , Rik van Riel , linux-mm@kvack.org On Fri, Jul 28, 2017 at 11:07:51AM +0200, Michal Hocko wrote: > On Thu 27-07-17 12:23:55, Johannes Weiner wrote: > > >From 14e3d7647b3cf524dbb005faaea96b00b6909c12 Mon Sep 17 00:00:00 2001 > > From: Johannes Weiner > > Date: Thu, 27 Jul 2017 11:59:38 -0400 > > Subject: [PATCH] mm: fix global NR_SLAB_.*CLAIMABLE counter reads > > > > As Tetsuo points out: > > > > Commit 385386cff4c6f047 ("mm: vmstat: move slab statistics from > > zone to node counters") broke "Slab:" field of /proc/meminfo . It > > shows nearly 0kB. > > > > In addition to /proc/meminfo, this problem also affects the slab > > counters OOM/allocation failure info dumps, can cause early -ENOMEM > > from overcommit protection, and miscalculate image size requirements > > during suspend-to-disk. > > > > This is because the patch in question switched the slab counters from > > the zone level to the node level, but forgot to update the global > > accessor functions to read the aggregate node data instead of the > > aggregate zone data. > > > > Use global_node_page_state() to access the global slab counters. > > > > Fixes: 385386cff4c6 ("mm: vmstat: move slab statistics from zone to node counters") > > Reported-by: Tetsuo Handa > > Signed-off-by: Johannes Weiner > > Looks good to me > > Acked-by: Michal Hocko Thanks > From: Michal Hocko > Date: Fri, 28 Jul 2017 11:02:51 +0200 > Subject: [PATCH] mm: rename global_page_state to global_zone_page_state > > global_page_state is error prone as a recent bug report pointed out [1]. > It only returns proper values for zone based counters as the enum it > gets suggests. We already have global_node_page_state so let's rename > global_page_state to global_zone_page_state to be more explicit here. > All existing users seems to be correct > $ git grep "global_page_state(NR_" | sed 's@.*(\(NR_[A-Z_]*\)).*@\1@' | sort | uniq -c > 2 NR_BOUNCE > 2 NR_FREE_CMA_PAGES > 11 NR_FREE_PAGES > 1 NR_KERNEL_STACK_KB > 1 NR_MLOCK > 2 NR_PAGETABLE > > This patch shouldn't introduce any functional change. > > [1] http://lkml.kernel.org/r/201707260628.v6Q6SmaS030814@www262.sakura.ne.jp > > Signed-off-by: Michal Hocko Yeah I think that's a good idea. I suspect Mel wanted to keep churn in unrelated callsites down when he introduced the node stuff, since that was already a big patch series. It makes sense to clean this up now. 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