From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751619AbdATJOM (ORCPT ); Fri, 20 Jan 2017 04:14:12 -0500 Received: from mx2.suse.de ([195.135.220.15]:46524 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751459AbdATJOJ (ORCPT ); Fri, 20 Jan 2017 04:14:09 -0500 Subject: Re: [patch] mm, oom: header nodemask is NULL when cpusets are disabled To: David Rientjes , Andrew Morton References: <279f10c2-3eaa-c641-094f-3070db67d84f@suse.cz> Cc: Michal Hocko , Johannes Weiner , Mel Gorman , linux-mm@kvack.org, LKML , Rasmus Villemoes From: Vlastimil Babka Message-ID: Date: Fri, 20 Jan 2017 10:00:06 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/19/2017 11:57 PM, David Rientjes wrote: > Commit 82e7d3abec86 ("oom: print nodemask in the oom report") implicitly > sets the allocation nodemask to cpuset_current_mems_allowed when there is > no effective mempolicy. cpuset_current_mems_allowed is only effective > when cpusets are enabled, which is also printed by dump_header(), so > setting the nodemask to cpuset_current_mems_allowed is redundant and > prevents debugging issues where ac->nodemask is not set properly in the > page allocator. > > This provides better debugging output since > cpuset_print_current_mems_allowed() is already provided. > > Suggested-by: Vlastimil Babka > Signed-off-by: David Rientjes > --- > mm/oom_kill.c | 16 +++++++++------- > 1 file changed, 9 insertions(+), 7 deletions(-) > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -403,12 +403,14 @@ static void dump_tasks(struct mem_cgroup *memcg, const nodemask_t *nodemask) > > static void dump_header(struct oom_control *oc, struct task_struct *p) > { > - nodemask_t *nm = (oc->nodemask) ? oc->nodemask : &cpuset_current_mems_allowed; > - > - pr_warn("%s invoked oom-killer: gfp_mask=%#x(%pGg), nodemask=%*pbl, order=%d, oom_score_adj=%hd\n", > - current->comm, oc->gfp_mask, &oc->gfp_mask, > - nodemask_pr_args(nm), oc->order, > - current->signal->oom_score_adj); > + pr_warn("%s invoked oom-killer: gfp_mask=%#x(%pGg), nodemask=", > + current->comm, oc->gfp_mask, &oc->gfp_mask); > + if (oc->nodemask) > + pr_cont("%*pbl", nodemask_pr_args(oc->nodemask)); > + else > + pr_cont("(null)\n"); > + pr_cont(", order=%d, oom_score_adj=%hd\n", > + oc->order, current->signal->oom_score_adj); > if (!IS_ENABLED(CONFIG_COMPACTION) && oc->order) > pr_warn("COMPACTION is disabled!!!\n"); > > @@ -417,7 +419,7 @@ static void dump_header(struct oom_control *oc, struct task_struct *p) > if (oc->memcg) > mem_cgroup_print_oom_info(oc->memcg, p); > else > - show_mem(SHOW_MEM_FILTER_NODES, nm); > + show_mem(SHOW_MEM_FILTER_NODES, oc->nodemask); > if (sysctl_oom_dump_tasks) > dump_tasks(oc->memcg, oc->nodemask); > } > Could we simplify both patches with something like this? Although the sizeof("null") is not the nicest thing, because it relies on knowledge that pointer() in lib/vsprintf.c uses this string. Maybe Rasmus has some better idea? Thanks, Vlastimil diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h index f746e44d4046..4add88ef63f0 100644 --- a/include/linux/nodemask.h +++ b/include/linux/nodemask.h @@ -103,7 +103,7 @@ extern nodemask_t _unused_nodemask_arg_; * * Can be used to provide arguments for '%*pb[l]' when printing a nodemask. */ -#define nodemask_pr_args(maskp) MAX_NUMNODES, (maskp)->bits +#define nodemask_pr_args(maskp) ((maskp) ? MAX_NUMNODES : (int) sizeof("null")), ((maskp) ? (maskp)->bits : NULL) /* * The inline keyword gives the compiler room to decide to inline, or