From: Michal Hocko <mhocko@kernel.org>
To: Yang Shi <yang.s@alibaba-inc.com>
Cc: cl@linux.com, penberg@kernel.org, rientjes@google.com,
iamjoonsoo.kim@lge.com, akpm@linux-foundation.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] mm: oom: show unreclaimable slab info when unreclaimable slabs > user memory
Date: Mon, 9 Oct 2017 08:33:16 +0200 [thread overview]
Message-ID: <20171009063316.qjmunbabyr2nzh52@dhcp22.suse.cz> (raw)
In-Reply-To: <ff7e0d92-0f12-46fa-dbc7-79c556ffb7c2@alibaba-inc.com>
On Sat 07-10-17 00:37:55, Yang Shi wrote:
>
>
> On 10/6/17 2:37 AM, Michal Hocko wrote:
> > On Thu 05-10-17 05:29:10, Yang Shi wrote:
[...]
> > > + list_for_each_entry_safe(s, s2, &slab_caches, list) {
> > > + if (!is_root_cache(s) || (s->flags & SLAB_RECLAIM_ACCOUNT))
> > > + continue;
> > > +
> > > + memset(&sinfo, 0, sizeof(sinfo));
> >
> > why do you zero out the structure. All the fields you are printing are
> > filled out in get_slabinfo.
>
> No special reason, just wipe out the potential stale data on the stack.
Do not add code that has no meaning. The OOM killer is a slow path but
that doesn't mean we should throw spare cycles out of the window.
--
Michal Hocko
SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@kernel.org>
To: Yang Shi <yang.s@alibaba-inc.com>
Cc: cl@linux.com, penberg@kernel.org, rientjes@google.com,
iamjoonsoo.kim@lge.com, akpm@linux-foundation.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] mm: oom: show unreclaimable slab info when unreclaimable slabs > user memory
Date: Mon, 9 Oct 2017 08:33:16 +0200 [thread overview]
Message-ID: <20171009063316.qjmunbabyr2nzh52@dhcp22.suse.cz> (raw)
In-Reply-To: <ff7e0d92-0f12-46fa-dbc7-79c556ffb7c2@alibaba-inc.com>
On Sat 07-10-17 00:37:55, Yang Shi wrote:
>
>
> On 10/6/17 2:37 AM, Michal Hocko wrote:
> > On Thu 05-10-17 05:29:10, Yang Shi wrote:
[...]
> > > + list_for_each_entry_safe(s, s2, &slab_caches, list) {
> > > + if (!is_root_cache(s) || (s->flags & SLAB_RECLAIM_ACCOUNT))
> > > + continue;
> > > +
> > > + memset(&sinfo, 0, sizeof(sinfo));
> >
> > why do you zero out the structure. All the fields you are printing are
> > filled out in get_slabinfo.
>
> No special reason, just wipe out the potential stale data on the stack.
Do not add code that has no meaning. The OOM killer is a slow path but
that doesn't mean we should throw spare cycles out of the window.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-10-09 6:33 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-04 21:29 [PATCH 0/3 v10] oom: capture unreclaimable slab info in oom message Yang Shi
2017-10-04 21:29 ` Yang Shi
2017-10-04 21:29 ` [PATCH 1/3] tools: slabinfo: add "-U" option to show unreclaimable slabs only Yang Shi
2017-10-04 21:29 ` Yang Shi
2017-10-04 21:29 ` [PATCH 2/3] mm: slabinfo: dump CONFIG_SLABINFO Yang Shi
2017-10-04 21:29 ` Yang Shi
2017-10-07 11:45 ` kbuild test robot
2017-10-07 11:45 ` kbuild test robot
2017-10-07 12:06 ` kbuild test robot
2017-10-07 12:06 ` kbuild test robot
2017-10-04 21:29 ` [PATCH 3/3] mm: oom: show unreclaimable slab info when unreclaimable slabs > user memory Yang Shi
2017-10-04 21:29 ` Yang Shi
2017-10-06 9:37 ` Michal Hocko
2017-10-06 9:37 ` Michal Hocko
2017-10-06 16:37 ` Yang Shi
2017-10-06 16:37 ` Yang Shi
2017-10-09 6:33 ` Michal Hocko [this message]
2017-10-09 6:33 ` Michal Hocko
2017-10-09 6:36 ` Michal Hocko
2017-10-09 6:36 ` Michal Hocko
2017-10-09 16:44 ` Yang Shi
2017-10-09 16:44 ` Yang Shi
2017-10-09 18:53 ` Yang Shi
2017-10-09 18:53 ` Yang Shi
2017-10-09 21:00 ` Yang Shi
2017-10-09 21:00 ` Yang Shi
2017-10-07 10:10 ` kbuild test robot
2017-10-07 10:10 ` kbuild test robot
2017-10-07 13:05 ` kbuild test robot
2017-10-07 13:05 ` kbuild test robot
-- strict thread matches above, loose matches on Subject: below --
2017-10-10 17:25 [PATCH 0/3 v11] oom: capture unreclaimable slab info in oom message Yang Shi
2017-10-10 17:25 ` [PATCH 3/3] mm: oom: show unreclaimable slab info when unreclaimable slabs > user memory Yang Shi
2017-10-10 17:25 ` Yang Shi
2017-10-17 0:15 ` David Rientjes
2017-10-17 0:15 ` David Rientjes
2017-10-17 7:44 ` Michal Hocko
2017-10-17 7:44 ` Michal Hocko
2017-10-17 20:59 ` David Rientjes
2017-10-17 20:59 ` David Rientjes
2017-10-17 21:40 ` Yang Shi
2017-10-17 21:40 ` Yang Shi
2017-10-17 21:50 ` David Rientjes
2017-10-17 21:50 ` David Rientjes
2017-10-17 22:20 ` Yang Shi
2017-10-17 22:20 ` Yang Shi
2017-10-17 22:39 ` David Rientjes
2017-10-17 22:39 ` David Rientjes
2017-10-18 19:09 ` Yang Shi
2017-10-18 19:09 ` Yang Shi
2017-10-19 7:28 ` Michal Hocko
2017-10-19 7:28 ` Michal Hocko
2017-10-19 23:12 ` Yang Shi
2017-10-19 23:12 ` Yang Shi
2017-10-03 18:06 [PATCH 0/3 v8] oom: capture unreclaimable slab info in oom message Yang Shi
2017-10-03 18:06 ` [PATCH 3/3] mm: oom: show unreclaimable slab info when unreclaimable slabs > user memory Yang Shi
2017-10-03 18:06 ` Yang Shi
2017-10-04 14:27 ` Michal Hocko
2017-10-04 14:27 ` Michal Hocko
2017-10-04 17:37 ` Yang Shi
2017-10-04 17:37 ` Yang Shi
2017-10-04 18:08 ` Yang Shi
2017-10-04 18:08 ` Yang Shi
2017-10-05 7:57 ` Michal Hocko
2017-10-05 7:57 ` Michal Hocko
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