linux-kernel - Re: [PATCH v2 0/5] Fix oom killer doesn't work at all if system have

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Date:	Tue, 31 May 2011 03:50:45 -0400 (EDT)
From:	CAI Qian <caiqian@...hat.com>
To:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org, rientjes@...gle.com, hughd@...gle.com,
	kamezawa hiroyu <kamezawa.hiroyu@...fujitsu.com>,
	minchan kim <minchan.kim@...il.com>, oleg@...hat.com
Subject: Re: [PATCH v2 0/5] Fix oom killer doesn't work at all if system
 have > gigabytes memory  (aka CAI founded issue)



----- Original Message -----
> >> - If you run the same program as root, non root process and
> >> privilege
> >> explicit
> >> dropping processes (e.g. irqbalance) will be killed at first.
> > Hmm, at least there were some programs were root processes but were
> > killed
> > first.
> > [ pid] ppid uid total_vm rss swap score_adj name
> > [ 5720] 5353 0 24421 257 0 0 sshd
> > [ 5353] 1 0 15998 189 0 0 sshd
> > [ 5451] 1 0 19648 235 0 0 master
> > [ 1626] 1 0 2287 129 0 0 dhclient
> 
> Hi
> 
> I can't reproduce this too. Are you sure these processes have a full
> root privilege?
> I've made new debugging patch. After applying following patch, do
> these processes show
> cap=1?
No, all of them had cap=0. Wondering why something like sshd not been
made cap=1 to avoid early oom kill.
> 
> 
> 
> index f0e34d4..fe788df 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -429,7 +429,7 @@ static void dump_tasks(const struct mem_cgroup
> *mem, const nodemask_t *no
> struct task_struct *p;
> struct task_struct *task;
> 
> - pr_info("[ pid] ppid uid total_vm rss swap score_adj name\n");
> + pr_info("[ pid] ppid uid cap total_vm rss swap score_adj name\n");
> for_each_process(p) {
> if (oom_unkillable_task(p, mem, nodemask))
> continue;
> @@ -444,9 +444,9 @@ static void dump_tasks(const struct mem_cgroup
> *mem, const nodemask_t *no
> continue;
> }
> 
> - pr_info("[%6d] %6d %5d %8lu %8lu %8lu %9d %s\n",
> + pr_info("[%6d] %6d %5d %3d %8lu %8lu %8lu %9d %s\n",
> task_tgid_nr(task), task_tgid_nr(task->real_parent),
> - task_uid(task),
> + task_uid(task), has_capability_noaudit(task, CAP_SYS_ADMIN),
> task->mm->total_vm,
> get_mm_rss(task->mm) + task->mm->nr_ptes,
> get_mm_counter(task->mm, MM_SWAPENTS),
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> --
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