Re: [PATCH v2 0/5] Fix oom killer doesn't work at all if system have > gigabytes memory (aka CAI founded issue)

CAI Qian
2011-05-31T07:51:25Z

----- 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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