On Sun, 13 Jun 2010, KOSAKI Motohiro wrote:
> I have no objection because it's policy matter. but if so, dump_tasks()
> should display mem_allowed mask too, probably.
You could, but we'd want to do that all under cpuset_buffer_lock so we
don't have to allocate it on the stack, which can be particularly lengthy
when the page allocator is called.
> > > (3) oom_kill_task (when oom_kill_allocating_task==1 only)
> > >
> >
> > Why would care about cpuset attachment in oom_kill_task()? You mean
> > oom_kill_process() to filter the children list?
>
> Ah, intersting question. OK, we have to discuss oom_kill_allocating_task
> design at first.
>
> First of All, oom_kill_process() to filter the children list and this issue
> are independent and unrelated. My patch was not correct too.
>
> Now, oom_kill_allocating_task basic logic is here. It mean, if oom_kill_process()
> return 0, oom kill finished successfully. but if oom_kill_process() return 1,
> fallback to normall __out_of_memory().
>
Right.
>
> ===================================================
> static void __out_of_memory(gfp_t gfp_mask, int order, nodemask_t *nodemask)
> {
> struct task_struct *p;
> unsigned long points;
>
> if (sysctl_oom_kill_allocating_task)
> if (!oom_kill_process(current, gfp_mask, order, 0, NULL, nodemask,
> "Out of memory (oom_kill_allocating_task)"))
> return;
> retry:
>
> When oom_kill_process() return 1?
> I think It should be
> - current is OOM_DISABLE
In this case, oom_kill_task() returns 1, which causes oom_kill_process()
to return 1 if current (and not one of its children) is actually selected
to die.
> - current have no intersected CPUSET
current will always intersect its own cpuset's mems.
> - current is KTHREAD
find_lock_task_mm() should take care of that in oom_kill_task() just like
it does for OOM_DISABLE, although we can still race with use_mm(), in
which case this would be a good chance.
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