On 2019/07/18 17:30, Michal Hocko wrote:
> On Wed 17-07-19 19:55:01, Tetsuo Handa wrote:
>> Currently dump_tasks() might call printk() for many thousands times under
>> RCU, which might take many minutes for slow consoles.
>
> Is is even wise to enable dumping tasks on systems with thousands of
> tasks and slow consoles? I mean you still have to call printk that is
> slow that many times. So why do we actually care? Because of RCU stall
> warnings?
>
That's a stupid question. WE DO CARE.
We are making efforts for avoid calling printk() on each thread group (e.g.
commit 0c1b2d783cf34324 ("mm/oom_kill: remove the wrong fatal_signal_pending() check in oom_kill_process()")
commit b2b469939e934587 ("proc, oom: do not report alien mms when setting oom_score_adj"))
) under RCU and this patch is one of them (except that we can't remove
printk() for dump_tasks() case).
