mm, oom: avoid printk() iteration under RCU
Currently dump_tasks() might call printk() for many thousands times under
RCU, which might take many minutes for slow consoles. Therefore, split
dump_tasks() into three stages; take a snapshot of possible OOM victim
candidates under RCU, dump the snapshot from reschedulable context, and
destroy the snapshot.
In a future patch, the first stage would be moved to select_bad_process()
and the third stage would be moved to after oom_kill_process(), and will
simplify refcount handling.
Link: http://lkml.kernel.org/r/1563360901-8277-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2 files changed
