[LTP] [BUG] oom hangs the system, NMI backtrace shows most CPUs in shrink_slab

[Tejun Heo]

On Wed, Jan 20, 2016 at 10:17:23PM +0900, Tetsuo Handa wrote:
> What happens if memory allocation requests from items using this workqueue
> got stuck due to OOM livelock? Are pending items in this workqueue cannot
> be processed because this workqueue was created without WQ_MEM_RECLAIM?

If something gets stuck due to OOM livelock, anything which tries to
allocate memory can hang.  That's why it's called a livelock.
WQ_MEM_RECLAIM or not wouldn't make any difference.

> I don't know whether accessing swap memory depends on this workqueue.
> But if disk driver depends on this workqueue for accessing swap partition
> on the disk, some event is looping inside memory allocator will result in
> unable to process disk I/O request for accessing swap partition on the disk?

What you're saying is too vauge for me to decipher exactly what you
have on mind.  Can you please elaborate?

-- 
tejun