Re: [PATCH] mm/swap: lru drain on memory reclaim workqueue

From: Keith Busch
Date: Tue May 31 2016 - 17:06:17 EST

On Tue, May 31, 2016 at 05:01:16PM -0400, Tejun Heo wrote:
> So, WQ_MEM_RECLAIM on a shared workqueue doesn't make much sense.
> That flag guarantees single concurrency level to the workqueue. How
> would multiple users of a shared workqueue coordinate around that?
> What prevents one events_mem_unbound user from depending on, say,
> draining lru? If lru draining requires a rescuer to guarantee forward
> progress under memory pressure, that rescuer worker must be dedicated
> for that purpose and can't be shared.

Gotchya, that fixes my understanding on the rescuer thread operation. In
this case, could we revive your previous proposal for consideration?