[Intel-gfx] [RFC] [PATCH] mm, oom: Offload OOM notify callback to a kernel thread.

[Michal Hocko]

On Mon 02-10-17 17:11:55, Michael S. Tsirkin wrote:
> On Mon, Oct 02, 2017 at 01:50:35PM +0200, Michal Hocko wrote:
[...]
> > and some
> > other call path is allocating while holding the lock. But you seem to be
> > right and
> > leak_balloon
> >   tell_host
> >     virtqueue_add_outbuf
> >       virtqueue_add
> > 
> > can do GFP_KERNEL allocation and this is clearly wrong. Nobody should
> > try to allocate while we are in the OOM path. Michael, is there any way
> > to drop this?
> 
> Yes - in practice it won't ever allocate - that path is never taken
> with add_outbuf - it is for add_sgs only.
> 
> IMHO the issue is balloon inflation which needs to allocate
> memory. It does it under a mutex, and oom handler tries to take the
> same mutex.

try_lock for the oom notifier path should heal the problem then, righ?
At least for as a quick fix.
-- 
Michal Hocko
SUSE Labs