On Fri 23-10-15 00:15:28, Tejun Heo wrote: > On Thu, Oct 22, 2015 at 05:06:23PM +0200, Michal Hocko wrote: > > Do I get it right that if vmstat_update has its own workqueue with > > WQ_MEM_RECLAIM then there is a _guarantee_ that the rescuer will always > > be able to process vmstat_update work from the requested CPU? > > Yeah.
Thanks for the confirmation. > > That should be sufficient because vmstat_update doesn't sleep on > > allocation. I agree that this would be a more appropriate fix. > > The problem seems to be reclaim path busy looping waiting for > vmstat_update and workqueue thinking that the work item must be making > forward-progress and thus not starting the next work item. But that shouldn't happen because the allocation path does cond_resched even when nothing is really reclaimable (e.g. wait_iff_congested from __alloc_pages_slowpath). -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
