Re: [patch] mm, compaction: drain pcps for zone when kcompactd fails

[David Rientjes]

On Thu, 1 Mar 2018, Andrew Morton wrote:

> On Thu, 1 Mar 2018 03:42:04 -0800 (PST) David Rientjes <rientjes@xxxxxxxxxx> wrote:
> 
> > It's possible for buddy pages to become stranded on pcps that, if drained,
> > could be merged with other buddy pages on the zone's free area to form
> > large order pages, including up to MAX_ORDER.
> 
> I grabbed this as-is.  Perhaps you could send along a new changelog so
> that others won't be asking the same questions as Vlastimil?
> 
> The patch has no reviews or acks at this time...
> 

Thanks.

As mentioned in my response to Vlastimil, I think the case could also be 
made that we should do drain_all_pages(zone) in try_to_compact_pages() 
when we defer for direct compactors.  It would be great to have feedback 
from those on the cc on that point, the patch in general, and then I can 
send an update.