Re: [PATCH v2] mm, page_alloc: enable pcpu_drain with zone capability

[Oscar Salvador <osalvador@suse.de>]

On Wed, Dec 12, 2018 at 10:25:50PM +0800, Wei Yang wrote:
> drain_all_pages is documented to drain per-cpu pages for a given zone (if
> non-NULL). The current implementation doesn't match the description though.
> It will drain all pcp pages for all zones that happen to have cached pages
> on the same cpu as the given zone. This will leave to premature pcp cache
> draining for zones that are not of an interest for the caller - e.g.
> compaction, hwpoison or memory offline.
> 
> This would force the page allocator to take locks and potential lock
> contention as a result.
> 
> There is no real reason for this sub-optimal implementnation. Replace
> per-cpu work item with a dedicated structure which contains a pointer to
> zone and pass it over to the worker. This will get the zone information all
> the way down to the worker function and do the right job.
> 
> [mhocko@suse.com: refactor the whole changelog]
> 
> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
> Acked-by: Michal Hocko <mhocko@suse.com>

Looks to me

Reviewed-by: Oscar Salvador <osalvador@suse.de>

thanks

-- 
Oscar Salvador
SUSE L3