Re: [PATCH v2] vmscan: force scan offline memory cgroups

[Johannes Weiner]

On Fri, Jan 09, 2015 at 11:09:43AM +0300, Vladimir Davydov wrote:
> Since commit b2052564e66d ("mm: memcontrol: continue cache reclaim from
> offlined groups") pages charged to a memory cgroup are not reparented
> when the cgroup is removed. Instead, they are supposed to be reclaimed
> in a regular way, along with pages accounted to online memory cgroups.
> 
> However, an lruvec of an offline memory cgroup will sooner or later get
> so small that it will be scanned only at low scan priorities (see
> get_scan_count()). Therefore, if there are enough reclaimable pages in
> big lruvecs, pages accounted to offline memory cgroups will never be
> scanned at all, wasting memory.
> 
> Fix this by unconditionally forcing scanning dead lruvecs from kswapd.
> 
> Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>

Looks good to me now, thank you.

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
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