Messages in this thread | | | Date | Mon, 23 Nov 2015 11:30:03 -0500 | From | Johannes Weiner <> | Subject | Re: [PATCH v2] vmscan: do not force-scan file lru if its absolute size is small |
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On Mon, Nov 23, 2015 at 01:39:33PM +0300, Vladimir Davydov wrote: > We assume there is enough inactive page cache if the size of inactive > file lru is greater than the size of active file lru, in which case we > force-scan file lru ignoring anonymous pages. While this logic works > fine when there are plenty of page cache pages, it fails if the size of > file lru is small (several MB): in this case (lru_size >> prio) will be > 0 for normal scan priorities, as a result, if inactive file lru happens > to be larger than active file lru, anonymous pages of a cgroup will > never get evicted unless the system experiences severe memory pressure, > even if there are gigabytes of unused anonymous memory there, which is > unfair in respect to other cgroups, whose workloads might be page cache > oriented. > > This patch attempts to fix this by elaborating the "enough inactive page > cache" check: it makes it not only check that inactive lru size > active > lru size, but also that we will scan something from the cgroup at the > current scan priority. If these conditions do not hold, we proceed to > SCAN_FRACT as usual. > > Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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