mm: workingset: update shadow limit to reflect bigger active list
Since commit 59dc76b0d4df ("mm: vmscan: reduce size of inactive file
list") the size of the active file list is no longer limited to half of
memory. Increase the shadow node limit accordingly to avoid throwing
out shadow entries that might still result in eligible refaults.
The exact size of the active list now depends on the overall size of the
page cache, but converges toward taking up most of the space:
In mm/vmscan.c::inactive_list_is_low(),
* total target max
* memory ratio inactive
* -------------------------------------
* 10MB 1 5MB
* 100MB 1 50MB
* 1GB 3 250MB
* 10GB 10 0.9GB
* 100GB 31 3GB
* 1TB 101 10GB
* 10TB 320 32GB
It would be possible to apply the same precise ratios when determining
the limit for radix tree nodes containing shadow entries, but since it
is merely an approximation of the oldest refault distances in the wild
and the code also makes assumptions about the node population density,
keep it simple and always target the full cache size.
While at it, clarify the comment and the formula for memory footprint.
Link: http://lkml.kernel.org/r/20161117214701.29000-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed