Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
mm,vmscan: fix divide by zero in get_scan_count
Commit f56ce41 ("mm: memcontrol: fix occasional OOMs due to proportional memory.low reclaim") introduced a divide by zero corner case when oomd is being used in combination with cgroup memory.low protection. When oomd decides to kill a cgroup, it will force the cgroup memory to be reclaimed after killing the tasks, by writing to the memory.max file for that cgroup, forcing the remaining page cache and reclaimable slab to be reclaimed down to zero. Previously, on cgroups with some memory.low protection that would result in the memory being reclaimed down to the memory.low limit, or likely not at all, having the page cache reclaimed asynchronously later. With f56ce41 the oomd write to memory.max tries to reclaim all the way down to zero, which may race with another reclaimer, to the point of ending up with the divide by zero below. This patch implements the obvious fix. Link: https://lkml.kernel.org/r/[email protected] Fixes: f56ce41 ("mm: memcontrol: fix occasional OOMs due to proportional memory.low reclaim") Signed-off-by: Rik van Riel <[email protected]> Acked-by: Roman Gushchin <[email protected]> Acked-by: Michal Hocko <[email protected]> Acked-by: Johannes Weiner <[email protected]> Acked-by: Chris Down <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
- Loading branch information