On Tue, 17 Aug 2021 14:05:06 -0400 Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > We've noticed occasional OOM killing when memory.low settings are in > effect for cgroups. This is unexpected and undesirable as memory.low > is supposed to express non-OOMing memory priorities between cgroups. > > The reason for this is proportional memory.low reclaim. When cgroups > are below their memory.low threshold, reclaim passes them over in the > first round, and then retries if it couldn't find pages anywhere else. > But when cgroups are slighly above their memory.low setting, page scan > force is scaled down and diminished in proportion to the overage, to > the point where it can cause reclaim to fail as well - only in that > case we currently don't retry, and instead trigger OOM. > > To fix this, hook proportional reclaim into the same retry logic we > have in place for when cgroups are skipped entirely. This way if > reclaim fails and some cgroups were scanned with dimished pressure, > we'll try another full-force cycle before giving up and OOMing. Which kernel version(s) do you think need this?
