On Tue, Mar 01, 2016 at 02:38:46PM +0100, Michal Hocko wrote: > > I'd expect a build in 224M > > RAM plus 2G of swap to take so long, that I'd be very grateful to be > > OOM killed, even if there is technically enough space. Unless > > perhaps it's some superfast swap that you have? > > the swap partition is a standard qcow image stored on my SSD disk. So > I guess the IO should be quite fast. This smells like a potential > contributor because my reclaim seems to be much faster and that should > lead to a more efficient reclaim (in the scanned/reclaimed sense).
Hmm... This looks like one of potential culprit. If page is in writeback, it can't be migrated by compaction with MIGRATE_SYNC_LIGHT. In this case, this page works as pinned page and prevent compaction. It'd be better to check that changing 'migration_mode = MIGRATE_SYNC' at 'no_progress_loops > XXX' will help in this situation. Thanks.