Hugh Dickins wrote: > mem_cgroup_charge_common shows a tendency to OOM without good reason, > when a memhog goes well beyond its rss limit but with plenty of swap > available. Seen on x86 but not on PowerPC; seen when the next patch > omits swapcache from memcgroup, but we presume it can happen without. > > mem_cgroup_isolate_pages is not quite satisfying reclaim's criteria > for OOM avoidance. Already it has to scan beyond the nr_to_scan limit > when it finds a !LRU page or an active page when handling inactive or > an inactive page when handling active. It needs to do exactly the same > when it finds a page from the wrong zone (the x86 tests had two zones, > the PowerPC tests had only one). > > Don't increment scan and then decrement it in these cases, just move > the incrementation down. Fix recent off-by-one when checking against > nr_to_scan. Cut out "Check if the meta page went away from under us", > presumably left over from early debugging: no amount of such checks > could save us if this list really were being updated without locking. > It's a spill over from the old code, we do all operations under the mem_cont's lru_lock. > This change does make the unlimited scan while holding two spinlocks > even worse - bad for latency and bad for containment; but that's a > separate issue which is better left to be fixed a little later. > > Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx> For the swapout test case scenario sent by Hugh Tested-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
