The commit is pushed to "branch-rh7-3.10.0-229.7.2-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git after rh7-3.10.0-229.7.2.vz7.6.3 ------> commit 703ed09d7ee4d9af6cec3c4970842f282176f5e0 Author: Vladimir Davydov <vdavy...@parallels.com> Date: Fri Aug 28 18:50:33 2015 +0400
ms/mm/vmscan: never isolate more pages than necessary ==== Along with "[PATCH rh7] mm: vmscan: use proportional scanning during direct reclaim and full scan at DEF_PRIORITY" this should fix https://jira.sw.ru/browse/PSBM-35275 I submitted this patch upstream (https://lkml.org/lkml/2015/8/3/404) and it was merged into the mmotm tree. Hopefully, it will get merged into Linus's tree soon. ==== If transparent huge pages are enabled, we can isolate many more pages than we actually need to scan, because we count both single and huge pages equally in isolate_lru_pages(). Since commit 5bc7b8aca942d ("mm: thp: add split tail pages to shrink page list in page reclaim"), we scan all the tail pages immediately after a huge page split (see shrink_page_list()). As a result, we can reclaim up to SWAP_CLUSTER_MAX * HPAGE_PMD_NR (512 MB) in one run! This is easy to catch on memcg reclaim with zswap enabled. The latter makes swapout instant so that if we happen to scan an unreferenced huge page we will evict both its head and tail pages immediately, which is likely to result in excessive reclaim. Signed-off-by: Vladimir Davydov <vdavy...@parallels.com> --- mm/vmscan.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 2bb62ce..7beadf5 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1297,7 +1297,8 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, unsigned long nr_taken = 0; unsigned long scan; - for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) { + for (scan = 0; scan < nr_to_scan && nr_taken < nr_to_scan && + !list_empty(src); scan++) { struct page *page; int nr_pages; _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel