From: Honglei Wang <honglei.wang@oracle.com>
To: linux-mm@kvack.org, vdavydov.dev@gmail.com, hannes@cmpxchg.org,
mhocko@kernel.org
Subject: [PATCH v2] mm/vmscan: get number of pages on the LRU list in memcgroup base on lru_zone_size
Date: Thu, 5 Sep 2019 15:10:34 +0800 [thread overview]
Message-ID: <20190905071034.16822-1-honglei.wang@oracle.com> (raw)
lruvec_lru_size() is involving lruvec_page_state_local() to get the
lru_size in the current code. It's base on lruvec_stat_local.count[]
of mem_cgroup_per_node. This counter is updated in batch. It won't
do charge if the number of coming pages doesn't meet the needs of
MEMCG_CHARGE_BATCH who's defined as 32 now.
The testcase in LTP madvise09[1] fails due to small block memory is
not charged. It creates a new memcgroup and sets up 32 MADV_FREE
pages. Then it forks child who will introduce memory pressure in the
memcgroup. The MADV_FREE pages are expected to be released under the
pressure, but 32 is not more than MEMCG_CHARGE_BATCH and these pages
won't be charged in lruvec_stat_local.count[] until some more pages
come in to satisfy the needs of batch charging. So these MADV_FREE
pages can't be freed in memory pressure which is a bit conflicted
with the definition of MADV_FREE.
Getting lru_size base on lru_zone_size of mem_cgroup_per_node which
is not updated in batch can make it a bit more accurate in similar
scenario.
[1] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/madvise/madvise09.c
Signed-off-by: Honglei Wang <honglei.wang@oracle.com>
---
mm/vmscan.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index c77d1e3761a7..c28672460868 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -354,12 +354,13 @@ unsigned long zone_reclaimable_pages(struct zone *zone)
*/
unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru, int zone_idx)
{
- unsigned long lru_size;
+ unsigned long lru_size = 0;
int zid;
- if (!mem_cgroup_disabled())
- lru_size = lruvec_page_state_local(lruvec, NR_LRU_BASE + lru);
- else
+ if (!mem_cgroup_disabled()) {
+ for (zid = 0; zid < MAX_NR_ZONES; zid++)
+ lru_size += mem_cgroup_get_zone_lru_size(lruvec, lru, zid);
+ } else
lru_size = node_page_state(lruvec_pgdat(lruvec), NR_LRU_BASE + lru);
for (zid = zone_idx + 1; zid < MAX_NR_ZONES; zid++) {
--
2.17.0
next reply other threads:[~2019-09-05 7:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-05 7:10 Honglei Wang [this message]
2019-10-06 0:10 ` [PATCH v2] mm/vmscan: get number of pages on the LRU list in memcgroup base on lru_zone_size Andrew Morton
2019-10-07 14:28 ` Michal Hocko
2019-10-08 9:34 ` Honglei Wang
2019-10-09 14:16 ` Michal Hocko
2019-10-10 8:40 ` Honglei Wang
2019-10-10 14:33 ` Michal Hocko
2019-10-11 1:40 ` Honglei Wang
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