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authorDave Hansen <dave.hansen@linux.intel.com>2021-09-02 14:59:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-09-03 09:58:16 -0700
commit3a235693d3930e1276c8d9cc0ca5807ef292cf0a (patch)
tree14f7ca5cdc45cdfc56fb6526beb7fd3801a2021c
parenta2a36488a61cefe3129295c6e75b3987b9d7fd13 (diff)
mm/vmscan: never demote for memcg reclaim
Global reclaim aims to reduce the amount of memory used on a given node or set of nodes. Migrating pages to another node serves this purpose. memcg reclaim is different. Its goal is to reduce the total memory consumption of the entire memcg, across all nodes. Migration does not assist memcg reclaim because it just moves page contents between nodes rather than actually reducing memory consumption. Link: https://lkml.kernel.org/r/20210715055145.195411-9-ying.huang@intel.com Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Suggested-by: Yang Shi <yang.shi@linux.alibaba.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Wei Xu <weixugc@google.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: Keith Busch <kbusch@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/vmscan.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b0970769b100..43289f5f8488 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -524,8 +524,13 @@ static long add_nr_deferred(long nr, struct shrinker *shrinker,
static bool can_demote(int nid, struct scan_control *sc)
{
- if (sc && sc->no_demotion)
- return false;
+ if (sc) {
+ if (sc->no_demotion)
+ return false;
+ /* It is pointless to do demotion in memcg reclaim */
+ if (cgroup_reclaim(sc))
+ return false;
+ }
if (next_demotion_node(nid) == NUMA_NO_NODE)
return false;