The patch titled
memcg: fix handling of shmem migration
has been removed from the -mm tree. Its filename was
vmscan-split-lru-lists-into-anon-file-sets-memcg-fix-handling-of-shmem-migrationv2.patch
This patch was dropped because it was folded into vmscan-split-lru-lists-into-anon-file-sets.patch
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: memcg: fix handling of shmem migration
From: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Before this patch, if migrating shmem/tmpfs pages, newpage would be
charged with PAGE_CGROUP_FLAG_FILE set, while oldpage has been charged
without the flag.
The problem here is mem_cgroup_move_lists doesn't clear(or set) the
PAGE_CGROUP_FLAG_FILE flag, so pc->flags of the newpage remains
PAGE_CGROUP_FLAG_FILE set even when the pc is moved to another lru(anon)
by mem_cgroup_move_lists. And this leads to incorrect MEM_CGROUP_ZSTAT.
In my test, I see an underflow of MEM_CGROUP_ZSTAT(active_file). As a
result, mem_cgroup_calc_reclaim returns very huge number and causes soft
lockup on page reclaim.
I'm not sure if mem_cgroup_move_lists should handle PAGE_CGROUP_FLAG_FILE
or not(I suppose it should be used to move between active <-> inactive,
not anon <-> file), I added MEM_CGROUP_CHARGE_TYPE_SHMEM for precharge at
shmem's page migration.
Signed-off-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff -puN mm/memcontrol.c~vmscan-split-lru-lists-into-anon-file-sets-memcg-fix-handling-of-shmem-migrationv2 mm/memcontrol.c
--- a/mm/memcontrol.c~vmscan-split-lru-lists-into-anon-file-sets-memcg-fix-handling-of-shmem-migrationv2
+++ a/mm/memcontrol.c
@@ -178,6 +178,7 @@ enum charge_type {
MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
MEM_CGROUP_CHARGE_TYPE_MAPPED,
MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
+ MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */
};
/*
@@ -575,8 +576,10 @@ static int mem_cgroup_charge_common(stru
pc->flags |= PAGE_CGROUP_FLAG_FILE;
else
pc->flags |= PAGE_CGROUP_FLAG_ACTIVE;
- } else
+ } else if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
+ else /* MEM_CGROUP_CHARGE_TYPE_SHMEM */
+ pc->flags = PAGE_CGROUP_FLAG_CACHE | PAGE_CGROUP_FLAG_ACTIVE;
lock_page_cgroup(page);
if (unlikely(page_get_page_cgroup(page))) {
@@ -735,8 +738,12 @@ int mem_cgroup_prepare_migration(struct
if (pc) {
mem = pc->mem_cgroup;
css_get(&mem->css);
- if (pc->flags & PAGE_CGROUP_FLAG_CACHE)
- ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
+ if (pc->flags & PAGE_CGROUP_FLAG_CACHE) {
+ if (page_is_file_cache(page))
+ ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
+ else
+ ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
+ }
}
unlock_page_cgroup(page);
if (mem) {
_
Patches currently in -mm which might be from nishimura@xxxxxxxxxxxxxxxxx are
vmscan-split-lru-lists-into-anon-file-sets.patch
vmscan-split-lru-lists-into-anon-file-sets-memcg-fix-handling-of-shmem-migrationv2.patch
unevictable-lru-infrastructure.patch
memcg-move-charge-swapin-under-lock.patch
memcg-make-page-mapping-null-before-uncharge.patch
memcg-avoid-accounting-special-pages.patch
memcg-optimize-per-cpu-statistics.patch
memcg-atomic-ops-for-page_cgroup-flags.patch
memcg-allocate-all-page_cgroup-at-boot.patch
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