The patch titled
Subject: memcg: make mem_cgroup_reparent_charges() non-failing
has been added to the -mm tree. Its filename is
memcg-make-mem_cgroup_reparent_charges-non-failing.patch
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------------------------------------------------------
From: Michal Hocko <mhocko@xxxxxxx>
Subject: memcg: make mem_cgroup_reparent_charges() non-failing
Now that pre_destroy() callbacks are called from the context where neither
any task can attach the group nor any children group can be added there is
no other way to fail from mem_cgroup_pre_destroy().
mem_cgroup_pre_destroy() doesn't have to take a reference to memcg's css
because all css' are marked dead already.
Signed-off-by: Michal Hocko <mhocko@xxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Reviewed-by: Glauber Costa <glommer@xxxxxxxxxxxxx>
Cc: Li Zefan <lizefan@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Balbir Singh <bsingharora@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 18 ++++++------------
1 file changed, 6 insertions(+), 12 deletions(-)
diff -puN mm/memcontrol.c~memcg-make-mem_cgroup_reparent_charges-non-failing mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-make-mem_cgroup_reparent_charges-non-failing
+++ a/mm/memcontrol.c
@@ -3757,14 +3757,12 @@ static void mem_cgroup_force_empty_list(
*
* Caller is responsible for holding css reference on the memcg.
*/
-static int mem_cgroup_reparent_charges(struct mem_cgroup *memcg)
+static void mem_cgroup_reparent_charges(struct mem_cgroup *memcg)
{
struct cgroup *cgrp = memcg->css.cgroup;
int node, zid;
do {
- if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
- return -EBUSY;
/* This is for making all *used* pages to be on LRU. */
lru_add_drain_all();
drain_all_stock_sync(memcg);
@@ -3790,8 +3788,6 @@ static int mem_cgroup_reparent_charges(s
* charge before adding to the LRU.
*/
} while (res_counter_read_u64(&memcg->res, RES_USAGE) > 0);
-
- return 0;
}
/*
@@ -3828,7 +3824,9 @@ static int mem_cgroup_force_empty(struct
}
lru_add_drain();
- return mem_cgroup_reparent_charges(memcg);
+ mem_cgroup_reparent_charges(memcg);
+
+ return 0;
}
static int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
@@ -5032,13 +5030,9 @@ free_out:
static int mem_cgroup_pre_destroy(struct cgroup *cont)
{
struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
- int ret;
- css_get(&memcg->css);
- ret = mem_cgroup_reparent_charges(memcg);
- css_put(&memcg->css);
-
- return ret;
+ mem_cgroup_reparent_charges(memcg);
+ return 0;
}
static void mem_cgroup_destroy(struct cgroup *cont)
_
Patches currently in -mm which might be from mhocko@xxxxxxx are
thp-clean-up-__collapse_huge_page_isolate.patch
thp-clean-up-__collapse_huge_page_isolate-v2.patch
mm-introduce-mm_find_pmd.patch
mm-introduce-mm_find_pmd-fix.patch
thp-introduce-hugepage_vma_check.patch
thp-cleanup-introduce-mk_huge_pmd.patch
memory-hotplug-allocate-zones-pcp-before-onlining-pages-fix.patch
memcg-split-mem_cgroup_force_empty-into-reclaiming-and-reparenting-parts.patch
memcg-root_cgroup-cannot-reach-mem_cgroup_move_parent.patch
memcg-simplify-mem_cgroup_force_empty_list-error-handling.patch
cgroups-forbid-pre_destroy-callback-to-fail.patch
memcg-make-mem_cgroup_reparent_charges-non-failing.patch
hugetlb-do-not-fail-in-hugetlb_cgroup_pre_destroy.patch
drop_caches-add-some-documentation-and-info-messsge.patch
drop_caches-add-some-documentation-and-info-messsge-checkpatch-fixes.patch
mm-memblock-reduce-overhead-in-binary-search.patch
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