When force_empty() called by ->pre_destroy(), no memory reclaim happens
and it doesn't take very long time which requires signal_pending() check.
And if we return -EINTR from pre_destroy(), cgroup.c show warning.
This patch removes signal check in force_empty(). By this, ->pre_destroy()
returns success always.
Note: check for 'cgroup is empty' remains for force_empty interface.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
---
mm/hugetlb.c | 10 +---------
mm/memcontrol.c | 14 +++++---------
2 files changed, 6 insertions(+), 18 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 4dd6b39..770f1642 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1922,20 +1922,12 @@ int hugetlb_force_memcg_empty(struct cgroup *cgroup)
int ret = 0, idx = 0;
do {
+ /* see memcontrol.c::mem_cgroup_force_empty() */
if (cgroup_task_count(cgroup)
|| !list_empty(&cgroup->children)) {
ret = -EBUSY;
goto out;
}
- /*
- * If the task doing the cgroup_rmdir got a signal
- * we don't really need to loop till the hugetlb resource
- * usage become zero.
- */
- if (signal_pending(current)) {
- ret = -EINTR;
- goto out;
- }
for_each_hstate(h) {
spin_lock(&hugetlb_lock);
list_for_each_entry(page, &h->hugepage_activelist, lru) {
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2715223..ee350c5 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3852,8 +3852,6 @@ static int mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
pc = lookup_page_cgroup(page);
ret = mem_cgroup_move_parent(page, pc, memcg, GFP_KERNEL);
- if (ret == -ENOMEM || ret == -EINTR)
- break;
if (ret == -EBUSY || ret == -EINVAL) {
/* found lock contention or "pc" is obsolete. */
@@ -3863,7 +3861,7 @@ static int mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
busy = NULL;
}
- if (!ret && !list_empty(list))
+ if (!loop)
return -EBUSY;
return ret;
}
@@ -3893,11 +3891,12 @@ static int mem_cgroup_force_empty(struct mem_cgroup *memcg, bool free_all)
move_account:
do {
ret = -EBUSY;
+ /*
+ * This never happens when this is called by ->pre_destroy().
+ * But we need to take care of force_empty interface.
+ */
if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
goto out;
- ret = -EINTR;
- if (signal_pending(current))
- goto out;
/* This is for making all *used* pages to be on LRU. */
lru_add_drain_all();
drain_all_stock_sync(memcg);
@@ -3918,9 +3917,6 @@ move_account:
}
mem_cgroup_end_move(memcg);
memcg_oom_recover(memcg);
- /* it seems parent cgroup doesn't have enough mem */
- if (ret == -ENOMEM)
- goto try_to_free;
cond_resched();
/* "ret" should also be checked to ensure all lists are empty. */
} while (res_counter_read_u64(&memcg->res, RES_USAGE) > 0 || ret);
--
1.7.4.1
--
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