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-rw-r--r--mm/memcontrol.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f4ec4e7ca4cd..930de9437271 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2091,6 +2091,7 @@ struct memcg_stock_pcp {
#define FLUSHING_CACHED_CHARGE (0)
};
static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
+static DEFINE_MUTEX(percpu_charge_mutex);
/*
* Try to consume stocked charge on this cpu. If success, one page is consumed
@@ -2197,8 +2198,7 @@ static void drain_all_stock(struct mem_cgroup *root_mem, bool sync)
for_each_online_cpu(cpu) {
struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
- if (mem_cgroup_same_or_subtree(root_mem, stock->cached) &&
- test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
+ if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
flush_work(&stock->work);
}
out:
@@ -2213,14 +2213,22 @@ out:
*/
static void drain_all_stock_async(struct mem_cgroup *root_mem)
{
+ /*
+ * If someone calls draining, avoid adding more kworker runs.
+ */
+ if (!mutex_trylock(&percpu_charge_mutex))
+ return;
drain_all_stock(root_mem, false);
+ mutex_unlock(&percpu_charge_mutex);
}
/* This is a synchronous drain interface. */
static void drain_all_stock_sync(struct mem_cgroup *root_mem)
{
/* called when force_empty is called */
+ mutex_lock(&percpu_charge_mutex);
drain_all_stock(root_mem, true);
+ mutex_unlock(&percpu_charge_mutex);
}
/*