From: Zachary Goldstein <[email protected]>
5.10 suffers from the same recursive locking issue that
commit a848d25434de4 ("mm/memcg: Opencode the inner part of
obj_cgroup_uncharge_pages() in drain_obj_stock()") fixes.
Modified description from the commit to reflect this patch changes:
Provide the inner part of refill_stock() as __refill_stock() without
disabling interrupts. This eases the integration of local_lock_t where
recursive locking must be avoided.
Open code __memcg_kmem_uncharge() in drain_obj_stock() and
obj_cgroup_release() and use __refill_stock(). The caller of
drain_obj_stock() and obj_cgroup_release() already disables interrupts.
Signed-off-by: Zachary Goldstein <[email protected]>
---
mm/memcontrol.c | 28 +++++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5dd77e260c25..d61918cc44c1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -260,6 +260,8 @@ struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
#ifdef CONFIG_MEMCG_KMEM
static DEFINE_SPINLOCK(objcg_lock);
+static void __refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages);
+
static void obj_cgroup_release(struct percpu_ref *ref)
{
struct obj_cgroup *objcg = container_of(ref, struct obj_cgroup, refcnt);
@@ -294,8 +296,12 @@ static void obj_cgroup_release(struct percpu_ref *ref)
spin_lock_irqsave(&objcg_lock, flags);
memcg = obj_cgroup_memcg(objcg);
- if (nr_pages)
- __memcg_kmem_uncharge(memcg, nr_pages);
+ if (nr_pages) {
+ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ page_counter_uncharge(&memcg->kmem, nr_pages);
+
+ __refill_stock(memcg, nr_pages);
+ }
list_del(&objcg->list);
mem_cgroup_put(memcg);
spin_unlock_irqrestore(&objcg_lock, flags);
@@ -2319,12 +2325,9 @@ static void drain_local_stock(struct work_struct *dummy)
* Cache charges(val) to local per_cpu area.
* This will be consumed by consume_stock() function, later.
*/
-static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
+static void __refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
{
struct memcg_stock_pcp *stock;
- unsigned long flags;
-
- local_lock_irqsave(&memcg_stock.lock, flags);
stock = this_cpu_ptr(&memcg_stock);
if (stock->cached != memcg) { /* reset if necessary */
@@ -2336,7 +2339,14 @@ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
if (stock->nr_pages > MEMCG_CHARGE_BATCH)
drain_stock(stock);
+}
+static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
+{
+ unsigned long flags;
+
+ local_lock_irqsave(&memcg_stock.lock, flags);
+ __refill_stock(memcg, nr_pages);
local_unlock_irqrestore(&memcg_stock.lock, flags);
}
@@ -3179,7 +3189,11 @@ static void drain_obj_stock(struct memcg_stock_pcp *stock)
goto retry;
rcu_read_unlock();
- __memcg_kmem_uncharge(memcg, nr_pages);
+ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ page_counter_uncharge(&memcg->kmem, nr_pages);
+
+ __refill_stock(memcg, nr_pages);
+
css_put(&memcg->css);
}
--
2.39.2