Let's make mod_memcg_state re-entrant safe against irqs. The only thing
needed is to convert the usage of __this_cpu_add() to this_cpu_add().
In addition, with re-entrant safety, there is no need to disable irqs.
mod_memcg_state() is not safe against nmi, so let's add warning if
someone tries to call it in nmi context.
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
---
include/linux/memcontrol.h | 20 ++------------------
mm/memcontrol.c | 12 ++++++++----
2 files changed, 10 insertions(+), 22 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index ed9acb68652a..84e2cea7e666 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -911,19 +911,9 @@ struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim,
struct mem_cgroup *oom_domain);
void mem_cgroup_print_oom_group(struct mem_cgroup *memcg);
-void __mod_memcg_state(struct mem_cgroup *memcg, enum memcg_stat_item idx,
- int val);
-
/* idx can be of type enum memcg_stat_item or node_stat_item */
-static inline void mod_memcg_state(struct mem_cgroup *memcg,
- enum memcg_stat_item idx, int val)
-{
- unsigned long flags;
-
- local_irq_save(flags);
- __mod_memcg_state(memcg, idx, val);
- local_irq_restore(flags);
-}
+void mod_memcg_state(struct mem_cgroup *memcg,
+ enum memcg_stat_item idx, int val);
static inline void mod_memcg_page_state(struct page *page,
enum memcg_stat_item idx, int val)
@@ -1390,12 +1380,6 @@ static inline void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
{
}
-static inline void __mod_memcg_state(struct mem_cgroup *memcg,
- enum memcg_stat_item idx,
- int nr)
-{
-}
-
static inline void mod_memcg_state(struct mem_cgroup *memcg,
enum memcg_stat_item idx,
int nr)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 62450e7991d8..373d36cae069 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -681,12 +681,12 @@ static int memcg_state_val_in_pages(int idx, int val)
}
/**
- * __mod_memcg_state - update cgroup memory statistics
+ * mod_memcg_state - update cgroup memory statistics
* @memcg: the memory cgroup
* @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
* @val: delta to add to the counter, can be negative
*/
-void __mod_memcg_state(struct mem_cgroup *memcg, enum memcg_stat_item idx,
+void mod_memcg_state(struct mem_cgroup *memcg, enum memcg_stat_item idx,
int val)
{
int i = memcg_stats_index(idx);
@@ -698,9 +698,13 @@ void __mod_memcg_state(struct mem_cgroup *memcg, enum memcg_stat_item idx,
if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx))
return;
+ if (WARN_ONCE(in_nmi(), "%s: called in nmi context for stat item %d\n",
+ __func__, idx))
+ return;
+
cpu = get_cpu();
- __this_cpu_add(memcg->vmstats_percpu->state[i], val);
+ this_cpu_add(memcg->vmstats_percpu->state[i], val);
val = memcg_state_val_in_pages(idx, val);
memcg_rstat_updated(memcg, val, cpu);
trace_mod_memcg_state(memcg, idx, val);
@@ -2969,7 +2973,7 @@ static void drain_obj_stock(struct obj_stock_pcp *stock)
memcg = get_mem_cgroup_from_objcg(old);
- __mod_memcg_state(memcg, MEMCG_KMEM, -nr_pages);
+ mod_memcg_state(memcg, MEMCG_KMEM, -nr_pages);
memcg1_account_kmem(memcg, -nr_pages);
if (!mem_cgroup_is_root(memcg))
memcg_uncharge(memcg, nr_pages);
--
2.47.1