[PATCH] memcg: remove memcg_kmem_skip_account

From: Shakeel Butt
Date: Tue Sep 18 2018 - 20:45:16 EST


The flag memcg_kmem_skip_account was added during the era of opt-out
kmem accounting. There is no need for such flag in the opt-in world as
there aren't any __GFP_ACCOUNT allocations within
memcg_create_cache_enqueue().

Signed-off-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
---
include/linux/sched.h | 3 ---
mm/memcontrol.c | 24 +-----------------------
2 files changed, 1 insertion(+), 26 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 977cb57d7bc9..c30e3cd4b81c 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -723,9 +723,6 @@ struct task_struct {
#endif
#ifdef CONFIG_MEMCG
unsigned in_user_fault:1;
-#ifdef CONFIG_MEMCG_KMEM
- unsigned memcg_kmem_skip_account:1;
-#endif
#endif
#ifdef CONFIG_COMPAT_BRK
unsigned brk_randomized:1;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e79cb59552d9..bde698a0bb99 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2460,7 +2460,7 @@ static void memcg_kmem_cache_create_func(struct work_struct *w)
/*
* Enqueue the creation of a per-memcg kmem_cache.
*/
-static void __memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
+static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
struct kmem_cache *cachep)
{
struct memcg_kmem_cache_create_work *cw;
@@ -2478,25 +2478,6 @@ static void __memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
queue_work(memcg_kmem_cache_wq, &cw->work);
}

-static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
- struct kmem_cache *cachep)
-{
- /*
- * We need to stop accounting when we kmalloc, because if the
- * corresponding kmalloc cache is not yet created, the first allocation
- * in __memcg_schedule_kmem_cache_create will recurse.
- *
- * However, it is better to enclose the whole function. Depending on
- * the debugging options enabled, INIT_WORK(), for instance, can
- * trigger an allocation. This too, will make us recurse. Because at
- * this point we can't allow ourselves back into memcg_kmem_get_cache,
- * the safest choice is to do it like this, wrapping the whole function.
- */
- current->memcg_kmem_skip_account = 1;
- __memcg_schedule_kmem_cache_create(memcg, cachep);
- current->memcg_kmem_skip_account = 0;
-}
-
static inline bool memcg_kmem_bypass(void)
{
if (in_interrupt() || !current->mm || (current->flags & PF_KTHREAD))
@@ -2531,9 +2512,6 @@ struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep)
if (memcg_kmem_bypass())
return cachep;

- if (current->memcg_kmem_skip_account)
- return cachep;
-
memcg = get_mem_cgroup_from_current();
kmemcg_id = READ_ONCE(memcg->kmemcg_id);
if (kmemcg_id < 0)
--
2.19.0.397.gdd90340f6a-goog