memcg-v1: remove memcg move locking code

The memcg v1's charge move feature has been deprecated.  All the places
using the memcg move lock, have stopped using it as they don't need the
protection any more.  Let's proceed to remove all the locking code related
to charge moving.

Link: https://lkml.kernel.org/r/20241025012304.2473312-7-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 0 insertions, 54 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 0b113267b2de..bb49e0d4b377 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -299,20 +299,10 @@ struct mem_cgroup {
 	/* For oom notifier event fd */
 	struct list_head oom_notify;
 
-	/* taken only while moving_account > 0 */
-	spinlock_t move_lock;
-	unsigned long move_lock_flags;
-
 	/* Legacy tcp memory accounting */
 	bool tcpmem_active;
 	int tcpmem_pressure;
 
-	/*
-	 * set > 0 if pages under this cgroup are moving to other cgroup.
-	 */
-	atomic_t moving_account;
-	struct task_struct *move_lock_task;
-
 	/* List of events which userspace want to receive */
 	struct list_head event_list;
 	spinlock_t event_list_lock;
@@ -428,9 +418,7 @@ static inline struct obj_cgroup *__folio_objcg(struct folio *folio)
  *
  * - the folio lock
  * - LRU isolation
- * - folio_memcg_lock()
  * - exclusive reference
- * - mem_cgroup_trylock_pages()
  *
  * For a kmem folio a caller should hold an rcu read lock to protect memcg
  * associated with a kmem folio from being released.
@@ -499,9 +487,7 @@ static inline struct mem_cgroup *folio_memcg_rcu(struct folio *folio)
  *
  * - the folio lock
  * - LRU isolation
- * - lock_folio_memcg()
  * - exclusive reference
- * - mem_cgroup_trylock_pages()
  *
  * For a kmem folio a caller should hold an rcu read lock to protect memcg
  * associated with a kmem folio from being released.
@@ -1867,26 +1853,6 @@ static inline bool task_in_memcg_oom(struct task_struct *p)
 	return p->memcg_in_oom;
 }
 
-void folio_memcg_lock(struct folio *folio);
-void folio_memcg_unlock(struct folio *folio);
-
-/* try to stablize folio_memcg() for all the pages in a memcg */
-static inline bool mem_cgroup_trylock_pages(struct mem_cgroup *memcg)
-{
-	rcu_read_lock();
-
-	if (mem_cgroup_disabled() || !atomic_read(&memcg->moving_account))
-		return true;
-
-	rcu_read_unlock();
-	return false;
-}
-
-static inline void mem_cgroup_unlock_pages(void)
-{
-	rcu_read_unlock();
-}
-
 static inline void mem_cgroup_enter_user_fault(void)
 {
 	WARN_ON(current->in_user_fault);
@@ -1908,26 +1874,6 @@ unsigned long memcg1_soft_limit_reclaim(pg_data_t *pgdat, int order,
 	return 0;
 }
 
-static inline void folio_memcg_lock(struct folio *folio)
-{
-}
-
-static inline void folio_memcg_unlock(struct folio *folio)
-{
-}
-
-static inline bool mem_cgroup_trylock_pages(struct mem_cgroup *memcg)
-{
-	/* to match folio_memcg_rcu() */
-	rcu_read_lock();
-	return true;
-}
-
-static inline void mem_cgroup_unlock_pages(void)
-{
-	rcu_read_unlock();
-}
-
 static inline bool task_in_memcg_oom(struct task_struct *p)
 {
 	return false;