| From: Shakeel Butt <shakeel.butt@linux.dev> |
| Subject: memcg-v1: remove memcg move locking code |
| Date: Thu, 24 Oct 2024 18:23:03 -0700 |
| |
| 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> |
| --- |
| |
| include/linux/memcontrol.h | 54 ----------------------- |
| mm/filemap.c | 1 |
| mm/memcontrol-v1.c | 82 ----------------------------------- |
| mm/memcontrol.c | 5 -- |
| mm/rmap.c | 1 |
| 5 files changed, 143 deletions(-) |
| |
| --- a/include/linux/memcontrol.h~memcg-v1-remove-memcg-move-locking-code |
| +++ a/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 |
| * |
| * - 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_m |
| * |
| * - 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. |
| @@ -1873,26 +1859,6 @@ static inline bool task_in_memcg_oom(str |
| 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); |
| @@ -1914,26 +1880,6 @@ unsigned long memcg1_soft_limit_reclaim( |
| 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; |
| --- a/mm/filemap.c~memcg-v1-remove-memcg-move-locking-code |
| +++ a/mm/filemap.c |
| @@ -119,7 +119,6 @@ |
| * ->i_pages lock (folio_remove_rmap_pte->set_page_dirty) |
| * bdi.wb->list_lock (folio_remove_rmap_pte->set_page_dirty) |
| * ->inode->i_lock (folio_remove_rmap_pte->set_page_dirty) |
| - * ->memcg->move_lock (folio_remove_rmap_pte->folio_memcg_lock) |
| * bdi.wb->list_lock (zap_pte_range->set_page_dirty) |
| * ->inode->i_lock (zap_pte_range->set_page_dirty) |
| * ->private_lock (zap_pte_range->block_dirty_folio) |
| --- a/mm/memcontrol.c~memcg-v1-remove-memcg-move-locking-code |
| +++ a/mm/memcontrol.c |
| @@ -1189,7 +1189,6 @@ void lruvec_memcg_debug(struct lruvec *l |
| * These functions are safe to use under any of the following conditions: |
| * - folio locked |
| * - folio_test_lru false |
| - * - folio_memcg_lock() |
| * - folio frozen (refcount of 0) |
| * |
| * Return: The lruvec this folio is on with its lock held. |
| @@ -1211,7 +1210,6 @@ struct lruvec *folio_lruvec_lock(struct |
| * These functions are safe to use under any of the following conditions: |
| * - folio locked |
| * - folio_test_lru false |
| - * - folio_memcg_lock() |
| * - folio frozen (refcount of 0) |
| * |
| * Return: The lruvec this folio is on with its lock held and interrupts |
| @@ -1235,7 +1233,6 @@ struct lruvec *folio_lruvec_lock_irq(str |
| * These functions are safe to use under any of the following conditions: |
| * - folio locked |
| * - folio_test_lru false |
| - * - folio_memcg_lock() |
| * - folio frozen (refcount of 0) |
| * |
| * Return: The lruvec this folio is on with its lock held and interrupts |
| @@ -2375,9 +2372,7 @@ static void commit_charge(struct folio * |
| * |
| * - the page lock |
| * - LRU isolation |
| - * - folio_memcg_lock() |
| * - exclusive reference |
| - * - mem_cgroup_trylock_pages() |
| */ |
| folio->memcg_data = (unsigned long)memcg; |
| } |
| --- a/mm/memcontrol-v1.c~memcg-v1-remove-memcg-move-locking-code |
| +++ a/mm/memcontrol-v1.c |
| @@ -401,87 +401,6 @@ unsigned long memcg1_soft_limit_reclaim( |
| return nr_reclaimed; |
| } |
| |
| -/** |
| - * folio_memcg_lock - Bind a folio to its memcg. |
| - * @folio: The folio. |
| - * |
| - * This function prevents unlocked LRU folios from being moved to |
| - * another cgroup. |
| - * |
| - * It ensures lifetime of the bound memcg. The caller is responsible |
| - * for the lifetime of the folio. |
| - */ |
| -void folio_memcg_lock(struct folio *folio) |
| -{ |
| - struct mem_cgroup *memcg; |
| - unsigned long flags; |
| - |
| - /* |
| - * The RCU lock is held throughout the transaction. The fast |
| - * path can get away without acquiring the memcg->move_lock |
| - * because page moving starts with an RCU grace period. |
| - */ |
| - rcu_read_lock(); |
| - |
| - if (mem_cgroup_disabled()) |
| - return; |
| -again: |
| - memcg = folio_memcg(folio); |
| - if (unlikely(!memcg)) |
| - return; |
| - |
| -#ifdef CONFIG_PROVE_LOCKING |
| - local_irq_save(flags); |
| - might_lock(&memcg->move_lock); |
| - local_irq_restore(flags); |
| -#endif |
| - |
| - if (atomic_read(&memcg->moving_account) <= 0) |
| - return; |
| - |
| - spin_lock_irqsave(&memcg->move_lock, flags); |
| - if (memcg != folio_memcg(folio)) { |
| - spin_unlock_irqrestore(&memcg->move_lock, flags); |
| - goto again; |
| - } |
| - |
| - /* |
| - * When charge migration first begins, we can have multiple |
| - * critical sections holding the fast-path RCU lock and one |
| - * holding the slowpath move_lock. Track the task who has the |
| - * move_lock for folio_memcg_unlock(). |
| - */ |
| - memcg->move_lock_task = current; |
| - memcg->move_lock_flags = flags; |
| -} |
| - |
| -static void __folio_memcg_unlock(struct mem_cgroup *memcg) |
| -{ |
| - if (memcg && memcg->move_lock_task == current) { |
| - unsigned long flags = memcg->move_lock_flags; |
| - |
| - memcg->move_lock_task = NULL; |
| - memcg->move_lock_flags = 0; |
| - |
| - spin_unlock_irqrestore(&memcg->move_lock, flags); |
| - } |
| - |
| - rcu_read_unlock(); |
| -} |
| - |
| -/** |
| - * folio_memcg_unlock - Release the binding between a folio and its memcg. |
| - * @folio: The folio. |
| - * |
| - * This releases the binding created by folio_memcg_lock(). This does |
| - * not change the accounting of this folio to its memcg, but it does |
| - * permit others to change it. |
| - */ |
| -void folio_memcg_unlock(struct folio *folio) |
| -{ |
| - __folio_memcg_unlock(folio_memcg(folio)); |
| -} |
| - |
| static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css, |
| struct cftype *cft) |
| { |
| @@ -1189,7 +1108,6 @@ void memcg1_memcg_init(struct mem_cgroup |
| { |
| INIT_LIST_HEAD(&memcg->oom_notify); |
| mutex_init(&memcg->thresholds_lock); |
| - spin_lock_init(&memcg->move_lock); |
| INIT_LIST_HEAD(&memcg->event_list); |
| spin_lock_init(&memcg->event_list_lock); |
| } |
| --- a/mm/rmap.c~memcg-v1-remove-memcg-move-locking-code |
| +++ a/mm/rmap.c |
| @@ -32,7 +32,6 @@ |
| * swap_lock (in swap_duplicate, swap_info_get) |
| * mmlist_lock (in mmput, drain_mmlist and others) |
| * mapping->private_lock (in block_dirty_folio) |
| - * folio_lock_memcg move_lock (in block_dirty_folio) |
| * i_pages lock (widely used) |
| * lruvec->lru_lock (in folio_lruvec_lock_irq) |
| * inode->i_lock (in set_page_dirty's __mark_inode_dirty) |
| _ |
