diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index bea3d997b076..a3fce570122e 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -707,6 +707,8 @@ static inline void mem_cgroup_uncharge_list(struct list_head *page_list) void mem_cgroup_cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages); +void mem_cgroup_replace_folio(struct folio *old, struct folio *new); + void mem_cgroup_migrate(struct folio *old, struct folio *new); /** @@ -1279,6 +1281,11 @@ static inline void mem_cgroup_cancel_charge(struct mem_cgroup *memcg, { } +static inline void mem_cgroup_replace_folio(struct folio *old, + struct folio *new) +{ +} + static inline void mem_cgroup_migrate(struct folio *old, struct folio *new) { } diff --git a/mm/filemap.c b/mm/filemap.c index b04ba896aac9..48cd16c54e86 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -816,7 +816,7 @@ void replace_page_cache_folio(struct folio *old, struct folio *new) new->mapping = mapping; new->index = offset; - mem_cgroup_migrate(old, new); + mem_cgroup_replace_folio(old, new); xas_lock_irq(&xas); xas_store(&xas, new); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b3e40a59f732..135d6637afe5 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -7292,16 +7292,17 @@ void __mem_cgroup_uncharge_list(struct list_head *page_list) } /** - * mem_cgroup_migrate - Charge a folio's replacement. + * mem_cgroup_replace_folio - Charge a folio's replacement. * @old: Currently circulating folio. * @new: Replacement folio. * * Charge @new as a replacement folio for @old. @old will - * be uncharged upon free. + * be uncharged upon free. This is only used by the page cache + * (in replace_page_cache_folio()). * * Both folios must be locked, @new->mapping must be set up. */ -void mem_cgroup_migrate(struct folio *old, struct folio *new) +void mem_cgroup_replace_folio(struct folio *old, struct folio *new) { struct mem_cgroup *memcg; long nr_pages = folio_nr_pages(new); @@ -7340,6 +7341,39 @@ void mem_cgroup_migrate(struct folio *old, struct folio *new) local_irq_restore(flags); } +/** + * mem_cgroup_migrate - Transfer the memcg data from the old to the new folio. + * @old: Currently circulating folio. + * @new: Replacement folio. + * + * Transfer the memcg data from the old folio to the new folio for migration. + * The old folio's data info will be cleared. Note that the memory counters + * will remain unchanged throughout the process. + * + * Both folios must be locked, @new->mapping must be set up. + */ +void mem_cgroup_migrate(struct folio *old, struct folio *new) +{ + struct mem_cgroup *memcg; + + VM_BUG_ON_FOLIO(!folio_test_locked(old), old); + VM_BUG_ON_FOLIO(!folio_test_locked(new), new); + VM_BUG_ON_FOLIO(folio_test_anon(old) != folio_test_anon(new), new); + VM_BUG_ON_FOLIO(folio_nr_pages(old) != folio_nr_pages(new), new); + + if (mem_cgroup_disabled()) + return; + + memcg = folio_memcg(old); + VM_WARN_ON_ONCE_FOLIO(!memcg, old); + if (!memcg) + return; + + /* Transfer the charge and the css ref */ + commit_charge(new, memcg); + old->memcg_data = 0; +} + DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key); EXPORT_SYMBOL(memcg_sockets_enabled_key);