From 1c824a680b1b67ad43c0908f11a70bcf37af56d5 Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Thu, 29 Apr 2021 22:55:32 -0700 Subject: mm: page-writeback: simplify memcg handling in test_clear_page_writeback() Page writeback doesn't hold a page reference, which allows truncate to free a page the second PageWriteback is cleared. This used to require special attention in test_clear_page_writeback(), where we had to be careful not to rely on the unstable page->memcg binding and look up all the necessary information before clearing the writeback flag. Since commit 073861ed77b6 ("mm: fix VM_BUG_ON(PageTail) and BUG_ON(PageWriteback)") test_clear_page_writeback() is called with an explicit reference on the page, and this dance is no longer needed. Use unlock_page_memcg() and dec_lruvec_page_state() directly. This removes the last user of the lock_page_memcg() return value, change it to void. Touch up the comments in there as well. This also removes the last extern user of __unlock_page_memcg(), make it static. Further, it removes the last user of dec_lruvec_state(), delete it, along with a few other unused helpers. Link: https://lkml.kernel.org/r/YCQbYAWg4nvBFL6h@cmpxchg.org Signed-off-by: Johannes Weiner Acked-by: Hugh Dickins Reviewed-by: Shakeel Butt Acked-by: Michal Hocko Cc: Roman Gushchin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) (limited to 'include/linux/memcontrol.h') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 0c04d39a7967..ae448d955a87 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -867,8 +867,7 @@ void mem_cgroup_print_oom_group(struct mem_cgroup *memcg); extern bool cgroup_memory_noswap; #endif -struct mem_cgroup *lock_page_memcg(struct page *page); -void __unlock_page_memcg(struct mem_cgroup *memcg); +void lock_page_memcg(struct page *page); void unlock_page_memcg(struct page *page); /* @@ -1289,12 +1288,7 @@ mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg) { } -static inline struct mem_cgroup *lock_page_memcg(struct page *page) -{ - return NULL; -} - -static inline void __unlock_page_memcg(struct mem_cgroup *memcg) +static inline void lock_page_memcg(struct page *page) { } -- cgit v1.2.3 From a3747b53b1771a787fea71d86a2fc39aea337685 Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Thu, 29 Apr 2021 22:56:14 -0700 Subject: mm: memcontrol: kill mem_cgroup_nodeinfo() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit No need to encapsulate a simple struct member access. Link: https://lkml.kernel.org/r/20210209163304.77088-3-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Reviewed-by: Shakeel Butt Reviewed-by: Roman Gushchin Acked-by: Michal Hocko Reviewed-by: Michal Koutný Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) (limited to 'include/linux/memcontrol.h') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index ae448d955a87..149dc2fd97a6 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -602,12 +602,6 @@ void mem_cgroup_uncharge_list(struct list_head *page_list); void mem_cgroup_migrate(struct page *oldpage, struct page *newpage); -static struct mem_cgroup_per_node * -mem_cgroup_nodeinfo(struct mem_cgroup *memcg, int nid) -{ - return memcg->nodeinfo[nid]; -} - /** * mem_cgroup_lruvec - get the lru list vector for a memcg & node * @memcg: memcg of the wanted lruvec @@ -631,7 +625,7 @@ static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg, if (!memcg) memcg = root_mem_cgroup; - mz = mem_cgroup_nodeinfo(memcg, pgdat->node_id); + mz = memcg->nodeinfo[pgdat->node_id]; lruvec = &mz->lruvec; out: /* -- cgit v1.2.3 From a18e6e6e150a98b9ce3e9acabeff407e7b6ba0c0 Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Thu, 29 Apr 2021 22:56:17 -0700 Subject: mm: memcontrol: privatize memcg_page_state query functions MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There are no users outside of the memory controller itself. The rest of the kernel cares either about node or lruvec stats. Link: https://lkml.kernel.org/r/20210209163304.77088-4-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Reviewed-by: Shakeel Butt Reviewed-by: Roman Gushchin Acked-by: Michal Hocko Reviewed-by: Michal Koutný Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 44 -------------------------------------------- 1 file changed, 44 deletions(-) (limited to 'include/linux/memcontrol.h') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 149dc2fd97a6..9a02aabd0000 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -864,39 +864,6 @@ extern bool cgroup_memory_noswap; void lock_page_memcg(struct page *page); void unlock_page_memcg(struct page *page); -/* - * idx can be of type enum memcg_stat_item or node_stat_item. - * Keep in sync with memcg_exact_page_state(). - */ -static inline unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx) -{ - long x = atomic_long_read(&memcg->vmstats[idx]); -#ifdef CONFIG_SMP - if (x < 0) - x = 0; -#endif - return x; -} - -/* - * idx can be of type enum memcg_stat_item or node_stat_item. - * Keep in sync with memcg_exact_page_state(). - */ -static inline unsigned long memcg_page_state_local(struct mem_cgroup *memcg, - int idx) -{ - long x = 0; - int cpu; - - for_each_possible_cpu(cpu) - x += per_cpu(memcg->vmstats_local->stat[idx], cpu); -#ifdef CONFIG_SMP - if (x < 0) - x = 0; -#endif - return x; -} - void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val); /* idx can be of type enum memcg_stat_item or node_stat_item */ @@ -1322,17 +1289,6 @@ static inline void mem_cgroup_print_oom_group(struct mem_cgroup *memcg) { } -static inline unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx) -{ - return 0; -} - -static inline unsigned long memcg_page_state_local(struct mem_cgroup *memcg, - int idx) -{ - return 0; -} - static inline void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int nr) -- cgit v1.2.3 From 2d146aa3aa842d7f5065802556b4f9a2c6e8ef12 Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Thu, 29 Apr 2021 22:56:26 -0700 Subject: mm: memcontrol: switch to rstat MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Replace the memory controller's custom hierarchical stats code with the generic rstat infrastructure provided by the cgroup core. The current implementation does batched upward propagation from the write side (i.e. as stats change). The per-cpu batches introduce an error, which is multiplied by the number of subgroups in a tree. In systems with many CPUs and sizable cgroup trees, the error can be large enough to confuse users (e.g. 32 batch pages * 32 CPUs * 32 subgroups results in an error of up to 128M per stat item). This can entirely swallow allocation bursts inside a workload that the user is expecting to see reflected in the statistics. In the past, we've done read-side aggregation, where a memory.stat read would have to walk the entire subtree and add up per-cpu counts. This became problematic with lazily-freed cgroups: we could have large subtrees where most cgroups were entirely idle. Hence the switch to change-driven upward propagation. Unfortunately, it needed to trade accuracy for speed due to the write side being so hot. Rstat combines the best of both worlds: from the write side, it cheaply maintains a queue of cgroups that have pending changes, so that the read side can do selective tree aggregation. This way the reported stats will always be precise and recent as can be, while the aggregation can skip over potentially large numbers of idle cgroups. The way rstat works is that it implements a tree for tracking cgroups with pending local changes, as well as a flush function that walks the tree upwards. The controller then drives this by 1) telling rstat when a local cgroup stat changes (e.g. mod_memcg_state) and 2) when a flush is required to get uptodate hierarchy stats for a given subtree (e.g. when memory.stat is read). The controller also provides a flush callback that is called during the rstat flush walk for each cgroup and aggregates its local per-cpu counters and propagates them upwards. This adds a second vmstats to struct mem_cgroup (MEMCG_NR_STAT + NR_VM_EVENT_ITEMS) to track pending subtree deltas during upward aggregation. It removes 3 words from the per-cpu data. It eliminates memcg_exact_page_state(), since memcg_page_state() is now exact. [akpm@linux-foundation.org: merge fix] [hannes@cmpxchg.org: fix a sleep in atomic section problem] Link: https://lkml.kernel.org/r/20210315234100.64307-1-hannes@cmpxchg.org Link: https://lkml.kernel.org/r/20210209163304.77088-7-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Reviewed-by: Roman Gushchin Acked-by: Michal Hocko Reviewed-by: Shakeel Butt Reviewed-by: Michal Koutný Acked-by: Balbir Singh Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 67 +++++++++++++++++++++++++++------------------- 1 file changed, 40 insertions(+), 27 deletions(-) (limited to 'include/linux/memcontrol.h') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 9a02aabd0000..74910ce9a3f9 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -76,10 +76,27 @@ enum mem_cgroup_events_target { }; struct memcg_vmstats_percpu { - long stat[MEMCG_NR_STAT]; - unsigned long events[NR_VM_EVENT_ITEMS]; - unsigned long nr_page_events; - unsigned long targets[MEM_CGROUP_NTARGETS]; + /* Local (CPU and cgroup) page state & events */ + long state[MEMCG_NR_STAT]; + unsigned long events[NR_VM_EVENT_ITEMS]; + + /* Delta calculation for lockless upward propagation */ + long state_prev[MEMCG_NR_STAT]; + unsigned long events_prev[NR_VM_EVENT_ITEMS]; + + /* Cgroup1: threshold notifications & softlimit tree updates */ + unsigned long nr_page_events; + unsigned long targets[MEM_CGROUP_NTARGETS]; +}; + +struct memcg_vmstats { + /* Aggregated (CPU and subtree) page state & events */ + long state[MEMCG_NR_STAT]; + unsigned long events[NR_VM_EVENT_ITEMS]; + + /* Pending child counts during tree propagation */ + long state_pending[MEMCG_NR_STAT]; + unsigned long events_pending[NR_VM_EVENT_ITEMS]; }; struct mem_cgroup_reclaim_iter { @@ -287,8 +304,8 @@ struct mem_cgroup { MEMCG_PADDING(_pad1_); - atomic_long_t vmstats[MEMCG_NR_STAT]; - atomic_long_t vmevents[NR_VM_EVENT_ITEMS]; + /* memory.stat */ + struct memcg_vmstats vmstats; /* memory.events */ atomic_long_t memory_events[MEMCG_NR_MEMORY_EVENTS]; @@ -315,10 +332,6 @@ struct mem_cgroup { atomic_t moving_account; struct task_struct *move_lock_task; - /* Legacy local VM stats and events */ - struct memcg_vmstats_percpu __percpu *vmstats_local; - - /* Subtree VM stats and events (batched updates) */ struct memcg_vmstats_percpu __percpu *vmstats_percpu; #ifdef CONFIG_CGROUP_WRITEBACK @@ -939,10 +952,6 @@ static inline void mod_memcg_lruvec_state(struct lruvec *lruvec, local_irq_restore(flags); } -unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, - gfp_t gfp_mask, - unsigned long *total_scanned); - void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx, unsigned long count); @@ -1023,6 +1032,10 @@ static inline void memcg_memory_event_mm(struct mm_struct *mm, void split_page_memcg(struct page *head, unsigned int nr); +unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, + gfp_t gfp_mask, + unsigned long *total_scanned); + #else /* CONFIG_MEMCG */ #define MEM_CGROUP_ID_SHIFT 0 @@ -1131,6 +1144,10 @@ static inline bool lruvec_holds_page_lru_lock(struct page *page, return lruvec == &pgdat->__lruvec; } +static inline void lruvec_memcg_debug(struct lruvec *lruvec, struct page *page) +{ +} + static inline struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg) { return NULL; @@ -1334,18 +1351,6 @@ static inline void mod_lruvec_kmem_state(void *p, enum node_stat_item idx, mod_node_page_state(page_pgdat(page), idx, val); } -static inline -unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, - gfp_t gfp_mask, - unsigned long *total_scanned) -{ - return 0; -} - -static inline void split_page_memcg(struct page *head, unsigned int nr) -{ -} - static inline void count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx, unsigned long count) @@ -1368,8 +1373,16 @@ void count_memcg_event_mm(struct mm_struct *mm, enum vm_event_item idx) { } -static inline void lruvec_memcg_debug(struct lruvec *lruvec, struct page *page) +static inline void split_page_memcg(struct page *head, unsigned int nr) +{ +} + +static inline +unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, + gfp_t gfp_mask, + unsigned long *total_scanned) { + return 0; } #endif /* CONFIG_MEMCG */ -- cgit v1.2.3 From 0add0c77a9bd0ce7cd3b53894fb08154881402a4 Mon Sep 17 00:00:00 2001 From: Shakeel Butt Date: Thu, 29 Apr 2021 22:56:36 -0700 Subject: memcg: charge before adding to swapcache on swapin Currently the kernel adds the page, allocated for swapin, to the swapcache before charging the page. This is fine but now we want a per-memcg swapcache stat which is essential for folks who wants to transparently migrate from cgroup v1's memsw to cgroup v2's memory and swap counters. In addition charging a page before exposing it to other parts of the kernel is a step in the right direction. To correctly maintain the per-memcg swapcache stat, this patch has adopted to charge the page before adding it to swapcache. One challenge in this option is the failure case of add_to_swap_cache() on which we need to undo the mem_cgroup_charge(). Specifically undoing mem_cgroup_uncharge_swap() is not simple. To resolve the issue, this patch decouples the charging for swapin pages from mem_cgroup_charge(). Two new functions are introduced, mem_cgroup_swapin_charge_page() for just charging the swapin page and mem_cgroup_swapin_uncharge_swap() for uncharging the swap slot once the page has been successfully added to the swapcache. [shakeelb@google.com: set page->private before calling swap_readpage] Link: https://lkml.kernel.org/r/20210318015959.2986837-1-shakeelb@google.com Link: https://lkml.kernel.org/r/20210305212639.775498-1-shakeelb@google.com Signed-off-by: Shakeel Butt Acked-by: Roman Gushchin Acked-by: Johannes Weiner Acked-by: Hugh Dickins Tested-by: Heiko Carstens Cc: Michal Hocko Cc: Stephen Rothwell Cc: Christian Borntraeger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/linux/memcontrol.h') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 74910ce9a3f9..e946c96daa32 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -609,6 +609,9 @@ static inline bool mem_cgroup_below_min(struct mem_cgroup *memcg) } int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask); +int mem_cgroup_swapin_charge_page(struct page *page, struct mm_struct *mm, + gfp_t gfp, swp_entry_t entry); +void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry); void mem_cgroup_uncharge(struct page *page); void mem_cgroup_uncharge_list(struct list_head *page_list); @@ -1112,6 +1115,16 @@ static inline int mem_cgroup_charge(struct page *page, struct mm_struct *mm, return 0; } +static inline int mem_cgroup_swapin_charge_page(struct page *page, + struct mm_struct *mm, gfp_t gfp, swp_entry_t entry) +{ + return 0; +} + +static inline void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry) +{ +} + static inline void mem_cgroup_uncharge(struct page *page) { } -- cgit v1.2.3 From b4e0b68fbd9d1fd7e31cbe8adca3ad6cf556e2ee Mon Sep 17 00:00:00 2001 From: Muchun Song Date: Thu, 29 Apr 2021 22:56:52 -0700 Subject: mm: memcontrol: use obj_cgroup APIs to charge kmem pages Since Roman's series "The new cgroup slab memory controller" applied. All slab objects are charged via the new APIs of obj_cgroup. The new APIs introduce a struct obj_cgroup to charge slab objects. It prevents long-living objects from pinning the original memory cgroup in the memory. But there are still some corner objects (e.g. allocations larger than order-1 page on SLUB) which are not charged via the new APIs. Those objects (include the pages which are allocated from buddy allocator directly) are charged as kmem pages which still hold a reference to the memory cgroup. We want to reuse the obj_cgroup APIs to charge the kmem pages. If we do that, we should store an object cgroup pointer to page->memcg_data for the kmem pages. Finally, page->memcg_data will have 3 different meanings. 1) For the slab pages, page->memcg_data points to an object cgroups vector. 2) For the kmem pages (exclude the slab pages), page->memcg_data points to an object cgroup. 3) For the user pages (e.g. the LRU pages), page->memcg_data points to a memory cgroup. We do not change the behavior of page_memcg() and page_memcg_rcu(). They are also suitable for LRU pages and kmem pages. Why? Because memory allocations pinning memcgs for a long time - it exists at a larger scale and is causing recurring problems in the real world: page cache doesn't get reclaimed for a long time, or is used by the second, third, fourth, ... instance of the same job that was restarted into a new cgroup every time. Unreclaimable dying cgroups pile up, waste memory, and make page reclaim very inefficient. We can convert LRU pages and most other raw memcg pins to the objcg direction to fix this problem, and then the page->memcg will always point to an object cgroup pointer. At that time, LRU pages and kmem pages will be treated the same. The implementation of page_memcg() will remove the kmem page check. This patch aims to charge the kmem pages by using the new APIs of obj_cgroup. Finally, the page->memcg_data of the kmem page points to an object cgroup. We can use the __page_objcg() to get the object cgroup associated with a kmem page. Or we can use page_memcg() to get the memory cgroup associated with a kmem page, but caller must ensure that the returned memcg won't be released (e.g. acquire the rcu_read_lock or css_set_lock). Link: https://lkml.kernel.org/r/20210401030141.37061-1-songmuchun@bytedance.com Link: https://lkml.kernel.org/r/20210319163821.20704-6-songmuchun@bytedance.com Signed-off-by: Muchun Song Acked-by: Johannes Weiner Reviewed-by: Shakeel Butt Acked-by: Roman Gushchin Reviewed-by: Miaohe Lin Cc: Michal Hocko Cc: Vladimir Davydov Cc: Xiongchun Duan Cc: Christian Borntraeger [songmuchun@bytedance.com: fix forget to obtain the ref to objcg in split_page_memcg] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 120 ++++++++++++++++++++++++++++++++++++--------- 1 file changed, 97 insertions(+), 23 deletions(-) (limited to 'include/linux/memcontrol.h') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index e946c96daa32..78ca34c935ab 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -371,6 +371,62 @@ enum page_memcg_data_flags { #define MEMCG_DATA_FLAGS_MASK (__NR_MEMCG_DATA_FLAGS - 1) +static inline bool PageMemcgKmem(struct page *page); + +/* + * After the initialization objcg->memcg is always pointing at + * a valid memcg, but can be atomically swapped to the parent memcg. + * + * The caller must ensure that the returned memcg won't be released: + * e.g. acquire the rcu_read_lock or css_set_lock. + */ +static inline struct mem_cgroup *obj_cgroup_memcg(struct obj_cgroup *objcg) +{ + return READ_ONCE(objcg->memcg); +} + +/* + * __page_memcg - get the memory cgroup associated with a non-kmem page + * @page: a pointer to the page struct + * + * Returns a pointer to the memory cgroup associated with the page, + * or NULL. This function assumes that the page is known to have a + * proper memory cgroup pointer. It's not safe to call this function + * against some type of pages, e.g. slab pages or ex-slab pages or + * kmem pages. + */ +static inline struct mem_cgroup *__page_memcg(struct page *page) +{ + unsigned long memcg_data = page->memcg_data; + + VM_BUG_ON_PAGE(PageSlab(page), page); + VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_OBJCGS, page); + VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_KMEM, page); + + return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK); +} + +/* + * __page_objcg - get the object cgroup associated with a kmem page + * @page: a pointer to the page struct + * + * Returns a pointer to the object cgroup associated with the page, + * or NULL. This function assumes that the page is known to have a + * proper object cgroup pointer. It's not safe to call this function + * against some type of pages, e.g. slab pages or ex-slab pages or + * LRU pages. + */ +static inline struct obj_cgroup *__page_objcg(struct page *page) +{ + unsigned long memcg_data = page->memcg_data; + + VM_BUG_ON_PAGE(PageSlab(page), page); + VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_OBJCGS, page); + VM_BUG_ON_PAGE(!(memcg_data & MEMCG_DATA_KMEM), page); + + return (struct obj_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK); +} + /* * page_memcg - get the memory cgroup associated with a page * @page: a pointer to the page struct @@ -380,20 +436,23 @@ enum page_memcg_data_flags { * proper memory cgroup pointer. It's not safe to call this function * against some type of pages, e.g. slab pages or ex-slab pages. * - * Any of the following ensures page and memcg binding stability: + * For a non-kmem page any of the following ensures page and memcg binding + * stability: + * * - the page lock * - LRU isolation * - lock_page_memcg() * - exclusive reference + * + * For a kmem page a caller should hold an rcu read lock to protect memcg + * associated with a kmem page from being released. */ static inline struct mem_cgroup *page_memcg(struct page *page) { - unsigned long memcg_data = page->memcg_data; - - VM_BUG_ON_PAGE(PageSlab(page), page); - VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_OBJCGS, page); - - return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK); + if (PageMemcgKmem(page)) + return obj_cgroup_memcg(__page_objcg(page)); + else + return __page_memcg(page); } /* @@ -407,11 +466,19 @@ static inline struct mem_cgroup *page_memcg(struct page *page) */ static inline struct mem_cgroup *page_memcg_rcu(struct page *page) { + unsigned long memcg_data = READ_ONCE(page->memcg_data); + VM_BUG_ON_PAGE(PageSlab(page), page); WARN_ON_ONCE(!rcu_read_lock_held()); - return (struct mem_cgroup *)(READ_ONCE(page->memcg_data) & - ~MEMCG_DATA_FLAGS_MASK); + if (memcg_data & MEMCG_DATA_KMEM) { + struct obj_cgroup *objcg; + + objcg = (void *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK); + return obj_cgroup_memcg(objcg); + } + + return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK); } /* @@ -419,15 +486,21 @@ static inline struct mem_cgroup *page_memcg_rcu(struct page *page) * @page: a pointer to the page struct * * Returns a pointer to the memory cgroup associated with the page, - * or NULL. This function unlike page_memcg() can take any page + * or NULL. This function unlike page_memcg() can take any page * as an argument. It has to be used in cases when it's not known if a page - * has an associated memory cgroup pointer or an object cgroups vector. + * has an associated memory cgroup pointer or an object cgroups vector or + * an object cgroup. + * + * For a non-kmem page any of the following ensures page and memcg binding + * stability: * - * Any of the following ensures page and memcg binding stability: * - the page lock * - LRU isolation * - lock_page_memcg() * - exclusive reference + * + * For a kmem page a caller should hold an rcu read lock to protect memcg + * associated with a kmem page from being released. */ static inline struct mem_cgroup *page_memcg_check(struct page *page) { @@ -440,6 +513,13 @@ static inline struct mem_cgroup *page_memcg_check(struct page *page) if (memcg_data & MEMCG_DATA_OBJCGS) return NULL; + if (memcg_data & MEMCG_DATA_KMEM) { + struct obj_cgroup *objcg; + + objcg = (void *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK); + return obj_cgroup_memcg(objcg); + } + return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK); } @@ -718,21 +798,15 @@ static inline void obj_cgroup_get(struct obj_cgroup *objcg) percpu_ref_get(&objcg->refcnt); } -static inline void obj_cgroup_put(struct obj_cgroup *objcg) +static inline void obj_cgroup_get_many(struct obj_cgroup *objcg, + unsigned long nr) { - percpu_ref_put(&objcg->refcnt); + percpu_ref_get_many(&objcg->refcnt, nr); } -/* - * After the initialization objcg->memcg is always pointing at - * a valid memcg, but can be atomically swapped to the parent memcg. - * - * The caller must ensure that the returned memcg won't be released: - * e.g. acquire the rcu_read_lock or css_set_lock. - */ -static inline struct mem_cgroup *obj_cgroup_memcg(struct obj_cgroup *objcg) +static inline void obj_cgroup_put(struct obj_cgroup *objcg) { - return READ_ONCE(objcg->memcg); + percpu_ref_put(&objcg->refcnt); } static inline void mem_cgroup_put(struct mem_cgroup *memcg) -- cgit v1.2.3 From bd290e1e75d8a8b2d87031b63db56ae165677870 Mon Sep 17 00:00:00 2001 From: Muchun Song Date: Thu, 29 Apr 2021 22:56:58 -0700 Subject: mm: memcontrol: move PageMemcgKmem to the scope of CONFIG_MEMCG_KMEM The page only can be marked as kmem when CONFIG_MEMCG_KMEM is enabled. So move PageMemcgKmem() to the scope of the CONFIG_MEMCG_KMEM. As a bonus, on !CONFIG_MEMCG_KMEM build some code can be compiled out. Link: https://lkml.kernel.org/r/20210319163821.20704-8-songmuchun@bytedance.com Signed-off-by: Muchun Song Acked-by: Roman Gushchin Reviewed-by: Shakeel Butt Acked-by: Johannes Weiner Cc: Michal Hocko Cc: Vladimir Davydov Cc: Xiongchun Duan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'include/linux/memcontrol.h') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 78ca34c935ab..bcf92b99f001 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -523,6 +523,7 @@ static inline struct mem_cgroup *page_memcg_check(struct page *page) return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK); } +#ifdef CONFIG_MEMCG_KMEM /* * PageMemcgKmem - check if the page has MemcgKmem flag set * @page: a pointer to the page struct @@ -537,7 +538,6 @@ static inline bool PageMemcgKmem(struct page *page) return page->memcg_data & MEMCG_DATA_KMEM; } -#ifdef CONFIG_MEMCG_KMEM /* * page_objcgs - get the object cgroups vector associated with a page * @page: a pointer to the page struct @@ -579,6 +579,11 @@ static inline struct obj_cgroup **page_objcgs_check(struct page *page) } #else +static inline bool PageMemcgKmem(struct page *page) +{ + return false; +} + static inline struct obj_cgroup **page_objcgs(struct page *page) { return NULL; -- cgit v1.2.3 From a10e995749a6c65833edd201c55665e5d44d14fc Mon Sep 17 00:00:00 2001 From: Wan Jiabing Date: Thu, 29 Apr 2021 22:57:01 -0700 Subject: linux/memcontrol.h: remove duplicate struct declaration struct mem_cgroup is declared twice. One has been declared at forward struct declaration. Remove the duplicate. Link: https://lkml.kernel.org/r/20210330020246.2265371-1-wanjiabing@vivo.com Signed-off-by: Wan Jiabing Reviewed-by: Muchun Song Acked-by: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux/memcontrol.h') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index bcf92b99f001..5904716f29ba 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1123,8 +1123,6 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, #define MEM_CGROUP_ID_SHIFT 0 #define MEM_CGROUP_ID_MAX 0 -struct mem_cgroup; - static inline struct mem_cgroup *page_memcg(struct page *page) { return NULL; -- cgit v1.2.3 From 2bfd36374edd9ed7f2ebf66cacebedf7273901cb Mon Sep 17 00:00:00 2001 From: Yang Shi Date: Tue, 4 May 2021 18:36:11 -0700 Subject: mm: vmscan: consolidate shrinker_maps handling code The shrinker map management is not purely memcg specific, it is at the intersection between memory cgroup and shrinkers. It's allocation and assignment of a structure, and the only memcg bit is the map is being stored in a memcg structure. So move the shrinker_maps handling code into vmscan.c for tighter integration with shrinker code, and remove the "memcg_" prefix. There is no functional change. Link: https://lkml.kernel.org/r/20210311190845.9708-3-shy828301@gmail.com Signed-off-by: Yang Shi Acked-by: Vlastimil Babka Acked-by: Kirill Tkhai Acked-by: Roman Gushchin Reviewed-by: Shakeel Butt Cc: Dave Chinner Cc: Johannes Weiner Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'include/linux/memcontrol.h') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 5904716f29ba..7dbd2c9bad32 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1610,10 +1610,9 @@ static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg) return false; } -extern int memcg_expand_shrinker_maps(int new_id); - -extern void memcg_set_shrinker_bit(struct mem_cgroup *memcg, - int nid, int shrinker_id); +int alloc_shrinker_maps(struct mem_cgroup *memcg); +void free_shrinker_maps(struct mem_cgroup *memcg); +void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id); #else #define mem_cgroup_sockets_enabled 0 static inline void mem_cgroup_sk_alloc(struct sock *sk) { }; @@ -1623,8 +1622,8 @@ static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg) return false; } -static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg, - int nid, int shrinker_id) +static inline void set_shrinker_bit(struct mem_cgroup *memcg, + int nid, int shrinker_id) { } #endif -- cgit v1.2.3 From e4262c4f51d6373447c9d89093f49ff6b1e607be Mon Sep 17 00:00:00 2001 From: Yang Shi Date: Tue, 4 May 2021 18:36:23 -0700 Subject: mm: memcontrol: rename shrinker_map to shrinker_info The following patch is going to add nr_deferred into shrinker_map, the change will make shrinker_map not only include map anymore, so rename it to "memcg_shrinker_info". And this should make the patch adding nr_deferred cleaner and readable and make review easier. Also remove the "memcg_" prefix. Link: https://lkml.kernel.org/r/20210311190845.9708-7-shy828301@gmail.com Signed-off-by: Yang Shi Acked-by: Vlastimil Babka Acked-by: Kirill Tkhai Acked-by: Roman Gushchin Reviewed-by: Shakeel Butt Cc: Dave Chinner Cc: Johannes Weiner Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include/linux/memcontrol.h') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 7dbd2c9bad32..6cd800fe9a67 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -117,7 +117,7 @@ struct batched_lruvec_stat { * Bitmap of shrinker::id corresponding to memcg-aware shrinkers, * which have elements charged to this memcg. */ -struct memcg_shrinker_map { +struct shrinker_info { struct rcu_head rcu; unsigned long map[]; }; @@ -145,7 +145,7 @@ struct mem_cgroup_per_node { struct mem_cgroup_reclaim_iter iter; - struct memcg_shrinker_map __rcu *shrinker_map; + struct shrinker_info __rcu *shrinker_info; struct rb_node tree_node; /* RB tree node */ unsigned long usage_in_excess;/* Set to the value by which */ @@ -1610,8 +1610,8 @@ static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg) return false; } -int alloc_shrinker_maps(struct mem_cgroup *memcg); -void free_shrinker_maps(struct mem_cgroup *memcg); +int alloc_shrinker_info(struct mem_cgroup *memcg); +void free_shrinker_info(struct mem_cgroup *memcg); void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id); #else #define mem_cgroup_sockets_enabled 0 -- cgit v1.2.3 From 3c6f17e6c5d048c8029578c475dd037dd5db58af Mon Sep 17 00:00:00 2001 From: Yang Shi Date: Tue, 4 May 2021 18:36:33 -0700 Subject: mm: vmscan: add per memcg shrinker nr_deferred Currently the number of deferred objects are per shrinker, but some slabs, for example, vfs inode/dentry cache are per memcg, this would result in poor isolation among memcgs. The deferred objects typically are generated by __GFP_NOFS allocations, one memcg with excessive __GFP_NOFS allocations may blow up deferred objects, then other innocent memcgs may suffer from over shrink, excessive reclaim latency, etc. For example, two workloads run in memcgA and memcgB respectively, workload in B is vfs heavy workload. Workload in A generates excessive deferred objects, then B's vfs cache might be hit heavily (drop half of caches) by B's limit reclaim or global reclaim. We observed this hit in our production environment which was running vfs heavy workload shown as the below tracing log: <...>-409454 [016] .... 28286961.747146: mm_shrink_slab_start: super_cache_scan+0x0/0x1a0 ffff9a83046f3458: nid: 1 objects to shrink 3641681686040 gfp_flags GFP_HIGHUSER_MOVABLE|__GFP_ZERO pgs_scanned 1 lru_pgs 15721 cache items 246404277 delta 31345 total_scan 123202138 <...>-409454 [022] .... 28287105.928018: mm_shrink_slab_end: super_cache_scan+0x0/0x1a0 ffff9a83046f3458: nid: 1 unused scan count 3641681686040 new scan count 3641798379189 total_scan 602 last shrinker return val 123186855 The vfs cache and page cache ratio was 10:1 on this machine, and half of caches were dropped. This also resulted in significant amount of page caches were dropped due to inodes eviction. Make nr_deferred per memcg for memcg aware shrinkers would solve the unfairness and bring better isolation. The following patch will add nr_deferred to parent memcg when memcg offline. To preserve nr_deferred when reparenting memcgs to root, root memcg needs shrinker_info allocated too. When memcg is not enabled (!CONFIG_MEMCG or memcg disabled), the shrinker's nr_deferred would be used. And non memcg aware shrinkers use shrinker's nr_deferred all the time. Link: https://lkml.kernel.org/r/20210311190845.9708-10-shy828301@gmail.com Signed-off-by: Yang Shi Acked-by: Roman Gushchin Acked-by: Kirill Tkhai Reviewed-by: Shakeel Butt Cc: Dave Chinner Cc: Johannes Weiner Cc: Michal Hocko Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'include/linux/memcontrol.h') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 6cd800fe9a67..32bd62047238 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -114,12 +114,13 @@ struct batched_lruvec_stat { }; /* - * Bitmap of shrinker::id corresponding to memcg-aware shrinkers, - * which have elements charged to this memcg. + * Bitmap and deferred work of shrinker::id corresponding to memcg-aware + * shrinkers, which have elements charged to this memcg. */ struct shrinker_info { struct rcu_head rcu; - unsigned long map[]; + atomic_long_t *nr_deferred; + unsigned long *map; }; /* -- cgit v1.2.3 From a178015cde69981cdcd8f109c5abc98703fead62 Mon Sep 17 00:00:00 2001 From: Yang Shi Date: Tue, 4 May 2021 18:36:42 -0700 Subject: mm: memcontrol: reparent nr_deferred when memcg offline Now shrinker's nr_deferred is per memcg for memcg aware shrinkers, add to parent's corresponding nr_deferred when memcg offline. Link: https://lkml.kernel.org/r/20210311190845.9708-13-shy828301@gmail.com Signed-off-by: Yang Shi Acked-by: Vlastimil Babka Acked-by: Kirill Tkhai Acked-by: Roman Gushchin Reviewed-by: Shakeel Butt Cc: Dave Chinner Cc: Johannes Weiner Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/memcontrol.h') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 32bd62047238..c193be760709 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1614,6 +1614,7 @@ static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg) int alloc_shrinker_info(struct mem_cgroup *memcg); void free_shrinker_info(struct mem_cgroup *memcg); void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id); +void reparent_shrinker_deferred(struct mem_cgroup *memcg); #else #define mem_cgroup_sockets_enabled 0 static inline void mem_cgroup_sk_alloc(struct sock *sk) { }; -- cgit v1.2.3