1 files changed, 136 insertions, 154 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 605f671203ef..845eec01ef9d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -255,6 +255,11 @@ struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
 #ifdef CONFIG_MEMCG_KMEM
 extern spinlock_t css_set_lock;
 
+static int __memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp,
+			       unsigned int nr_pages);
+static void __memcg_kmem_uncharge(struct mem_cgroup *memcg,
+				  unsigned int nr_pages);
+
 static void obj_cgroup_release(struct percpu_ref *ref)
 {
 	struct obj_cgroup *objcg = container_of(ref, struct obj_cgroup, refcnt);
@@ -447,8 +452,7 @@ static void memcg_free_shrinker_maps(struct mem_cgroup *memcg)
 	for_each_node(nid) {
 		pn = mem_cgroup_nodeinfo(memcg, nid);
 		map = rcu_dereference_protected(pn->shrinker_map, true);
-		if (map)
-			kvfree(map);
+		kvfree(map);
 		rcu_assign_pointer(pn->shrinker_map, NULL);
 	}
 }
@@ -1043,29 +1047,6 @@ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
 }
 EXPORT_SYMBOL(get_mem_cgroup_from_mm);
 
-/**
- * get_mem_cgroup_from_page: Obtain a reference on given page's memcg.
- * @page: page from which memcg should be extracted.
- *
- * Obtain a reference on page->memcg and returns it if successful. Otherwise
- * root_mem_cgroup is returned.
- */
-struct mem_cgroup *get_mem_cgroup_from_page(struct page *page)
-{
-	struct mem_cgroup *memcg = page_memcg(page);
-
-	if (mem_cgroup_disabled())
-		return NULL;
-
-	rcu_read_lock();
-	/* Page should not get uncharged and freed memcg under us. */
-	if (!memcg || WARN_ON_ONCE(!css_tryget(&memcg->css)))
-		memcg = root_mem_cgroup;
-	rcu_read_unlock();
-	return memcg;
-}
-EXPORT_SYMBOL(get_mem_cgroup_from_page);
-
 static __always_inline struct mem_cgroup *active_memcg(void)
 {
 	if (in_interrupt())
@@ -1080,13 +1061,9 @@ static __always_inline struct mem_cgroup *get_active_memcg(void)
 
 	rcu_read_lock();
 	memcg = active_memcg();
-	if (memcg) {
-		/* current->active_memcg must hold a ref. */
-		if (WARN_ON_ONCE(!css_tryget(&memcg->css)))
-			memcg = root_mem_cgroup;
-		else
-			memcg = current->active_memcg;
-	}
+	/* remote memcg must hold a ref. */
+	if (memcg && WARN_ON_ONCE(!css_tryget(&memcg->css)))
+		memcg = root_mem_cgroup;
 	rcu_read_unlock();
 
 	return memcg;
@@ -1346,20 +1323,19 @@ void lruvec_memcg_debug(struct lruvec *lruvec, struct page *page)
  * lock_page_lruvec - lock and return lruvec for a given page.
  * @page: the page
  *
- * This series functions should be used in either conditions:
- * PageLRU is cleared or unset
- * or page->_refcount is zero
- * or page is locked.
+ * These functions are safe to use under any of the following conditions:
+ * - page locked
+ * - PageLRU cleared
+ * - lock_page_memcg()
+ * - page->_refcount is zero
  */
 struct lruvec *lock_page_lruvec(struct page *page)
 {
 	struct lruvec *lruvec;
 	struct pglist_data *pgdat = page_pgdat(page);
 
-	rcu_read_lock();
 	lruvec = mem_cgroup_page_lruvec(page, pgdat);
 	spin_lock(&lruvec->lru_lock);
-	rcu_read_unlock();
 
 	lruvec_memcg_debug(lruvec, page);
 
@@ -1371,10 +1347,8 @@ struct lruvec *lock_page_lruvec_irq(struct page *page)
 	struct lruvec *lruvec;
 	struct pglist_data *pgdat = page_pgdat(page);
 
-	rcu_read_lock();
 	lruvec = mem_cgroup_page_lruvec(page, pgdat);
 	spin_lock_irq(&lruvec->lru_lock);
-	rcu_read_unlock();
 
 	lruvec_memcg_debug(lruvec, page);
 
@@ -1386,10 +1360,8 @@ struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags)
 	struct lruvec *lruvec;
 	struct pglist_data *pgdat = page_pgdat(page);
 
-	rcu_read_lock();
 	lruvec = mem_cgroup_page_lruvec(page, pgdat);
 	spin_lock_irqsave(&lruvec->lru_lock, *flags);
-	rcu_read_unlock();
 
 	lruvec_memcg_debug(lruvec, page);
 
@@ -1512,72 +1484,73 @@ static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
 
 struct memory_stat {
 	const char *name;
-	unsigned int ratio;
 	unsigned int idx;
 };
 
-static struct memory_stat memory_stats[] = {
-	{ "anon", PAGE_SIZE, NR_ANON_MAPPED },
-	{ "file", PAGE_SIZE, NR_FILE_PAGES },
-	{ "kernel_stack", 1024, NR_KERNEL_STACK_KB },
-	{ "pagetables", PAGE_SIZE, NR_PAGETABLE },
-	{ "percpu", 1, MEMCG_PERCPU_B },
-	{ "sock", PAGE_SIZE, MEMCG_SOCK },
-	{ "shmem", PAGE_SIZE, NR_SHMEM },
-	{ "file_mapped", PAGE_SIZE, NR_FILE_MAPPED },
-	{ "file_dirty", PAGE_SIZE, NR_FILE_DIRTY },
-	{ "file_writeback", PAGE_SIZE, NR_WRITEBACK },
+static const struct memory_stat memory_stats[] = {
+	{ "anon",			NR_ANON_MAPPED			},
+	{ "file",			NR_FILE_PAGES			},
+	{ "kernel_stack",		NR_KERNEL_STACK_KB		},
+	{ "pagetables",			NR_PAGETABLE			},
+	{ "percpu",			MEMCG_PERCPU_B			},
+	{ "sock",			MEMCG_SOCK			},
+	{ "shmem",			NR_SHMEM			},
+	{ "file_mapped",		NR_FILE_MAPPED			},
+	{ "file_dirty",			NR_FILE_DIRTY			},
+	{ "file_writeback",		NR_WRITEBACK			},
+#ifdef CONFIG_SWAP
+	{ "swapcached",			NR_SWAPCACHE			},
+#endif
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	/*
-	 * The ratio will be initialized in memory_stats_init(). Because
-	 * on some architectures, the macro of HPAGE_PMD_SIZE is not
-	 * constant(e.g. powerpc).
-	 */
-	{ "anon_thp", 0, NR_ANON_THPS },
-	{ "file_thp", 0, NR_FILE_THPS },
-	{ "shmem_thp", 0, NR_SHMEM_THPS },
+	{ "anon_thp",			NR_ANON_THPS			},
+	{ "file_thp",			NR_FILE_THPS			},
+	{ "shmem_thp",			NR_SHMEM_THPS			},
 #endif
-	{ "inactive_anon", PAGE_SIZE, NR_INACTIVE_ANON },
-	{ "active_anon", PAGE_SIZE, NR_ACTIVE_ANON },
-	{ "inactive_file", PAGE_SIZE, NR_INACTIVE_FILE },
-	{ "active_file", PAGE_SIZE, NR_ACTIVE_FILE },
-	{ "unevictable", PAGE_SIZE, NR_UNEVICTABLE },
-
-	/*
-	 * Note: The slab_reclaimable and slab_unreclaimable must be
-	 * together and slab_reclaimable must be in front.
-	 */
-	{ "slab_reclaimable", 1, NR_SLAB_RECLAIMABLE_B },
-	{ "slab_unreclaimable", 1, NR_SLAB_UNRECLAIMABLE_B },
+	{ "inactive_anon",		NR_INACTIVE_ANON		},
+	{ "active_anon",		NR_ACTIVE_ANON			},
+	{ "inactive_file",		NR_INACTIVE_FILE		},
+	{ "active_file",		NR_ACTIVE_FILE			},
+	{ "unevictable",		NR_UNEVICTABLE			},
+	{ "slab_reclaimable",		NR_SLAB_RECLAIMABLE_B		},
+	{ "slab_unreclaimable",		NR_SLAB_UNRECLAIMABLE_B		},
 
 	/* The memory events */
-	{ "workingset_refault_anon", 1, WORKINGSET_REFAULT_ANON },
-	{ "workingset_refault_file", 1, WORKINGSET_REFAULT_FILE },
-	{ "workingset_activate_anon", 1, WORKINGSET_ACTIVATE_ANON },
-	{ "workingset_activate_file", 1, WORKINGSET_ACTIVATE_FILE },
-	{ "workingset_restore_anon", 1, WORKINGSET_RESTORE_ANON },
-	{ "workingset_restore_file", 1, WORKINGSET_RESTORE_FILE },
-	{ "workingset_nodereclaim", 1, WORKINGSET_NODERECLAIM },
+	{ "workingset_refault_anon",	WORKINGSET_REFAULT_ANON		},
+	{ "workingset_refault_file",	WORKINGSET_REFAULT_FILE		},
+	{ "workingset_activate_anon",	WORKINGSET_ACTIVATE_ANON	},
+	{ "workingset_activate_file",	WORKINGSET_ACTIVATE_FILE	},
+	{ "workingset_restore_anon",	WORKINGSET_RESTORE_ANON		},
+	{ "workingset_restore_file",	WORKINGSET_RESTORE_FILE		},
+	{ "workingset_nodereclaim",	WORKINGSET_NODERECLAIM		},
 };
 
-static int __init memory_stats_init(void)
-{
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-		if (memory_stats[i].idx == NR_ANON_THPS ||
-		    memory_stats[i].idx == NR_FILE_THPS ||
-		    memory_stats[i].idx == NR_SHMEM_THPS)
-			memory_stats[i].ratio = HPAGE_PMD_SIZE;
-#endif
-		VM_BUG_ON(!memory_stats[i].ratio);
-		VM_BUG_ON(memory_stats[i].idx >= MEMCG_NR_STAT);
+/* Translate stat items to the correct unit for memory.stat output */
+static int memcg_page_state_unit(int item)
+{
+	switch (item) {
+	case MEMCG_PERCPU_B:
+	case NR_SLAB_RECLAIMABLE_B:
+	case NR_SLAB_UNRECLAIMABLE_B:
+	case WORKINGSET_REFAULT_ANON:
+	case WORKINGSET_REFAULT_FILE:
+	case WORKINGSET_ACTIVATE_ANON:
+	case WORKINGSET_ACTIVATE_FILE:
+	case WORKINGSET_RESTORE_ANON:
+	case WORKINGSET_RESTORE_FILE:
+	case WORKINGSET_NODERECLAIM:
+		return 1;
+	case NR_KERNEL_STACK_KB:
+		return SZ_1K;
+	default:
+		return PAGE_SIZE;
 	}
+}
 
-	return 0;
+static inline unsigned long memcg_page_state_output(struct mem_cgroup *memcg,
+						    int item)
+{
+	return memcg_page_state(memcg, item) * memcg_page_state_unit(item);
 }
-pure_initcall(memory_stats_init);
 
 static char *memory_stat_format(struct mem_cgroup *memcg)
 {
@@ -1602,13 +1575,12 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
 	for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
 		u64 size;
 
-		size = memcg_page_state(memcg, memory_stats[i].idx);
-		size *= memory_stats[i].ratio;
+		size = memcg_page_state_output(memcg, memory_stats[i].idx);
 		seq_buf_printf(&s, "%s %llu\n", memory_stats[i].name, size);
 
 		if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) {
-			size = memcg_page_state(memcg, NR_SLAB_RECLAIMABLE_B) +
-			       memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B);
+			size += memcg_page_state_output(memcg,
+							NR_SLAB_RECLAIMABLE_B);
 			seq_buf_printf(&s, "slab %llu\n", size);
 		}
 	}
@@ -2935,9 +2907,10 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg)
 
 #ifdef CONFIG_MEMCG_KMEM
 int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
-				 gfp_t gfp)
+				 gfp_t gfp, bool new_page)
 {
 	unsigned int objects = objs_per_slab_page(s, page);
+	unsigned long memcg_data;
 	void *vec;
 
 	vec = kcalloc_node(objects, sizeof(struct obj_cgroup *), gfp,
@@ -2945,11 +2918,25 @@ int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
 	if (!vec)
 		return -ENOMEM;
 
-	if (!set_page_objcgs(page, vec))
+	memcg_data = (unsigned long) vec | MEMCG_DATA_OBJCGS;
+	if (new_page) {
+		/*
+		 * If the slab page is brand new and nobody can yet access
+		 * it's memcg_data, no synchronization is required and
+		 * memcg_data can be simply assigned.
+		 */
+		page->memcg_data = memcg_data;
+	} else if (cmpxchg(&page->memcg_data, 0, memcg_data)) {
+		/*
+		 * If the slab page is already in use, somebody can allocate
+		 * and assign obj_cgroups in parallel. In this case the existing
+		 * objcg vector should be reused.
+		 */
 		kfree(vec);
-	else
-		kmemleak_not_leak(vec);
+		return 0;
+	}
 
+	kmemleak_not_leak(vec);
 	return 0;
 }
 
@@ -3077,8 +3064,8 @@ static void memcg_free_cache_id(int id)
  *
  * Returns 0 on success, an error code on failure.
  */
-int __memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp,
-			unsigned int nr_pages)
+static int __memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp,
+			       unsigned int nr_pages)
 {
 	struct page_counter *counter;
 	int ret;
@@ -3110,14 +3097,12 @@ int __memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp,
  * @memcg: memcg to uncharge
  * @nr_pages: number of pages to uncharge
  */
-void __memcg_kmem_uncharge(struct mem_cgroup *memcg, unsigned int nr_pages)
+static void __memcg_kmem_uncharge(struct mem_cgroup *memcg, unsigned int nr_pages)
 {
 	if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
 		page_counter_uncharge(&memcg->kmem, nr_pages);
 
-	page_counter_uncharge(&memcg->memory, nr_pages);
-	if (do_memsw_account())
-		page_counter_uncharge(&memcg->memsw, nr_pages);
+	refill_stock(memcg, nr_pages);
 }
 
 /**
@@ -4074,10 +4059,6 @@ static int memcg_stat_show(struct seq_file *m, void *v)
 		if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
 			continue;
 		nr = memcg_page_state_local(memcg, memcg1_stats[i]);
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-		if (memcg1_stats[i] == NR_ANON_THPS)
-			nr *= HPAGE_PMD_NR;
-#endif
 		seq_printf(m, "%s %lu\n", memcg1_stat_names[i], nr * PAGE_SIZE);
 	}
 
@@ -4108,10 +4089,6 @@ static int memcg_stat_show(struct seq_file *m, void *v)
 		if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
 			continue;
 		nr = memcg_page_state(memcg, memcg1_stats[i]);
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-		if (memcg1_stats[i] == NR_ANON_THPS)
-			nr *= HPAGE_PMD_NR;
-#endif
 		seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i],
 						(u64)nr * PAGE_SIZE);
 	}
@@ -4899,7 +4876,7 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
 
 	/* the process need read permission on control file */
 	/* AV: shouldn't we check that it's been opened for read instead? */
-	ret = inode_permission(file_inode(cfile.file), MAY_READ);
+	ret = file_permission(cfile.file, MAY_READ);
 	if (ret < 0)
 		goto out_put_cfile;
 
@@ -5195,7 +5172,7 @@ static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
 		return 1;
 	}
 
-	pn->lruvec_stat_cpu = alloc_percpu_gfp(struct lruvec_stat,
+	pn->lruvec_stat_cpu = alloc_percpu_gfp(struct batched_lruvec_stat,
 					       GFP_KERNEL_ACCOUNT);
 	if (!pn->lruvec_stat_cpu) {
 		free_percpu(pn->lruvec_stat_local);
@@ -5644,7 +5621,6 @@ static int mem_cgroup_move_account(struct page *page,
 				__mod_lruvec_state(to_vec, NR_ANON_THPS,
 						   nr_pages);
 			}
-
 		}
 	} else {
 		__mod_lruvec_state(from_vec, NR_FILE_PAGES, -nr_pages);
@@ -6273,6 +6249,8 @@ static ssize_t memory_high_write(struct kernfs_open_file *of,
 	if (err)
 		return err;
 
+	page_counter_set_high(&memcg->memory, high);
+
 	for (;;) {
 		unsigned long nr_pages = page_counter_read(&memcg->memory);
 		unsigned long reclaimed;
@@ -6296,10 +6274,7 @@ static ssize_t memory_high_write(struct kernfs_open_file *of,
 			break;
 	}
 
-	page_counter_set_high(&memcg->memory, high);
-
 	memcg_wb_domain_size_changed(memcg);
-
 	return nbytes;
 }
 
@@ -6396,6 +6371,12 @@ static int memory_stat_show(struct seq_file *m, void *v)
 }
 
 #ifdef CONFIG_NUMA
+static inline unsigned long lruvec_page_state_output(struct lruvec *lruvec,
+						     int item)
+{
+	return lruvec_page_state(lruvec, item) * memcg_page_state_unit(item);
+}
+
 static int memory_numa_stat_show(struct seq_file *m, void *v)
 {
 	int i;
@@ -6413,8 +6394,8 @@ static int memory_numa_stat_show(struct seq_file *m, void *v)
 			struct lruvec *lruvec;
 
 			lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
-			size = lruvec_page_state(lruvec, memory_stats[i].idx);
-			size *= memory_stats[i].ratio;
+			size = lruvec_page_state_output(lruvec,
+							memory_stats[i].idx);
 			seq_printf(m, " N%d=%llu", nid, size);
 		}
 		seq_putc(m, '\n');
@@ -6763,7 +6744,19 @@ int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
 	memcg_check_events(memcg, page);
 	local_irq_enable();
 
-	if (PageSwapCache(page)) {
+	/*
+	 * Cgroup1's unified memory+swap counter has been charged with the
+	 * new swapcache page, finish the transfer by uncharging the swap
+	 * slot. The swap slot would also get uncharged when it dies, but
+	 * it can stick around indefinitely and we'd count the page twice
+	 * the entire time.
+	 *
+	 * Cgroup2 has separate resource counters for memory and swap,
+	 * so this is a non-issue here. Memory and swap charge lifetimes
+	 * correspond 1:1 to page and swap slot lifetimes: we charge the
+	 * page to memory here, and uncharge swap when the slot is freed.
+	 */
+	if (do_memsw_account() && PageSwapCache(page)) {
 		swp_entry_t entry = { .val = page_private(page) };
 		/*
 		 * The swap entry might not get freed for a long time,
@@ -6854,31 +6847,6 @@ static void uncharge_page(struct page *page, struct uncharge_gather *ug)
 	css_put(&ug->memcg->css);
 }
 
-static void uncharge_list(struct list_head *page_list)
-{
-	struct uncharge_gather ug;
-	struct list_head *next;
-
-	uncharge_gather_clear(&ug);
-
-	/*
-	 * Note that the list can be a single page->lru; hence the
-	 * do-while loop instead of a simple list_for_each_entry().
-	 */
-	next = page_list->next;
-	do {
-		struct page *page;
-
-		page = list_entry(next, struct page, lru);
-		next = page->lru.next;
-
-		uncharge_page(page, &ug);
-	} while (next != page_list);
-
-	if (ug.memcg)
-		uncharge_batch(&ug);
-}
-
 /**
  * mem_cgroup_uncharge - uncharge a page
  * @page: page to uncharge
@@ -6910,11 +6878,17 @@ void mem_cgroup_uncharge(struct page *page)
  */
 void mem_cgroup_uncharge_list(struct list_head *page_list)
 {
+	struct uncharge_gather ug;
+	struct page *page;
+
 	if (mem_cgroup_disabled())
 		return;
 
-	if (!list_empty(page_list))
-		uncharge_list(page_list);
+	uncharge_gather_clear(&ug);
+	list_for_each_entry(page, page_list, lru)
+		uncharge_page(page, &ug);
+	if (ug.memcg)
+		uncharge_batch(&ug);
 }
 
 /**
@@ -7081,6 +7055,14 @@ static int __init mem_cgroup_init(void)
 {
 	int cpu, node;
 
+	/*
+	 * Currently s32 type (can refer to struct batched_lruvec_stat) is
+	 * used for per-memcg-per-cpu caching of per-node statistics. In order
+	 * to work fine, we should make sure that the overfill threshold can't
+	 * exceed S32_MAX / PAGE_SIZE.
+	 */
+	BUILD_BUG_ON(MEMCG_CHARGE_BATCH > S32_MAX / PAGE_SIZE);
+
 	cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL,
 				  memcg_hotplug_cpu_dead);