1 files changed, 166 insertions, 77 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6a921890739f..4ead5a4817de 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1777,6 +1777,62 @@ cleanup:
 }
 
 /**
+ * mem_cgroup_get_oom_group - get a memory cgroup to clean up after OOM
+ * @victim: task to be killed by the OOM killer
+ * @oom_domain: memcg in case of memcg OOM, NULL in case of system-wide OOM
+ *
+ * Returns a pointer to a memory cgroup, which has to be cleaned up
+ * by killing all belonging OOM-killable tasks.
+ *
+ * Caller has to call mem_cgroup_put() on the returned non-NULL memcg.
+ */
+struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim,
+					    struct mem_cgroup *oom_domain)
+{
+	struct mem_cgroup *oom_group = NULL;
+	struct mem_cgroup *memcg;
+
+	if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
+		return NULL;
+
+	if (!oom_domain)
+		oom_domain = root_mem_cgroup;
+
+	rcu_read_lock();
+
+	memcg = mem_cgroup_from_task(victim);
+	if (memcg == root_mem_cgroup)
+		goto out;
+
+	/*
+	 * Traverse the memory cgroup hierarchy from the victim task's
+	 * cgroup up to the OOMing cgroup (or root) to find the
+	 * highest-level memory cgroup with oom.group set.
+	 */
+	for (; memcg; memcg = parent_mem_cgroup(memcg)) {
+		if (memcg->oom_group)
+			oom_group = memcg;
+
+		if (memcg == oom_domain)
+			break;
+	}
+
+	if (oom_group)
+		css_get(&oom_group->css);
+out:
+	rcu_read_unlock();
+
+	return oom_group;
+}
+
+void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
+{
+	pr_info("Tasks in ");
+	pr_cont_cgroup_path(memcg->css.cgroup);
+	pr_cont(" are going to be killed due to memory.oom.group set\n");
+}
+
+/**
  * lock_page_memcg - lock a page->mem_cgroup binding
  * @page: the page
  *
@@ -2899,29 +2955,34 @@ static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
 	return retval;
 }
 
-static void tree_stat(struct mem_cgroup *memcg, unsigned long *stat)
-{
-	struct mem_cgroup *iter;
-	int i;
-
-	memset(stat, 0, sizeof(*stat) * MEMCG_NR_STAT);
-
-	for_each_mem_cgroup_tree(iter, memcg) {
-		for (i = 0; i < MEMCG_NR_STAT; i++)
-			stat[i] += memcg_page_state(iter, i);
-	}
-}
+struct accumulated_stats {
+	unsigned long stat[MEMCG_NR_STAT];
+	unsigned long events[NR_VM_EVENT_ITEMS];
+	unsigned long lru_pages[NR_LRU_LISTS];
+	const unsigned int *stats_array;
+	const unsigned int *events_array;
+	int stats_size;
+	int events_size;
+};
 
-static void tree_events(struct mem_cgroup *memcg, unsigned long *events)
+static void accumulate_memcg_tree(struct mem_cgroup *memcg,
+				  struct accumulated_stats *acc)
 {
-	struct mem_cgroup *iter;
+	struct mem_cgroup *mi;
 	int i;
 
-	memset(events, 0, sizeof(*events) * NR_VM_EVENT_ITEMS);
+	for_each_mem_cgroup_tree(mi, memcg) {
+		for (i = 0; i < acc->stats_size; i++)
+			acc->stat[i] += memcg_page_state(mi,
+				acc->stats_array ? acc->stats_array[i] : i);
 
-	for_each_mem_cgroup_tree(iter, memcg) {
-		for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
-			events[i] += memcg_sum_events(iter, i);
+		for (i = 0; i < acc->events_size; i++)
+			acc->events[i] += memcg_sum_events(mi,
+				acc->events_array ? acc->events_array[i] : i);
+
+		for (i = 0; i < NR_LRU_LISTS; i++)
+			acc->lru_pages[i] +=
+				mem_cgroup_nr_lru_pages(mi, BIT(i));
 	}
 }
 
@@ -3332,6 +3393,7 @@ static int memcg_stat_show(struct seq_file *m, void *v)
 	unsigned long memory, memsw;
 	struct mem_cgroup *mi;
 	unsigned int i;
+	struct accumulated_stats acc;
 
 	BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats));
 	BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
@@ -3364,32 +3426,27 @@ static int memcg_stat_show(struct seq_file *m, void *v)
 		seq_printf(m, "hierarchical_memsw_limit %llu\n",
 			   (u64)memsw * PAGE_SIZE);
 
-	for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
-		unsigned long long val = 0;
+	memset(&acc, 0, sizeof(acc));
+	acc.stats_size = ARRAY_SIZE(memcg1_stats);
+	acc.stats_array = memcg1_stats;
+	acc.events_size = ARRAY_SIZE(memcg1_events);
+	acc.events_array = memcg1_events;
+	accumulate_memcg_tree(memcg, &acc);
 
+	for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
 		if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
 			continue;
-		for_each_mem_cgroup_tree(mi, memcg)
-			val += memcg_page_state(mi, memcg1_stats[i]) *
-			PAGE_SIZE;
-		seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i], val);
+		seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i],
+			   (u64)acc.stat[i] * PAGE_SIZE);
 	}
 
-	for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) {
-		unsigned long long val = 0;
-
-		for_each_mem_cgroup_tree(mi, memcg)
-			val += memcg_sum_events(mi, memcg1_events[i]);
-		seq_printf(m, "total_%s %llu\n", memcg1_event_names[i], val);
-	}
-
-	for (i = 0; i < NR_LRU_LISTS; i++) {
-		unsigned long long val = 0;
+	for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
+		seq_printf(m, "total_%s %llu\n", memcg1_event_names[i],
+			   (u64)acc.events[i]);
 
-		for_each_mem_cgroup_tree(mi, memcg)
-			val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE;
-		seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val);
-	}
+	for (i = 0; i < NR_LRU_LISTS; i++)
+		seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i],
+			   (u64)acc.lru_pages[i] * PAGE_SIZE);
 
 #ifdef CONFIG_DEBUG_VM
 	{
@@ -5486,8 +5543,7 @@ static int memory_events_show(struct seq_file *m, void *v)
 static int memory_stat_show(struct seq_file *m, void *v)
 {
 	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
-	unsigned long stat[MEMCG_NR_STAT];
-	unsigned long events[NR_VM_EVENT_ITEMS];
+	struct accumulated_stats acc;
 	int i;
 
 	/*
@@ -5501,70 +5557,97 @@ static int memory_stat_show(struct seq_file *m, void *v)
 	 * Current memory state:
 	 */
 
-	tree_stat(memcg, stat);
-	tree_events(memcg, events);
+	memset(&acc, 0, sizeof(acc));
+	acc.stats_size = MEMCG_NR_STAT;
+	acc.events_size = NR_VM_EVENT_ITEMS;
+	accumulate_memcg_tree(memcg, &acc);
 
 	seq_printf(m, "anon %llu\n",
-		   (u64)stat[MEMCG_RSS] * PAGE_SIZE);
+		   (u64)acc.stat[MEMCG_RSS] * PAGE_SIZE);
 	seq_printf(m, "file %llu\n",
-		   (u64)stat[MEMCG_CACHE] * PAGE_SIZE);
+		   (u64)acc.stat[MEMCG_CACHE] * PAGE_SIZE);
 	seq_printf(m, "kernel_stack %llu\n",
-		   (u64)stat[MEMCG_KERNEL_STACK_KB] * 1024);
+		   (u64)acc.stat[MEMCG_KERNEL_STACK_KB] * 1024);
 	seq_printf(m, "slab %llu\n",
-		   (u64)(stat[NR_SLAB_RECLAIMABLE] +
-			 stat[NR_SLAB_UNRECLAIMABLE]) * PAGE_SIZE);
+		   (u64)(acc.stat[NR_SLAB_RECLAIMABLE] +
+			 acc.stat[NR_SLAB_UNRECLAIMABLE]) * PAGE_SIZE);
 	seq_printf(m, "sock %llu\n",
-		   (u64)stat[MEMCG_SOCK] * PAGE_SIZE);
+		   (u64)acc.stat[MEMCG_SOCK] * PAGE_SIZE);
 
 	seq_printf(m, "shmem %llu\n",
-		   (u64)stat[NR_SHMEM] * PAGE_SIZE);
+		   (u64)acc.stat[NR_SHMEM] * PAGE_SIZE);
 	seq_printf(m, "file_mapped %llu\n",
-		   (u64)stat[NR_FILE_MAPPED] * PAGE_SIZE);
+		   (u64)acc.stat[NR_FILE_MAPPED] * PAGE_SIZE);
 	seq_printf(m, "file_dirty %llu\n",
-		   (u64)stat[NR_FILE_DIRTY] * PAGE_SIZE);
+		   (u64)acc.stat[NR_FILE_DIRTY] * PAGE_SIZE);
 	seq_printf(m, "file_writeback %llu\n",
-		   (u64)stat[NR_WRITEBACK] * PAGE_SIZE);
-
-	for (i = 0; i < NR_LRU_LISTS; i++) {
-		struct mem_cgroup *mi;
-		unsigned long val = 0;
+		   (u64)acc.stat[NR_WRITEBACK] * PAGE_SIZE);
 
-		for_each_mem_cgroup_tree(mi, memcg)
-			val += mem_cgroup_nr_lru_pages(mi, BIT(i));
-		seq_printf(m, "%s %llu\n",
-			   mem_cgroup_lru_names[i], (u64)val * PAGE_SIZE);
-	}
+	for (i = 0; i < NR_LRU_LISTS; i++)
+		seq_printf(m, "%s %llu\n", mem_cgroup_lru_names[i],
+			   (u64)acc.lru_pages[i] * PAGE_SIZE);
 
 	seq_printf(m, "slab_reclaimable %llu\n",
-		   (u64)stat[NR_SLAB_RECLAIMABLE] * PAGE_SIZE);
+		   (u64)acc.stat[NR_SLAB_RECLAIMABLE] * PAGE_SIZE);
 	seq_printf(m, "slab_unreclaimable %llu\n",
-		   (u64)stat[NR_SLAB_UNRECLAIMABLE] * PAGE_SIZE);
+		   (u64)acc.stat[NR_SLAB_UNRECLAIMABLE] * PAGE_SIZE);
 
 	/* Accumulated memory events */
 
-	seq_printf(m, "pgfault %lu\n", events[PGFAULT]);
-	seq_printf(m, "pgmajfault %lu\n", events[PGMAJFAULT]);
+	seq_printf(m, "pgfault %lu\n", acc.events[PGFAULT]);
+	seq_printf(m, "pgmajfault %lu\n", acc.events[PGMAJFAULT]);
 
-	seq_printf(m, "pgrefill %lu\n", events[PGREFILL]);
-	seq_printf(m, "pgscan %lu\n", events[PGSCAN_KSWAPD] +
-		   events[PGSCAN_DIRECT]);
-	seq_printf(m, "pgsteal %lu\n", events[PGSTEAL_KSWAPD] +
-		   events[PGSTEAL_DIRECT]);
-	seq_printf(m, "pgactivate %lu\n", events[PGACTIVATE]);
-	seq_printf(m, "pgdeactivate %lu\n", events[PGDEACTIVATE]);
-	seq_printf(m, "pglazyfree %lu\n", events[PGLAZYFREE]);
-	seq_printf(m, "pglazyfreed %lu\n", events[PGLAZYFREED]);
+	seq_printf(m, "pgrefill %lu\n", acc.events[PGREFILL]);
+	seq_printf(m, "pgscan %lu\n", acc.events[PGSCAN_KSWAPD] +
+		   acc.events[PGSCAN_DIRECT]);
+	seq_printf(m, "pgsteal %lu\n", acc.events[PGSTEAL_KSWAPD] +
+		   acc.events[PGSTEAL_DIRECT]);
+	seq_printf(m, "pgactivate %lu\n", acc.events[PGACTIVATE]);
+	seq_printf(m, "pgdeactivate %lu\n", acc.events[PGDEACTIVATE]);
+	seq_printf(m, "pglazyfree %lu\n", acc.events[PGLAZYFREE]);
+	seq_printf(m, "pglazyfreed %lu\n", acc.events[PGLAZYFREED]);
 
 	seq_printf(m, "workingset_refault %lu\n",
-		   stat[WORKINGSET_REFAULT]);
+		   acc.stat[WORKINGSET_REFAULT]);
 	seq_printf(m, "workingset_activate %lu\n",
-		   stat[WORKINGSET_ACTIVATE]);
+		   acc.stat[WORKINGSET_ACTIVATE]);
 	seq_printf(m, "workingset_nodereclaim %lu\n",
-		   stat[WORKINGSET_NODERECLAIM]);
+		   acc.stat[WORKINGSET_NODERECLAIM]);
+
+	return 0;
+}
+
+static int memory_oom_group_show(struct seq_file *m, void *v)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+
+	seq_printf(m, "%d\n", memcg->oom_group);
 
 	return 0;
 }
 
+static ssize_t memory_oom_group_write(struct kernfs_open_file *of,
+				      char *buf, size_t nbytes, loff_t off)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+	int ret, oom_group;
+
+	buf = strstrip(buf);
+	if (!buf)
+		return -EINVAL;
+
+	ret = kstrtoint(buf, 0, &oom_group);
+	if (ret)
+		return ret;
+
+	if (oom_group != 0 && oom_group != 1)
+		return -EINVAL;
+
+	memcg->oom_group = oom_group;
+
+	return nbytes;
+}
+
 static struct cftype memory_files[] = {
 	{
 		.name = "current",
@@ -5606,6 +5689,12 @@ static struct cftype memory_files[] = {
 		.flags = CFTYPE_NOT_ON_ROOT,
 		.seq_show = memory_stat_show,
 	},
+	{
+		.name = "oom.group",
+		.flags = CFTYPE_NOT_ON_ROOT | CFTYPE_NS_DELEGATABLE,
+		.seq_show = memory_oom_group_show,
+		.write = memory_oom_group_write,
+	},
 	{ }	/* terminate */
 };