[PATCH 1/2] memcg: dirty pages accounting and limiting infrastructure

[Andrea Righi]

Infrastructure to account dirty pages per cgroup + add memory.dirty_bytes limit
in cgroupfs.

Signed-off-by: Andrea Righi <arighi@xxxxxxxxxxx>
---
 include/linux/memcontrol.h |   31 ++++++
 mm/memcontrol.c            |  218 +++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 248 insertions(+), 1 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 1f9b119..ba3fe0d 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -25,6 +25,16 @@ struct page_cgroup;
 struct page;
 struct mm_struct;
 
+/* Cgroup memory statistics items exported to the kernel */
+enum memcg_page_stat_item {
+	MEMCG_NR_FREE_PAGES,
+	MEMCG_NR_RECLAIMABLE_PAGES,
+	MEMCG_NR_FILE_DIRTY,
+	MEMCG_NR_WRITEBACK,
+	MEMCG_NR_WRITEBACK_TEMP,
+	MEMCG_NR_UNSTABLE_NFS,
+};
+
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
 /*
  * All "charge" functions with gfp_mask should use GFP_KERNEL or
@@ -48,6 +58,8 @@ extern void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *ptr);
 
 extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
 					gfp_t gfp_mask);
+extern void mem_cgroup_charge_dirty(struct page *page,
+			enum zone_stat_item idx, int charge);
 extern void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru);
 extern void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru);
 extern void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru);
@@ -117,6 +129,10 @@ extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
 extern int do_swap_account;
 #endif
 
+extern unsigned long mem_cgroup_dirty_bytes(void);
+
+extern u64 mem_cgroup_page_state(enum memcg_page_stat_item item);
+
 static inline bool mem_cgroup_disabled(void)
 {
 	if (mem_cgroup_subsys.disabled)
@@ -144,6 +160,11 @@ static inline int mem_cgroup_cache_charge(struct page *page,
 	return 0;
 }
 
+static inline void mem_cgroup_charge_dirty(struct page *page,
+			enum zone_stat_item idx, int charge)
+{
+}
+
 static inline int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
 		struct page *page, gfp_t gfp_mask, struct mem_cgroup **ptr)
 {
@@ -312,6 +333,16 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 	return 0;
 }
 
+static inline unsigned long mem_cgroup_dirty_bytes(void)
+{
+	return vm_dirty_bytes;
+}
+
+static inline u64 mem_cgroup_page_state(enum memcg_page_stat_item item)
+{
+	return 0;
+}
+
 #endif /* CONFIG_CGROUP_MEM_CONT */
 
 #endif /* _LINUX_MEMCONTROL_H */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 954032b..288b9a4 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -64,13 +64,18 @@ enum mem_cgroup_stat_index {
 	/*
 	 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
 	 */
-	MEM_CGROUP_STAT_CACHE, 	   /* # of pages charged as cache */
+	MEM_CGROUP_STAT_CACHE,	   /* # of pages charged as cache */
 	MEM_CGROUP_STAT_RSS,	   /* # of pages charged as anon rss */
 	MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
 	MEM_CGROUP_STAT_PGPGIN_COUNT,	/* # of pages paged in */
 	MEM_CGROUP_STAT_PGPGOUT_COUNT,	/* # of pages paged out */
 	MEM_CGROUP_STAT_EVENTS,	/* sum of pagein + pageout for internal use */
 	MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
+	MEM_CGROUP_STAT_FILE_DIRTY,   /* # of dirty pages in page cache */
+	MEM_CGROUP_STAT_WRITEBACK,   /* # of pages under writeback */
+	MEM_CGROUP_STAT_WRITEBACK_TEMP,   /* # of pages under writeback using
+						temporary buffers */
+	MEM_CGROUP_STAT_UNSTABLE_NFS,   /* # of NFS unstable pages */
 
 	MEM_CGROUP_STAT_NSTATS,
 };
@@ -225,6 +230,9 @@ struct mem_cgroup {
 	/* set when res.limit == memsw.limit */
 	bool		memsw_is_minimum;
 
+	/* control memory cgroup dirty pages */
+	unsigned long dirty_bytes;
+
 	/*
 	 * statistics. This must be placed at the end of memcg.
 	 */
@@ -519,6 +527,67 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
 	put_cpu();
 }
 
+static struct mem_cgroup *get_mem_cgroup_from_page(struct page *page)
+{
+	struct page_cgroup *pc;
+	struct mem_cgroup *mem = NULL;
+
+	pc = lookup_page_cgroup(page);
+	if (unlikely(!pc))
+		return NULL;
+	lock_page_cgroup(pc);
+	if (PageCgroupUsed(pc)) {
+		mem = pc->mem_cgroup;
+		if (mem)
+			css_get(&mem->css);
+	}
+	unlock_page_cgroup(pc);
+	return mem;
+}
+
+void mem_cgroup_charge_dirty(struct page *page,
+			enum zone_stat_item idx, int charge)
+{
+	struct mem_cgroup *mem;
+	struct mem_cgroup_stat_cpu *cpustat;
+	unsigned long flags;
+	int cpu;
+
+	if (mem_cgroup_disabled())
+		return;
+	/* Translate the zone_stat_item into a mem_cgroup_stat_index */
+	switch (idx) {
+	case NR_FILE_DIRTY:
+		idx = MEM_CGROUP_STAT_FILE_DIRTY;
+		break;
+	case NR_WRITEBACK:
+		idx = MEM_CGROUP_STAT_WRITEBACK;
+		break;
+	case NR_WRITEBACK_TEMP:
+		idx = MEM_CGROUP_STAT_WRITEBACK_TEMP;
+		break;
+	case NR_UNSTABLE_NFS:
+		idx = MEM_CGROUP_STAT_UNSTABLE_NFS;
+		break;
+	default:
+		return;
+	}
+	/* Charge the memory cgroup statistics */
+	mem = get_mem_cgroup_from_page(page);
+	if (!mem) {
+		mem = root_mem_cgroup;
+		css_get(&mem->css);
+	}
+
+	local_irq_save(flags);
+	cpu = get_cpu();
+	cpustat = &mem->stat.cpustat[cpu];
+	__mem_cgroup_stat_add_safe(cpustat, idx, charge);
+	put_cpu();
+	local_irq_restore(flags);
+	css_put(&mem->css);
+}
+
 static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
 					enum lru_list idx)
 {
@@ -992,6 +1061,97 @@ static unsigned int get_swappiness(struct mem_cgroup *memcg)
 	return swappiness;
 }
 
+static unsigned long get_dirty_bytes(struct mem_cgroup *memcg)
+{
+	struct cgroup *cgrp = memcg->css.cgroup;
+	unsigned long dirty_bytes;
+
+	/* root ? */
+	if (cgrp->parent == NULL)
+		return vm_dirty_bytes;
+
+	spin_lock(&memcg->reclaim_param_lock);
+	dirty_bytes = memcg->dirty_bytes;
+	spin_unlock(&memcg->reclaim_param_lock);
+
+	return dirty_bytes;
+}
+
+unsigned long mem_cgroup_dirty_bytes(void)
+{
+	struct mem_cgroup *memcg;
+	unsigned long dirty_bytes;
+
+	if (mem_cgroup_disabled())
+		return vm_dirty_bytes;
+
+	rcu_read_lock();
+	memcg = mem_cgroup_from_task(current);
+	if (memcg == NULL)
+		dirty_bytes = vm_dirty_bytes;
+	else
+		dirty_bytes = get_dirty_bytes(memcg);
+	rcu_read_unlock();
+
+	return dirty_bytes;
+}
+
+u64 mem_cgroup_page_state(enum memcg_page_stat_item item)
+{
+	struct mem_cgroup *memcg;
+	struct cgroup *cgrp;
+	u64 ret = 0;
+
+	if (mem_cgroup_disabled())
+		return 0;
+
+	rcu_read_lock();
+	memcg = mem_cgroup_from_task(current);
+	if (memcg == NULL)
+		goto out;
+	cgrp = memcg->css.cgroup;
+	/* Use system-wide statistics for the root cgroup */
+	if (cgrp->parent == NULL)
+		goto out;
+	switch (item) {
+	case MEMCG_NR_FREE_PAGES:
+		ret = res_counter_read_u64(&memcg->res, RES_LIMIT) -
+			res_counter_read_u64(&memcg->res, RES_USAGE);
+		/*
+		 * Translate free memory in pages and ensure we never return 0.
+		 */
+		ret = (ret >> PAGE_SHIFT) + 1;
+		break;
+	case MEMCG_NR_RECLAIMABLE_PAGES:
+		ret = mem_cgroup_read_stat(&memcg->stat, LRU_ACTIVE_ANON) +
+			mem_cgroup_read_stat(&memcg->stat, LRU_ACTIVE_FILE) +
+			mem_cgroup_read_stat(&memcg->stat, LRU_INACTIVE_ANON) +
+			mem_cgroup_read_stat(&memcg->stat, LRU_INACTIVE_FILE);
+		break;
+	case MEMCG_NR_FILE_DIRTY:
+		ret = mem_cgroup_read_stat(&memcg->stat,
+				MEM_CGROUP_STAT_FILE_DIRTY);
+		break;
+	case MEMCG_NR_WRITEBACK:
+		ret = mem_cgroup_read_stat(&memcg->stat,
+				MEM_CGROUP_STAT_WRITEBACK);
+		break;
+	case MEMCG_NR_WRITEBACK_TEMP:
+		ret = mem_cgroup_read_stat(&memcg->stat,
+				MEM_CGROUP_STAT_WRITEBACK_TEMP);
+		break;
+	case MEMCG_NR_UNSTABLE_NFS:
+		ret = mem_cgroup_read_stat(&memcg->stat,
+				MEM_CGROUP_STAT_UNSTABLE_NFS);
+		break;
+	default:
+		WARN_ON(1);
+	}
+out:
+	rcu_read_unlock();
+	return ret;
+}
+
 static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data)
 {
 	int *val = data;
@@ -2874,6 +3034,10 @@ enum {
 	MCS_PGPGIN,
 	MCS_PGPGOUT,
 	MCS_SWAP,
+	MCS_FILE_DIRTY,
+	MCS_WRITEBACK,
+	MCS_WRITEBACK_TEMP,
+	MCS_UNSTABLE_NFS,
 	MCS_INACTIVE_ANON,
 	MCS_ACTIVE_ANON,
 	MCS_INACTIVE_FILE,
@@ -2896,6 +3060,10 @@ struct {
 	{"pgpgin", "total_pgpgin"},
 	{"pgpgout", "total_pgpgout"},
 	{"swap", "total_swap"},
+	{"filedirty", "dirty_pages"},
+	{"writeback", "writeback_pages"},
+	{"writeback_tmp", "writeback_temp_pages"},
+	{"nfs", "nfs_unstable"},
 	{"inactive_anon", "total_inactive_anon"},
 	{"active_anon", "total_active_anon"},
 	{"inactive_file", "total_inactive_file"},
@@ -2924,6 +3092,14 @@ static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data)
 		val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_SWAPOUT);
 		s->stat[MCS_SWAP] += val * PAGE_SIZE;
 	}
+	val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_FILE_DIRTY);
+	s->stat[MCS_FILE_DIRTY] += val;
+	val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_WRITEBACK);
+	s->stat[MCS_WRITEBACK] += val;
+	val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_WRITEBACK_TEMP);
+	s->stat[MCS_WRITEBACK_TEMP] += val;
+	val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_UNSTABLE_NFS);
+	s->stat[MCS_UNSTABLE_NFS] += val;
 
 	/* per zone stat */
 	val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
@@ -3049,6 +3225,41 @@ static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
 	return 0;
 }
 
+static u64 mem_cgroup_dirty_bytes_read(struct cgroup *cgrp, struct cftype *cft)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+
+	return get_dirty_bytes(memcg);
+}
+
+static int mem_cgroup_dirty_bytes_write(struct cgroup *cgrp, struct cftype *cft,
+				       u64 val)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+	struct mem_cgroup *parent;
+
+	if (cgrp->parent == NULL)
+		return -EINVAL;
+
+	parent = mem_cgroup_from_cont(cgrp->parent);
+
+	cgroup_lock();
+
+	/* If under hierarchy, only empty-root can set this value */
+	if ((parent->use_hierarchy) ||
+	    (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
+		cgroup_unlock();
+		return -EINVAL;
+	}
+
+	spin_lock(&memcg->reclaim_param_lock);
+	memcg->dirty_bytes = val;
+	spin_unlock(&memcg->reclaim_param_lock);
+
+	cgroup_unlock();
+
+	return 0;
+}
 
 static struct cftype mem_cgroup_files[] = {
 	{
@@ -3098,6 +3309,11 @@ static struct cftype mem_cgroup_files[] = {
 		.read_u64 = mem_cgroup_swappiness_read,
 		.write_u64 = mem_cgroup_swappiness_write,
 	},
+	{
+		.name = "dirty_bytes",
+		.read_u64 = mem_cgroup_dirty_bytes_read,
+		.write_u64 = mem_cgroup_dirty_bytes_write,
+	},
 };
 
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
-- 
1.6.3.3

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