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

[Andrea Righi]

Infrastructure to account dirty pages per cgroup and add dirty limit
interfaces in the cgroupfs:

 - Active write-out: memory.dirty_ratio, memory.dirty_bytes
 - Background write-out: memory.dirty_background_ratio, memory.dirty_background_bytes

Signed-off-by: Andrea Righi <arighi@xxxxxxxxxxx>
---
 include/linux/memcontrol.h |   74 +++++++++-
 mm/memcontrol.c            |  354 ++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 399 insertions(+), 29 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 1f9b119..e6af95c 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -25,6 +25,41 @@ struct page_cgroup;
 struct page;
 struct mm_struct;
 
+/* Cgroup memory statistics items exported to the kernel */
+enum mem_cgroup_page_stat_item {
+	MEMCG_NR_DIRTYABLE_PAGES,
+	MEMCG_NR_RECLAIM_PAGES,
+	MEMCG_NR_WRITEBACK,
+	MEMCG_NR_DIRTY_WRITEBACK_PAGES,
+};
+
+/*
+ * Statistics for memory cgroup.
+ */
+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_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_SOFTLIMIT, /* decrements on each page in/out.
+					used by soft limit implementation */
+	MEM_CGROUP_STAT_THRESHOLDS, /* decrements on each page in/out.
+					used by threshold implementation */
+	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,
+};
+
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
 /*
  * All "charge" functions with gfp_mask should use GFP_KERNEL or
@@ -117,6 +152,13 @@ extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
 extern int do_swap_account;
 #endif
 
+extern long mem_cgroup_dirty_ratio(void);
+extern unsigned long mem_cgroup_dirty_bytes(void);
+extern long mem_cgroup_dirty_background_ratio(void);
+extern unsigned long mem_cgroup_dirty_background_bytes(void);
+
+extern s64 mem_cgroup_page_stat(enum mem_cgroup_page_stat_item item);
+
 static inline bool mem_cgroup_disabled(void)
 {
 	if (mem_cgroup_subsys.disabled)
@@ -125,7 +167,8 @@ static inline bool mem_cgroup_disabled(void)
 }
 
 extern bool mem_cgroup_oom_called(struct task_struct *task);
-void mem_cgroup_update_file_mapped(struct page *page, int val);
+void mem_cgroup_update_stat(struct page *page,
+			enum mem_cgroup_stat_index idx, int val);
 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 						gfp_t gfp_mask, int nid,
 						int zid);
@@ -300,8 +343,8 @@ mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
 {
 }
 
-static inline void mem_cgroup_update_file_mapped(struct page *page,
-							int val)
+static inline void mem_cgroup_update_stat(struct page *page,
+			enum mem_cgroup_stat_index idx, int val)
 {
 }
 
@@ -312,6 +355,31 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 	return 0;
 }
 
+static inline long mem_cgroup_dirty_ratio(void)
+{
+	return vm_dirty_ratio;
+}
+
+static inline unsigned long mem_cgroup_dirty_bytes(void)
+{
+	return vm_dirty_bytes;
+}
+
+static inline long mem_cgroup_dirty_background_ratio(void)
+{
+	return dirty_background_ratio;
+}
+
+static inline unsigned long mem_cgroup_dirty_background_bytes(void)
+{
+	return dirty_background_bytes;
+}
+
+static inline s64 mem_cgroup_page_stat(enum mem_cgroup_page_stat_item item)
+{
+	return -ENOMEM;
+}
+
 #endif /* CONFIG_CGROUP_MEM_CONT */
 
 #endif /* _LINUX_MEMCONTROL_H */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a443c30..56f3204 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -66,31 +66,16 @@ static int really_do_swap_account __initdata = 1; /* for remember boot option*/
 #define SOFTLIMIT_EVENTS_THRESH (1000)
 #define THRESHOLDS_EVENTS_THRESH (100)
 
-/*
- * Statistics for memory cgroup.
- */
-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_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_SWAPOUT, /* # of pages, swapped out */
-	MEM_CGROUP_STAT_SOFTLIMIT, /* decrements on each page in/out.
-					used by soft limit implementation */
-	MEM_CGROUP_STAT_THRESHOLDS, /* decrements on each page in/out.
-					used by threshold implementation */
-
-	MEM_CGROUP_STAT_NSTATS,
-};
-
 struct mem_cgroup_stat_cpu {
 	s64 count[MEM_CGROUP_STAT_NSTATS];
 };
 
+/* Per cgroup page statistics */
+struct mem_cgroup_page_stat {
+	enum mem_cgroup_page_stat_item item;
+	s64 value;
+};
+
 /*
  * per-zone information in memory controller.
  */
@@ -205,6 +190,14 @@ struct mem_cgroup {
 
 	unsigned int	swappiness;
 
+	/* control memory cgroup dirty pages */
+	long dirty_ratio;
+	unsigned long dirty_bytes;
+
+	/* control background writeback (via writeback threads) */
+	long dirty_background_ratio;
+	unsigned long dirty_background_bytes;
+
 	/* set when res.limit == memsw.limit */
 	bool		memsw_is_minimum;
 
@@ -1021,6 +1014,169 @@ static unsigned int get_swappiness(struct mem_cgroup *memcg)
 	return swappiness;
 }
 
+enum mem_cgroup_dirty_param {
+	MEM_CGROUP_DIRTY_RATIO,
+	MEM_CGROUP_DIRTY_BYTES,
+	MEM_CGROUP_DIRTY_BACKGROUND_RATIO,
+	MEM_CGROUP_DIRTY_BACKGROUND_BYTES,
+};
+
+static unsigned long get_dirty_param(struct mem_cgroup *memcg,
+			enum mem_cgroup_dirty_param idx)
+{
+	unsigned long ret;
+
+	spin_lock(&memcg->reclaim_param_lock);
+	switch (idx) {
+	case MEM_CGROUP_DIRTY_RATIO:
+		ret = memcg->dirty_ratio;
+		break;
+	case MEM_CGROUP_DIRTY_BYTES:
+		ret = memcg->dirty_bytes;
+		break;
+	case MEM_CGROUP_DIRTY_BACKGROUND_RATIO:
+		ret = memcg->dirty_background_ratio;
+		break;
+	case MEM_CGROUP_DIRTY_BACKGROUND_BYTES:
+		ret = memcg->dirty_background_bytes;
+		break;
+	default:
+		VM_BUG_ON(1);
+	}
+	spin_unlock(&memcg->reclaim_param_lock);
+
+	return ret;
+}
+
+long mem_cgroup_dirty_ratio(void)
+{
+	struct mem_cgroup *memcg;
+	long ret = vm_dirty_ratio;
+
+	if (mem_cgroup_disabled())
+		goto out;
+	rcu_read_lock();
+	memcg = mem_cgroup_from_task(current);
+	if (likely(memcg))
+		ret = get_dirty_param(memcg, MEM_CGROUP_DIRTY_RATIO);
+	rcu_read_unlock();
+out:
+	return ret;
+}
+
+unsigned long mem_cgroup_dirty_bytes(void)
+{
+	struct mem_cgroup *memcg;
+	unsigned long ret = vm_dirty_bytes;
+
+	if (mem_cgroup_disabled())
+		goto out;
+	rcu_read_lock();
+	memcg = mem_cgroup_from_task(current);
+	if (likely(memcg))
+		ret = get_dirty_param(memcg, MEM_CGROUP_DIRTY_BYTES);
+	rcu_read_unlock();
+out:
+	return ret;
+}
+
+long mem_cgroup_dirty_background_ratio(void)
+{
+	struct mem_cgroup *memcg;
+	long ret = dirty_background_ratio;
+
+	if (mem_cgroup_disabled())
+		goto out;
+	rcu_read_lock();
+	memcg = mem_cgroup_from_task(current);
+	if (likely(memcg))
+		ret = get_dirty_param(memcg, MEM_CGROUP_DIRTY_BACKGROUND_RATIO);
+	rcu_read_unlock();
+out:
+	return ret;
+}
+
+unsigned long mem_cgroup_dirty_background_bytes(void)
+{
+	struct mem_cgroup *memcg;
+	unsigned long ret = dirty_background_bytes;
+
+	if (mem_cgroup_disabled())
+		goto out;
+	rcu_read_lock();
+	memcg = mem_cgroup_from_task(current);
+	if (likely(memcg))
+		ret = get_dirty_param(memcg, MEM_CGROUP_DIRTY_BACKGROUND_BYTES);
+	rcu_read_unlock();
+out:
+	return ret;
+}
+
+static s64 mem_cgroup_get_local_page_stat(struct mem_cgroup *memcg,
+				enum mem_cgroup_page_stat_item item)
+{
+	s64 ret;
+
+	switch (item) {
+	case MEMCG_NR_DIRTYABLE_PAGES:
+		ret = res_counter_read_u64(&memcg->res, RES_LIMIT) -
+			res_counter_read_u64(&memcg->res, RES_USAGE);
+		/* Translate free memory in pages */
+		ret >>= PAGE_SHIFT;
+		ret += mem_cgroup_read_stat(memcg, LRU_ACTIVE_ANON) +
+			mem_cgroup_read_stat(memcg, LRU_ACTIVE_FILE) +
+			mem_cgroup_read_stat(memcg, LRU_INACTIVE_ANON) +
+			mem_cgroup_read_stat(memcg, LRU_INACTIVE_FILE);
+		break;
+	case MEMCG_NR_RECLAIM_PAGES:
+		ret = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_FILE_DIRTY) +
+			mem_cgroup_read_stat(memcg,
+					MEM_CGROUP_STAT_UNSTABLE_NFS);
+		break;
+	case MEMCG_NR_WRITEBACK:
+		ret = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_WRITEBACK);
+		break;
+	case MEMCG_NR_DIRTY_WRITEBACK_PAGES:
+		ret = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_WRITEBACK) +
+			mem_cgroup_read_stat(memcg,
+				MEM_CGROUP_STAT_UNSTABLE_NFS);
+		break;
+	default:
+		ret = 0;
+		WARN_ON_ONCE(1);
+	}
+	return ret;
+}
+
+static int mem_cgroup_page_stat_cb(struct mem_cgroup *mem, void *data)
+{
+	struct mem_cgroup_page_stat *stat = (struct mem_cgroup_page_stat *)data;
+
+	stat->value += mem_cgroup_get_local_page_stat(mem, stat->item);
+	return 0;
+}
+
+s64 mem_cgroup_page_stat(enum mem_cgroup_page_stat_item item)
+{
+	struct mem_cgroup_page_stat stat = {};
+	struct mem_cgroup *memcg;
+
+	rcu_read_lock();
+	memcg = mem_cgroup_from_task(current);
+	if (memcg) {
+		/*
+		 * Recursively evaulate page statistics against all cgroup
+		 * under hierarchy tree
+		 */
+		stat.item = item;
+		mem_cgroup_walk_tree(memcg, &stat, mem_cgroup_page_stat_cb);
+	} else
+		stat.value = -ENOMEM;
+	rcu_read_unlock();
+
+	return stat.value;
+}
+
 static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data)
 {
 	int *val = data;
@@ -1263,10 +1419,10 @@ static void record_last_oom(struct mem_cgroup *mem)
 }
 
 /*
- * Currently used to update mapped file statistics, but the routine can be
- * generalized to update other statistics as well.
+ * Generalized routine to update memory cgroup statistics.
  */
-void mem_cgroup_update_file_mapped(struct page *page, int val)
+void mem_cgroup_update_stat(struct page *page,
+			enum mem_cgroup_stat_index idx, int val)
 {
 	struct mem_cgroup *mem;
 	struct page_cgroup *pc;
@@ -1286,7 +1442,8 @@ void mem_cgroup_update_file_mapped(struct page *page, int val)
 	/*
 	 * Preemption is already disabled. We can use __this_cpu_xxx
 	 */
-	__this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], val);
+	VM_BUG_ON(idx >= MEM_CGROUP_STAT_NSTATS);
+	__this_cpu_add(mem->stat->count[idx], val);
 
 done:
 	unlock_page_cgroup(pc);
@@ -3033,6 +3190,10 @@ 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,
@@ -3055,6 +3216,10 @@ 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"},
@@ -3083,6 +3248,14 @@ static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data)
 		val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
 		s->stat[MCS_SWAP] += val * PAGE_SIZE;
 	}
+	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_DIRTY);
+	s->stat[MCS_FILE_DIRTY] += val;
+	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_WRITEBACK);
+	s->stat[MCS_WRITEBACK] += val;
+	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_WRITEBACK_TEMP);
+	s->stat[MCS_WRITEBACK_TEMP] += val;
+	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_UNSTABLE_NFS);
+	s->stat[MCS_UNSTABLE_NFS] += val;
 
 	/* per zone stat */
 	val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
@@ -3467,6 +3640,100 @@ unlock:
 	return ret;
 }
 
+static u64 mem_cgroup_dirty_ratio_read(struct cgroup *cgrp, struct cftype *cft)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+
+	return get_dirty_param(memcg, MEM_CGROUP_DIRTY_RATIO);
+}
+
+static int
+mem_cgroup_dirty_ratio_write(struct cgroup *cgrp, struct cftype *cft, u64 val)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+
+	if ((cgrp->parent == NULL) || (val > 100))
+		return -EINVAL;
+
+	spin_lock(&memcg->reclaim_param_lock);
+	memcg->dirty_ratio = val;
+	memcg->dirty_bytes = 0;
+	spin_unlock(&memcg->reclaim_param_lock);
+
+	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_param(memcg, MEM_CGROUP_DIRTY_BYTES);
+}
+
+static int
+mem_cgroup_dirty_bytes_write(struct cgroup *cgrp, struct cftype *cft, u64 val)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+
+	if (cgrp->parent == NULL)
+		return -EINVAL;
+
+	spin_lock(&memcg->reclaim_param_lock);
+	memcg->dirty_ratio = 0;
+	memcg->dirty_bytes = val;
+	spin_unlock(&memcg->reclaim_param_lock);
+
+	return 0;
+}
+
+static u64
+mem_cgroup_dirty_background_ratio_read(struct cgroup *cgrp, struct cftype *cft)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+
+	return get_dirty_param(memcg, MEM_CGROUP_DIRTY_BACKGROUND_RATIO);
+}
+
+static int mem_cgroup_dirty_background_ratio_write(struct cgroup *cgrp,
+				struct cftype *cft, u64 val)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+
+	if ((cgrp->parent == NULL) || (val > 100))
+		return -EINVAL;
+
+	spin_lock(&memcg->reclaim_param_lock);
+	memcg->dirty_background_ratio = val;
+	memcg->dirty_background_bytes = 0;
+	spin_unlock(&memcg->reclaim_param_lock);
+
+	return 0;
+}
+
+static u64
+mem_cgroup_dirty_background_bytes_read(struct cgroup *cgrp, struct cftype *cft)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+
+	return get_dirty_param(memcg, MEM_CGROUP_DIRTY_BACKGROUND_BYTES);
+}
+
+static int mem_cgroup_dirty_background_bytes_write(struct cgroup *cgrp,
+				struct cftype *cft, u64 val)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+
+	if (cgrp->parent == NULL)
+		return -EINVAL;
+
+	spin_lock(&memcg->reclaim_param_lock);
+	memcg->dirty_background_ratio = 0;
+	memcg->dirty_background_bytes = val;
+	spin_unlock(&memcg->reclaim_param_lock);
+
+	return 0;
+}
+
 static struct cftype mem_cgroup_files[] = {
 	{
 		.name = "usage_in_bytes",
@@ -3518,6 +3785,26 @@ static struct cftype mem_cgroup_files[] = {
 		.write_u64 = mem_cgroup_swappiness_write,
 	},
 	{
+		.name = "dirty_ratio",
+		.read_u64 = mem_cgroup_dirty_ratio_read,
+		.write_u64 = mem_cgroup_dirty_ratio_write,
+	},
+	{
+		.name = "dirty_bytes",
+		.read_u64 = mem_cgroup_dirty_bytes_read,
+		.write_u64 = mem_cgroup_dirty_bytes_write,
+	},
+	{
+		.name = "dirty_background_ratio",
+		.read_u64 = mem_cgroup_dirty_background_ratio_read,
+		.write_u64 = mem_cgroup_dirty_background_ratio_write,
+	},
+	{
+		.name = "dirty_background_bytes",
+		.read_u64 = mem_cgroup_dirty_background_bytes_read,
+		.write_u64 = mem_cgroup_dirty_background_bytes_write,
+	},
+	{
 		.name = "move_charge_at_immigrate",
 		.read_u64 = mem_cgroup_move_charge_read,
 		.write_u64 = mem_cgroup_move_charge_write,
@@ -3776,8 +4063,23 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 	mem->last_scanned_child = 0;
 	spin_lock_init(&mem->reclaim_param_lock);
 
-	if (parent)
+	if (parent) {
 		mem->swappiness = get_swappiness(parent);
+
+		mem->dirty_ratio = get_dirty_param(parent,
+					MEM_CGROUP_DIRTY_RATIO);
+		mem->dirty_bytes = get_dirty_param(parent,
+					MEM_CGROUP_DIRTY_BYTES);
+		mem->dirty_background_ratio = get_dirty_param(parent,
+					MEM_CGROUP_DIRTY_BACKGROUND_RATIO);
+		mem->dirty_background_bytes = get_dirty_param(parent,
+					MEM_CGROUP_DIRTY_BACKGROUND_BYTES);
+	} else {
+		mem->dirty_ratio = vm_dirty_ratio;
+		mem->dirty_bytes = vm_dirty_bytes;
+		mem->dirty_background_ratio = vm_dirty_ratio;
+		mem->dirty_background_bytes = vm_dirty_bytes;
+	}
 	atomic_set(&mem->refcnt, 1);
 	mem->move_charge_at_immigrate = 0;
 	mutex_init(&mem->thresholds_lock);
-- 
1.6.3.3

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