From: xu xin <xu.xin16@zte.com.cn>

Users can obtain ksm_zero_pages of a cgroup just by:

    'cat /sys/fs/cgroup/memory.stat | grep ksm_zero_pages

Signed-off-by: xu xin <xu.xin16@zte.com.cn>
---
 mm/ksm.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/mm/ksm.c b/mm/ksm.c
index be0efa0f8f2b..2fb4198458a4 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -3312,6 +3312,7 @@ long ksm_process_profit(struct mm_struct *mm)
 #ifdef CONFIG_MEMCG
 struct memcg_ksm_stat {
 	unsigned long ksm_rmap_items;
+	long ksm_zero_pages;
 };

 static int evaluate_memcg_ksm_stat(struct task_struct *task, void *arg)
@@ -3322,6 +3323,7 @@ static int evaluate_memcg_ksm_stat(struct task_struct *task, void *arg)
 	mm = get_task_mm(task);
 	if (mm) {
 		ksm_stat->ksm_rmap_items += mm->ksm_rmap_items;
+		ksm_stat->ksm_zero_pages += mm_ksm_zero_pages(mm);
 		mmput(mm);
 	}

@@ -3336,14 +3338,17 @@ void memcg_stat_ksm_show(struct mem_cgroup *memcg, struct seq_buf *s)
 	if (mem_cgroup_is_root(memcg)) {
 		/* Just use the global counters when root memcg */
 		ksm_stat.ksm_rmap_items = ksm_rmap_items;
+		ksm_stat.ksm_zero_pages = atomic_long_read(&ksm_zero_pages);
 	} else {
 		/* Initialization */
 		ksm_stat.ksm_rmap_items = 0;
+		ksm_stat.ksm_zero_pages = 0;
 		/* Summing all processes'ksm statistic items */
 		mem_cgroup_scan_tasks(memcg, evaluate_memcg_ksm_stat, &ksm_stat);
 	}
 	/* Print memcg ksm statistic items */
 	seq_buf_printf(s, "ksm_rmap_items %lu\n", ksm_stat.ksm_rmap_items);
+	seq_buf_printf(s, "ksm_zero_pages %lu\n", ksm_stat.ksm_zero_pages);
 }
 #endif

-- 
2.25.1