[RFC PATCH v1 5/5] zram: add pages_folded to stats

[Alexey Romanov]

This counter show how many objects folded into single one
at the zsmalloc allocator level.

Signed-off-by: Alexey Romanov <avromanov@xxxxxxxxxxxxxx>
---
 Documentation/admin-guide/blockdev/zram.rst | 2 ++
 drivers/block/zram/zram_drv.c               | 5 +++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst
index e4551579cb12..349f13a2d310 100644
--- a/Documentation/admin-guide/blockdev/zram.rst
+++ b/Documentation/admin-guide/blockdev/zram.rst
@@ -209,6 +209,7 @@ compact           	WO	trigger memory compaction
 debug_stat        	RO	this file is used for zram debugging purposes
 backing_dev	  	RW	set up backend storage for zram to write out
 idle		  	WO	mark allocated slot as idle
+fold			WO	trigger memory folding
 ======================  ======  ===============================================
 
 
@@ -267,6 +268,7 @@ line of text and contains the following stats separated by whitespace:
  pages_compacted  the number of pages freed during compaction
  huge_pages	  the number of incompressible pages
  huge_pages_since the number of incompressible pages since zram set up
+ pages_folded     the number of pages freed during folding
  ================ =============================================================
 
 File /sys/block/zram<id>/bd_stat
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 06a614d1643d..3012b297ade5 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1242,7 +1242,7 @@ static ssize_t mm_stat_show(struct device *dev,
 	max_used = atomic_long_read(&zram->stats.max_used_pages);
 
 	ret = scnprintf(buf, PAGE_SIZE,
-			"%8llu %8llu %8llu %8lu %8ld %8llu %8lu %8llu %8llu\n",
+			"%8llu %8llu %8llu %8lu %8ld %8llu %8lu %8llu %8llu %8lu\n",
 			orig_size << PAGE_SHIFT,
 			(u64)atomic64_read(&zram->stats.compr_data_size),
 			mem_used << PAGE_SHIFT,
@@ -1251,7 +1251,8 @@ static ssize_t mm_stat_show(struct device *dev,
 			(u64)atomic64_read(&zram->stats.same_pages),
 			atomic_long_read(&pool_stats.pages_compacted),
 			(u64)atomic64_read(&zram->stats.huge_pages),
-			(u64)atomic64_read(&zram->stats.huge_pages_since));
+			(u64)atomic64_read(&zram->stats.huge_pages_since),
+			atomic_long_read(&pool_stats.pages_folded));
 	up_read(&zram->init_lock);
 
 	return ret;
-- 
2.38.1