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Commit 63c8a466 authored by Minchan Kim's avatar Minchan Kim Committed by Srinivas Paladugu
Browse files

UPSTREAM: zram: add bd_stat statistics 

bd_stat represents things that happened in the backing device.  Currently
it supports bd_counts, bd_reads and bd_writes which are helpful to
understand wearout of flash and memory saving.

[minchan@kernel.org: v4]
  Link: http://lkml.kernel.org/r/20181203024045.153534-7-minchan@kernel.org
Link: http://lkml.kernel.org/r/20181127055429.251614-7-minchan@kernel.org


Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
Reviewed-by: default avatarSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Joey Pabalinas <joeypabalinas@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 23eddf39b2c28c05cb8f8203d38e61807d701b38)

Bug: 117683045
Change-Id: I9ae38c3b15876be9188dd40366caa0baa06742c0
Signed-off-by: default avatarSrinivas Paladugu <srnvs@google.com>
parent 8a42676b

Documentation/ABI/testing/sysfs-block-zram

+8 −0
Original line number Diff line number Diff line
@@ -113,3 +113,11 @@ Contact: Minchan Kim <minchan@kernel.org> 
Description:

		The writeback file is write-only and trigger idle and/or

		huge page writeback to backing device.



What:		/sys/block/zram<id>/bd_stat

Date:		November 2018

Contact:	Minchan Kim <minchan@kernel.org>

Description:

		The bd_stat file is read-only and represents backing device's

		statistics (bd_count, bd_reads, bd_writes) in a format

		similar to block layer statistics file format.

Documentation/blockdev/zram.txt

+11 −0
Original line number Diff line number Diff line
@@ -221,6 +221,17 @@ 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



File /sys/block/zram<id>/bd_stat



The stat file represents device's backing device statistics. It consists of

a single line of text and contains the following stats separated by whitespace:

 bd_count	size of data written in backing device.

		Unit: 4K bytes

 bd_reads	the number of reads from backing device

		Unit: 4K bytes

 bd_writes	the number of writes to backing device

		Unit: 4K bytes



9) Deactivate:

	swapoff /dev/zram0

	umount /dev/zram1

drivers/block/zram/zram_drv.c

+29 −0
Original line number Diff line number Diff line
@@ -502,6 +502,7 @@ static unsigned long alloc_block_bdev(struct zram *zram) 
	if (test_and_set_bit(blk_idx, zram->bitmap))

		goto retry;



	atomic64_inc(&zram->stats.bd_count);

	return blk_idx;

}
@@ -511,6 +512,7 @@ static void free_block_bdev(struct zram *zram, unsigned long blk_idx) 


	was_set = test_and_clear_bit(blk_idx, zram->bitmap);

	WARN_ON_ONCE(!was_set);

	atomic64_dec(&zram->stats.bd_count);

}



static void zram_page_end_io(struct bio *bio)
@@ -668,6 +670,7 @@ static ssize_t writeback_store(struct device *dev, 
			continue;

		}



		atomic64_inc(&zram->stats.bd_writes);

		/*

		 * We released zram_slot_lock so need to check if the slot was

		 * changed. If there is freeing for the slot, we can catch it
@@ -757,6 +760,7 @@ static int read_from_bdev_sync(struct zram *zram, struct bio_vec *bvec, 
static int read_from_bdev(struct zram *zram, struct bio_vec *bvec,

			unsigned long entry, struct bio *parent, bool sync)

{

	atomic64_inc(&zram->stats.bd_reads);

	if (sync)

		return read_from_bdev_sync(zram, bvec, entry, parent);

	else
@@ -1013,6 +1017,25 @@ static ssize_t mm_stat_show(struct device *dev, 
	return ret;

}



#ifdef CONFIG_ZRAM_WRITEBACK

static ssize_t bd_stat_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{

	struct zram *zram = dev_to_zram(dev);

	ssize_t ret;



	down_read(&zram->init_lock);

	ret = scnprintf(buf, PAGE_SIZE,

		"%8llu %8llu %8llu\n",

		(u64)atomic64_read(&zram->stats.bd_count) * (PAGE_SHIFT - 12),

		(u64)atomic64_read(&zram->stats.bd_reads) * (PAGE_SHIFT - 12),

		(u64)atomic64_read(&zram->stats.bd_writes) * (PAGE_SHIFT - 12));

	up_read(&zram->init_lock);



	return ret;

}

#endif



static ssize_t debug_stat_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{
@@ -1033,6 +1056,9 @@ static ssize_t debug_stat_show(struct device *dev, 


static DEVICE_ATTR_RO(io_stat);

static DEVICE_ATTR_RO(mm_stat);

#ifdef CONFIG_ZRAM_WRITEBACK

static DEVICE_ATTR_RO(bd_stat);

#endif

static DEVICE_ATTR_RO(debug_stat);



static void zram_meta_free(struct zram *zram, u64 disksize)
@@ -1759,6 +1785,9 @@ static struct attribute *zram_disk_attrs[] = { 
#endif

	&dev_attr_io_stat.attr,

	&dev_attr_mm_stat.attr,

#ifdef CONFIG_ZRAM_WRITEBACK

	&dev_attr_bd_stat.attr,

#endif

	&dev_attr_debug_stat.attr,

	NULL,

};

drivers/block/zram/zram_drv.h

+5 −0
Original line number Diff line number Diff line
@@ -82,6 +82,11 @@ struct zram_stats { 
	atomic_long_t max_used_pages;	/* no. of maximum pages stored */

	atomic64_t writestall;		/* no. of write slow paths */

	atomic64_t miss_free;		/* no. of missed free */

#ifdef	CONFIG_ZRAM_WRITEBACK

	atomic64_t bd_count;		/* no. of pages in backing device */

	atomic64_t bd_reads;		/* no. of reads from backing device */

	atomic64_t bd_writes;		/* no. of writes from backing device */

#endif

};



struct zram {