[PATCHv3 4/4] zram: document max_buffers

[Sergey Senozhatsky]

Add max_buffers device attribute documentation.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
---
 Documentation/ABI/testing/sysfs-block-zram |  9 ++++++++-
 Documentation/blockdev/zram.txt            | 21 ++++++++++++++++-----
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram
index 8aa0468..0e36bf7 100644
--- a/Documentation/ABI/testing/sysfs-block-zram
+++ b/Documentation/ABI/testing/sysfs-block-zram
@@ -50,7 +50,6 @@ Description:
 		The failed_reads file is read-only and specifies the number of
 		failed reads happened on this device.
 
-
 What:		/sys/block/zram<id>/failed_writes
 Date:		February 2014
 Contact:	Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
@@ -58,6 +57,14 @@ Description:
 		The failed_writes file is read-only and specifies the number of
 		failed writes happened on this device.
 
+What:		/sys/block/zram<id>/max_buffers
+Date:		February 2014
+Contact:	Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
+Description:
+		The max_buffers file is read-write and specifies the number of
+		compression backend's workmem buffers (number of concurrent
+		compress/decompress operations).
+
 What:		/sys/block/zram<id>/notify_free
 Date:		August 2010
 Contact:	Nitin Gupta <ngupta@xxxxxxxxxx>
diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt
index b31ac5e..b525c8e 100644
--- a/Documentation/blockdev/zram.txt
+++ b/Documentation/blockdev/zram.txt
@@ -21,7 +21,18 @@ Following shows a typical sequence of steps for using zram.
 	This creates 4 devices: /dev/zram{0,1,2,3}
 	(num_devices parameter is optional. Default: 1)
 
-2) Set Disksize
+2) Set max number of compression buffers
+	Compression backend may use up to max_buffers workmem buffers,
+	thus allowing up to max_buffers concurrent compression/decompression
+	operations.
+	Examples:
+	#set max buffers to 3
+	echo 3 > /sys/block/zram0/max_buffers
+
+	#show max buffers
+	cat /sys/block/zram0/max_buffers
+
+3) Set Disksize
         Set disk size by writing the value to sysfs node 'disksize'.
         The value can be either in bytes or you can use mem suffixes.
         Examples:
@@ -38,14 +49,14 @@ There is little point creating a zram of greater than twice the size of memory
 since we expect a 2:1 compression ratio. Note that zram uses about 0.1% of the
 size of the disk when not in use so a huge zram is wasteful.
 
-3) Activate:
+4) Activate:
 	mkswap /dev/zram0
 	swapon /dev/zram0
 
 	mkfs.ext4 /dev/zram1
 	mount /dev/zram1 /tmp
 
-4) Stats:
+5) Stats:
 	Per-device statistics are exported as various nodes under
 	/sys/block/zram<id>/
 		disksize
@@ -60,11 +71,11 @@ size of the disk when not in use so a huge zram is wasteful.
 		compr_data_size
 		mem_used_total
 
-5) Deactivate:
+6) Deactivate:
 	swapoff /dev/zram0
 	umount /dev/zram1
 
-6) Reset:
+7) Reset:
 	Write any positive value to 'reset' sysfs node
 	echo 1 > /sys/block/zram0/reset
 	echo 1 > /sys/block/zram1/reset
-- 
1.9.0.rc3.244.g3497008

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