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-rw-r--r--Documentation/ABI/testing/sysfs-block-zram9
-rw-r--r--Documentation/blockdev/zram.txt24
2 files changed, 29 insertions, 4 deletions
diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram
index 2775966c2d12..f861cbfab6b1 100644
--- a/Documentation/ABI/testing/sysfs-block-zram
+++ b/Documentation/ABI/testing/sysfs-block-zram
@@ -127,3 +127,12 @@ Description:
efficiency can be calculated using compr_data_size and this
statistic.
Unit: bytes
+
+What: /sys/block/zram<id>/mem_limit
+Date: August 2014
+Contact: Minchan Kim <minchan@kernel.org>
+Description:
+ The mem_limit file is read/write and specifies the maximum
+ amount of memory ZRAM can use to store the compressed data. The
+ limit could be changed in run time and "0" means disable the
+ limit. No limit is the initial state. Unit: bytes
diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt
index 2db1687a4b10..4331ebf94bf0 100644
--- a/Documentation/blockdev/zram.txt
+++ b/Documentation/blockdev/zram.txt
@@ -74,14 +74,30 @@ 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.
-5) Activate:
+5) Set memory limit: Optional
+ Set memory limit by writing the value to sysfs node 'mem_limit'.
+ The value can be either in bytes or you can use mem suffixes.
+ In addition, you could change the value in runtime.
+ Examples:
+ # limit /dev/zram0 with 50MB memory
+ echo $((50*1024*1024)) > /sys/block/zram0/mem_limit
+
+ # Using mem suffixes
+ echo 256K > /sys/block/zram0/mem_limit
+ echo 512M > /sys/block/zram0/mem_limit
+ echo 1G > /sys/block/zram0/mem_limit
+
+ # To disable memory limit
+ echo 0 > /sys/block/zram0/mem_limit
+
+6) Activate:
mkswap /dev/zram0
swapon /dev/zram0
mkfs.ext4 /dev/zram1
mount /dev/zram1 /tmp
-6) Stats:
+7) Stats:
Per-device statistics are exported as various nodes under
/sys/block/zram<id>/
disksize
@@ -95,11 +111,11 @@ size of the disk when not in use so a huge zram is wasteful.
compr_data_size
mem_used_total
-7) Deactivate:
+8) Deactivate:
swapoff /dev/zram0
umount /dev/zram1
-8) Reset:
+9) Reset:
Write any positive value to 'reset' sysfs node
echo 1 > /sys/block/zram0/reset
echo 1 > /sys/block/zram1/reset