diff options
| author | Sergey Senozhatsky <sergey.senozhatsky@gmail.com> | 2014-04-07 15:38:17 -0700 |
|---|---|---|
| committer | Mister Oyster <oysterized@gmail.com> | 2016-12-11 13:00:51 +0100 |
| commit | 4b10f7c4be47c84e2bf91d89d1d2981db93046d0 (patch) | |
| tree | aafb28bf1f1bc6dede5fb478935edb512f794efb /Documentation | |
| parent | 6f910c187b06beacad8b85ebe154e05ab45a8cb3 (diff) | |
zram: make compression algorithm selection possible
Add and document `comp_algorithm' device attribute. This attribute allows
to show supported compression and currently selected compression
algorithms:
cat /sys/block/zram0/comp_algorithm
[lzo] lz4
and change selected compression algorithm:
echo lzo > /sys/block/zram0/comp_algorithm
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-block-zram | 8 | ||||
| -rw-r--r-- | Documentation/blockdev/zram.txt | 24 |
2 files changed, 27 insertions, 5 deletions
diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram index d67f0bb1c..2775966c2 100644 --- a/Documentation/ABI/testing/sysfs-block-zram +++ b/Documentation/ABI/testing/sysfs-block-zram @@ -64,6 +64,14 @@ Description: number of backend's zcomp_strm compression streams (number of concurrent compress operations). +What: /sys/block/zram<id>/comp_algorithm +Date: February 2014 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The comp_algorithm file is read-write and lets to show + available and selected compression algorithms, change + compression algorithm selection. + What: /sys/block/zram<id>/notify_free Date: August 2010 Contact: Nitin Gupta <ngupta@vflare.org> diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt index e82c03f26..4ab2ce98f 100644 --- a/Documentation/blockdev/zram.txt +++ b/Documentation/blockdev/zram.txt @@ -42,7 +42,21 @@ will not take any effect, because single stream compression backend implemented as a special case and does not support dynamic max_comp_streams. Only multi stream backend supports dynamic max_comp_streams adjustment. -3) Set Disksize +3) Select compression algorithm + Using comp_algorithm device attribute one can see available and + currently selected (shown in square brackets) compression algortithms, + change selected compression algorithm (once the device is initialised + there is no way to change compression algorithm). + + Examples: + #show supported compression algorithms + cat /sys/block/zram0/comp_algorithm + lzo [lz4] + + #select lzo compression algorithm + echo lzo > /sys/block/zram0/comp_algorithm + +4) 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: @@ -59,14 +73,14 @@ 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. -4) Activate: +5) Activate: mkswap /dev/zram0 swapon /dev/zram0 mkfs.ext4 /dev/zram1 mount /dev/zram1 /tmp -5) Stats: +6) Stats: Per-device statistics are exported as various nodes under /sys/block/zram<id>/ disksize @@ -80,11 +94,11 @@ size of the disk when not in use so a huge zram is wasteful. compr_data_size mem_used_total -6) Deactivate: +7) Deactivate: swapoff /dev/zram0 umount /dev/zram1 -7) Reset: +8) Reset: Write any positive value to 'reset' sysfs node echo 1 > /sys/block/zram0/reset echo 1 > /sys/block/zram1/reset |