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zram: cosmetic: cleanup documentation

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zram documentation is a mix of different styles: spaces, tabs, tabs +
spaces, etc.  Clean it up.

Link: http://lkml.kernel.org/r/20160531122017.2878-6-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Sergey Senozhatsky
2016-07-26 15:22:51 -07:00
committed by Linus Torvalds
parent 415403be37
commit 69a30a8d2a
1 changed files with 42 additions and 43 deletions
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57
Documentation/blockdev/zram.txt
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@@ -59,23 +59,23 @@ num_devices parameter is optional and tells zram how many devices should be
pre-created. Default: 1. pre-created. Default: 1.
2) Set max number of compression streams 2) Set max number of compression streams
Regardless the value passed to this attribute, ZRAM will always Regardless the value passed to this attribute, ZRAM will always
allocate multiple compression streams - one per online CPUs - thus allocate multiple compression streams - one per online CPUs - thus
allowing several concurrent compression operations. The number of allowing several concurrent compression operations. The number of
allocated compression streams goes down when some of the CPUs allocated compression streams goes down when some of the CPUs
become offline. There is no single-compression-stream mode anymore, become offline. There is no single-compression-stream mode anymore,
unless you are running a UP system or has only 1 CPU online. unless you are running a UP system or has only 1 CPU online.
To find out how many streams are currently available: To find out how many streams are currently available:
cat /sys/block/zram0/max_comp_streams cat /sys/block/zram0/max_comp_streams
3) Select compression algorithm 3) Select compression algorithm
Using comp_algorithm device attribute one can see available and Using comp_algorithm device attribute one can see available and
currently selected (shown in square brackets) compression algorithms, currently selected (shown in square brackets) compression algorithms,
change selected compression algorithm (once the device is initialised change selected compression algorithm (once the device is initialised
there is no way to change compression algorithm). there is no way to change compression algorithm).
Examples: Examples:
#show supported compression algorithms #show supported compression algorithms
cat /sys/block/zram0/comp_algorithm cat /sys/block/zram0/comp_algorithm
lzo [lz4] lzo [lz4]
@@ -83,21 +83,20 @@ pre-created. Default: 1.
#select lzo compression algorithm #select lzo compression algorithm
echo lzo > /sys/block/zram0/comp_algorithm echo lzo > /sys/block/zram0/comp_algorithm
For the time being, the `comp_algorithm' content does not necessarily For the time being, the `comp_algorithm' content does not necessarily
show every compression algorithm supported by the kernel. We keep this show every compression algorithm supported by the kernel. We keep this
list primarily to simplify device configuration and one can configure list primarily to simplify device configuration and one can configure
a new device with a compression algorithm that is not listed in a new device with a compression algorithm that is not listed in
`comp_algorithm'. The thing is that, internally, ZRAM uses Crypto API `comp_algorithm'. The thing is that, internally, ZRAM uses Crypto API
and, if some of the algorithms were built as modules, it's impossible and, if some of the algorithms were built as modules, it's impossible
to list all of them using, for instance, /proc/crypto or any other to list all of them using, for instance, /proc/crypto or any other
method. This, however, has an advantage of permitting the usage of method. This, however, has an advantage of permitting the usage of
custom crypto compression modules (implementing S/W or H/W custom crypto compression modules (implementing S/W or H/W compression).
compression).
4) Set Disksize 4) Set Disksize
Set disk size by writing the value to sysfs node '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. The value can be either in bytes or you can use mem suffixes.
Examples: Examples:
# Initialize /dev/zram0 with 50MB disksize # Initialize /dev/zram0 with 50MB disksize
echo $((50*1024*1024)) > /sys/block/zram0/disksize echo $((50*1024*1024)) > /sys/block/zram0/disksize
@@ -112,10 +111,10 @@ 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. size of the disk when not in use so a huge zram is wasteful.
5) Set memory limit: Optional 5) Set memory limit: Optional
Set memory limit by writing the value to sysfs node 'mem_limit'. 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. The value can be either in bytes or you can use mem suffixes.
In addition, you could change the value in runtime. In addition, you could change the value in runtime.
Examples: Examples:
# limit /dev/zram0 with 50MB memory # limit /dev/zram0 with 50MB memory
echo $((50*1024*1024)) > /sys/block/zram0/mem_limit echo $((50*1024*1024)) > /sys/block/zram0/mem_limit