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Diffstat (limited to 'Documentation/blockdev/zram.txt')
| -rw-r--r-- | Documentation/blockdev/zram.txt | 29 |
1 files changed, 24 insertions, 5 deletions
diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt index 48a183e29988..c4de576093af 100644 --- a/Documentation/blockdev/zram.txt +++ b/Documentation/blockdev/zram.txt @@ -19,7 +19,9 @@ Following shows a typical sequence of steps for using zram. 1) Load Module: modprobe zram num_devices=4 This creates 4 devices: /dev/zram{0,1,2,3} - (num_devices parameter is optional. Default: 1) + +num_devices parameter is optional and tells zram how many devices should be +pre-created. Default: 1. 2) Set max number of compression streams Compression backend may use up to max_comp_streams compression streams, @@ -97,7 +99,24 @@ size of the disk when not in use so a huge zram is wasteful. mkfs.ext4 /dev/zram1 mount /dev/zram1 /tmp -7) Stats: +7) Add/remove zram devices + +zram provides a control interface, which enables dynamic (on-demand) device +addition and removal. + +In order to add a new /dev/zramX device, perform read operation on hot_add +attribute. This will return either new device's device id (meaning that you +can use /dev/zram<id>) or error code. + +Example: + cat /sys/class/zram-control/hot_add + 1 + +To remove the existing /dev/zramX device (where X is a device id) +execute + echo X > /sys/class/zram-control/hot_remove + +8) Stats: Per-device statistics are exported as various nodes under /sys/block/zram<id>/ A brief description of exported device attritbutes. For more details please @@ -126,7 +145,7 @@ mem_used_max RW the maximum amount memory zram have consumed to mem_limit RW the maximum amount of memory ZRAM can use to store the compressed data num_migrated RO the number of objects migrated migrated by compaction - +compact WO trigger memory compaction WARNING ======= @@ -172,11 +191,11 @@ line of text and contains the following stats separated by whitespace: zero_pages num_migrated -8) Deactivate: +9) Deactivate: swapoff /dev/zram0 umount /dev/zram1 -9) Reset: +10) Reset: Write any positive value to 'reset' sysfs node echo 1 > /sys/block/zram0/reset echo 1 > /sys/block/zram1/reset |