drivers/staging/zram/zram.txt

   1 zram: Compressed RAM based block devices
   2 ----------------------------------------
   3
   4 Project home: http://compcache.googlecode.com/
   5
   6 * Introduction
   7
   8 The zram module creates RAM based block devices: /dev/ramX (X = 0, 1, ...).
   9 Pages written to these disks are compressed and stored in memory itself.
  10 These disks allow very fast I/O and compression provides good amounts of
  11 memory savings.
  12
  13 See project home for use cases, performance numbers and a lot more.
  14
  15 Individual zram devices are configured and initialized using zramconfig
  16 userspace utility as shown in examples below. See zramconfig man page for
  17 more details.
  18
  19 * Usage
  20
  21 Following shows a typical sequence of steps for using zram.
  22
  23 1) Load Modules:
  24         modprobe zram num_devices=4
  25         This creates 4 (uninitialized) devices: /dev/zram{0,1,2,3}
  26         (num_devices parameter is optional. Default: 1)
  27
  28 2) Initialize:
  29         Use zramconfig utility to configure and initialize individual
  30         zram devices. For example:
  31         zramconfig /dev/zram0 --init # uses default value of disksize_kb
  32         zramconfig /dev/zram1 --disksize_kb=102400 # 100MB /dev/zram1
  33
  34         *See zramconfig man page for more details and examples*
  35
  36 3) Activate:
  37         mkswap /dev/zram0
  38         swapon /dev/zram0
  39
  40         mkfs.ext4 /dev/zram1
  41         mount /dev/zram1 /tmp
  42
  43 4) Stats:
  44         zramconfig /dev/zram0 --stats
  45         zramconfig /dev/zram1 --stats
  46
  47 5) Deactivate:
  48         swapoff /dev/zram0
  49         umount /dev/zram1
  50
  51 6) Reset:
  52         zramconfig /dev/zram0 --reset
  53         zramconfig /dev/zram1 --reset
  54         (This frees memory allocated for the given device).
  55
  56
  57 Please report any problems at:
  58  - Mailing list: linux-mm-cc at laptop dot org
  59  - Issue tracker: http://code.google.com/p/compcache/issues/list
  60
  61 Nitin Gupta
  62 ngupta@vflare.org