block/Kconfig.iosched

   1 if BLOCK
   2
   3 menu "IO Schedulers"
   4
   5 config IOSCHED_NOOP
   6         bool
   7         default y
   8         ---help---
   9           The no-op I/O scheduler is a minimal scheduler that does basic merging
  10           and sorting. Its main uses include non-disk based block devices like
  11           memory devices, and specialised software or hardware environments
  12           that do their own scheduling and require only minimal assistance from
  13           the kernel.
  14
  15 config IOSCHED_DEADLINE
  16         tristate "Deadline I/O scheduler"
  17         default y
  18         ---help---
  19           The deadline I/O scheduler is simple and compact. It will provide
  20           CSCAN service with FIFO expiration of requests, switching to
  21           a new point in the service tree and doing a batch of IO from there
  22           in case of expiry.
  23
  24 config IOSCHED_CFQ
  25         tristate "CFQ I/O scheduler"
  26         # If BLK_CGROUP is a module, CFQ has to be built as module.
  27         depends on (BLK_CGROUP=m && m) || !BLK_CGROUP || BLK_CGROUP=y
  28         default y
  29         ---help---
  30           The CFQ I/O scheduler tries to distribute bandwidth equally
  31           among all processes in the system. It should provide a fair
  32           and low latency working environment, suitable for both desktop
  33           and server systems.
  34
  35           This is the default I/O scheduler.
  36
  37           Note: If BLK_CGROUP=m, then CFQ can be built only as module.
  38
  39 config CFQ_GROUP_IOSCHED
  40         bool "CFQ Group Scheduling support"
  41         depends on IOSCHED_CFQ && BLK_CGROUP
  42         default n
  43         ---help---
  44           Enable group IO scheduling in CFQ.
  45
  46 choice
  47         prompt "Default I/O scheduler"
  48         default DEFAULT_CFQ
  49         help
  50           Select the I/O scheduler which will be used by default for all
  51           block devices.
  52
  53         config DEFAULT_DEADLINE
  54                 bool "Deadline" if IOSCHED_DEADLINE=y
  55
  56         config DEFAULT_CFQ
  57                 bool "CFQ" if IOSCHED_CFQ=y
  58
  59         config DEFAULT_NOOP
  60                 bool "No-op"
  61
  62 endchoice
  63
  64 config DEFAULT_IOSCHED
  65         string
  66         default "deadline" if DEFAULT_DEADLINE
  67         default "cfq" if DEFAULT_CFQ
  68         default "noop" if DEFAULT_NOOP
  69
  70 endmenu
  71
  72 endif