LXR linux/block/Kconfig.iosched

   1if BLOCK
   2
   3menu "IO Schedulers"
   4
   5config 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
  15config 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
  24config 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
  39config 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
  46choice
  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
  62endchoice
  63
  64config DEFAULT_IOSCHED
  65        string
  66        default "deadline" if DEFAULT_DEADLINE
  67        default "cfq" if DEFAULT_CFQ
  68        default "noop" if DEFAULT_NOOP
  69
  70endmenu
  71
  72endif
  73