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0001 if BLOCK
0002 
0003 menu "IO Schedulers"
0004 
0005 config IOSCHED_NOOP
0006         bool
0007         default y
0008         ---help---
0009           The no-op I/O scheduler is a minimal scheduler that does basic merging
0010           and sorting. Its main uses include non-disk based block devices like
0011           memory devices, and specialised software or hardware environments
0012           that do their own scheduling and require only minimal assistance from
0013           the kernel.
0014 
0015 config IOSCHED_DEADLINE
0016         tristate "Deadline I/O scheduler"
0017         default y
0018         ---help---
0019           The deadline I/O scheduler is simple and compact. It will provide
0020           CSCAN service with FIFO expiration of requests, switching to
0021           a new point in the service tree and doing a batch of IO from there
0022           in case of expiry.
0023 
0024 config IOSCHED_CFQ
0025         tristate "CFQ I/O scheduler"
0026         default y
0027         ---help---
0028           The CFQ I/O scheduler tries to distribute bandwidth equally
0029           among all processes in the system. It should provide a fair
0030           and low latency working environment, suitable for both desktop
0031           and server systems.
0032 
0033           This is the default I/O scheduler.
0034 
0035 config CFQ_GROUP_IOSCHED
0036         bool "CFQ Group Scheduling support"
0037         depends on IOSCHED_CFQ && BLK_CGROUP
0038         default n
0039         ---help---
0040           Enable group IO scheduling in CFQ.
0041 
0042 choice
0043         prompt "Default I/O scheduler"
0044         default DEFAULT_CFQ
0045         help
0046           Select the I/O scheduler which will be used by default for all
0047           block devices.
0048 
0049         config DEFAULT_DEADLINE
0050                 bool "Deadline" if IOSCHED_DEADLINE=y
0051 
0052         config DEFAULT_CFQ
0053                 bool "CFQ" if IOSCHED_CFQ=y
0054 
0055         config DEFAULT_NOOP
0056                 bool "No-op"
0057 
0058 endchoice
0059 
0060 config DEFAULT_IOSCHED
0061         string
0062         default "deadline" if DEFAULT_DEADLINE
0063         default "cfq" if DEFAULT_CFQ
0064         default "noop" if DEFAULT_NOOP
0065 
0066 endmenu
0067 
0068 endif