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