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