Root/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

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