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    select BLK_CGROUP if CFQ_GROUP_IOSCHED
27    default y
28    ---help---
29      The CFQ I/O scheduler tries to distribute bandwidth equally
30      among all processes in the system. It should provide a fair
31      and low latency working environment, suitable for both desktop
32      and server systems.
33
34      This is the default I/O scheduler.
35
36config CFQ_GROUP_IOSCHED
37    bool "CFQ Group Scheduling support"
38    depends on IOSCHED_CFQ && CGROUPS
39    default n
40    ---help---
41      Enable group IO scheduling in CFQ.
42
43config DEBUG_CFQ_IOSCHED
44    bool "Debug CFQ Scheduling"
45    depends on CFQ_GROUP_IOSCHED
46    select DEBUG_BLK_CGROUP
47    default n
48    ---help---
49      Enable CFQ IO scheduling debugging in CFQ. Currently it makes
50      blktrace output more verbose.
51
52choice
53    prompt "Default I/O scheduler"
54    default DEFAULT_CFQ
55    help
56      Select the I/O scheduler which will be used by default for all
57      block devices.
58
59    config DEFAULT_DEADLINE
60        bool "Deadline" if IOSCHED_DEADLINE=y
61
62    config DEFAULT_CFQ
63        bool "CFQ" if IOSCHED_CFQ=y
64
65    config DEFAULT_NOOP
66        bool "No-op"
67
68endchoice
69
70config DEFAULT_IOSCHED
71    string
72    default "deadline" if DEFAULT_DEADLINE
73    default "cfq" if DEFAULT_CFQ
74    default "noop" if DEFAULT_NOOP
75
76endmenu
77
78endif
79

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