linux/block/Kconfig.iosched
Tejun Heo 32e380aedc blkcg: make CONFIG_BLK_CGROUP bool
Block cgroup core can be built as module; however, it isn't too useful
as blk-throttle can only be built-in and cfq-iosched is usually the
default built-in scheduler.  Scheduled blkcg cleanup requires calling
into blkcg from block core.  To simplify that, disallow building blkcg
as module by making CONFIG_BLK_CGROUP bool.

If building blkcg core as module really matters, which I doubt, we can
revisit it after blkcg API cleanup.

-v2: Vivek pointed out that IOSCHED_CFQ was incorrectly updated to
     depend on BLK_CGROUP.  Fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-03-06 21:27:21 +01:00

68 lines
1.6 KiB
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if BLOCK
menu "IO Schedulers"
config IOSCHED_NOOP
bool
default y
---help---
The no-op I/O scheduler is a minimal scheduler that does basic merging
and sorting. Its main uses include non-disk based block devices like
memory devices, and specialised software or hardware environments
that do their own scheduling and require only minimal assistance from
the kernel.
config IOSCHED_DEADLINE
tristate "Deadline I/O scheduler"
default y
---help---
The deadline I/O scheduler is simple and compact. It will provide
CSCAN service with FIFO expiration of requests, switching to
a new point in the service tree and doing a batch of IO from there
in case of expiry.
config IOSCHED_CFQ
tristate "CFQ I/O scheduler"
default y
---help---
The CFQ I/O scheduler tries to distribute bandwidth equally
among all processes in the system. It should provide a fair
and low latency working environment, suitable for both desktop
and server systems.
This is the default I/O scheduler.
config CFQ_GROUP_IOSCHED
bool "CFQ Group Scheduling support"
depends on IOSCHED_CFQ && BLK_CGROUP
default n
---help---
Enable group IO scheduling in CFQ.
choice
prompt "Default I/O scheduler"
default DEFAULT_CFQ
help
Select the I/O scheduler which will be used by default for all
block devices.
config DEFAULT_DEADLINE
bool "Deadline" if IOSCHED_DEADLINE=y
config DEFAULT_CFQ
bool "CFQ" if IOSCHED_CFQ=y
config DEFAULT_NOOP
bool "No-op"
endchoice
config DEFAULT_IOSCHED
string
default "deadline" if DEFAULT_DEADLINE
default "cfq" if DEFAULT_CFQ
default "noop" if DEFAULT_NOOP
endmenu
endif