block: remove the anticipatory IO scheduler
AS is mostly a subset of CFQ, so there's little point in still
providing this separate IO scheduler. Hopefully at some point we
can get down to one single IO scheduler again, at least this brings
us closer by having only one intelligent IO scheduler.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index 7e803fc8..baad3da 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -12,24 +12,14 @@
that do their own scheduling and require only minimal assistance from
the kernel.
-config IOSCHED_AS
- tristate "Anticipatory I/O scheduler"
- default y
- ---help---
- The anticipatory I/O scheduler is generally a good choice for most
- environments, but is quite large and complex when compared to the
- deadline I/O scheduler, it can also be slower in some cases
- especially some database loads.
-
config IOSCHED_DEADLINE
tristate "Deadline I/O scheduler"
default y
---help---
- The deadline I/O scheduler is simple and compact, and is often as
- good as the anticipatory I/O scheduler, and in some database
- workloads, better. In the case of a single process performing I/O to
- a disk at any one time, its behaviour is almost identical to the
- anticipatory I/O scheduler and so is a good choice.
+ 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"
@@ -47,9 +37,6 @@
Select the I/O scheduler which will be used by default for all
block devices.
- config DEFAULT_AS
- bool "Anticipatory" if IOSCHED_AS=y
-
config DEFAULT_DEADLINE
bool "Deadline" if IOSCHED_DEADLINE=y
@@ -63,7 +50,6 @@
config DEFAULT_IOSCHED
string
- default "anticipatory" if DEFAULT_AS
default "deadline" if DEFAULT_DEADLINE
default "cfq" if DEFAULT_CFQ
default "noop" if DEFAULT_NOOP