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Commit 492af635 authored by Jens Axboe's avatar Jens Axboe
Browse files

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: default avatarJens Axboe <jens.axboe@oracle.com>
parent 6a0afdf5

block/Kconfig.iosched

+4 −18
Original line number Diff line number Diff line
@@ -12,24 +12,14 @@ config IOSCHED_NOOP 
	  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 @@ choice 
	  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 @@ endchoice 


config DEFAULT_IOSCHED

	string

	default "anticipatory" if DEFAULT_AS

	default "deadline" if DEFAULT_DEADLINE

	default "cfq" if DEFAULT_CFQ

	default "noop" if DEFAULT_NOOP

block/Makefile

+0 −1
Original line number Diff line number Diff line
@@ -9,7 +9,6 @@ obj-$(CONFIG_BLOCK) := elevator.o blk-core.o blk-tag.o blk-sysfs.o \ 


obj-$(CONFIG_BLK_DEV_BSG)	+= bsg.o

obj-$(CONFIG_IOSCHED_NOOP)	+= noop-iosched.o

obj-$(CONFIG_IOSCHED_AS)	+= as-iosched.o

obj-$(CONFIG_IOSCHED_DEADLINE)	+= deadline-iosched.o

obj-$(CONFIG_IOSCHED_CFQ)	+= cfq-iosched.o

block/as-iosched.c

deleted100644 → 0
+0 −1520

File deleted.

Preview size limit exceeded, changes collapsed.

block/elevator.c

+2 −8
Original line number Diff line number Diff line
@@ -154,9 +154,6 @@ static struct elevator_type *elevator_get(const char *name) 


		spin_unlock(&elv_list_lock);



		if (!strcmp(name, "anticipatory"))

			sprintf(elv, "as-iosched");

		else

		sprintf(elv, "%s-iosched", name);



		request_module("%s", elv);
@@ -193,9 +190,6 @@ static int __init elevator_setup(char *str) 
	 * Be backwards-compatible with previous kernels, so users

	 * won't get the wrong elevator.

	 */

	if (!strcmp(str, "as"))

		strcpy(chosen_elevator, "anticipatory");

	else

	strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1);

	return 1;

}