Re: Problem with the default IOSCHED

From: Jens Axboe
Date: Wed Nov 02 2005 - 06:56:20 EST


On Wed, Nov 02 2005, Marcel Holtmann wrote:
> Hi guys,
>
> by accident I selected the anticipatory IO scheduler as default in my
> kernel config, but only the CFQ was built in. The anticipatory and
> deadline were only available as modules. This caused an oops at boot.
> After selecting CFQ as default schedule and a recompile and reboot
> everything was fine again.

Hmm yes, that looks like a bug introduced with the io scheduler
selection reorg. There's really no support in place for requesting this
module out of initrd, I'd rather just make your selection illegal. Does
this work for you?

diff --git a/drivers/block/Kconfig.iosched b/drivers/block/Kconfig.iosched
index 5b90d2f..f3b7753 100644
--- a/drivers/block/Kconfig.iosched
+++ b/drivers/block/Kconfig.iosched
@@ -46,13 +46,13 @@ choice
block devices.

config DEFAULT_AS
- bool "Anticipatory" if IOSCHED_AS
+ bool "Anticipatory" if IOSCHED_AS=y

config DEFAULT_DEADLINE
- bool "Deadline" if IOSCHED_DEADLINE
+ bool "Deadline" if IOSCHED_DEADLINE=y

config DEFAULT_CFQ
- bool "CFQ" if IOSCHED_CFQ
+ bool "CFQ" if IOSCHED_CFQ=y

config DEFAULT_NOOP
bool "No-op"

--
Jens Axboe

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