Commit Graph

15 Commits

Author SHA1 Message Date
Nate Diller
5f00397644 [BLOCK] elevator: default choice selection
My previous default iosched patch did a poor job dealing with the
'elevator=' boot-time option.  The old behavior falls back to the
compiled-in default if the requested one is not registered at boot
time.  This patch dynamically evaluates which default
to use, and emits a suitable error message when the requested scheduler
is not available.  It also does the 'as' -> 'anticipatory' conversion
before elevator registration, which along with a modified registration
function, allows it to correctly indicate which default scheduler is
in use.

Tested for a range of boot options on 2.6.16-rc1-mm2.

Signed-off-by: Nate Diller <nate.diller@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-01-24 10:07:58 +01:00
Jens Axboe
b7bfcf7cbd [BLOCK] elevator: if specified scheduler is not found, fall back to default
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-01-16 09:48:58 +01:00
Chuck Ebbert
752a3b7963 [BLOCK] elevator: Make elevator=as work again for anticipatory
Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-01-16 09:47:37 +01:00
Tejun Heo
1bc691d357 [PATCH] fix queue stalling while barrier sequencing
If ordered tag isn't supported, request ordering for barrier
sequencing is performed by queue draining, which basically hangs the
request queue until elv_completed_request() reports completion of all
previous fs requests.

The condition check in elv_completed_request() was only performed for
fs requests.  If a special request is queued between the last
to-be-drained request and the barrier sequence, draining is never
completed and the queue is stalled forever.

This patch moves the end-of-draining condition check such that it's
performed for all requests.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-12 09:05:39 -08:00
Coywolf Qi Hunt
769db45b73 make elv_try_merge() static, kill the dead declaration of
elv_try_last_merge().

Signed-off-by: Coywolf Qi Hunt <qiyong@fc-cn.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-01-09 14:44:15 +01:00
Tejun Heo
797e7dbbee [BLOCK] reimplement handling of barrier request
Reimplement handling of barrier requests.

* Flexible handling to deal with various capabilities of
  target devices.
* Retry support for falling back.
* Tagged queues which don't support ordered tag can do ordered.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-01-06 09:51:03 +01:00
Tejun Heo
8ffdc6550c [BLOCK] add @uptodate to end_that_request_last() and @error to rq_end_io_fn()
add @uptodate argument to end_that_request_last() and @error
to rq_end_io_fn().  there's no generic way to pass error code
to request completion function, making generic error handling
of non-fs request difficult (rq->errors is driver-specific and
each driver uses it differently).  this patch adds @uptodate
to end_that_request_last() and @error to rq_end_io_fn().

for fs requests, this doesn't really matter, so just using the
same uptodate argument used in the last call to
end_that_request_first() should suffice.  imho, this can also
help the generic command-carrying request jens is working on.

Signed-off-by: tejun heo <htejun@gmail.com>
Signed-Off-By: Jens Axboe <axboe@suse.de>
2006-01-06 09:49:03 +01:00
Coywolf Qi Hunt
eb97b73d75 [BLOCK] new block/ directory comment tidy
Some leftover comments referring to drivers/block that are now block/.
They don't add any information we don't already have, so kill them.

Signed-off-by: Coywolf Qi Hunt <qiyong@fc-cn.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-18 21:59:31 +01:00
Tejun Heo
3beb207712 [BLOCK] elevator: elv_latter/former_request update
With generic dispatch queue update, implicit former/latter request
handling using rq->queuelist.prev/next doesn't work as expected
anymore.  Also, the only iosched dependent on this feature was
noop-iosched and it has been reimplemented to have its own
latter/former methods.  This patch removes implicit former/latter
handling.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-12 10:57:05 +01:00
Tejun Heo
be56123568 [BLOCK] fix string handling in elv_iosched_store
elv_iosched_store doesn't terminate string passed from userspace if
it's too long.  Also, if the written length is zero (probably not
possible), it accesses elevator_name[-1].  This patch fixes both bugs.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-12 10:56:21 +01:00
Tejun Heo
15853af9f0 [BLOCK] Implement elv_drain_elevator for improved switch error detection
This patch adds request_queue->nr_sorted which keeps the number of
requests in the iosched and implement elv_drain_elevator which
performs forced dispatching.  elv_drain_elevator checks whether
iosched actually dispatches all requests it has and prints error
message if it doesn't.  As buggy forced dispatching can result in
wrong barrier operations, I think this extra check is worthwhile.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-12 10:56:06 +01:00
Tejun Heo
407df2aa29 [BLOCK] elevator: run queue in elevator_switch
elevator_dispatch needs to run queue after forced dispatching;
otherwise, the queue might stall.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-12 10:55:37 +01:00
Zachary Amsden
cff3ba2204 [BLOCK] elevator init fixes #2
In addition to the first patch, which is probably goodness, I found the
cause of my panic - applying this patch fixes it and now I am booting.
If the chosen_elevator[] is not found, fall back to noop.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-12 10:55:05 +01:00
Zachary Amsden
b8ea2cb512 [BLOCK] elevator init fixes
I got a panic in the elevator code, backtrace :

Unable to handle kernel NULL pointer dereference at virtual address 00000060
..
EIP is at elevator_put+0x0/0x30 (null elevator_type passed)
..
elevator_init+0x38
blk_init_queu_node+0xc9
floppy_init+0xdb
do_initcalls+0x23
init+0x10a
init+0x0

Clearly if the kmalloc here fails, e->elevator_type is not yet set; this
appears to be the correct fix, but I think I probably hit the second case
due to a race condition.  Someone more familiar with the elevator code
should look at this more closely until I can determine if I can reproduce.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-12 10:54:48 +01:00
Jens Axboe
3a65dfe8c0 [BLOCK] Move all core block layer code to new block/ directory
drivers/block/ is right now a mix of core and driver parts. Lets move
the core parts to a new top level directory. Al will move the fs/
related block parts to block/ next.

Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-04 08:43:35 +01:00