linux.git/block/elevator.c, branch v2.6.22

[PATCH] elevator: elv_list_lock does not need irq disabling

2007-04-30T07:08:17+00:00

It's never grabbed from irq context, so just make it plain spin_lock().

Signed-off-by: Jens Axboe

make elv_register() output atomic

2007-03-27T06:53:04+00:00

Booting 2.6.21-rc3-g45592145 I noticed the following on one of my
machines in the bootlog:

io scheduler noop registered<6>Time: jiffies clocksource has been installed.

io scheduler deadline registered (default)

Looking at block/elevator.c, it appears that elv_register() uses two
consecutive printks in a non-atomic way, leading to the above glitch. The
attached trivial patch fixes this issue, by using a single printk.

Signed-off-by: Thibaut VARENE 
Signed-off-by: Jens Axboe

elevator: don't sort reads between writes

2007-02-11T22:14:44+00:00

Don't allow elv_dispatch_sort() to mix reads and writes together,
it's rarely a good idea.

Signed-off-by: Jens Axboe

elevator: abstract out the activate and deactivate functions

2007-02-11T22:14:44+00:00

Signed-off-by: Jens Axboe

[PATCH] elevator: move clearing of unplug flag earlier

2007-01-23T19:01:17+00:00

A flag was recently added to the elevator code to avoid
performing an unplug when reuests are being re-queued.
The goal of this flag was to avoid a deep recursion that
can occur when re-queueing requests after a SCSI device/host
reset.  See http://lkml.org/lkml/2006/5/17/254

However, that fix added the flag near the bottom of a case
statement, where an earlier break (in an if statement) could
transport one out of the case, without setting the flag.
This patch sets the flag earlier in the case statement.

I re-discovered the deep recursion recently during testing;
I was told that it was a known problem, and the fix to it was
in the kernel I was testing. Indeed it was ... but it didn't
fix the bug. With the patch below, I no longer see the bug.

Signed-off by: Linas Vepstas 
Signed-off-by: Jens Axboe 
Cc: Chris Wright 
Signed-off-by: Linus Torvalds

[PATCH] elevator: fixup typo in merge logic

2006-12-22T06:01:04+00:00

The recent io scheduler allow_merge commit left the block layer with
no merging, oops. This patch fixes that up.

That means the CFQ change needs to be verified again, it might not fix
the original bug now.  But that's a seperate thing, I'll double check
that tomorrow.

Signed-off-by: Jens Axboe 
Signed-off-by: Linus Torvalds

[PATCH] cfq-iosched: don't allow sync merges across queues

2006-12-20T10:04:12+00:00

Currently we allow any merge, even if the io originates from different
processes. This can cause really bad starvation and unfairness, if those
ios happen to be synchronous (reads or direct writes).

So add a allow_merge hook to the io scheduler ops, so an io scheduler can
help decide whether a bio/process combination may be merged with an
existing request.

Signed-off-by: Jens Axboe

[BLOCK] Cleanup unused variable passing

2006-12-01T09:42:33+00:00

- ->init_queue() does not need the elevator passed in
- ->put_request() is a hot path and need not have the queue passed in
- cfq_update_io_seektime() does not need cfqd passed in

Signed-off-by: Jens Axboe

[PATCH] block layer: elv_iosched_show should get elv_list_lock

2006-10-12T13:08:51+00:00

elv_iosched_show function iterates other elv_list, hence
elv_list_lock should be got.

Signed-off-by: Vasily Tarasov 
Signed-off-by: Vasily Tarasov

[PATCH] block layer: elevator_find function cleanup

2006-10-12T13:08:51+00:00

We can easily produce search through the elevator list
without introducing additional elevator_type variable.

Signed-off-by: Vasily Tarasov 
Signed-off-by: Jens Axboe