linux-toradex.git/block/cfq-iosched.c, branch v2.6.28.9

block: as/cfq ssd idle check update

2008-10-09T06:56:19+00:00

We really need to know about the hardware tagging support as well,
since if the SSD does not do tagging then we still want to idle.
Otherwise have the same dependent sync IO vs flooding async IO
problem as on rotational media.

Signed-off-by: Jens Axboe

block: add queue flag for SSD/non-rotational devices

2008-10-09T06:56:19+00:00

We don't want to idle in AS/CFQ if the device doesn't have a seek
penalty. So add a QUEUE_FLAG_NONROT to indicate a non-rotational
device, low level drivers should set this flag upon discovery of
an SSD or similar device type.

Signed-off-by: Jens Axboe

cfq-iosched: fix queue depth detection

2008-10-09T06:56:09+00:00

CFQ's detection of queueing devices assumes a non-queuing device and detects
if the queue depth reaches a certain threshold.  Under some workloads (e.g.
synchronous reads), CFQ effectively forces a unit queue depth, thus defeating
the detection logic.  This leads to poor performance on queuing hardware,
since the idle window remains enabled.

This patch inverts the sense of the logic: assume a queuing-capable device,
and detect if the depth does not exceed the threshold.

Signed-off-by: Aaron Carroll 
Signed-off-by: Jens Axboe

block: make kblockd_schedule_work() take the queue as parameter

2008-10-09T06:56:09+00:00

Preparatory patch for checking queuing affinity.

Signed-off-by: Jens Axboe

cfq-iosched: get rid of enable_idle being unused warning

2008-07-03T11:21:14+00:00

Signed-off-by: Jens Axboe

cfq-iosched: add message logging through blktrace

2008-07-03T11:21:12+00:00

Now that blktrace has the ability to carry arbitrary messages in
its stream, use that for some CFQ logging.

Signed-off-by: Jens Axboe

cfq-iosched: properly protect ioc_gone and ioc count

2008-07-03T11:21:12+00:00

If we have multiple tasks freeing cfq_io_contexts when cfq-iosched
is being unloaded, we could complete() ioc_gone twice. Fix that by
protecting ioc_gone complete() and clearing with a spinlock for
just that purpose. Doesn't matter from a performance perspective,
since it'll only enter that path when ioc_gone != NULL (when cfq-iosched
is being rmmod'ed).

Signed-off-by: Jens Axboe

cfq-iosched: fix RCU problem in cfq_cic_lookup()

2008-05-28T12:49:28+00:00

cfq_cic_lookup() needs to properly protect ioc->ioc_data before
dereferencing it and also exclude updaters of ioc->ioc_data as well.

Also add a number of comments documenting why the existing RCU usage
is OK.

Thanks a lot to "Paul E. McKenney"  for
review and comments!

Signed-off-by: Jens Axboe

block: reorder cfq_queue to save space on 64bit builds

2008-05-28T12:49:27+00:00

saves 8 bytes of padding & increases objects/slab from 30 to 32 on my
AMD64 config

Signed-off-by: Richard Kennedy 
Signed-off-by: Jens Axboe

cfq-iosched: make io priorities inherit CPU scheduling class as well as nice

2008-05-07T07:51:23+00:00

We currently set all processes to the best-effort scheduling class,
regardless of what CPU scheduling class they belong to. Improve that
so that we correctly track idle and rt scheduling classes as well.

Signed-off-by: Jens Axboe