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| author |   Corrado Zoccolo <czoccolo@gmail.com> | 2009-11-26 10:02:58 +0100 |
|---|---|---|
| committer |   Jens Axboe <jens.axboe@oracle.com> | 2009-11-26 10:39:31 +0100 |
| commit | e4a229196a7c676514c78f6783f8994f64bf681c (patch) | |
| tree | b2a9e72f863cfaadaad697158969214cd8bb5681 /block/blk-barrier.c | |
| parent | cfq-iosched: fix ncq detection code (diff) | |
| download | linux-dev-e4a229196a7c676514c78f6783f8994f64bf681c.tar.xz linux-dev-e4a229196a7c676514c78f6783f8994f64bf681c.zip | |
cfq-iosched: fix no-idle preemption logic
An incoming no-idle queue should preempt the active no-idle queue
only if the active queue is idling due to service tree empty.
Previous code was buggy in two ways:
* it relied on service_tree field to be set on the active queue, while
it is not set when the code is idling for a new request
* it didn't check for the service tree empty condition, so could lead to
LIFO behaviour if multiple queues with depth > 1 were preempting each
other on an non-NCQ device.
Reported-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-barrier.c')
0 files changed, 0 insertions, 0 deletions