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

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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 <jens.axboe@oracle.com>

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Jens Axboe 2006-12-20 11:04:12 +01:00

parent 8e5cfc45e7

commit da77526502

3 changed files with 58 additions and 4 deletions

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include/linux/elevator.h

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