block: Add flag for telling the IO schedulers NOT to anticipate more IO

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By default, CFQ will anticipate more IO from a given io context if the
previously completed IO was sync. This used to be fine, since the only
sync IO was reads and O_DIRECT writes. But with more "normal" sync writes
being used now, we don't want to anticipate for those.

Add a bio/request flag that informs the IO scheduler that this is a sync
request that we should not idle for. Introduce WRITE_ODIRECT specifically
for O_DIRECT writes, and make sure that the other sync writes set this
flag.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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Jens Axboe 2009-04-06 14:48:07 +02:00 • committed by Linus Torvalds

parent 644b2d99b7

commit aeb6fafb8f

6 changed files with 25 additions and 14 deletions

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include/linux/blkdev.h

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