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| author | Jens Axboe <jaxboe@fusionio.com> | 2011-03-21 12:14:27 +0300 |
|---|---|---|
| committer | Jens Axboe <jaxboe@fusionio.com> | 2011-03-21 12:14:27 +0300 |
| commit | 5e84ea3a9c662dc2d7a48703a4468fad954a3b7f (patch) | |
| tree | 3fa0fb26a7c8a970213584104cc2498ef46d60a3 /include/linux/elevator.h | |
| parent | 4345caba340f051e10847924fc078ae18ed6695c (diff) | |
| download | linux-5e84ea3a9c662dc2d7a48703a4468fad954a3b7f.tar.xz | |
block: attempt to merge with existing requests on plug flush
One of the disadvantages of on-stack plugging is that we potentially
lose out on merging since all pending IO isn't always visible to
everybody. When we flush the on-stack plugs, right now we don't do
any checks to see if potential merge candidates could be utilized.
Correct this by adding a new insert variant, ELEVATOR_INSERT_SORT_MERGE.
It works just ELEVATOR_INSERT_SORT, but first checks whether we can
merge with an existing request before doing the insertion (if we fail
merging).
This fixes a regression with multiple processes issuing IO that
can be merged.
Thanks to Shaohua Li <shaohua.li@intel.com> for testing and fixing
an accounting bug.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'include/linux/elevator.h')
| -rw-r--r-- | include/linux/elevator.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/elevator.h b/include/linux/elevator.h index ec6f72b84477..d93efcc44570 100644 --- a/include/linux/elevator.h +++ b/include/linux/elevator.h @@ -166,6 +166,7 @@ extern struct request *elv_rb_find(struct rb_root *, sector_t); #define ELEVATOR_INSERT_SORT 3 #define ELEVATOR_INSERT_REQUEUE 4 #define ELEVATOR_INSERT_FLUSH 5 +#define ELEVATOR_INSERT_SORT_MERGE 6 /* * return values from elevator_may_queue_fn |