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| author | Shaohua Li <shaohua.li@intel.com> | 2010-03-19 08:03:04 +0100 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2010-03-19 08:03:04 +0100 |
| commit | e9ce335df51ff782035a15c261a3c0c9892a1767 (patch) | |
| tree | 9ecb3c0eab9dbb0117ad9d726456850ff2f49b78 /block | |
| parent | 910ac735bad53ce54741a72a5b19ab69794ae069 (diff) | |
| download | linux-e9ce335df51ff782035a15c261a3c0c9892a1767.tar.gz linux-e9ce335df51ff782035a15c261a3c0c9892a1767.tar.bz2 linux-e9ce335df51ff782035a15c261a3c0c9892a1767.zip | |
cfq-iosched: fix a kbuild regression
Alex Shi reported a kbuild regression which is about 10% performance lost.
He bisected to this commit: 3dde36ddea3e07dd025c4c1ba47edec91606fec0.
The reason is cfqq_close() can't find close cooperator. Restoring
cfq_rq_close()'s threshold to original value makes the regression go away.
Since for_preempt parameter isn't used anymore, this patch deletes it.
Reported-by: Alex Shi <alex.shi@intel.com>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/cfq-iosched.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index dee9d9378fee..8d5a2f2f7fb9 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -47,6 +47,7 @@ static const int cfq_hist_divisor = 4; #define CFQ_SERVICE_SHIFT 12 #define CFQQ_SEEK_THR (sector_t)(8 * 100) +#define CFQQ_CLOSE_THR (sector_t)(8 * 1024) #define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32) #define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8) @@ -1660,9 +1661,9 @@ static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, } static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct request *rq, bool for_preempt) + struct request *rq) { - return cfq_dist_from_last(cfqd, rq) <= CFQQ_SEEK_THR; + return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR; } static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, @@ -1689,7 +1690,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, * will contain the closest sector. */ __cfqq = rb_entry(parent, struct cfq_queue, p_node); - if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false)) + if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) return __cfqq; if (blk_rq_pos(__cfqq->next_rq) < sector) @@ -1700,7 +1701,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, return NULL; __cfqq = rb_entry(node, struct cfq_queue, p_node); - if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false)) + if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) return __cfqq; return NULL; @@ -3103,7 +3104,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, * if this request is as-good as one we would expect from the * current cfqq, let it preempt */ - if (cfq_rq_close(cfqd, cfqq, rq, true)) + if (cfq_rq_close(cfqd, cfqq, rq)) return true; return false; |