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authorShaohua Li <shaohua.li@intel.com>2010-03-19 08:03:04 +0100
committerJens Axboe <jens.axboe@oracle.com>2010-03-19 08:03:04 +0100
commite9ce335df51ff782035a15c261a3c0c9892a1767 (patch)
tree9ecb3c0eab9dbb0117ad9d726456850ff2f49b78 /block
parentblock: make CONFIG_BLK_CGROUP visible (diff)
downloadlinux-dev-e9ce335df51ff782035a15c261a3c0c9892a1767.tar.xz
linux-dev-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.c11
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;