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-rw-r--r--block/cfq-iosched.c54
1 files changed, 14 insertions, 40 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 10eb286f1f49..3fd8afc2174e 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -46,8 +46,8 @@ static const int cfq_hist_divisor = 4;
#define CFQ_HW_QUEUE_MIN (5)
#define CFQ_SERVICE_SHIFT 12
-#define CFQQ_SEEK_THR 8 * 1024
-#define CFQQ_SEEKY(cfqq) ((cfqq)->seek_mean > CFQQ_SEEK_THR)
+#define CFQQ_SEEK_THR (sector_t)(8 * 100)
+#define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8)
#define RQ_CIC(rq) \
((struct cfq_io_context *) (rq)->elevator_private)
@@ -132,9 +132,7 @@ struct cfq_queue {
pid_t pid;
- unsigned int seek_samples;
- u64 seek_total;
- sector_t seek_mean;
+ u32 seek_history;
sector_t last_request_pos;
struct cfq_rb_root *service_tree;
@@ -1668,16 +1666,7 @@ 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)
{
- sector_t sdist = cfqq->seek_mean;
-
- if (!sample_valid(cfqq->seek_samples))
- sdist = CFQQ_SEEK_THR;
-
- /* if seek_mean is big, using it as close criteria is meaningless */
- if (sdist > CFQQ_SEEK_THR && !for_preempt)
- sdist = CFQQ_SEEK_THR;
-
- return cfq_dist_from_last(cfqd, rq) <= sdist;
+ return cfq_dist_from_last(cfqd, rq) <= CFQQ_SEEK_THR;
}
static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
@@ -2975,30 +2964,16 @@ static void
cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct request *rq)
{
- sector_t sdist;
- u64 total;
-
- if (!cfqq->last_request_pos)
- sdist = 0;
- else if (cfqq->last_request_pos < blk_rq_pos(rq))
- sdist = blk_rq_pos(rq) - cfqq->last_request_pos;
- else
- sdist = cfqq->last_request_pos - blk_rq_pos(rq);
-
- /*
- * Don't allow the seek distance to get too large from the
- * odd fragment, pagein, etc
- */
- if (cfqq->seek_samples <= 60) /* second&third seek */
- sdist = min(sdist, (cfqq->seek_mean * 4) + 2*1024*1024);
- else
- sdist = min(sdist, (cfqq->seek_mean * 4) + 2*1024*64);
+ sector_t sdist = 0;
+ if (cfqq->last_request_pos) {
+ if (cfqq->last_request_pos < blk_rq_pos(rq))
+ sdist = blk_rq_pos(rq) - cfqq->last_request_pos;
+ else
+ sdist = cfqq->last_request_pos - blk_rq_pos(rq);
+ }
- cfqq->seek_samples = (7*cfqq->seek_samples + 256) / 8;
- cfqq->seek_total = (7*cfqq->seek_total + (u64)256*sdist) / 8;
- total = cfqq->seek_total + (cfqq->seek_samples/2);
- do_div(total, cfqq->seek_samples);
- cfqq->seek_mean = (sector_t)total;
+ cfqq->seek_history <<= 1;
+ cfqq->seek_history |= (sdist > CFQQ_SEEK_THR);
}
/*
@@ -3023,8 +2998,7 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
cfq_mark_cfqq_deep(cfqq);
if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
- (!cfq_cfqq_deep(cfqq) && sample_valid(cfqq->seek_samples)
- && CFQQ_SEEKY(cfqq)))
+ (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq)))
enable_idle = 0;
else if (sample_valid(cic->ttime_samples)) {
if (cic->ttime_mean > cfqd->cfq_slice_idle)