cfq-iosched: rethink seeky detection for SSDs

[pandora-kernel.git] / block / cfq-iosched.c

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 3fd8afc..423aee3 100644 (file)
--- 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_SECT_THR_NONROT   (sector_t)(2 * 32)
 #define CFQQ_SEEKY(cfqq)       (hweight32(cfqq->seek_history) > 32/8)
 
 #define RQ_CIC(rq)             \
@@ -2965,6 +2966,7 @@ cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                       struct request *rq)
 {
        sector_t sdist = 0;
+       sector_t n_sec = blk_rq_sectors(rq);
        if (cfqq->last_request_pos) {
                if (cfqq->last_request_pos < blk_rq_pos(rq))
                        sdist = blk_rq_pos(rq) - cfqq->last_request_pos;
@@ -2973,7 +2975,10 @@ cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq,
        }
 
        cfqq->seek_history <<= 1;
-       cfqq->seek_history |= (sdist > CFQQ_SEEK_THR);
+       if (blk_queue_nonrot(cfqd->queue))
+               cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT);
+       else
+               cfqq->seek_history |= (sdist > CFQQ_SEEK_THR);
 }
 
 /*