block: separate priority boosting from REQ_META

Add a new REQ_PRIO to let requests preempt others in the cfq I/O schedule,
and lave REQ_META purely for marking requests as metadata in blktrace.

All existing callers of REQ_META except for XFS are updated to also
set REQ_PRIO for now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 10 insertions, 10 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index a33bd4377c61..16ace89613bc 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -130,8 +130,8 @@ struct cfq_queue {
         unsigned long slice_end;
         long slice_resid;
 
-        /* pending metadata requests */
-        int meta_pending;
+        /* pending priority requests */
+        int prio_pending;
         /* number of requests that are on the dispatch list or inside driver */
         int dispatched;
 
@@ -684,8 +684,8 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2,
         if (rq_is_sync(rq1) != rq_is_sync(rq2))
                 return rq_is_sync(rq1) ? rq1 : rq2;
 
-        if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_META)
-                return rq1->cmd_flags & REQ_META ? rq1 : rq2;
+        if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_PRIO)
+                return rq1->cmd_flags & REQ_PRIO ? rq1 : rq2;
 
         s1 = blk_rq_pos(rq1);
         s2 = blk_rq_pos(rq2);
@@ -1612,9 +1612,9 @@ static void cfq_remove_request(struct request *rq)
         cfqq->cfqd->rq_queued--;
         cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg,
                                         rq_data_dir(rq), rq_is_sync(rq));
-        if (rq->cmd_flags & REQ_META) {
-                WARN_ON(!cfqq->meta_pending);
-                cfqq->meta_pending--;
+        if (rq->cmd_flags & REQ_PRIO) {
+                WARN_ON(!cfqq->prio_pending);
+                cfqq->prio_pending--;
         }
 }
 
@@ -3372,7 +3372,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
          * So both queues are sync. Let the new request get disk time if
          * it's a metadata request and the current queue is doing regular IO.
          */
-        if ((rq->cmd_flags & REQ_META) && !cfqq->meta_pending)
+        if ((rq->cmd_flags & REQ_PRIO) && !cfqq->prio_pending)
                 return true;
 
         /*
@@ -3439,8 +3439,8 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
         struct cfq_io_context *cic = RQ_CIC(rq);
 
         cfqd->rq_queued++;
-        if (rq->cmd_flags & REQ_META)
-                cfqq->meta_pending++;
+        if (rq->cmd_flags & REQ_PRIO)
+                cfqq->prio_pending++;
 
         cfq_update_io_thinktime(cfqd, cfqq, cic);
         cfq_update_io_seektime(cfqd, cfqq, rq);