Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6

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

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 1411048..d3d7613 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -4,7 +4,7 @@
  *  Based on ideas from a previously unfinished io
  *  scheduler (round robin per-process disk scheduling) and Andrea Arcangeli.
  *
- *  Copyright (C) 2003 Jens Axboe <axboe@suse.de>
+ *  Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
  */
 #include <linux/module.h>
 #include <linux/blkdev.h>
@@ -141,6 +141,8 @@ struct cfq_queue {
        int queued[2];
        /* currently allocated requests */
        int allocated[2];
+       /* pending metadata requests */
+       int meta_pending;
        /* fifo list of requests in sort_list */
        struct list_head fifo;
 
@@ -248,6 +250,10 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2)
                return rq1;
        else if (rq_is_sync(rq2) && !rq_is_sync(rq1))
                return rq2;
+       if (rq_is_meta(rq1) && !rq_is_meta(rq2))
+               return rq1;
+       else if (rq_is_meta(rq2) && !rq_is_meta(rq1))
+               return rq2;
 
        s1 = rq1->sector;
        s2 = rq2->sector;
@@ -510,6 +516,11 @@ static void cfq_remove_request(struct request *rq)
 
        list_del_init(&rq->queuelist);
        cfq_del_rq_rb(rq);
+
+       if (rq_is_meta(rq)) {
+               WARN_ON(!cfqq->meta_pending);
+               cfqq->meta_pending--;
+       }
 }
 
 static int
@@ -1527,8 +1538,18 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
         */
        if (new_cfqq->slice_left < cfqd->cfq_slice_idle)
                return 0;
+       /*
+        * if the new request is sync, but the currently running queue is
+        * not, let the sync request have priority.
+        */
        if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq))
                return 1;
+       /*
+        * 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_is_meta(rq) && !cfqq->meta_pending)
+               return 1;
 
        return 0;
 }
@@ -1564,6 +1585,9 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 {
        struct cfq_io_context *cic = RQ_CIC(rq);
 
+       if (rq_is_meta(rq))
+               cfqq->meta_pending++;
+
        /*
         * check if this request is a better next-serve candidate)) {
         */
@@ -2136,7 +2160,7 @@ static int __init cfq_init(void)
 
 static void __exit cfq_exit(void)
 {
-       DECLARE_COMPLETION(all_gone);
+       DECLARE_COMPLETION_ONSTACK(all_gone);
        elv_unregister(&iosched_cfq);
        ioc_gone = &all_gone;
        /* ioc_gone's update must be visible before reading ioc_count */