[PATCH] Block queue IO tracing support (blktrace) as of 2006-03-23

Signed-off-by: Jens Axboe <axboe@suse.de>

1 files changed, 42 insertions, 2 deletions

diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 6c793b196aa9..062067fa7ead 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -28,6 +28,7 @@
 #include <linux/writeback.h>
 #include <linux/interrupt.h>
 #include <linux/cpu.h>
+#include <linux/blktrace_api.h>
 
 /*
  * for max sense size
@@ -1556,8 +1557,10 @@ void blk_plug_device(request_queue_t *q)
         if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))
                 return;
 
-        if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
+        if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) {
                 mod_timer(&q->unplug_timer, jiffies + q->unplug_delay);
+                blk_add_trace_generic(q, NULL, 0, BLK_TA_PLUG);
+        }
 }
 
 EXPORT_SYMBOL(blk_plug_device);
@@ -1621,14 +1624,21 @@ static void blk_backing_dev_unplug(struct backing_dev_info *bdi,
         /*
          * devices don't necessarily have an ->unplug_fn defined
          */
-        if (q->unplug_fn)
+        if (q->unplug_fn) {
+                blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
+                                        q->rq.count[READ] + q->rq.count[WRITE]);
+
                 q->unplug_fn(q);
+        }
 }
 
 static void blk_unplug_work(void *data)
 {
         request_queue_t *q = data;
 
+        blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
+                                q->rq.count[READ] + q->rq.count[WRITE]);
+
         q->unplug_fn(q);
 }
 
@@ -1636,6 +1646,9 @@ static void blk_unplug_timeout(unsigned long data)
 {
         request_queue_t *q = (request_queue_t *)data;
 
+        blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_TIMER, NULL,
+                                q->rq.count[READ] + q->rq.count[WRITE]);
+
         kblockd_schedule_work(&q->unplug_work);
 }
 
@@ -1753,6 +1766,9 @@ static void blk_release_queue(struct kobject *kobj)
         if (q->queue_tags)
                 __blk_queue_free_tags(q);
 
+        if (q->blk_trace)
+                blk_trace_shutdown(q);
+
         kmem_cache_free(requestq_cachep, q);
 }
 
@@ -2129,6 +2145,8 @@ rq_starved:
         
         rq_init(q, rq);
         rq->rl = rl;
+
+        blk_add_trace_generic(q, bio, rw, BLK_TA_GETRQ);
 out:
         return rq;
 }
@@ -2157,6 +2175,8 @@ static struct request *get_request_wait(request_queue_t *q, int rw,
                 if (!rq) {
                         struct io_context *ioc;
 
+                        blk_add_trace_generic(q, bio, rw, BLK_TA_SLEEPRQ);
+
                         __generic_unplug_device(q);
                         spin_unlock_irq(q->queue_lock);
                         io_schedule();
@@ -2210,6 +2230,8 @@ EXPORT_SYMBOL(blk_get_request);
  */
 void blk_requeue_request(request_queue_t *q, struct request *rq)
 {
+        blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
+
         if (blk_rq_tagged(rq))
                 blk_queue_end_tag(q, rq);
 
@@ -2844,6 +2866,8 @@ static int __make_request(request_queue_t *q, struct bio *bio)
                         if (!q->back_merge_fn(q, req, bio))
                                 break;
 
+                        blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
+
                         req->biotail->bi_next = bio;
                         req->biotail = bio;
                         req->nr_sectors = req->hard_nr_sectors += nr_sectors;
@@ -2859,6 +2883,8 @@ static int __make_request(request_queue_t *q, struct bio *bio)
                         if (!q->front_merge_fn(q, req, bio))
                                 break;
 
+                        blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
+
                         bio->bi_next = req->bio;
                         req->bio = bio;
 
@@ -2976,6 +3002,7 @@ void generic_make_request(struct bio *bio)
         request_queue_t *q;
         sector_t maxsector;
         int ret, nr_sectors = bio_sectors(bio);
+        dev_t old_dev;
 
         might_sleep();
         /* Test device or partition size, when known. */
@@ -3002,6 +3029,8 @@ void generic_make_request(struct bio *bio)
          * NOTE: we don't repeat the blk_size check for each new device.
          * Stacking drivers are expected to know what they are doing.
          */
+        maxsector = -1;
+        old_dev = 0;
         do {
                 char b[BDEVNAME_SIZE];
 
@@ -3034,6 +3063,15 @@ end_io:
                  */
                 blk_partition_remap(bio);
 
+                if (maxsector != -1)
+                        blk_add_trace_remap(q, bio, old_dev, bio->bi_sector, 
+                                            maxsector);
+
+                blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
+
+                maxsector = bio->bi_sector;
+                old_dev = bio->bi_bdev->bd_dev;
+
                 ret = q->make_request_fn(q, bio);
         } while (ret);
 }
@@ -3153,6 +3191,8 @@ static int __end_that_request_first(struct request *req, int uptodate,
         int total_bytes, bio_nbytes, error, next_idx = 0;
         struct bio *bio;
 
+        blk_add_trace_rq(req->q, req, BLK_TA_COMPLETE);
+
         /*
          * extend uptodate bool to allow < 0 value to be direct io error
          */