Currently, there is a single in_flight counter measuring the number of
requests in the request_queue. But some monitoring tools would like to know
how many read requests and write requests are in progress. Split the current
in_flight counter into two seperate counters for read and write.
This patch is based on a patch from Mark Landis <mark.landis@xxxxxxxxxxxx>
Signed-off-by: Nikanth Karthikesan <knikanth@xxxxxxx>
---
diff --git a/Documentation/iostats.txt b/Documentation/iostats.txt
index 59a69ec..e4dff73 100644
--- a/Documentation/iostats.txt
+++ b/Documentation/iostats.txt
@@ -26,11 +26,11 @@ Here are examples of these different formats:
2.6 sysfs:
- 446216 784926 9550688 4382310 424847 312726 5922052 19310380 0 3376340 23705160
+ 446216 784926 9550688 4382310 424847 312726 5922052 19310380 0 0 3376340 23705160
35486 38030 38030 38030
2.6 diskstats:
- 3 0 hda 446216 784926 9550688 4382310 424847 312726 5922052 19310380 0 3376340 23705160
+ 3 0 hda 446216 784926 9550688 4382310 424847 312726 5922052 19310380 0 0 3376340 23705160
3 1 hda1 35486 38030 38030 38030
On 2.4 you might execute "grep 'hda ' /proc/partitions". On 2.6, you have
@@ -77,12 +77,15 @@ Field 7 -- # of sectors written
Field 8 -- # of milliseconds spent writing
This is the total number of milliseconds spent by all writes (as
measured from __make_request() to end_that_request_last()).
-Field 9 -- # of I/Os currently in progress
- The only field that should go to zero. Incremented as requests are
- given to appropriate struct request_queue and decremented as they finish.
-Field 10 -- # of milliseconds spent doing I/Os
+Field 9 -- # of read I/Os currently in progress
+ This field should go to zero. Incremented as read requests are given
+ to appropriate struct request_queue and decremented as they finish.
+Field 10 -- # of write I/Os currently in progress
+ This field should go to zero. Incremented as write requests are given
+ to appropriate struct request_queue and decremented as they finish.
+Field 11 -- # of milliseconds spent doing I/Os
This field is increases so long as field 9 is nonzero.
-Field 11 -- weighted # of milliseconds spent doing I/Os
+Field 12 -- weighted # of milliseconds spent doing I/Os
This field is incremented at each I/O start, I/O completion, I/O
merge, or read of these stats by the number of I/Os in progress
(field 9) times the number of milliseconds spent doing I/O since the
diff --git a/block/blk-core.c b/block/blk-core.c
index e3299a7..e0ce820 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -69,7 +69,7 @@ static void drive_stat_acct(struct request *rq, int new_io)
part_stat_inc(cpu, part, merges[rw]);
else {
part_round_stats(cpu, part);
- part_inc_in_flight(part);
+ part_inc_in_flight(part, rw);
}
part_stat_unlock();
@@ -1030,7 +1030,7 @@ static void part_round_stats_single(int cpu, struct hd_struct *part,
if (part->in_flight) {
__part_stat_add(cpu, part, time_in_queue,
- part->in_flight * (now - part->stamp));
+ part_in_flight(part) * (now - part->stamp));
__part_stat_add(cpu, part, io_ticks, (now - part->stamp));
}
part->stamp = now;
@@ -1686,7 +1686,7 @@ static void blk_account_io_done(struct request *req)
part_stat_inc(cpu, part, ios[rw]);
part_stat_add(cpu, part, ticks[rw], duration);
part_round_stats(cpu, part);
- part_dec_in_flight(part);
+ part_dec_in_flight(part, rw);
part_stat_unlock();
}
diff --git a/block/blk-merge.c b/block/blk-merge.c
index e199967..97ea454 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -321,7 +321,7 @@ static void blk_account_io_merge(struct request *req)
part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
part_round_stats(cpu, part);
- part_dec_in_flight(part);
+ part_dec_in_flight(part, rq_data_dir(req));
part_stat_unlock();
}
diff --git a/block/genhd.c b/block/genhd.c
index f4c64c2..ce4fbd2 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1042,7 +1042,7 @@ static int diskstats_show(struct seq_file *seqf, void *v)
part_round_stats(cpu, hd);
part_stat_unlock();
seq_printf(seqf, "%4d %7d %s %lu %lu %llu "
- "%u %lu %lu %llu %u %u %u %u\n",
+ "%u %lu %lu %llu %u %u %u %u %u\n",
MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
disk_name(gp, hd->partno, buf),
part_stat_read(hd, ios[0]),
@@ -1053,7 +1053,8 @@ static int diskstats_show(struct seq_file *seqf, void *v)
part_stat_read(hd, merges[1]),
(unsigned long long)part_stat_read(hd, sectors[1]),
jiffies_to_msecs(part_stat_read(hd, ticks[1])),
- hd->in_flight,
+ hd->in_flight[0],
+ hd->in_flight[1],
jiffies_to_msecs(part_stat_read(hd, io_ticks)),
jiffies_to_msecs(part_stat_read(hd, time_in_queue))
);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 8a311ea..ba2fe6b 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -130,7 +130,7 @@ struct mapped_device {
/*
* A list of ios that arrived while we were suspended.
*/
- atomic_t pending;
+ atomic_t pending[2];
wait_queue_head_t wait;
struct work_struct work;
struct bio_list deferred;
@@ -453,13 +453,14 @@ static void start_io_acct(struct dm_io *io)
{
struct mapped_device *md = io->md;
int cpu;
+ int rw = bio_data_dir(io->bio);
io->start_time = jiffies;
cpu = part_stat_lock();
part_round_stats(cpu, &dm_disk(md)->part0);
part_stat_unlock();
- dm_disk(md)->part0.in_flight = atomic_inc_return(&md->pending);
+ dm_disk(md)->part0.in_flight[rw] = atomic_inc_return(&md->pending[rw]);
}
static void end_io_acct(struct dm_io *io)
@@ -479,8 +480,9 @@ static void end_io_acct(struct dm_io *io)
* After this is decremented the bio must not be touched if it is
* a barrier.
*/
- dm_disk(md)->part0.in_flight = pending =
- atomic_dec_return(&md->pending);
+ dm_disk(md)->part0.in_flight[rw] = pending =
+ atomic_dec_return(&md->pending[rw]);
+ pending += atomic_read(&md->pending[rw^0x1]);
/* nudge anyone waiting on suspend queue */
if (!pending)
@@ -1780,7 +1782,8 @@ static struct mapped_device *alloc_dev(int minor)
if (!md->disk)
goto bad_disk;
- atomic_set(&md->pending, 0);
+ atomic_set(&md->pending[0], 0);
+ atomic_set(&md->pending[1], 0);
init_waitqueue_head(&md->wait);
INIT_WORK(&md->work, dm_wq_work);
init_waitqueue_head(&md->eventq);
@@ -2083,7 +2086,8 @@ static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
break;
}
spin_unlock_irqrestore(q->queue_lock, flags);
- } else if (!atomic_read(&md->pending))
+ } else if (!atomic_read(&md->pending[0]) &&
+ !atomic_read(&md->pending[1]))
break;
if (interruptible == TASK_INTERRUPTIBLE &&
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index ea4e6cb..6adc764 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -238,7 +238,7 @@ ssize_t part_stat_show(struct device *dev,
return sprintf(buf,
"%8lu %8lu %8llu %8u "
"%8lu %8lu %8llu %8u "
- "%8u %8u %8u"
+ "%8u %8u %8u %8u"
"\n",
part_stat_read(p, ios[READ]),
part_stat_read(p, merges[READ]),
@@ -248,7 +248,8 @@ ssize_t part_stat_show(struct device *dev,
part_stat_read(p, merges[WRITE]),
(unsigned long long)part_stat_read(p, sectors[WRITE]),
jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
- p->in_flight,
+ p->in_flight[0],
+ p->in_flight[1],
jiffies_to_msecs(part_stat_read(p, io_ticks)),
jiffies_to_msecs(part_stat_read(p, time_in_queue)));
}
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 45fc320..ebd878e 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -98,7 +98,7 @@ struct hd_struct {
int make_it_fail;
#endif
unsigned long stamp;
- int in_flight;
+ int in_flight[2];
#ifdef CONFIG_SMP
struct disk_stats *dkstats;
#else
@@ -322,18 +322,23 @@ static inline void free_part_stats(struct hd_struct *part)
#define part_stat_sub(cpu, gendiskp, field, subnd) \
part_stat_add(cpu, gendiskp, field, -subnd)
-static inline void part_inc_in_flight(struct hd_struct *part)
+static inline void part_inc_in_flight(struct hd_struct *part, int rw)
{
- part->in_flight++;
+ part->in_flight[rw]++;
if (part->partno)
- part_to_disk(part)->part0.in_flight++;
+ part_to_disk(part)->part0.in_flight[rw]++;
}
-static inline void part_dec_in_flight(struct hd_struct *part)
+static inline void part_dec_in_flight(struct hd_struct *part, int rw)
{
- part->in_flight--;
+ part->in_flight[rw]--;
if (part->partno)
- part_to_disk(part)->part0.in_flight--;
+ part_to_disk(part)->part0.in_flight[rw]--;
+}
+
+static inline int part_in_flight(struct hd_struct *part)
+{
+ return part->in_flight[0] + part->in_flight[1];
}
/* block/blk-core.c */
--
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