xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Revert "Seperate read and write statistics of in_flight requests"

Browse Source 
This reverts commit a9327cac44.

Corrado Zoccolo <czoccolo@gmail.com> reports:

"with 2.6.32-rc1 I started getting the following strange output from
"iostat -kx 2":
Linux 2.6.31bisect (et2) 	04/10/2009 	_i686_	(2 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
          10,70    0,00    3,16   15,75    0,00   70,38

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s
avgrq-sz avgqu-sz   await  svctm  %util
sda              18,22     0,00    0,67    0,01    14,77     0,02
43,94     0,01   10,53 39043915,03 2629219,87
sdb              60,89     9,68   50,79    3,04  1724,43    50,52
65,95     0,70   13,06 488437,47 2629219,87

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           2,72    0,00    0,74    0,00    0,00   96,53

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s
avgrq-sz avgqu-sz   await  svctm  %util
sda               0,00     0,00    0,00    0,00     0,00     0,00
0,00     0,00    0,00   0,00 100,00
sdb               0,00     0,00    0,00    0,00     0,00     0,00
0,00     0,00    0,00   0,00 100,00

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           6,68    0,00    0,99    0,00    0,00   92,33

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s
avgrq-sz avgqu-sz   await  svctm  %util
sda               0,00     0,00    0,00    0,00     0,00     0,00
0,00     0,00    0,00   0,00 100,00
sdb               0,00     0,00    0,00    0,00     0,00     0,00
0,00     0,00    0,00   0,00 100,00

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           4,40    0,00    0,73    1,47    0,00   93,40

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s
avgrq-sz avgqu-sz   await  svctm  %util
sda               0,00     0,00    0,00    0,00     0,00     0,00
0,00     0,00    0,00   0,00 100,00
sdb               0,00     4,00    0,00    3,00     0,00    28,00
18,67     0,06   19,50 333,33 100,00

Global values for service time and utilization are garbage. For
interval values, utilization is always 100%, and service time is
higher than normal.

I bisected it down to:
[a9327cac44] Seperate read and write
statistics of in_flight requests
and verified that reverting just that commit indeed solves the issue
on 2.6.32-rc1."

So until this is debugged, revert the bad commit.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Jens Axboe
2009-10-04 21:04:38 +02:00
parent e00c54c36a
commit 0f78ab9899
6 changed files with 19 additions and 42 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
drivers/md/dm.c
View File

@@ -130,7 +130,7 @@ struct mapped_device {
/*
* A list of ios that arrived while we were suspended.
*/
atomic_t pending[2];
atomic_t pending;
wait_queue_head_t wait;
struct work_struct work;
struct bio_list deferred;
@@ -453,14 +453,13 @@ 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[rw] = atomic_inc_return(&md->pending[rw]);
dm_disk(md)->part0.in_flight = atomic_inc_return(&md->pending);
}
static void end_io_acct(struct dm_io *io)
@@ -480,9 +479,8 @@ 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[rw] = pending =
atomic_dec_return(&md->pending[rw]);
pending += atomic_read(&md->pending[rw^0x1]);
dm_disk(md)->part0.in_flight = pending =
atomic_dec_return(&md->pending);
/* nudge anyone waiting on suspend queue */
if (!pending)
@@ -1787,8 +1785,7 @@ static struct mapped_device *alloc_dev(int minor)
if (!md->disk)
goto bad_disk;
atomic_set(&md->pending[0], 0);
atomic_set(&md->pending[1], 0);
atomic_set(&md->pending, 0);
init_waitqueue_head(&md->wait);
INIT_WORK(&md->work, dm_wq_work);
init_waitqueue_head(&md->eventq);
@@ -2091,8 +2088,7 @@ 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[0]) &&
!atomic_read(&md->pending[1]))
} else if (!atomic_read(&md->pending))
break;
if (interruptible == TASK_INTERRUPTIBLE &&