From: Li Nan <[email protected]>
/sys/block/[device]/queue/iostats is used to control whether to count io
stat. Write 0 to it will clear queue_flags QUEUE_FLAG_IO_STAT which means
iostats is disabled. If we disable iostats and later endable it, the io
issued during this period will be counted incorrectly, inflight will be
decreased to -1.
//T1 set iostats
echo 0 > /sys/block/md0/queue/iostats
clear QUEUE_FLAG_IO_STAT
//T2 issue io
if (QUEUE_FLAG_IO_STAT) -> false
bio_start_io_acct
inflight++
echo 1 > /sys/block/md0/queue/iostats
set QUEUE_FLAG_IO_STAT
//T3 io end
if (QUEUE_FLAG_IO_STAT) -> true
bio_end_io_acct
inflight-- -> -1
Also, if iostats is enabled while issuing io but disabled while io end,
inflight will never be decreased.
Fix it by checking start_time when io end. Only check QUEUE_FLAG_IO_STAT
while issuing io, just like request based devices.
Fixes: 528bc2cf2fcc ("md/raid10: enable io accounting")
Signed-off-by: Li Nan <[email protected]>
---
drivers/md/raid10.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 381c21f7fb06..bf9dca5c25c3 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -325,7 +325,7 @@ static void raid_end_bio_io(struct r10bio *r10_bio)
if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
bio->bi_status = BLK_STS_IOERR;
- if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
+ if (r10_bio->start_time)
bio_end_io_acct(bio, r10_bio->start_time);
bio_endio(bio);
/*
--
2.39.2
Hi,
?? 2023/06/09 17:43, [email protected] д??:
> From: Li Nan <[email protected]>
>
> /sys/block/[device]/queue/iostats is used to control whether to count io
> stat. Write 0 to it will clear queue_flags QUEUE_FLAG_IO_STAT which means
> iostats is disabled. If we disable iostats and later endable it, the io
> issued during this period will be counted incorrectly, inflight will be
> decreased to -1.
>
> //T1 set iostats
> echo 0 > /sys/block/md0/queue/iostats
> clear QUEUE_FLAG_IO_STAT
>
> //T2 issue io
> if (QUEUE_FLAG_IO_STAT) -> false
> bio_start_io_acct
> inflight++
>
> echo 1 > /sys/block/md0/queue/iostats
> set QUEUE_FLAG_IO_STAT
>
> //T3 io end
> if (QUEUE_FLAG_IO_STAT) -> true
> bio_end_io_acct
> inflight-- -> -1
>
> Also, if iostats is enabled while issuing io but disabled while io end,
> inflight will never be decreased.
>
> Fix it by checking start_time when io end. Only check QUEUE_FLAG_IO_STAT
> while issuing io, just like request based devices.
>
> Fixes: 528bc2cf2fcc ("md/raid10: enable io accounting")
> Signed-off-by: Li Nan <[email protected]>
> ---
> drivers/md/raid10.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 381c21f7fb06..bf9dca5c25c3 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -325,7 +325,7 @@ static void raid_end_bio_io(struct r10bio *r10_bio)
> if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
> bio->bi_status = BLK_STS_IOERR;
>
> - if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
> + if (r10_bio->start_time)
> bio_end_io_acct(bio, r10_bio->start_time);
This patch LGTM, can you change this for raid1 as well? raid0 and
raid456 is using md_account_bio(), and they don't have such problem.
Thanks,
Kuai
> bio_endio(bio);
> /*
>
在 2023/6/10 10:32, Yu Kuai 写道:
> Hi,
>
> 在 2023/06/09 17:43, [email protected] 写道:
>> From: Li Nan <[email protected]>
>>
>> /sys/block/[device]/queue/iostats is used to control whether to count io
>> stat. Write 0 to it will clear queue_flags QUEUE_FLAG_IO_STAT which means
>> iostats is disabled. If we disable iostats and later endable it, the io
>> issued during this period will be counted incorrectly, inflight will be
>> decreased to -1.
>>
>> //T1 set iostats
>> echo 0 > /sys/block/md0/queue/iostats
>> clear QUEUE_FLAG_IO_STAT
>>
>> //T2 issue io
>> if (QUEUE_FLAG_IO_STAT) -> false
>> bio_start_io_acct
>> inflight++
>>
>> echo 1 > /sys/block/md0/queue/iostats
>> set QUEUE_FLAG_IO_STAT
>>
>> //T3 io end
>> if (QUEUE_FLAG_IO_STAT) -> true
>> bio_end_io_acct
>> inflight-- -> -1
>>
>> Also, if iostats is enabled while issuing io but disabled while io end,
>> inflight will never be decreased.
>>
>> Fix it by checking start_time when io end. Only check QUEUE_FLAG_IO_STAT
>> while issuing io, just like request based devices.
>>
>> Fixes: 528bc2cf2fcc ("md/raid10: enable io accounting")
>> Signed-off-by: Li Nan <[email protected]>
>> ---
>> drivers/md/raid10.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
>> index 381c21f7fb06..bf9dca5c25c3 100644
>> --- a/drivers/md/raid10.c
>> +++ b/drivers/md/raid10.c
>> @@ -325,7 +325,7 @@ static void raid_end_bio_io(struct r10bio *r10_bio)
>> if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
>> bio->bi_status = BLK_STS_IOERR;
>> - if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
>> + if (r10_bio->start_time)
>> bio_end_io_acct(bio, r10_bio->start_time);
>
> This patch LGTM, can you change this for raid1 as well? raid0 and
> raid456 is using md_account_bio(), and they don't have such problem.
>
OK, I will fix raid1 later. Thanks for suggestion.
> Thanks,
> Kuai
--
Thanks,
Nan
On Fri, Jun 9, 2023 at 2:47 AM <[email protected]> wrote:
>
> From: Li Nan <[email protected]>
>
> /sys/block/[device]/queue/iostats is used to control whether to count io
> stat. Write 0 to it will clear queue_flags QUEUE_FLAG_IO_STAT which means
> iostats is disabled. If we disable iostats and later endable it, the io
> issued during this period will be counted incorrectly, inflight will be
> decreased to -1.
>
> //T1 set iostats
> echo 0 > /sys/block/md0/queue/iostats
> clear QUEUE_FLAG_IO_STAT
>
> //T2 issue io
> if (QUEUE_FLAG_IO_STAT) -> false
> bio_start_io_acct
> inflight++
>
> echo 1 > /sys/block/md0/queue/iostats
> set QUEUE_FLAG_IO_STAT
>
> //T3 io end
> if (QUEUE_FLAG_IO_STAT) -> true
> bio_end_io_acct
> inflight-- -> -1
>
> Also, if iostats is enabled while issuing io but disabled while io end,
> inflight will never be decreased.
>
> Fix it by checking start_time when io end. Only check QUEUE_FLAG_IO_STAT
> while issuing io, just like request based devices.
>
> Fixes: 528bc2cf2fcc ("md/raid10: enable io accounting")
> Signed-off-by: Li Nan <[email protected]>
The subject and commit log is a little confusing. I updated it a little
bit and applied to md-next.
Thanks,
Song
> ---
> drivers/md/raid10.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 381c21f7fb06..bf9dca5c25c3 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -325,7 +325,7 @@ static void raid_end_bio_io(struct r10bio *r10_bio)
> if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
> bio->bi_status = BLK_STS_IOERR;
>
> - if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
> + if (r10_bio->start_time)
> bio_end_io_acct(bio, r10_bio->start_time);
> bio_endio(bio);
> /*
> --
> 2.39.2
>