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* [PATCH] md/raid10: Only check QUEUE_FLAG_IO_STAT when issuing io
@ 2023-06-09  9:43 linan666
  2023-06-10  2:32 ` Yu Kuai
  2023-06-16  6:12 ` Song Liu
  0 siblings, 2 replies; 4+ messages in thread
From: linan666 @ 2023-06-09  9:43 UTC (permalink / raw)
  To: song, jgq516
  Cc: linux-raid, linux-kernel, linan122, yukuai3, yi.zhang, houtao1,
	yangerkun

From: Li Nan <linan122@huawei.com>

/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 <linan122@huawei.com>
---
 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


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* Re: [PATCH] md/raid10: Only check QUEUE_FLAG_IO_STAT when issuing io
  2023-06-09  9:43 [PATCH] md/raid10: Only check QUEUE_FLAG_IO_STAT when issuing io linan666
@ 2023-06-10  2:32 ` Yu Kuai
  2023-06-10  8:42   ` Li Nan
  2023-06-16  6:12 ` Song Liu
  1 sibling, 1 reply; 4+ messages in thread
From: Yu Kuai @ 2023-06-10  2:32 UTC (permalink / raw)
  To: linan666, song, jgq516
  Cc: linux-raid, linux-kernel, linan122, yi.zhang, houtao1, yangerkun,
	yukuai (C)

Hi,

在 2023/06/09 17:43, linan666@huaweicloud.com 写道:
> From: Li Nan <linan122@huawei.com>
> 
> /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 <linan122@huawei.com>
> ---
>   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);
>   	/*
> 


^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH] md/raid10: Only check QUEUE_FLAG_IO_STAT when issuing io
  2023-06-10  2:32 ` Yu Kuai
@ 2023-06-10  8:42   ` Li Nan
  0 siblings, 0 replies; 4+ messages in thread
From: Li Nan @ 2023-06-10  8:42 UTC (permalink / raw)
  To: Yu Kuai, linan666, song, jgq516
  Cc: linux-raid, linux-kernel, yi.zhang, houtao1, yangerkun, yukuai (C)



在 2023/6/10 10:32, Yu Kuai 写道:
> Hi,
> 
> 在 2023/06/09 17:43, linan666@huaweicloud.com 写道:
>> From: Li Nan <linan122@huawei.com>
>>
>> /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 <linan122@huawei.com>
>> ---
>>   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


^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH] md/raid10: Only check QUEUE_FLAG_IO_STAT when issuing io
  2023-06-09  9:43 [PATCH] md/raid10: Only check QUEUE_FLAG_IO_STAT when issuing io linan666
  2023-06-10  2:32 ` Yu Kuai
@ 2023-06-16  6:12 ` Song Liu
  1 sibling, 0 replies; 4+ messages in thread
From: Song Liu @ 2023-06-16  6:12 UTC (permalink / raw)
  To: linan666
  Cc: jgq516, linux-raid, linux-kernel, linan122, yukuai3, yi.zhang,
	houtao1, yangerkun

On Fri, Jun 9, 2023 at 2:47 AM <linan666@huaweicloud.com> wrote:
>
> From: Li Nan <linan122@huawei.com>
>
> /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 <linan122@huawei.com>

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
>

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-06-16  6:12 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-06-09  9:43 [PATCH] md/raid10: Only check QUEUE_FLAG_IO_STAT when issuing io linan666
2023-06-10  2:32 ` Yu Kuai
2023-06-10  8:42   ` Li Nan
2023-06-16  6:12 ` Song Liu

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