[SPDK] I/O getting lost on retry?

[SPDK] I/O getting lost on retry?

[Andrey Kuzmin]

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Just looking at the code below, doesn't the command being retried get lost
after the break statement  if the block device is still in the nomem
condition?

Regards,
Andrey

diff --git a/lib/bdev/bdev.c b/lib/bdev/bdev.c
index ba64994..77328ae 100644
--- a/lib/bdev/bdev.c
+++ b/lib/bdev/bdev.c
@@ -1567,10 +1567,11 @@
  TAILQ_REMOVE(&bdev_ch->nomem_io, bdev_io, link);
  bdev_ch->io_outstanding++;
  bdev_io->status = SPDK_BDEV_IO_STATUS_PENDING;
  bdev->fn_table->submit_request(bdev_ch->channel, bdev_io);
  if (bdev_io->status == SPDK_BDEV_IO_STATUS_NOMEM) {
+ /** Doesn't the io get lost here? */
  break;
  }
  }
 }

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Re: [SPDK] I/O getting lost on retry?

[Andrey Kuzmin]

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On Fri, Jan 19, 2018 at 9:02 PM, Harris, James R <james.r.harris(a)intel.com>
wrote:

>
>
>
>
> *From: *SPDK <spdk-bounces(a)lists.01.org> on behalf of Andrey Kuzmin <
> andrey.v.kuzmin(a)gmail.com>
> *Reply-To: *Storage Performance Development Kit <spdk(a)lists.01.org>
> *Date: *Friday, January 19, 2018 at 10:36 AM
> *To: *Storage Performance Development Kit <spdk(a)lists.01.org>
> *Subject: *[SPDK] I/O getting lost on retry?
>
>
>
> Just looking at the code below, doesn't the command being retried get lost
> after the break statement  if the block device is still in the nomem
> condition?
>
> Regards,
> Andrey
>
> Hi Andrey,
>
> diff --git a/lib/bdev/bdev.c b/lib/bdev/bdev.c
>
> index ba64994..77328ae 100644
>
> --- a/lib/bdev/bdev.c
>
> +++ b/lib/bdev/bdev.c
>
> @@ -1567,10 +1567,11 @@
>
>   TAILQ_REMOVE(&bdev_ch->nomem_io, bdev_io, link);
>
>   bdev_ch->io_outstanding++;
>
>   bdev_io->status = SPDK_BDEV_IO_STATUS_PENDING;
>
>   bdev->fn_table->submit_request(bdev_ch->channel, bdev_io);
>
>   if (bdev_io->status == SPDK_BDEV_IO_STATUS_NOMEM) {
>
> + /** Doesn't the io get lost here? */
>
>   break;
>
>   }
>
>   }
>
>  }
>
>
>
> In this case, the bdev module will have called spdk_bdev_io_complete()
> within the submit_request() context.  spdk_bdev_io_complete() puts this
> bdev_io back at the head of the TAILQ.
>

Thanks Jim, that makes sense.

Regards,
Andrey


>
>
> Regards,
>
>
>
> -Jim
>
>
>
>
>
> _______________________________________________
> SPDK mailing list
> SPDK(a)lists.01.org
> https://lists.01.org/mailman/listinfo/spdk
>
>

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Re: [SPDK] I/O getting lost on retry?

[Harris, James R]

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From: SPDK <spdk-bounces(a)lists.01.org> on behalf of Andrey Kuzmin <andrey.v.kuzmin(a)gmail.com>
Reply-To: Storage Performance Development Kit <spdk(a)lists.01.org>
Date: Friday, January 19, 2018 at 10:36 AM
To: Storage Performance Development Kit <spdk(a)lists.01.org>
Subject: [SPDK] I/O getting lost on retry?

Just looking at the code below, doesn't the command being retried get lost after the break statement  if the block device is still in the nomem condition?

Regards,
Andrey
Hi Andrey,
diff --git a/lib/bdev/bdev.c b/lib/bdev/bdev.c
index ba64994..77328ae 100644
--- a/lib/bdev/bdev.c
+++ b/lib/bdev/bdev.c
@@ -1567,10 +1567,11 @@
  TAILQ_REMOVE(&bdev_ch->nomem_io, bdev_io, link);
  bdev_ch->io_outstanding++;
  bdev_io->status = SPDK_BDEV_IO_STATUS_PENDING;
  bdev->fn_table->submit_request(bdev_ch->channel, bdev_io);
  if (bdev_io->status == SPDK_BDEV_IO_STATUS_NOMEM) {
+ /** Doesn't the io get lost here? */
  break;
  }
  }
 }

In this case, the bdev module will have called spdk_bdev_io_complete() within the submit_request() context.  spdk_bdev_io_complete() puts this bdev_io back at the head of the TAILQ.

Regards,

-Jim



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