Re: [PATCH RFC v2 02/24] scsi: allocate separate queue for reserved commands

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 10/03/2020 18:32, Christoph Hellwig wrote:
On Wed, Mar 11, 2020 at 12:25:28AM +0800, John Garry wrote:
From: Hannes Reinecke <hare@xxxxxxxx>

Allocate a separate 'reserved_cmd_q' for sending reserved commands.

Why?  Reserved command specifically are not in any way tied to queues.
.


So the v1 series used a combination of the sdev queue and the per-host reserved_cmd_q. Back then you questioned using the sdev queue for virtio scsi, and the unconfirmed conclusion was to use a common per-host q. This is the best link I can find now:

https://www.mail-archive.com/linux-scsi@xxxxxxxxxxxxxxx/msg83177.html

"

>> My implementation actually allows for per-device reserved tags (eg for
>> virtio). But some drivers require to use internal commands prior to any
>> device setup, so they have to use a separate reserved command queue just to
>> be able to allocate tags.
>
> Why would virtio-scsi need per-device reserved commands? It currently uses
> a global mempool to allocate the reset commands.
>
Oh, I'm perfectly fine with dropping the per-device reserved commands,
and use the host-wide queue in general.
It turns out most of the drivers use it that way already.
Will be doing so for the next iteration.

"

Cheers



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [SCSI Target Devel]     [Linux SCSI Target Infrastructure]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Linux IIO]     [Samba]     [Device Mapper]

  Powered by Linux