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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Mike Christie <michael.christie@oracle.com>
Cc: martin.petersen@oracle.com, linux-scsi@vger.kernel.org,
	target-devel@vger.kernel.org, jasowang@redhat.com,
	pbonzini@redhat.com, stefanha@redhat.com,
	virtualization@lists.linux-foundation.org
Subject: Re: [PATCH 00/17 V3] vhost: fix scsi cmd handling and cgroup support
Date: Thu, 29 Oct 2020 21:47:59 +0000	[thread overview]
Message-ID: <20201029174719-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <1603326903-27052-1-git-send-email-michael.christie@oracle.com>

On Wed, Oct 21, 2020 at 07:34:46PM -0500, Mike Christie wrote:
> In-Reply-To: 
> 
> The following patches were made over Michael's vhost branch here:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git/log/?h=vhost
> 
> They fix a couple issues with vhost-scsi when we hit the 256 cmd limit
> that result in the guest getting IO errors, add LUN reset support so
> devices are not offlined during transient errors, allow us to manage
> vhost scsi IO with cgroups, and imrpove IOPs up to 2X.
> 
> The following patches are a follow up to this post:
> https://patchwork.kernel.org/project/target-devel/cover/1600712588-9514-1-git-send-email-michael.christie@oracle.com/
> which originally was fixing how vhost-scsi handled cmds so we would
> not get IO errors when sending more than 256 cmds.
> 
> In that patchset I needed to detect if a vq was in use and for this
> patch:
> https://patchwork.kernel.org/project/target-devel/patch/1600712588-9514-3-git-send-email-michael.christie@oracle.com/
> It was suggested to add support for VHOST_RING_ENABLE. While doing
> that though I hit a couple problems:
> 
> 1. The patches moved how vhost-scsi allocated cmds from per lio
> session to per vhost vq. To support both VHOST_RING_ENABLE and
> where userspace didn't support it, I would have to keep around the
> old per session/device cmd allocator/completion and then also maintain
> the new code. Or, I would still have to use this patch
> patchwork.kernel.org/cover/11790763/ for the compat case so there
> adding the new ioctl would not help much.
> 
> 2. For vhost-scsi I also wanted to prevent where we allocate iovecs
> for 128 vqs even though we normally use a couple. To do this, I needed
> something similar to #1, but the problem is that the VHOST_RING_ENABLE
> call would come too late.
> 
> To try and balance #1 and #2, these patches just allow vhost-scsi
> to setup a vq when userspace starts to config it. This allows the
> driver to only fully setup (we still waste some memory to support older
> setups but do not have to preallocate everything like before) what
> is used plus I do not need to maintain 2 code paths.


OK, so could we get a patchset with just bugfixes for this release
please?
And features should go into next one ...

> V3:
> - fix compile errors
> - fix possible crash where cmd could be freed while adding it to
> completion list
> - fix issue where we added the worker thread to the blk cgroup but
> the blk IO was submitted by a driver workqueue.
> 
> V2:
> - fix use before set cpu var errors
> - drop vhost_vq_is_setup
> - include patches to do a worker thread per scsi IO vq
> 

  parent reply	other threads:[~2020-10-29 21:47 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-22  0:34 [PATCH 00/17 V3] vhost: fix scsi cmd handling and cgroup support Mike Christie
2020-10-22  0:34 ` [PATCH 01/17] vhost scsi: add lun parser helper Mike Christie
2020-10-26  3:33   ` Jason Wang
2020-10-22  0:34 ` [PATCH 02/17] vhost: remove work arg from vhost_work_flush Mike Christie
2020-10-22  0:51   ` Chaitanya Kulkarni
2020-10-22  0:34 ` [PATCH 03/17] vhost net: use goto error handling in open Mike Christie
2020-10-22  0:45   ` Chaitanya Kulkarni
2020-10-26  3:34   ` Jason Wang
2020-10-22  0:34 ` [PATCH 04/17] vhost: prep vhost_dev_init users to handle failures Mike Christie
2020-10-22  5:22   ` kernel test robot
2020-10-23 16:15   ` Mike Christie
2020-11-02  5:57   ` Jason Wang
2020-11-03 10:04   ` Dan Carpenter
2020-10-22  0:34 ` [PATCH 05/17] vhost: move vq iovec allocation to dev init time Mike Christie
2020-10-22  0:34 ` [PATCH 06/17] vhost: support delayed vq creation Mike Christie
2020-10-22  0:34 ` [PATCH 07/17] vhost scsi: support delayed IO " Mike Christie
2020-10-26  3:51   ` Jason Wang
2020-10-27  5:47     ` Mike Christie
2020-10-28  1:55       ` Jason Wang
2020-10-30  8:47       ` Michael S. Tsirkin
2020-10-30 16:30         ` Mike Christie
2020-10-30 17:26           ` Mike Christie
2020-11-01 22:06         ` Mike Christie
2020-11-02  6:36         ` Jason Wang
2020-11-02  6:49           ` Jason Wang
2020-11-02 16:19             ` Mike Christie
2020-10-22  0:34 ` [PATCH 08/17] vhost scsi: alloc cmds per vq instead of session Mike Christie
2020-10-22  0:34 ` [PATCH 09/17] vhost scsi: fix cmd completion race Mike Christie
2020-10-27 13:07   ` Maurizio Lombardi
2020-10-30  8:51   ` Michael S. Tsirkin
2020-10-30 16:04     ` Paolo Bonzini
2020-10-22  0:34 ` [PATCH 10/17] vhost scsi: Add support for LUN resets Mike Christie
2020-10-22  0:34 ` [PATCH 11/17] vhost scsi: remove extra flushes Mike Christie
2020-10-22  0:34 ` [PATCH 12/17] vhost poll: fix coding style Mike Christie
2020-10-22  0:39   ` Chaitanya Kulkarni
2020-10-22  0:34 ` [PATCH 13/17] vhost: support multiple worker threads Mike Christie
2020-10-22  0:35 ` [PATCH 14/17] vhost: poll support support multiple workers Mike Christie
2020-10-22  0:35 ` [PATCH 15/17] host: support delayed vq creation Mike Christie
2020-10-22  0:50   ` Mike Christie
2020-10-22  0:35 ` [PATCH 16/17] vhost scsi: multiple worker support Mike Christie
2020-10-22  0:35 ` [PATCH 17/17] vhost scsi: drop submission workqueue Mike Christie
2020-10-29 21:47 ` Michael S. Tsirkin [this message]
2020-10-29 22:19   ` [PATCH 00/17 V3] vhost: fix scsi cmd handling and cgroup support Mike Christie

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