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From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: "Eugenio Pérez" <eperezma@redhat.com>,
	"Eli Cohen" <elic@nvidia.com>, qemu-devel <qemu-devel@nongnu.org>,
	"Cindy Lu" <lulu@redhat.com>
Subject: Re: [PATCH v3] vhost-vdpa: Do not send empty IOTLB update batches
Date: Mon, 16 Aug 2021 14:00:46 +0800	[thread overview]
Message-ID: <9e3949a3-11f3-ae2a-f6d4-7ebe440f5a6e@redhat.com> (raw)
In-Reply-To: <20210816013610-mutt-send-email-mst@kernel.org>


在 2021/8/16 下午1:36, Michael S. Tsirkin 写道:
> On Mon, Aug 16, 2021 at 10:51:57AM +0800, Jason Wang wrote:
>> On Thu, Aug 12, 2021 at 10:09 PM Eugenio Pérez<eperezma@redhat.com>  wrote:
>>> With the introduction of the batch hinting, meaningless batches can be
>>> created with no IOTLB updates if the memory region was skipped by
>>> vhost_vdpa_listener_skipped_section. This is the case of host notifiers
>>> memory regions, device un/realize, and others. This causes the vdpa
>>> device to receive dma mapping settings with no changes, a possibly
>>> expensive operation for nothing.
>>>
>>> To avoid that, VHOST_IOTLB_BATCH_BEGIN hint is delayed until we have a
>>> meaningful (not skipped section) mapping or unmapping operation, and
>>> VHOST_IOTLB_BATCH_END is not written unless at least one of _UPDATE /
>>> _INVALIDATE has been issued.
>> Acked-by: Jason Wang<jasowang@redhat.com>
> Oops. You missed by pull request by a hairwidth.


It's fine.

Thanks




      reply	other threads:[~2021-08-16  6:01 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-12 14:09 [PATCH v3] vhost-vdpa: Do not send empty IOTLB update batches Eugenio Pérez
2021-08-16  2:51 ` Jason Wang
2021-08-16  5:36   ` Michael S. Tsirkin
2021-08-16  6:00     ` Jason Wang [this message]

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