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Subject: Re: [virtio-comment] Re: [EXT] Re: [virtio-comment] Re: [PATCH] virtio-net: Add equal-sized receive buffers feature
On 2019/11/25 äå4:30, Michael S. Tsirkin wrote:
On Mon, Nov 25, 2019 at 04:22:47PM +0800, Jason Wang wrote:On 2019/11/25 äå4:18, Michael S. Tsirkin wrote:Again I can see how we might want to disallow crazy setups with e.g. 1 byte per buffer. That's just abuse, no guest does that anyway. So asking e.g. for a minimal buffer size sounds very reasonable.One question here is that, the minimal buffer size should depends on various factors. E.g the ring size. Consider a 256 entries ring, the minimal size should be 64K/256=256 ...I guess you are right. We can make this driver programmable I guess? Basically pass min_buf_len to the device.Then it still have the chance to program the min_buf_len to 1?If it wants to - yes - presumably device won't work as well, fetching all kind of extra data e.g. unnecessary descriptors.Technically, device should still work for small packet and drop large packet.I am not sure I agree. How is this different from just not being sufficient space in the RX ring? We certainly do not want to drop packets just because there's not enough buffers - it's a temporary condition.
I think not? Spec doesn't forbid e.g 1 byte buffer. So when a large packet come, if we don't drop packet. Device may think no available buffer but driver may think all buffers are available.
Vhost has a bug that will stall RX in the case.I think we want to spec this first then.
I agree the clarification in the spec, but it wold be too late for existed drivers?
Will post a fix. ThanksThis publicly archived list offers a means to provide input to the OASIS Virtual I/O Device (VIRTIO) TC. In order to verify user consent to the Feedback License terms and to minimize spam in the list archive, subscription is required before posting. Subscribe: email@example.com Unsubscribe: firstname.lastname@example.org List help: email@example.com List archive: https://lists.oasis-open.org/archives/virtio-comment/ Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lists Committee: https://www.oasis-open.org/committees/virtio/ Join OASIS: https://www.oasis-open.org/join/