Re: [Xen-devel] [Problem] about src/xen/include/public/io/ring.h

[éç <aware.why@xxxxxxxxx>]

On Fri, Apr 12, 2013 at 3:49 PM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:

On Fri, 2013-04-12 at 03:21 +0100, 马磊 wrote:


> On Thu, Apr 11, 2013 at 9:20 PM, Konrad Rzeszutek Wilk
> <konrad.wilk@xxxxxxxxxx> wrote:

>         Please don't top post.

马磊, Can you also stop posting HTML mails, thanks.

I use the gmail client,  reply through clicking `reply to all` in the input text frame at bottom of the html page, and then send it away. 

Do you mean to not to copy too many long time ago message?

> Then rsp = RING_SIZE(r) - (X - Y),  I can't figure out this and the
> return value ` req < rsp ? req : rsp` ?

Perhaps think about the case when the ring becomes full of either
responses or requests and what that means in terms of "wrapping" in the
ring.

Ian.

 

It's difficult for me to image the ring buffer scene where the ring becomes full of either

responses or requests , because the src/docs/misc/blkif-drivers-explained.txt mentioned  that

a ring is partitioned into a request and a response region by four pointers and pointers may only 

advance, and may not pass one another.

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