From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: 马磊 <aware.why@gmail.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: [Problem] about src/xen/include/public/io/ring.h
Date: Thu, 11 Apr 2013 09:20:35 -0400 [thread overview]
Message-ID: <20130411132034.GA6113@konrad-lan.dumpdata.com> (raw)
In-Reply-To: <CA+ePHTBQgzYA6btJ4wHXmye6Q6tn_T5rTPunLWEPg=NRQyrwKQ@mail.gmail.com>
On Thu, Apr 11, 2013 at 03:46:25PM +0800, 马磊 wrote:
> I means, in ring.h,
> The macro for unconsumed response is :
> 207#define RING_HAS_UNCONSUMED_RESPONSES(_r)
> \
> 208 ((_r)->sring->rsp_prod - (_r)->rsp_cons)
>
> *Should the macro for unconsumed request be written like this:*
> #define RING_HAS_UNCONSUMED_REQUESTS(_r) \
> ((_r)->sring->req_prod - (_r)->req_cons)
>
Please don't top post.
It is close to that in the code:
#define RING_HAS_UNCONSUMED_REQUESTS(_r) \
({ \
unsigned int req = (_r)->sring->req_prod - (_r)->req_cons; \
unsigned int rsp = RING_SIZE(_r) - \
((_r)->req_cons - (_r)->rsp_prod_pvt); \
req < rsp ? req : rsp; \
})
Can you figure out why it has the check against resp_cons and rsp_prod_pvt ?
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next prev parent reply other threads:[~2013-04-11 13:20 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-08 8:10 [Problem] about src/xen/include/public/io/ring.h 马磊
2013-04-08 13:32 ` Konrad Rzeszutek Wilk
2013-04-09 3:05 ` 马磊
2013-04-10 13:15 ` Konrad Rzeszutek Wilk
2013-04-11 7:46 ` 马磊
2013-04-11 13:20 ` Konrad Rzeszutek Wilk [this message]
2013-04-12 2:21 ` 马磊
2013-04-12 7:49 ` Ian Campbell
2013-04-12 10:35 ` 马磊
2013-04-12 11:14 ` Ian Campbell
2013-04-12 11:24 ` 马磊
2013-04-12 13:45 ` Konrad Rzeszutek Wilk
2013-04-15 2:52 ` 马磊
2013-04-10 6:20 ` 马磊
2013-04-10 13:15 ` Konrad Rzeszutek Wilk
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