From: Zoltan Kiss <zoltan.kiss@citrix.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
Wei Liu <wei.liu2@citrix.com>,
Ian Campbell <Ian.Campbell@citrix.com>
Subject: RING_HAS_UNCONSUMED_REQUESTS oddness
Date: Thu, 6 Mar 2014 15:47:08 +0000 [thread overview]
Message-ID: <5318987C.3030303@citrix.com> (raw)
Hi,
I was wondering for a while why this macro looks like this:
#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; \
})
I would expect to check prod - cons, like RING_HAS_UNCONSUMED_RESPONSES does:
#define RING_HAS_UNCONSUMED_RESPONSES(_r) \
((_r)->sring->rsp_prod - (_r)->rsp_cons)
By my understanding, there is no way rsp could be smaller than req, so
there is no point having this. Am I missing something?
Regards,
Zoli
next reply other threads:[~2014-03-06 15:47 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-06 15:47 Zoltan Kiss [this message]
2014-03-06 15:53 ` RING_HAS_UNCONSUMED_REQUESTS oddness Ian Campbell
2014-03-06 16:31 ` Zoltan Kiss
2014-03-06 17:30 ` Tim Deegan
2014-03-06 21:39 ` Zoltan Kiss
2014-03-07 9:23 ` Paul Durrant
2014-03-07 17:43 ` Zoltan Kiss
2014-03-07 12:02 ` Wei Liu
2014-03-07 18:58 ` Zoltan Kiss
2014-03-11 15:55 ` Ian Campbell
2014-03-11 23:34 ` Zoltan Kiss
2014-03-13 16:38 ` [PATCH RFC] xen/public/ring.h: simplify RING_HAS_UNCONSUMED_REQUESTS() Tim Deegan
2014-03-22 14:18 ` Zoltan Kiss
2014-03-22 17:14 ` Tim Deegan
2014-03-24 7:38 ` Jan Beulich
2014-03-24 9:39 ` Paul Durrant
2014-03-24 9:59 ` Jan Beulich
2014-03-24 11:03 ` Paul Durrant
2014-03-24 12:23 ` Zoltan Kiss
2014-03-24 13:52 ` Paul Durrant
2014-03-24 23:55 ` Zoltan Kiss
2014-04-03 9:38 ` Tim Deegan
2014-04-03 15:34 ` Zoltan Kiss
2014-03-11 15:44 ` RING_HAS_UNCONSUMED_REQUESTS oddness Ian Campbell
2014-03-11 23:24 ` Zoltan Kiss
2014-03-12 10:28 ` Ian Campbell
2014-03-12 10:48 ` Roger Pau Monné
2014-03-12 11:25 ` Paul Durrant
2014-03-12 11:38 ` Paul Durrant
2014-03-12 14:41 ` Zoltan Kiss
2014-03-12 15:23 ` Paul Durrant
2014-03-12 15:42 ` Wei Liu
2014-03-12 15:56 ` Paul Durrant
2014-03-12 16:02 ` Paul Durrant
2014-03-12 16:13 ` Zoltan Kiss
2014-03-12 16:42 ` Paul Durrant
2014-03-12 19:06 ` Zoltan Kiss
2014-03-13 9:26 ` Paul Durrant
2014-03-13 10:02 ` Ian Campbell
2014-03-13 10:58 ` Paul Durrant
2014-03-13 12:19 ` Ian Campbell
2014-03-13 12:28 ` Zoltan Kiss
2014-03-13 12:29 ` Paul Durrant
2014-03-13 12:44 ` Ian Campbell
2014-03-12 14:25 ` Zoltan Kiss
2014-03-12 14:27 ` Zoltan Kiss
2014-03-12 14:30 ` Ian Campbell
2014-03-12 15:14 ` Zoltan Kiss
2014-03-12 15:37 ` Ian Campbell
2014-03-12 17:14 ` Zoltan Kiss
2014-03-12 17:43 ` Ian Campbell
2014-03-12 21:10 ` Zoltan Kiss
2014-03-13 10:04 ` Ian Campbell
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5318987C.3030303@citrix.com \
--to=zoltan.kiss@citrix.com \
--cc=Ian.Campbell@citrix.com \
--cc=wei.liu2@citrix.com \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.