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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Haakon Bugge <haakon.bugge@oracle.com>
Cc: Bob Pearson <rpearsonhpe@gmail.com>,
	"yangx.jy@fujitsu.com" <yangx.jy@fujitsu.com>,
	Leon Romanovsky <leon@kernel.org>,
	OFED mailing list <linux-rdma@vger.kernel.org>
Subject: Re: [rdma-core PATCH] providers/rxe: Replace '%' with '&' in check_qp_queue_full()
Date: Mon, 17 Jan 2022 10:35:04 -0400	[thread overview]
Message-ID: <20220117143504.GA8034@ziepe.ca> (raw)
In-Reply-To: <5A111A92-427C-4FE1-BDA1-6E8877350D20@oracle.com>

On Mon, Jan 17, 2022 at 11:12:12AM +0000, Haakon Bugge wrote:

> > The way these queues work they can only hold 2^n - 1 entries. The
> > reason for this is to distinguish empty and full.
> 
> You can simply mitigate that by having free-running counters, right?

That is generally the best design, with the cost of doing the & on
every use of queue data vs only on ++

Jason

      reply	other threads:[~2022-01-17 14:35 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-11  1:41 [rdma-core PATCH] providers/rxe: Replace '%' with '&' in check_qp_queue_full() Xiao Yang
2022-01-11  2:22 ` yangx.jy
2022-01-13 20:51   ` Bob Pearson
2022-01-17 11:12     ` Haakon Bugge
2022-01-17 14:35       ` Jason Gunthorpe [this message]

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