Message-ID: <4227A606.50703@pobox.com>
Date: Thu, 03 Mar 2005 19:04:22 -0500
From: Jeff Garzik <jgarzik@pobox.com>
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To: Roland Dreier <roland@topspin.com>
CC: akpm@osdl.org, linux-kernel@vger.kernel.org, openib-general@openib.org
Subject: Re: [PATCH][16/26] IB/mthca: mem-free doorbell record writing
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Roland Dreier wrote:
> Add a mthca_write_db_rec() to wrap writing doorbell records.  On
> 64-bit archs, this is just a 64-bit write, while on 32-bit archs it
> splits the write into two 32-bit writes with a memory barrier to make
> sure the two halves of the record are written in the correct order.

> +static inline void mthca_write_db_rec(u32 val[2], u32 *db)
> +{
> +	db[0] = val[0];
> +	wmb();
> +	db[1] = val[1];
> +}
> +


Are you concerned about ordering, or write-combining?

I am unaware of a situation where writes are re-ordered into a reversed, 
descending order for no apparent reason.

	Jeff


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