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From: David Miller <davem@davemloft.net>
To: dhowells@redhat.com
Cc: sgruszka@redhat.com, vladz@broadcom.com,
	paulmck@linux.vnet.ibm.com, netdev@vger.kernel.org,
	eilong@broadcom.com
Subject: Re: [RFC PATCH] bnx2x: fix tx queue locking and memory barriers
Date: Wed, 10 Mar 2010 09:49:21 -0800 (PST)	[thread overview]
Message-ID: <20100310.094921.211568569.davem@davemloft.net> (raw)
In-Reply-To: <31355.1268240990@redhat.com>

From: David Howells <dhowells@redhat.com>
Date: Wed, 10 Mar 2010 17:09:50 +0000

> The barrier() didn't tell the compiler that fp->tx_bd_prod and fp->tx_bd_cons
> could change.  What it did was to say that the accesses to those two variables
> must be performed after all the other accesses issued by that CPU prior to the
> barrier - at least as far as the compiler is concerned.

barrier() has a "memory" asm clobber which says that all memory could
have changed.

  reply	other threads:[~2010-03-10 17:49 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-25 13:08 [RFC PATCH] bnx2x: fix tx queue locking and memory barriers Stanislaw Gruszka
2010-02-25 10:18 ` David Miller
2010-02-25 15:40   ` Stanislaw Gruszka
2010-02-25 15:49     ` Vladislav Zolotarov
2010-02-25 16:03       ` Stanislaw Gruszka
2010-02-25 16:06         ` David Miller
2010-02-25 16:16           ` Stanislaw Gruszka
2010-02-25 16:14         ` Vladislav Zolotarov
2010-02-25 13:28 ` Vladislav Zolotarov
2010-03-10 17:09 ` David Howells
2010-03-10 17:49   ` David Miller [this message]
2010-03-10 18:32   ` David Howells
2010-03-11 13:10   ` Stanislaw Gruszka
2010-03-10 17:19 ` David Howells

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