From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Linas Vepstas <linas@austin.ibm.com>
Cc: Michael Ellerman <michael@ellerman.id.au>,
netdev@vger.kernel.org, Jeff Garzik <jgarzik@pobox.com>,
cbe-oss-dev@ozlabs.org
Subject: Re: [Cbe-oss-dev] [PATCH 4/10] spidernet: zero out a pointer.
Date: Wed, 23 May 2007 13:23:27 +1000 [thread overview]
Message-ID: <1179890607.32247.896.camel@localhost.localdomain> (raw)
In-Reply-To: <20070522233517.GU5921@austin.ibm.com>
> Here's a delusional reply: I didn't see any point to it.
> 1) a wmb would add overhead
> 2) the hardware is supposed to be looking at the status flag,
> anyway, and not misbehaving.
> 3) there is a wmb when the descr is actually refilled in such
> a way as to actually mean something to the hardware.
>
> All that I really acomplished here is a minor trick to
> aid in debug printing when looking for something bad.
And the whole thing is moot because 0 is actually a perfectly valid DMA
address :-) I suspect spider will end up trying to hit some internal
register or it's PCIe or whatever it has mapped at 0 internally and will
blow up ... At least on spider, it's not RAM there....
Ben.
next prev parent reply other threads:[~2007-05-23 3:23 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-16 21:56 [PATCH 0/10] spidernet assorted fixes Linas Vepstas
2007-05-16 21:58 ` [PATCH 1/10] spidernet: node-aware skbuff allocation Linas Vepstas
2007-05-18 0:46 ` Jeff Garzik
2007-05-18 17:01 ` Linas Vepstas
2007-05-16 22:00 ` [PATCH 2/10] spidernet: beautify error messages Linas Vepstas
2007-05-16 23:28 ` [Cbe-oss-dev] " Michael Ellerman
2007-05-18 17:08 ` Linas Vepstas
2007-05-16 22:03 ` [PATCH 3/10] spidernet: move a block of code around Linas Vepstas
2007-05-16 22:09 ` [PATCH 4/10] spidernet: zero out a pointer Linas Vepstas
2007-05-16 23:32 ` [Cbe-oss-dev] " Michael Ellerman
2007-05-22 23:35 ` Linas Vepstas
2007-05-23 0:29 ` Segher Boessenkool
2007-05-23 3:23 ` Benjamin Herrenschmidt [this message]
2007-05-16 22:12 ` [PATCH 5/10] spidernet: null out skb pointer after its been used Linas Vepstas
2007-05-16 22:15 ` [PATCH 6/10] spidernet: Don't terminate the RX ring Linas Vepstas
2007-05-16 22:17 ` [PATCH 7/10] spidernet: enhance the dump routine Linas Vepstas
2007-05-16 22:19 ` [PATCH 8/10] spidernet: reset the card when an rxramfull is seen Linas Vepstas
2007-05-16 22:21 ` [PATCH 9/10] spidernet: service TX later Linas Vepstas
2007-05-16 22:23 ` [PATCH 10/10] spidernet: increase the NAPI weight Linas Vepstas
2007-05-16 23:34 ` [Cbe-oss-dev] " Michael Ellerman
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