From: Andi Kleen <ak@suse.de>
To: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Ming Zhang <mingz@ele.uri.edu>,
E1000 <e1000-devel@lists.sourceforge.net>,
iet-dev <iscsitarget-devel@lists.sourceforge.net>,
netdev@vger.kernel.org
Subject: Re: [E1000-devel] Page Allocation Failure with e1000 using jumboframe
Date: Fri, 19 Aug 2005 19:42:01 +0200 [thread overview]
Message-ID: <20050819174201.GJ3953@verdi.suse.de> (raw)
In-Reply-To: <Pine.WNT.4.63.0508191023130.3796@jbrandeb-desk.amr.corp.intel.com>
> Ahh, okay. I'm pretty sure that SuSE did some changes (not sure what) to
> memory management.
I don't think so.
>
> the formula for the size that the current e1000 looks for is something
> like
>
> a = MTU roundup to next power of 2
> a += 2 (skb_reserve(NET_IP_ALIGN))
> a += 16 (skb_reserve 16 by __dev_alloc_skb)
>
> so, a = 2048 + 2 + 16, or 2066
> request (a) from slab, which does a power of 2 roundup
> so the skb comes from the 4k (single page) slab for standard mtu.
That's very suboptimal because you're wasting nearly 2k. It would
be better if you allocated 4k or exactly 2k
-Andi
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next prev parent reply other threads:[~2005-08-19 17:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1124326404.5546.215.camel@localhost.localdomain>
2005-08-19 16:51 ` [E1000-devel] Page Allocation Failure with e1000 using jumbo frame Jesse Brandeburg
2005-08-19 17:01 ` Ming Zhang
2005-08-19 17:33 ` Page Allocation Failure with e1000 using jumboframe Jesse Brandeburg
2005-08-19 17:42 ` Andi Kleen [this message]
2005-08-19 17:51 ` [E1000-devel] " Jesse Brandeburg
2005-08-19 18:01 ` Andi Kleen
2005-08-19 19:07 ` Ming Zhang
2005-08-19 21:10 ` Jesse Brandeburg
2005-08-19 17:52 ` Ming Zhang
2005-08-20 1:46 ` Michael Iatrou
2005-08-19 17:02 ` Page Allocation Failure with e1000 using jumbo frame Andi Kleen
2005-08-19 18:10 ` [E1000-devel] " Martin Josefsson
2005-08-19 17:03 ` Nivedita Singhvi
2005-08-20 1:43 ` [E1000-devel] " Michael Iatrou
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