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Date:      Sun, 13 Oct 2002 12:35:38 +0200
From:      Bernd Walter <ticso@cicely8.cicely.de>
To:        "M. Warner Losh" <imp@bsdimp.com>
Cc:        hch@infradead.org, wes@softweyr.com, dillon@apollo.backplane.com, vova@sw.ru, nate@root.org, arch@FreeBSD.org
Subject:   Re: Database indexes and ram
Message-ID:  <20021013103538.GG17920@cicely8.cicely.de>
In-Reply-To: <20021012.150616.129769790.imp@bsdimp.com>
References:  <200210082051.g98KpjU1084793@apollo.backplane.com> <3DA4C271.37AACAA3@softweyr.com> <20021012135245.A16453@infradead.org> <20021012.150616.129769790.imp@bsdimp.com>

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On Sat, Oct 12, 2002 at 03:06:16PM -0600, M. Warner Losh wrote:
> In message: <20021012135245.A16453@infradead.org>
>             Christoph Hellwig <hch@infradead.org> writes:
> : On Wed, Oct 09, 2002 at 04:57:37PM -0700, Wes Peters wrote:
> : > Linux solved this problem by refusing to do it.  The candidates for DMA
> : > transfers include skbufs and buffers from the disk buffer pool, both of
> : > which are allocated from the lowest 4GB of physical ram when using PAE
> : > mode.
> : 
> : Umm, Linux _does_ DMA into any memory if the NIC/HBA/whatever supports
> : it.
> 
> Unless the card is 64bit, it can't DMA past 4G.

Shouldn't all modern pci chips support two 32bit word addresses.

-- 
B.Walter              COSMO-Project         http://www.cosmo-project.de
ticso@cicely.de         Usergroup           info@cosmo-project.de


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