Date: Sun, 13 Oct 2002 19:24:44 -0700 From: Wes Peters <wes@softweyr.com> To: ticso@cicely.de Cc: "M. Warner Losh" <imp@bsdimp.com>, hch@infradead.org, dillon@apollo.backplane.com, vova@sw.ru, nate@root.org, arch@FreeBSD.org Subject: Re: Database indexes and ram Message-ID: <3DAA2AEC.EFF1C9F1@softweyr.com> References: <200210082051.g98KpjU1084793@apollo.backplane.com> <3DA4C271.37AACAA3@softweyr.com> <20021012135245.A16453@infradead.org> <20021012.150616.129769790.imp@bsdimp.com> <20021013103538.GG17920@cicely8.cicely.de>
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Bernd Walter wrote:
>
> 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.
Yeah, right. Find me a 64-bit ATAPI controller...
--
"Where am I, and what am I doing in this handbasket?"
Wes Peters Softweyr LLC
wes@softweyr.com http://softweyr.com/
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