Date: Sun, 13 Oct 2002 06:08:51 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: tlambert2@mindspring.com Cc: ticso@cicely.de, 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: <20021013.060851.113437955.imp@bsdimp.com> In-Reply-To: <3DA954CF.98B0891A@mindspring.com> References: <20021012.150616.129769790.imp@bsdimp.com> <20021013103538.GG17920@cicely8.cicely.de> <3DA954CF.98B0891A@mindspring.com>
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In message: <3DA954CF.98B0891A@mindspring.com>
Terry Lambert <tlambert2@mindspring.com> writes:
: In most cases, the DMA gets put directly into memory mapped by the
: VM of the kernel (the KVA).
Actually, in most cases on i386 the memory gets DMAd to a phyiscal
address, which is why there is a 4G limit in the hardware. Since it
is a phyiscal address, knowing VM tricks I don't think is relevant.
PAE is basically a vm trick.
Warner
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