Re: Confirmation request about new 2.4.x. kernel limits

Stephen C. Tweedie (sct@redhat.com)
Tue, 9 Jan 2001 14:05:04 +0000


Hi,

On Mon, Jan 08, 2001 at 11:11:05PM -0500, Venkatesh Ramamurthy wrote:
>
> > Max. RAM size: 64 GB (any slowness
> accessing RAM over 4 GB
> * with 32 bit machines ?)
> Imore than 4GB in RAM is bounce buffered, so there is performance
> penalty as the data have to be copied into the 4GB RAM area

Any memory over 1GB is bounce-buffered, but we don't use that memory
for anything other than process data pages or file cache, so only
swapping and disk IO to regular files gets the extra copy. In
particular, things like network buffers are still all kept in the low
1GB so never need to be buffered.

--Stephen
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