Re: Big mallocs, mmap sorrows and double buffering.

Boris Tobotras (
Wed, 12 Feb 1997 13:57:30 +0300

On Tue, 11 Feb 1997 16:10:39 +0100, Ingo Molnar wrote:

> > Hmm. I remember using a facility like this on the old vaxen. The
> > glitch was if I mapped an entire satellite image (+-400megabytes) the
> > page tables used up so much physical memory that the thing started
> > thrashing again. (There we just settled down to using two 32k buffers
> > and doing NO_WAIT read/writes.)
> 400M mmap()-ed file takes ~400K page tables (for every 4K page there is a
> 4 byte descriptor). So this shouldnt be an issue even on low-end machines.

Can kernel use Pentium 4M pages, if process tries to map continuous
large chunks of memory?

	Best regards, -- Boris.