Re: context overflow

Gabriel Paubert writes:

quoted

CONFIG_HIGHMEM has little to do with the kernel virtual space. The main
purpose is to get the memory into user space, where user programs can use
them. I really don't understand, what problem you're trying to solve. The
kernel only wants to manage high memory and rarely access it (and uses
kmap for this), most of the time these pages should be in the user virtual
address space only.

Confused. If you have up to 64 Gb or RAM (the 7450 has 36 address lines)
and can use not even use one gigabyte for cache, you end up with a
seriously unbalanced system. Depending on what you do of course.

The highmem pages are used mainly as page-cache pages and anonymous
user pages.  At the moment the kernel uses bounce buffers for doing
I/O to/from highmem pages but that is on the list of things to be
fixed. :)

Paul.

--
Paul Mackerras, Open Source Research Fellow, Linuxcare, Inc.
+61 2 6262 8990 tel, +61 2 6262 8991 fax
paulus@linuxcare.com.au, http://www.linuxcare.com.au/
Linuxcare.  Putting open source to work.

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