Re: madvise (MADV_FREE)

[lars brinkhoff <lars.brinkhoff@intermec.com>]

Jamie Lokier wrote:
> Well, I guess we will never know until it has been tried, but it looks
> like it should be experimented with by someone writing a garbage
> collector before it becomes a standard kernel feature.  I really don't
> like the way mprotect breaks syscalls though, even if it performs well.

And please remember that not only garbage collectors can benefit from dirty
and accessed bits.  There are a number of applications doing paging in user
space.  For example, the Brown Simulator
(http://www.cs.brown.edu/software/brownsim/)
and a386 (http://a386.nocrew.org/) both provide virtual CPUs with MMUs which
can run operating system kernels.  Per-page accessed and dirty information
from the hosting kernel would ease the implementation of a simulated MMU.

Perhaps also the user-mode Linux kernel would benefit, but I'm not sure.
Jeff?
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