Re: Discardable mappings?

[Marcelo Tosatti <marcelo@conectiva.com.br>]

On Mon, 15 Oct 2001, H. Peter Anvin wrote:

> I have been working on a user-space persistent memory system, and would
> like to bring up (again?) the possibility of a "discardable" class of
> mappings.  "Discardable" means that the system is free to throw away a
> page without storing it to swap, and return SIGSEGV on access, since the
> application can regenerate the data on that page if needed.
> 
> My personal preference would be if this was a PROT_* flag that could be
> used with mprotect(), since my system, and probably most other systems
> which need this kind of functionality, use mprotect() on these pages
> already, and it'd be nice to avoid Yet Another System Call[TM] in a very
> performance-critical part of the system; furthermore, I tend to think of
> mprotect() as controlling when to raise SIGSEGV, so it's not *completely*
> out of place there...

I don't see any problem with doing that. 

Just Write The Code. :) 

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