Superpages on amd64 FreeBSD 7.2-STABLE

[Christian Brueffer]

On Mon, Dec 07, 2009 at 04:20:03PM +0100, Mel Flynn wrote:
> On Thursday 26 November 2009 18:11:10 Linda Messerschmidt wrote:
> 
> > I did not mean to suggest that we were asking for help solving a
> > problem with squid rotation.  I provided that information as
> > background to discuss what we observed as a potential misbehavior in
> > the new VM superpages feature, in the hope that if there is a problem
> > with the new feature, we can help find/resolve it or, if this is
> > working as intended, hopefully gain some insight as to what's going
> > on.
> 
> I tend to agree with this, though I don't know the nitty gritty of the 
> implementation, it seems that:
> a) superpages aren't copied efficiently (at all?) on fork and probably other 
> workloads
> b) vfork is encouraged for memory intensive applications, yet:
> BUGS
>      This system call will be eliminated when proper system sharing mechanisms
>      are implemented.  Users should not depend on the memory sharing semantics
>      of vfork() as it will, in that case, be made synonymous to fork(2).
> 

FYI, this comment has been removed a couple of weeks ago in HEAD and
the STABLE branches.

- Christian

-- 
Christian Brueffer	chris at unixpages.org	brueffer at FreeBSD.org
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