Re: [patch 2/3] MAP_NOZERO - implement sys_brk2()

From: Davide Libenzi
Date: Wed Jun 27 2007 - 15:23:15 EST


On Wed, 27 Jun 2007, Rik van Riel wrote:

> Ulrich Drepper wrote:
> > On 6/27/07, Hugh Dickins <hugh@xxxxxxxxxxx> wrote:
> > > Not so: if an mmap can be done by extending either adjacent vma (prot
> > > and flags and file and offset all match up), that's what's done and no
> > > separate vma is created. (And adjacent vmas get merged when mprotect
> > > removes the difference in protection.)
> >
> > mmap return values are randomized. If they would be mergable
> > something would be wrong.
>
> You can easily pass a hint address to mmap(), causing it to
> extend a malloc arena instead of creating a new VMA.

You mean something like the F_DUPFD, where you pass an fd and that serves
as from-there-up hint?



- Davide


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