Re: [PATCH][RFC] add MAP_UNLOCKED mmap flag

[Olivier Galibert]

On Wed, Oct 07, 2009 at 08:59:52PM +0200, Gleb Natapov wrote:
> On Wed, Oct 07, 2009 at 08:50:54PM +0200, Olivier Galibert wrote:
> > On Tue, Oct 06, 2009 at 02:16:03PM +0200, Gleb Natapov wrote:
> > > I did. It allows me to achieve something I can't now. Steps you provide
> > > just don't fit my needs. I need all memory areas (current and feature) to be
> > > locked except one. Very big one. You propose to lock memory at some
> > > arbitrary point and from that point on all newly mapped memory areas will
> > > be unlocked. Don't you see it is different?
> > 
> > What about mlockall(MCL_CURRENT); mmap(...); mlockall(MCL_FUTURE);?
> > Or toggle MCL_FUTURE if a mlockall call can stop it?
> > 
> This may work. And MCL_FUTURE can be toggled, but this is not thread
> safe.

Just ensure that your one special mmap is done with the other threads
not currently allocating stuff.  It's probably a synchronization point
for the whole process anyway.

  OG.


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