On 1 June 2011 00:13, Theo de Raadt <dera...@cvs.openbsd.org> wrote: >> On Tue, May 31, 2011 at 10:39 PM, Corey <clinge...@gmail.com> wrote: >> > data in "unused" bits in a pointer? Even I know that's a bad idea. Is it >> > really that important to run your Javascript 2% faster? >> >> The difference is quite a bit more than 2%. The technique is sound, >> imo, but it seems the implementations are lacking some safeguards. > > The implementations are forcing OS developers to remove safeguards > from our kernels. > > google MAP_32BIT > > Go see what linux and other systems do with the "hint" argument to > mmap(), regarding address space randomization. Go read some of these > implementations to see how often they pass a non-NULL hint. > > I'm so glad we have more performance in the most dangerous > applications.... > >
I wonder if the MAP_32BIT flag was pushed cause it broke apps, or if they were really concerned about the performance implication of having high addresses in amd64. Can't decide which is worst.