On Sat, Jun 4, 2011 at 10:39 AM, Marc Espie <es...@nerim.net> wrote: > Well, the official fix for mono is in, from the mono team. > > Guess what ? Mono uses MAP_32BIT if it's available. > > From Linux's mmap manpage: > MAP_32BIT (since Linux 2.4.20, 2.6) > Put the mapping into the first 2 Gigabytes of the process > address space. This flag is only supported on x86-64, for > 64-bit programs. It was added to allow thread stacks to be > allocated somewhere in the first 2GB of memory, so as to improve > context-switch performance on some early 64-bit processors. > Modern x86-64 processors no longer have this performance prob- > lem, so use of this flag is not required on those systems. The > MAP_32BIT flag is ignored when MAP_FIXED is set. > > From my point of view, it certainly looks like MAP_32BIT was only put there > to address one specific issue in the lifetime of 64 bit platforms, but that > some people got some nifty ideas about how to abuse it, and now it's probably > there to stay, since software would break without it...
Thanks. That's vastly better than simply impugning other people's code without reading it.
