On Wed, Jul 14, 2010 at 11:06:38AM -0700, johan...@opensolaris.org wrote: > On Tue, Jul 13, 2010 at 06:41:32PM -0500, Nicolas Williams wrote: > > As to your question, posix_spawn(2) wouldn't fork at all under the > > covers: as a syscall it'd not have to. It'd create a new process as a > > child of the parent, but it'd not use the parent's address space at all. > > There'd still be some amount of locking to copy the file descriptor > > table and so on, of course, but nothing quite like the copying or > > borrowing of the parent's address space (almost certainly the most > > expensive part of fork(2)/ vfork(2)). > > I'd like to see data for this assertion too. The code that's executed > for vfork performs very few address space manipulations while borrowing > the parent's address space. All it does today is clear and restore > watched pages. Most processes don't have watchpoints on their pages.
"Borrowing the parent's address space" means stopping all of the parent's threads, at least for vfork() because that's what the documented semantics of it are. I've explained this elsewhere in this thread. I'm sorry you thought that I meant that vfork() does expensive address space manipulations. _______________________________________________ on-discuss mailing list on-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/on-discuss
