On Mon, Apr 25, 2011 at 05:46:33PM +0200, C. P. Ghost wrote: > On Mon, Apr 25, 2011 at 5:15 PM, Bob Hall <rjh...@gmail.com> wrote: > > On Mon, Apr 25, 2011 at 03:18:46PM +0100, RW wrote: > >> I don't believe the heap is allocated zeroed pages. The kernel > >> does allocate such pages to the BSS segment, but that's because it > >> holds zeroed data such as C static variables. > > > > According to McKusick and Neville-Neil's book on FreeBSD, sbrk extends > > the uninitialized data segment with zero-filled pages. Since malloc() is > > an interface to sbrk, it does the same thing. > > True, except that malloc(3) now uses both sbrk(2) and mmap(2) allocators, > depending on the user-settable flags in /etc/malloc.conf, MALLOC_OPTIONS > and the global variable _malloc_options. So you have to look into mmap(2) > too.
Good point. From the man page: "Any such extension beyond the end of the mapped object will be zero-filled." and "A successful mmap deletes any previous mapping in the allocated address range." _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
