http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50636
--- Comment #10 from Andi Kleen <andi-gcc at firstfloor dot org> 2011-10-07 14:44:10 UTC --- To track the pattern you can simply use strace or ftrace (I did ftrace) I checked the kernel code now and if the madvise is big enough it won't split up the 2MB page. So doing it aggressively should be ok, but still it may be beneficial to skip it for very scattered pages. I suspect other OS don't have MADV_DONTNEED, they would probably need Honza's pool idea. I did a prototype patch now, will be testing it.
