[Bug other/50636] GC in large LTO builds cause excessive fragmentation in memory map

[andi-gcc at firstfloor dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50636

--- Comment #5 from Andi Kleen <andi-gcc at firstfloor dot org> 2011-10-06 21:46:32 UTC ---
If it's a 2MB page then madvise MADV_DONTNEED will split it if it's not
2MB aligned. It would be good to optimize the freeing pattern so that this
happens
rarely.

I will try to do some numbers how much 2MB pages improves performance. If yes
we could also do a MADV_HUGEPAGE by default.

But short term fix would be simply to have a threshold for freepages before
freeing?