Mikulas Patoka wants to ensure that no fallback to lower order happens. I
think __GFP_NORETRY should work correctly in that case too and not fall
back.
Allocating at a smaller order is a retry operation and should not
be attempted.
If the caller does not want retries then respect that.
GFP_NORETRY allows callers to ensure that only maximum order
allocations are attempted.
Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
Index: linux/mm/slub.c
===================================================================
--- linux.orig/mm/slub.c
+++ linux/mm/slub.c
@@ -1598,7 +1598,7 @@ static struct page *allocate_slab(struct
alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
page = alloc_slab_page(s, alloc_gfp, node, oo);
- if (unlikely(!page)) {
+ if (unlikely(!page) && !(flags & __GFP_NORETRY)) {
oo = s->min;
alloc_gfp = flags;
/*
