Commit 64b4a954 authored Feb 04, 2006 by Christoph Lameter Committed by Linus Torvalds Feb 05, 2006

[PATCH] hugetlb: add comment explaining reasons for Bus Errors



I just spent some time researching a Bus Error.  Turns out that the huge
page fault handler can return VM_FAULT_SIGBUS for various conditions where
no huge page is available.

Add a note explaining the reasoning in the source.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: William Lee Irwin III <wli@holomorphy.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent fe1dcbc4

mm/hugetlb.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -444,6 +444,15 @@ retry:
		page = alloc_huge_page(vma, address);
		if (!page) {
		hugetlb_put_quota(mapping);
		/*
		* No huge pages available. So this is an OOM
		* condition but we do not want to trigger the OOM
		* killer, so we return VM_FAULT_SIGBUS.
		*
		* A program using hugepages may fault with Bus Error
		* because no huge pages are available in the cpuset, per
		* memory policy or because all are in use!
		*/
		goto out;
		}