Subject: slub: Deal with hyperthetical case of PAGE_SIZE > 2M kmalloc_index() currently returns -1 if the PAGE_SIZE is larger than 2M which seems to cause some concern since the callers do not check for -1. Insert a BUG() and add a comment to the -1 explaining that the code cannot be reached. Signed-off-by: Christoph Lameter <cl@xxxxxxxxx> --- include/linux/slub_def.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) Index: linux-2.6/include/linux/slub_def.h =================================================================== --- linux-2.6.orig/include/linux/slub_def.h 2011-05-20 09:37:02.000000000 -0500 +++ linux-2.6/include/linux/slub_def.h 2011-05-20 09:39:07.000000000 -0500 @@ -179,7 +179,8 @@ static __always_inline int kmalloc_index if (size <= 4 * 1024) return 12; /* * The following is only needed to support architectures with a larger page - * size than 4k. + * size than 4k. We need to support 2 * PAGE_SIZE here. So for a 64k page + * size we would have to go up to 128k. */ if (size <= 8 * 1024) return 13; if (size <= 16 * 1024) return 14; @@ -190,7 +191,8 @@ static __always_inline int kmalloc_index if (size <= 512 * 1024) return 19; if (size <= 1024 * 1024) return 20; if (size <= 2 * 1024 * 1024) return 21; - return -1; + BUG(); + return -1; /* Will never be reached */ /* * What we really wanted to do and cannot do because of compiler issues is: -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>