Re: [bug] SLUB + mm/slab.c boot crash in -rc9

[Ingo Molnar <mingo@elte.hu>]

* Ingo Molnar <mingo@elte.hu> wrote:

> -#if !(NODES_WIDTH > 0 || NODES_SHIFT == 0)
> +#if NODES_WIDTH <= 0 || NODES_SHIFT == 0
>  #define NODE_NOT_IN_PAGE_FLAGS
>  #endif

Peter "radar eye" Zijlstra noticed an ugly and annoying typo in mm.h:

-#ifdef NODE_NOT_IN_PAGEFLAGS
+#ifdef NODE_NOT_IN_PAGE_FLAGS

but even with the full fix (see below) the same crash remains.

i think getting NODE_NOT_IN_PAGEFLAGS wrong seems to result in 
non-optimal but still correct code - by virtue of NODES_MASK ending up 
zero.

	Ingo

----------------------->
Subject: nodes: shift fix
From: Ingo Molnar <mingo@elte.hu>
Date: Tue Apr 15 21:15:21 CEST 2008

Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 include/linux/mm.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: linux/include/linux/mm.h
===================================================================
--- linux.orig/include/linux/mm.h
+++ linux/include/linux/mm.h
@@ -424,7 +424,7 @@ static inline void set_compound_order(st
  * We are going to use the flags for the page to node mapping if its in
  * there.  This includes the case where there is no node, so it is implicit.
  */
-#if !(NODES_WIDTH > 0 || NODES_SHIFT == 0)
+#if NODES_WIDTH <= 0 || NODES_SHIFT == 0
 #define NODE_NOT_IN_PAGE_FLAGS
 #endif
 
@@ -442,7 +442,7 @@ static inline void set_compound_order(st
 #define ZONES_PGSHIFT		(ZONES_PGOFF * (ZONES_WIDTH != 0))
 
 /* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allcator */
-#ifdef NODE_NOT_IN_PAGEFLAGS
+#ifdef NODE_NOT_IN_PAGE_FLAGS
 #define ZONEID_SHIFT		(SECTIONS_SHIFT + ZONES_SHIFT)
 #define ZONEID_PGOFF		((SECTIONS_PGOFF < ZONES_PGOFF)? \
 						SECTIONS_PGOFF : ZONES_PGOFF)