The patch titled
Avoid __GFP_xx becoming 0
has been added to the -mm tree. Its filename is
reduce-max_nr_zones-make-zone_highmem-optional-fix.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Avoid __GFP_xx becoming 0
From: Christoph Lameter <clameter@xxxxxxx>
We sometimes do comparisons like
xx & (__GFP_x| __GFP_y)) == GFP_y
This becomes a problem if GFP_y is redefined to be zero.
Both __GFP_HIGHMEM (caused by me) and __GFP_DMA32 (was this way before) can
become zero in order to cause a fall back to ZONE_NORMAL.
We also have a GFP_MASK that is applied before indexing into the nodelists
array. We can use that mask to avoid having both become zero and instead
use the GFP_MASK to clear the respective bits before retrieving the
zonelist.
- Remove #ifdefs that cause __GFP_HIGHMEM or __GFP_DMA32 to become zero.
- GFP_MASK works nicely to cause fall back to ZONE_NORMAL except if
CONFIG_ZONE_DMA32 and !CONFIG_HIGHMEM are set. In that case the
fallback to ZONE_NORMAL does not work. So add a special case
to mmzone.h to define a special mask that switches off the highmem
bit for this particular configuration.
Signed-off-by: Christoph Lameter <clameter@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/linux/gfp.h | 9 +--------
include/linux/mmzone.h | 21 ++++++++++++++++++---
2 files changed, 19 insertions(+), 11 deletions(-)
diff -puN include/linux/gfp.h~reduce-max_nr_zones-make-zone_highmem-optional-fix include/linux/gfp.h
--- a/include/linux/gfp.h~reduce-max_nr_zones-make-zone_highmem-optional-fix
+++ a/include/linux/gfp.h
@@ -12,17 +12,10 @@ struct vm_area_struct;
*/
/* Zone modifiers in GFP_ZONEMASK (see linux/mmzone.h - low three bits) */
#define __GFP_DMA ((__force gfp_t)0x01u)
-
-#ifdef CONFIG_HIGHMEM
#define __GFP_HIGHMEM ((__force gfp_t)0x02u)
-#else
-#define __GFP_HIGHMEM ((__force gfp_t)0x00) /* NORMAL is HIGHMEM */
-#endif
-#ifndef CONFIG_ZONE_DMA32
+#if !defined(CONFIG_ZONE_DMA32) && BITS_PER_LONG >= 64
#define __GFP_DMA32 ((__force gfp_t)0x01) /* ZONE_DMA is ZONE_DMA32 */
-#elif BITS_PER_LONG < 64
-#define __GFP_DMA32 ((__force gfp_t)0x00) /* ZONE_NORMAL is ZONE_DMA32 */
#else
#define __GFP_DMA32 ((__force gfp_t)0x04) /* Has own ZONE_DMA32 */
#endif
diff -puN include/linux/mmzone.h~reduce-max_nr_zones-make-zone_highmem-optional-fix include/linux/mmzone.h
--- a/include/linux/mmzone.h~reduce-max_nr_zones-make-zone_highmem-optional-fix
+++ a/include/linux/mmzone.h
@@ -162,18 +162,33 @@ enum zone_type {
*
* NOTE! Make sure this matches the zones in <linux/gfp.h>
*/
-#define GFP_ZONETYPES ((GFP_ZONEMASK + 1) / 2 + 1) /* Loner */
#ifdef CONFIG_ZONE_DMA32
+
+#ifdef CONFIG_HIGHMEM
+#define GFP_ZONETYPES ((GFP_ZONEMASK + 1) / 2 + 1) /* Loner */
#define GFP_ZONEMASK 0x07
-#define ZONES_SHIFT 2 /* ceil(log2(MAX_NR_ZONES)) */
+#define ZONES_SHIFT 2 /* ceil(log2(MAX_NR_ZONES)) */
+#else
+#define GFP_ZONETYPES ((0x07 + 1) / 2 + 1) /* Loner */
+/* Mask __GFP_HIGHMEM */
+#define GFP_ZONEMASK 0x05
+#define ZONES_SHIFT 2
+#endif
+
#else
#ifdef CONFIG_HIGHMEM
+
#define GFP_ZONEMASK 0x03
-#define ZONES_SHIFT 2
+#define ZONES_SHIFT 2
+#define GFP_ZONETYPES 3
+
#else
+
#define GFP_ZONEMASK 0x01
#define ZONES_SHIFT 1
+#define GFP_ZONETYPES 2
+
#endif
#endif
_
Patches currently in -mm which might be from clameter@xxxxxxx are
zvc-add-__inc_zone_state-for-smp-configuration.patch
reduce-max_nr_zones-remove-two-strange-uses-of-max_nr_zones.patch
reduce-max_nr_zones-fix-max_nr_zones-array-initializations.patch
reduce-max_nr_zones-make-display-of-highmem-counters-conditional-on-config_highmem.patch
reduce-max_nr_zones-make-display-of-highmem-counters-conditional-on-config_highmem-tidy.patch
reduce-max_nr_zones-move-highmem-counters-into-highmemc-h.patch
reduce-max_nr_zones-page-allocator-zone_highmem-cleanup.patch
reduce-max_nr_zones-use-enum-to-define-zones-reformat-and-comment.patch
reduce-max_nr_zones-use-enum-to-define-zones-reformat-and-comment-cleanup.patch
reduce-max_nr_zones-make-zone_dma32-optional.patch
reduce-max_nr_zones-make-zone_highmem-optional.patch
reduce-max_nr_zones-make-zone_highmem-optional-fix.patch
reduce-max_nr_zones-remove-display-of-counters-for-unconfigured-zones.patch
reduce-max_nr_zones-fix-i386-srat-check-for-max_nr_zones.patch
reduce-max_nr_zones-swap_prefetch-remove-incorrect-use-of-zone_highmem.patch
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