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authorRavikiran G Thirumalai <kiran@scalex86.org>2006-01-08 01:01:27 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-08 20:13:38 -0800
commit22fc6eccbf4ce4eb6265e6ada7b50a7b9cc57d05 (patch)
tree3887dc6f1eeb658d773be037971b98d6f5fb3dd7 /include
parent6d524aed1f50b2b1d5b4ad5a4e2fe3f38106d0a6 (diff)
downloadlinux-stericsson-22fc6eccbf4ce4eb6265e6ada7b50a7b9cc57d05.tar.gz
[PATCH] Change maxaligned_in_smp alignemnt macros to internodealigned_in_smp macros
____cacheline_maxaligned_in_smp is currently used to align critical structures and avoid false sharing. It uses per-arch L1_CACHE_SHIFT_MAX and people find L1_CACHE_SHIFT_MAX useless. However, we have been using ____cacheline_maxaligned_in_smp to align structures on the internode cacheline size. As per Andi's suggestion, following patch kills ____cacheline_maxaligned_in_smp and introduces INTERNODE_CACHE_SHIFT, which defaults to L1_CACHE_SHIFT for all arches. Arches needing L3/Internode cacheline alignment can define INTERNODE_CACHE_SHIFT in the arch asm/cache.h. Patch replaces ____cacheline_maxaligned_in_smp with ____cacheline_internodealigned_in_smp With this patch, L1_CACHE_SHIFT_MAX can be killed Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org> Signed-off-by: Shai Fultheim <shai@scalex86.org> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/cache.h17
-rw-r--r--include/linux/ide.h2
-rw-r--r--include/linux/mmzone.h4
-rw-r--r--include/linux/rcupdate.h2
4 files changed, 17 insertions, 8 deletions
diff --git a/include/linux/cache.h b/include/linux/cache.h
index 0b7ecf3af78a..ffe52210fc4f 100644
--- a/include/linux/cache.h
+++ b/include/linux/cache.h
@@ -45,12 +45,21 @@
#endif /* CONFIG_SMP */
#endif
-#if !defined(____cacheline_maxaligned_in_smp)
+/*
+ * The maximum alignment needed for some critical structures
+ * These could be inter-node cacheline sizes/L3 cacheline
+ * size etc. Define this in asm/cache.h for your arch
+ */
+#ifndef INTERNODE_CACHE_SHIFT
+#define INTERNODE_CACHE_SHIFT L1_CACHE_SHIFT
+#endif
+
+#if !defined(____cacheline_internodealigned_in_smp)
#if defined(CONFIG_SMP)
-#define ____cacheline_maxaligned_in_smp \
- __attribute__((__aligned__(1 << (L1_CACHE_SHIFT_MAX))))
+#define ____cacheline_internodealigned_in_smp \
+ __attribute__((__aligned__(1 << (INTERNODE_CACHE_SHIFT))))
#else
-#define ____cacheline_maxaligned_in_smp
+#define ____cacheline_internodealigned_in_smp
#endif
#endif
diff --git a/include/linux/ide.h b/include/linux/ide.h
index 7b6a6a58e465..4dd6694963c0 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -801,7 +801,7 @@ typedef struct hwif_s {
unsigned dma;
void (*led_act)(void *data, int rw);
-} ____cacheline_maxaligned_in_smp ide_hwif_t;
+} ____cacheline_internodealigned_in_smp ide_hwif_t;
/*
* internal ide interrupt handler type
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 2a89c132ba9c..7e4ae6ab1977 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -38,7 +38,7 @@ struct pglist_data;
#if defined(CONFIG_SMP)
struct zone_padding {
char x[0];
-} ____cacheline_maxaligned_in_smp;
+} ____cacheline_internodealigned_in_smp;
#define ZONE_PADDING(name) struct zone_padding name;
#else
#define ZONE_PADDING(name)
@@ -233,7 +233,7 @@ struct zone {
* rarely used fields:
*/
char *name;
-} ____cacheline_maxaligned_in_smp;
+} ____cacheline_internodealigned_in_smp;
/*
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index a471f3bb713e..51747cd88d1a 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -65,7 +65,7 @@ struct rcu_ctrlblk {
long cur; /* Current batch number. */
long completed; /* Number of the last completed batch */
int next_pending; /* Is the next batch already waiting? */
-} ____cacheline_maxaligned_in_smp;
+} ____cacheline_internodealigned_in_smp;
/* Is batch a before batch b ? */
static inline int rcu_batch_before(long a, long b)