[patch] Cache align futex hash buckets

[Ravikiran G Thirumalai <kiran@scalex86.org>]

Following change places each element of the futex_queues hashtable on a 
different cacheline.  Spinlocks of adjacent hash buckets lie on the same 
cacheline otherwise.

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>

Index: linux-2.6.16-rc2/kernel/futex.c
===================================================================
--- linux-2.6.16-rc2.orig/kernel/futex.c	2006-02-07 23:14:04.000000000 -0800
+++ linux-2.6.16-rc2/kernel/futex.c	2006-02-09 14:04:22.000000000 -0800
@@ -100,9 +100,10 @@ struct futex_q {
 struct futex_hash_bucket {
        spinlock_t              lock;
        struct list_head       chain;
-};
+} ____cacheline_internodealigned_in_smp;
 
-static struct futex_hash_bucket futex_queues[1<<FUTEX_HASHBITS];
+static struct futex_hash_bucket futex_queues[1<<FUTEX_HASHBITS] 
+				__cacheline_aligned_in_smp;
 
 /* Futex-fs vfsmount entry: */
 static struct vfsmount *futex_mnt;
-
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