[PATCH] Align VM locks

[Mark Hemment <markhe@veritas.com>]

Hi,

  The patch below ensures the pagecache_lock and pagemap_lru_lock aren't
sharing an L1 cacheline with anyone else - espically each other!

Mark


diff -ur -X dontdiff linux-2.4.9-pre4/mm/filemap.c L1-2.4.9-pre4/mm/filemap.c
--- linux-2.4.9-pre4/mm/filemap.c	Thu Aug 16 15:57:51 2001
+++ L1-2.4.9-pre4/mm/filemap.c	Thu Aug 16 18:28:24 2001
@@ -45,12 +45,12 @@
 unsigned int page_hash_bits;
 struct page **page_hash_table;

-spinlock_t pagecache_lock = SPIN_LOCK_UNLOCKED;
+spinlock_t __cacheline_aligned pagecache_lock = SPIN_LOCK_UNLOCKED;
 /*
  * NOTE: to avoid deadlocking you must never acquire the pagecache_lock with
  *       the pagemap_lru_lock held.
  */
-spinlock_t pagemap_lru_lock = SPIN_LOCK_UNLOCKED;
+spinlock_t __cacheline_aligned pagemap_lru_lock = SPIN_LOCK_UNLOCKED;

 #define CLUSTER_PAGES		(1 << page_cluster)
 #define CLUSTER_OFFSET(x)	(((x) >> page_cluster) << page_cluster)