Merge bk://are.twiddle.net/axp-2.5

into home.transmeta.com:/home/torvalds/v2.5/linux

1 files changed, 54 insertions, 24 deletions

diff --git a/fs/xfs/pagebuf/page_buf.c b/fs/xfs/pagebuf/page_buf.c
index 5663f6d4b4..05e086ad25 100644
--- a/fs/xfs/pagebuf/page_buf.c
+++ b/fs/xfs/pagebuf/page_buf.c
@@ -119,9 +119,9 @@ pb_trace_func(
 
 STATIC kmem_cache_t *pagebuf_cache;
 STATIC void pagebuf_daemon_wakeup(int);
+STATIC void pagebuf_delwri_queue(page_buf_t *, int);
 STATIC struct workqueue_struct *pagebuf_workqueue;
 
-
 /*
  * Pagebuf module configuration parameters, exported via
  * /proc/sys/vm/pagebuf
@@ -155,35 +155,37 @@ struct pbstats pbstats;
  * Pagebuf hashing
  */
 
-#define NBITS	5
-#define NHASH	(1<<NBITS)
-
+/* This structure must be a power of 2 long for the hash to work */
 typedef struct {
 	struct list_head	pb_hash;
 	int			pb_count;
 	spinlock_t		pb_hash_lock;
 } pb_hash_t;
 
-STATIC pb_hash_t	pbhash[NHASH];
+static pb_hash_t	*pbhash;
+static unsigned int	pb_hash_mask;
+static unsigned int	pb_hash_shift;
+static unsigned int	pb_order;
 #define pb_hash(pb)	&pbhash[pb->pb_hash_index]
 
-STATIC int
+/*
+ * This hash is the same one as used on the Linux buffer cache,
+ * see fs/buffer.c
+ */
+
+#define _hashfn(dev,block)      \
+        ((((dev)<<(pb_hash_shift - 6)) ^ ((dev)<<(pb_hash_shift - 9))) ^ \
+         (((block)<<(pb_hash_shift - 6)) ^ ((block) >> 13) ^ \
+          ((block) << (pb_hash_shift - 12))))
+
+static inline int
 _bhash(
 	dev_t		dev,
 	loff_t		base)
 {
-	int		bit, hval;
-
 	base >>= 9;
-	/*
-	 * dev_t is 16 bits, loff_t is always 64 bits
-	 */
-	base ^= dev;
-	for (bit = hval = 0; base != 0 && bit < sizeof(base) * 8; bit += NBITS) {
-		hval ^= (int)base & (NHASH-1);
-		base >>= NBITS;
-	}
-	return hval;
+	
+	return (_hashfn(dev, base) & pb_hash_mask);
 }
 
 /*
@@ -1516,7 +1518,7 @@ STATIC int pbd_active = 1;
 STATIC LIST_HEAD(pbd_delwrite_queue);
 STATIC spinlock_t pbd_delwrite_lock = SPIN_LOCK_UNLOCKED;
 
-void
+STATIC void
 pagebuf_delwri_queue(
 	page_buf_t		*pb,
 	int			unlock)
@@ -1862,7 +1864,39 @@ pagebuf_shaker(void)
 int __init
 pagebuf_init(void)
 {
-	int			i;
+	int		order, mempages, i;
+	unsigned int	nr_hash;
+	extern int	xfs_physmem;
+
+	mempages = xfs_physmem >>= 16;
+	mempages *= sizeof(pb_hash_t);
+	for (order = 0; (1 << order) < mempages; order++)
+		;
+
+	if (order > 3) order = 3;	/* cap us at 2K buckets */
+
+	do {
+		unsigned long tmp;
+
+		nr_hash = (PAGE_SIZE << order) / sizeof(pb_hash_t);	
+		nr_hash = 1 << (ffs(nr_hash) - 1);
+		pb_hash_mask =  (nr_hash - 1);
+		tmp = nr_hash;
+		pb_hash_shift = 0;
+		while((tmp >>= 1UL) != 0UL)
+			pb_hash_shift++;
+
+		pbhash = (pb_hash_t *)
+			__get_free_pages(GFP_KERNEL, order);
+		pb_order = order;
+	} while (pbhash == NULL && --order > 0);
+	printk("pagebuf cache hash table entries: %d (order: %d, %ld bytes)\n",
+		nr_hash, order, (PAGE_SIZE << order));
+
+	for(i = 0; i < nr_hash; i++) {
+		spin_lock_init(&pbhash[i].pb_hash_lock);
+		INIT_LIST_HEAD(&pbhash[i].pb_hash);
+	} 
 
 	pagebuf_table_header = register_sysctl_table(pagebuf_root_table, 1);
 
@@ -1880,11 +1914,6 @@ pagebuf_init(void)
 		return -ENOMEM;
 	}
 
-	for (i = 0; i < NHASH; i++) {
-		spin_lock_init(&pbhash[i].pb_hash_lock);
-		INIT_LIST_HEAD(&pbhash[i].pb_hash);
-	}
-
 #ifdef PAGEBUF_TRACE
 	pb_trace.buf = (pagebuf_trace_t *)kmalloc(
 			PB_TRACE_BUFSIZE * sizeof(pagebuf_trace_t), GFP_KERNEL);
@@ -1911,6 +1940,7 @@ pagebuf_terminate(void)
 
 	kmem_cache_destroy(pagebuf_cache);
 	kmem_shake_deregister(pagebuf_shaker);
+	free_pages((unsigned long)pbhash, pb_order);
 
 	unregister_sysctl_table(pagebuf_table_header);
 #ifdef	CONFIG_PROC_FS