[XFS] Rework the dquot hash sizing heuristics.

SGI-PV: 943123
SGI-Modid: xfs-linux:xfs-kern:24012a
Signed-off-by: Nathan Scott <nathans@sgi.com>

fs/xfs/linux-2.6/xfs_linux.h

@@ -217,19 +217,7 @@ static inline void set_buffer_unwritten_io(struct buffer_head *bh)
 #define Q_XSETPQLIM	XQM_CMD(10)	/* set projects disk limits */
 #define Q_XGETPQUOTA	XQM_CMD(11)	/* get projects disk limits */
 
-/* IRIX uses a dynamic sizing algorithm (ndquot = 200 + numprocs*2) */
-/* we may well need to fine-tune this if it ever becomes an issue.  */
-#define DQUOT_MAX_HEURISTIC	1024	/* NR_DQUOTS */
-#define ndquot			DQUOT_MAX_HEURISTIC
-
-/* IRIX uses the current size of the name cache to guess a good value */
-/* - this isn't the same but is a good enough starting point for now. */
-#define DQUOT_HASH_HEURISTIC	files_stat.nr_files
-
-/* IRIX inodes maintain the project ID also, zero this field on Linux */
-#define DEFAULT_PROJID	0
-#define dfltprid	DEFAULT_PROJID
-
+#define dfltprid	0
 #define MAXPATHLEN	1024
 
 #define MIN(a,b)	(min(a,b))

fs/xfs/quota/xfs_qm.c

@@ -60,8 +60,9 @@
  * quota functionality, including maintaining the freelist and hash
  * tables of dquots.
  */
-mutex_t xfs_Gqm_lock;
+mutex_t		xfs_Gqm_lock;
 struct xfs_qm	*xfs_Gqm;
+uint		ndquot;
 
 kmem_zone_t	*qm_dqzone;
 kmem_zone_t	*qm_dqtrxzone;
@@ -108,25 +109,25 @@ extern mutex_t	qcheck_lock;
 STATIC struct xfs_qm *
 xfs_Gqm_init(void)
 {
-	xfs_qm_t		*xqm;
-	int			hsize, i;
-
-	xqm = kmem_zalloc(sizeof(xfs_qm_t), KM_SLEEP);
-	ASSERT(xqm);
+	xfs_dqhash_t	*udqhash, *gdqhash;
+	xfs_qm_t	*xqm;
+	uint		i, hsize, flags = KM_SLEEP | KM_MAYFAIL;
 
 	/*
 	 * Initialize the dquot hash tables.
 	 */
-	hsize = (DQUOT_HASH_HEURISTIC < XFS_QM_NCSIZE_THRESHOLD) ?
-		XFS_QM_HASHSIZE_LOW : XFS_QM_HASHSIZE_HIGH;
-	xqm->qm_dqhashmask = hsize - 1;
+	hsize = XFS_QM_HASHSIZE_HIGH;
+	while (!(udqhash = kmem_zalloc(hsize * sizeof(xfs_dqhash_t), flags))) {
+		if ((hsize >>= 1) <= XFS_QM_HASHSIZE_LOW)
+			flags = KM_SLEEP;
+	}
+	gdqhash = kmem_zalloc(hsize * sizeof(xfs_dqhash_t), KM_SLEEP);
+	ndquot = hsize << 8;
 
-	xqm->qm_usr_dqhtable = (xfs_dqhash_t *)kmem_zalloc(hsize *
-						      sizeof(xfs_dqhash_t),
-						      KM_SLEEP);
-	xqm->qm_grp_dqhtable = (xfs_dqhash_t *)kmem_zalloc(hsize *
-						      sizeof(xfs_dqhash_t),
-						      KM_SLEEP);
+	xqm = kmem_zalloc(sizeof(xfs_qm_t), KM_SLEEP);
+	xqm->qm_dqhashmask = hsize - 1;
+	xqm->qm_usr_dqhtable = udqhash;
+	xqm->qm_grp_dqhtable = gdqhash;
 	ASSERT(xqm->qm_usr_dqhtable != NULL);
 	ASSERT(xqm->qm_grp_dqhtable != NULL);
 

fs/xfs/quota/xfs_qm.h

@@ -26,6 +26,7 @@
 struct xfs_qm;
 struct xfs_inode;
 
+extern uint		ndquot;
 extern mutex_t		xfs_Gqm_lock;
 extern struct xfs_qm	*xfs_Gqm;
 extern kmem_zone_t	*qm_dqzone;
@@ -51,9 +52,8 @@ extern kmem_zone_t	*qm_dqtrxzone;
 /*
  * Dquot hashtable constants/threshold values.
  */
-#define XFS_QM_NCSIZE_THRESHOLD		5000
-#define XFS_QM_HASHSIZE_LOW		32
-#define XFS_QM_HASHSIZE_HIGH		64
+#define XFS_QM_HASHSIZE_LOW		(NBPP / sizeof(xfs_dqhash_t))
+#define XFS_QM_HASHSIZE_HIGH		((NBPP * 4) / sizeof(xfs_dqhash_t))
 
 /*
  * We output a cmn_err when quotachecking a quota file with more than