[XFS] Scale default number of log buffers based on memory size

SGI Modid: 2.5.x-xfs:slinx:153273a

fs/xfs/xfs_log.c

@@ -1066,7 +1066,7 @@ xlog_get_iclog_buffer_size(xfs_mount_t	*mp,
 	if (mp->m_logbufs == 0) {
 		xlog_debug = 0;
 		xlog_devt = log->l_dev;
-		log->l_iclog_bufs = XLOG_NUM_ICLOGS;
+		log->l_iclog_bufs = XLOG_MIN_ICLOGS;
 	} else
 #endif
 	{
@@ -1074,9 +1074,16 @@ xlog_get_iclog_buffer_size(xfs_mount_t	*mp,
 		 * This is the normal path.  If m_logbufs == -1, then the
 		 * admin has chosen to use the system defaults for logbuffers.
 		 */
-		if (mp->m_logbufs == -1)
-			log->l_iclog_bufs = XLOG_NUM_ICLOGS;
-		else
+		if (mp->m_logbufs == -1) { 
+			if (xfs_physmem <= btoc(128*1024*1024)) { 
+				log->l_iclog_bufs = XLOG_MIN_ICLOGS; 
+			} else if (xfs_physmem <= btoc(400*1024*1024)) { 
+				log->l_iclog_bufs = XLOG_MED_ICLOGS;; 
+			} else {
+				/* 256K with 32K bufs */
+				log->l_iclog_bufs = XLOG_MAX_ICLOGS;
+			}
+		} else
 			log->l_iclog_bufs = mp->m_logbufs;
 
 #if defined(DEBUG) || defined(XLOG_NOLOG)

fs/xfs/xfs_log_priv.h

@@ -50,7 +50,8 @@ struct xfs_mount;
  * Macros, structures, prototypes for internal log manager use.
  */
 
-#define XLOG_NUM_ICLOGS		2
+#define XLOG_MIN_ICLOGS		2
+#define XLOG_MED_ICLOGS		4
 #define XLOG_MAX_ICLOGS		8
 #define XLOG_CALLBACK_SIZE	10
 #define XLOG_HEADER_MAGIC_NUM	0xFEEDbabe	/* Illegal cycle number */

fs/xfs/xfs_vfsops.c

@@ -235,11 +235,11 @@ xfs_start_flags(
 	}
 
 	if (ap->logbufs != 0 && ap->logbufs != -1 &&
-	    (ap->logbufs < XLOG_NUM_ICLOGS ||
+	    (ap->logbufs < XLOG_MIN_ICLOGS ||
 	     ap->logbufs > XLOG_MAX_ICLOGS)) {
 		cmn_err(CE_WARN,
 			"XFS: invalid logbufs value: %d [not %d-%d]",
-			ap->logbufs, XLOG_NUM_ICLOGS, XLOG_MAX_ICLOGS);
+			ap->logbufs, XLOG_MIN_ICLOGS, XLOG_MAX_ICLOGS);
 		return XFS_ERROR(EINVAL);
 	}
 	mp->m_logbufs = ap->logbufs;