diff -urNp --exclude CVS --exclude BitKeeper x-ref/kernel/printk.c x/kernel/printk.c
--- x-ref/kernel/printk.c	2003-08-26 00:13:17.000000000 +0200
+++ x/kernel/printk.c	2003-09-01 21:38:16.000000000 +0200
@@ -30,13 +30,13 @@
 #include <asm/uaccess.h>
 
 #if defined(CONFIG_MULTIQUAD) || defined(CONFIG_IA64)
-#define LOG_BUF_LEN	(65536)
+#define __LOG_BUF_LEN	(65536)
 #elif defined(CONFIG_ARCH_S390)
-#define LOG_BUF_LEN	(131072)
+#define __LOG_BUF_LEN	(131072)
 #elif defined(CONFIG_SMP)
-#define LOG_BUF_LEN	(32768)
+#define __LOG_BUF_LEN	(32768)
 #else	
-#define LOG_BUF_LEN	(16384)			/* This must be a power of two */
+#define __LOG_BUF_LEN	(16384)			/* This must be a power of two */
 #endif
 
 #define LOG_BUF_MASK	(LOG_BUF_LEN-1)
@@ -78,7 +78,9 @@ struct console *console_drivers;
  */
 static spinlock_t logbuf_lock = SPIN_LOCK_UNLOCKED;
 
-static char log_buf[LOG_BUF_LEN];
+static char __log_buf[__LOG_BUF_LEN];
+static char * log_buf = __log_buf;
+static int LOG_BUF_LEN = __LOG_BUF_LEN;
 #define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK])
 
 /*
@@ -151,6 +153,39 @@ static int __init console_setup(char *st
 
 __setup("console=", console_setup);
 
+static int __init log_buf_len_setup(char *str)
+{
+	unsigned long size = simple_strtoul(str, &str, 0);
+
+	if (size & (size-1))
+		printk("log_buf_len: invalid size - needs a power of two\n");
+
+	spin_lock_irq(&logbuf_lock);
+	if (size > LOG_BUF_LEN) {
+		unsigned long start, end, dest_idx, offset;
+
+		LOG_BUF_LEN = size;
+		log_buf = alloc_exact(LOG_BUF_LEN);
+
+		offset = start = min(con_start, log_start);
+		end = log_end;
+		dest_idx = 0;
+		while (start != end) {
+			log_buf[dest_idx] = __log_buf[start & (__LOG_BUF_LEN - 1)];
+			start++;
+			dest_idx++;
+		}
+		log_start -= offset;
+		con_start -= offset;
+		log_end -= offset;
+	}
+	spin_unlock_irq(&logbuf_lock);
+
+	return 1;
+}
+
+__setup("log_buf_len=", log_buf_len_setup);
+
 /*
  * Commands to do_syslog:
  *