svn commit: r317341 - head/sys/kern

[Edward Tomasz Napierala]

Author: trasz
Date: Sun Apr 23 17:39:31 2017
New Revision: 317341
URL: https://svnweb.freebsd.org/changeset/base/317341

Log:
  Improve BUF_TRACKING by not displaying NULL entries.
  
  Reviewed by:	cem
  MFC after:	2 weeks
  Differential Revision:	https://reviews.freebsd.org/D10443

Modified:
  head/sys/kern/vfs_bio.c

Modified: head/sys/kern/vfs_bio.c
==============================================================================
--- head/sys/kern/vfs_bio.c	Sun Apr 23 14:25:51 2017	(r317340)
+++ head/sys/kern/vfs_bio.c	Sun Apr 23 17:39:31 2017	(r317341)
@@ -4927,9 +4927,12 @@ DB_SHOW_COMMAND(buffer, db_show_buffer)
 	db_printf("b_io_tracking: b_io_tcnt = %u\n", bp->b_io_tcnt);
 
 	i = bp->b_io_tcnt % BUF_TRACKING_SIZE;
-	for (j = 1; j <= BUF_TRACKING_SIZE; j++)
+	for (j = 1; j <= BUF_TRACKING_SIZE; j++) {
+		if (bp->b_io_tracking[BUF_TRACKING_ENTRY(i - j)] == NULL)
+			continue;
 		db_printf(" %2u: %s\n", j,
 		    bp->b_io_tracking[BUF_TRACKING_ENTRY(i - j)]);
+	}
 #elif defined(BUF_TRACKING)
 	db_printf("b_io_tracking: %s\n", bp->b_io_tracking);
 #endif