svn commit: r277760 - stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[Alexander Motin]

Author: mav
Date: Mon Jan 26 16:29:07 2015
New Revision: 277760
URL: https://svnweb.freebsd.org/changeset/base/277760

Log:
  MFC r277096: Skip extra bcopy() when scrubbing vdev without redundancy.
  
  According to profiler, this bcopy() can use about 10% of CPU time.

Modified:
  stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_mirror.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_mirror.c
==============================================================================
--- stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_mirror.c	Mon Jan 26 16:26:28 2015	(r277759)
+++ stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_mirror.c	Mon Jan 26 16:29:07 2015	(r277760)
@@ -441,7 +441,8 @@ vdev_mirror_io_start(zio_t *zio)
 	mm = vdev_mirror_map_init(zio);
 
 	if (zio->io_type == ZIO_TYPE_READ) {
-		if ((zio->io_flags & ZIO_FLAG_SCRUB) && !mm->mm_replacing) {
+		if ((zio->io_flags & ZIO_FLAG_SCRUB) && !mm->mm_replacing &&
+		    mm->mm_children > 1) {
 			/*
 			 * For scrubbing reads we need to allocate a read
 			 * buffer for each child and issue reads to all