svn commit: r277096 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[Alexander Motin]

Author: mav
Date: Mon Jan 12 22:38:55 2015
New Revision: 277096
URL: https://svnweb.freebsd.org/changeset/base/277096

Log:
  Skip extra bcopy() when scrubbing vdev without redundancy.
  
  According to profiler, this bcopy() can use about 10% of CPU time.
  
  MFC after:	2 weeks

Modified:
  head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_mirror.c

Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_mirror.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_mirror.c	Mon Jan 12 22:36:50 2015	(r277095)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_mirror.c	Mon Jan 12 22:38:55 2015	(r277096)
@@ -435,7 +435,8 @@ 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