Author: mav
Date: Fri Aug 17 15:17:09 2018
New Revision: 337972
URL: https://svnweb.freebsd.org/changeset/base/337972
Log:
9751 Allocation throttling misplacing ditto blocks
Relax allocation throttling for ditto blocks. Due to random imbalances
in allocation it tends to push block copies to one vdev, that looks
slightly better at the moment. Slightly less strict policy allows both
improve data security and surprisingly write performance, since we don't
need to touch extra metaslabs on each vdev to respect the min distance.
Sponsored by: iXsystems, Inc.
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c Fri Aug
17 15:02:58 2018 (r337971)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c Fri Aug
17 15:17:09 2018 (r337972)
@@ -1081,7 +1081,7 @@ metaslab_group_fragmentation(metaslab_group_t *mg)
*/
static boolean_t
metaslab_group_allocatable(metaslab_group_t *mg, metaslab_group_t *rotor,
- uint64_t psize, int allocator)
+ uint64_t psize, int allocator, int d)
{
spa_t *spa = mg->mg_vd->vdev_spa;
metaslab_class_t *mc = mg->mg_class;
@@ -1122,6 +1122,13 @@ metaslab_group_allocatable(metaslab_group_t *mg, metas
if (mg->mg_no_free_space)
return (B_FALSE);
+ /*
+ * Relax allocation throttling for ditto blocks. Due to
+ * random imbalances in allocation it tends to push copies
+ * to one vdev, that looks a bit better at the moment.
+ */
+ qmax = qmax * (4 + d) / 4;
+
qdepth = refcount_count(&mg->mg_alloc_queue_depth[allocator]);
/*
@@ -1142,7 +1149,7 @@ metaslab_group_allocatable(metaslab_group_t *mg, metas
*/
for (mgp = mg->mg_next; mgp != rotor; mgp = mgp->mg_next) {
qmax = mgp->mg_cur_max_alloc_queue_depth[allocator];
-
+ qmax = qmax * (4 + d) / 4;
qdepth = refcount_count(
&mgp->mg_alloc_queue_depth[allocator]);
@@ -3424,7 +3431,7 @@ top:
*/
if (allocatable && !GANG_ALLOCATION(flags) && !try_hard) {
allocatable = metaslab_group_allocatable(mg, rotor,
- psize, allocator);
+ psize, allocator, d);
}
if (!allocatable) {
_______________________________________________
svn-src-head@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
