Author: delphij
Date: Sat Dec 13 01:39:24 2014
New Revision: 275738
URL: https://svnweb.freebsd.org/changeset/base/275738
Log:
MFV r275546:
Reduce scrub activities when system there is enough dirty data, namely when
dirty data is more than zfs_vdev_async_write_active_min_dirty_percent (once
we start to increase the number of concurrent async writes).
While there also correct rounding error which would make scrub end up
pausing for (zfs_txg_timeout + 1) seconds instead of the desired
zfs_txg_timeout seconds.
Illumos issue:
5351 scrub goes for an extra second each txg
5352 scrub should pause when there is some dirty data
MFC after: 2 weeks
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_scan.c
Directory Properties:
head/sys/cddl/contrib/opensolaris/ (props changed)
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_scan.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_scan.c Sat Dec
13 01:26:06 2014 (r275737)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_scan.c Sat Dec
13 01:39:24 2014 (r275738)
@@ -414,12 +414,11 @@ dsl_scan_sync_state(dsl_scan_t *scn, dmu
&scn->scn_phys, tx));
}
+extern int zfs_vdev_async_write_active_min_dirty_percent;
+
static boolean_t
dsl_scan_check_pause(dsl_scan_t *scn, const zbookmark_phys_t *zb)
{
- uint64_t elapsed_nanosecs;
- unsigned int mintime;
-
/* we never skip user/group accounting objects */
if (zb && (int64_t)zb->zb_object < 0)
return (B_FALSE);
@@ -434,12 +433,28 @@ dsl_scan_check_pause(dsl_scan_t *scn, co
if (zb && zb->zb_level != 0)
return (B_FALSE);
- mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
+ /*
+ * We pause if:
+ * - we have scanned for the maximum time: an entire txg
+ * timeout (default 5 sec)
+ * or
+ * - we have scanned for at least the minimum time (default 1 sec
+ * for scrub, 3 sec for resilver), and either we have sufficient
+ * dirty data that we are starting to write more quickly
+ * (default 30%), or someone is explicitly waiting for this txg
+ * to complete.
+ * or
+ * - the spa is shutting down because this pool is being exported
+ * or the machine is rebooting.
+ */
+ int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
zfs_resilver_min_time_ms : zfs_scan_min_time_ms;
- elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
- if (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
+ uint64_t elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
+ int dirty_pct = scn->scn_dp->dp_dirty_total * 100 / zfs_dirty_data_max;
+ if (elapsed_nanosecs / NANOSEC >= zfs_txg_timeout ||
(NSEC2MSEC(elapsed_nanosecs) > mintime &&
- txg_sync_waiting(scn->scn_dp)) ||
+ (txg_sync_waiting(scn->scn_dp) ||
+ dirty_pct >= zfs_vdev_async_write_active_min_dirty_percent)) ||
spa_shutting_down(scn->scn_dp->dp_spa)) {
if (zb) {
dprintf("pausing at bookmark %llx/%llx/%llx/%llx\n",
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