Author: mav
Date: Tue Jan 20 13:09:12 2015
New Revision: 277419
URL: https://svnweb.freebsd.org/changeset/base/277419
Log:
Allow skipping dmu_buf_will_dirty() call in dsl_dir_transfer_space().
dsl_dir_transfer_space() is mostly called after dsl_dir_diduse_space(),
which already calls dmu_buf_will_dirty() for the same dbuf and tx, so
its duplicate call in those cases will change nothing, only spend time.
Skipping this call by four times reduces time spent in dbuf_write_done()
and descendants, updating dataset statistics with several congested lock
acquisitions. When rewriting 8K zvol blocks at 1GB/s rate, this reduces
CPU time spent inside dbuf_write_done(), according to profiling, from 45%
of 683K samples to 18% of 422K.
MFC after: 2 weeks
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dir.c
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c Tue Jan
20 12:28:24 2015 (r277418)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c Tue Jan
20 13:09:12 2015 (r277419)
@@ -136,7 +136,7 @@ dsl_dataset_block_born(dsl_dataset_t *ds
dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD, delta,
compressed, uncompressed, tx);
dsl_dir_transfer_space(ds->ds_dir, used - delta,
- DD_USED_REFRSRV, DD_USED_HEAD, tx);
+ DD_USED_REFRSRV, DD_USED_HEAD, NULL);
}
int
@@ -179,7 +179,7 @@ dsl_dataset_block_kill(dsl_dataset_t *ds
dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
delta, -compressed, -uncompressed, tx);
dsl_dir_transfer_space(ds->ds_dir, -used - delta,
- DD_USED_REFRSRV, DD_USED_HEAD, tx);
+ DD_USED_REFRSRV, DD_USED_HEAD, NULL);
} else {
dprintf_bp(bp, "putting on dead list: %s", "");
if (async) {
@@ -2837,7 +2837,7 @@ dsl_dataset_clone_swap_sync_impl(dsl_dat
origin_head->ds_dir->dd_origin_txg, UINT64_MAX,
&odl_used, &odl_comp, &odl_uncomp);
dsl_dir_transfer_space(origin_head->ds_dir, cdl_used - odl_used,
- DD_USED_HEAD, DD_USED_SNAP, tx);
+ DD_USED_HEAD, DD_USED_SNAP, NULL);
}
/* swap ds_*_bytes */
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dir.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dir.c Tue Jan
20 12:28:24 2015 (r277418)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dir.c Tue Jan
20 13:09:12 2015 (r277419)
@@ -1389,7 +1389,7 @@ dsl_dir_diduse_space(dsl_dir_t *dd, dd_u
accounted_delta, compressed, uncompressed, tx);
dsl_dir_transfer_space(dd->dd_parent,
used - accounted_delta,
- DD_USED_CHILD_RSRV, DD_USED_CHILD, tx);
+ DD_USED_CHILD_RSRV, DD_USED_CHILD, NULL);
}
}
@@ -1397,7 +1397,7 @@ void
dsl_dir_transfer_space(dsl_dir_t *dd, int64_t delta,
dd_used_t oldtype, dd_used_t newtype, dmu_tx_t *tx)
{
- ASSERT(dmu_tx_is_syncing(tx));
+ ASSERT(tx == NULL || dmu_tx_is_syncing(tx));
ASSERT(oldtype < DD_USED_NUM);
ASSERT(newtype < DD_USED_NUM);
@@ -1405,7 +1405,8 @@ dsl_dir_transfer_space(dsl_dir_t *dd, in
!(dsl_dir_phys(dd)->dd_flags & DD_FLAG_USED_BREAKDOWN))
return;
- dmu_buf_will_dirty(dd->dd_dbuf, tx);
+ if (tx != NULL)
+ dmu_buf_will_dirty(dd->dd_dbuf, tx);
mutex_enter(&dd->dd_lock);
ASSERT(delta > 0 ?
dsl_dir_phys(dd)->dd_used_breakdown[oldtype] >= delta :
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