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Introduce dsl_dir_diduse_transfer_space() 

Most of dsl_dir_diduse_space() and dsl_dir_transfer_space() CPU time
is a dd_lock overhead and time spent in dmu_buf_will_dirty(). Calling
them one after another is a waste of time and even more contention.
Doing that twice for each rewritten block within dbuf_write_done()
via dsl_dataset_block_kill() and dsl_dataset_block_born() created one
of the biggest CPU overheads in case of small blocks rewrite.

dsl_dir_diduse_transfer_space() combines functionality of these two
functions for cases where it is needed, but without double overhead,
practically for the cost of dsl_dir_diduse_space() or even cheaper.

While there, optimize dsl_dir_phys() calls in dsl_dir_diduse_space()
and dsl_dir_transfer_space().  It seems Clang detects some aliasing
there, repeating dd->dd_dbuf->db_data dereference multiple times,
increasing dd_lock scope and contention.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Author: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes #12300
This commit is contained in:
Alexander Motin 2021-07-16 15:39:24 -04:00 committed by GitHub
parent 41eba77061
commit c1b5869bab
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 85 additions and 38 deletions
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3
include/sys/dsl_dir.h
View File

@ -174,6 +174,9 @@ void dsl_dir_diduse_space(dsl_dir_t *dd, dd_used_t type,
int64_t used, int64_t compressed, int64_t uncompressed, dmu_tx_t *tx);
void dsl_dir_transfer_space(dsl_dir_t *dd, int64_t delta,
dd_used_t oldtype, dd_used_t newtype, dmu_tx_t *tx);
void dsl_dir_diduse_transfer_space(dsl_dir_t *dd, int64_t used,
int64_t compressed, int64_t uncompressed, int64_t tonew,
dd_used_t oldtype, dd_used_t newtype, dmu_tx_t *tx);
int dsl_dir_set_quota(const char *ddname, zprop_source_t source,
uint64_t quota);
int dsl_dir_set_reservation(const char *ddname, zprop_source_t source,

10
module/zfs/dsl_dataset.c
View File

@ -192,9 +192,8 @@ dsl_dataset_block_born(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx)
}
mutex_exit(&ds->ds_lock);
dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD, delta,
compressed, uncompressed, tx);
dsl_dir_transfer_space(ds->ds_dir, used - delta,
dsl_dir_diduse_transfer_space(ds->ds_dir, delta,
compressed, uncompressed, used,
DD_USED_REFRSRV, DD_USED_HEAD, tx);
}
@ -291,9 +290,8 @@ dsl_dataset_block_kill(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx,
delta = parent_delta(ds, -used);
dsl_dataset_phys(ds)->ds_unique_bytes -= used;
mutex_exit(&ds->ds_lock);
dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
delta, -compressed, -uncompressed, tx);
dsl_dir_transfer_space(ds->ds_dir, -used - delta,
dsl_dir_diduse_transfer_space(ds->ds_dir,
delta, -compressed, -uncompressed, -used,
DD_USED_REFRSRV, DD_USED_HEAD, tx);
} else {
dprintf_bp(bp, "putting on dead list: %s", "");

110
module/zfs/dsl_dir.c
View File

@ -1517,6 +1517,11 @@ dsl_dir_diduse_space(dsl_dir_t *dd, dd_used_t type,
{
int64_t accounted_delta;
ASSERT(dmu_tx_is_syncing(tx));
ASSERT(type < DD_USED_NUM);
dmu_buf_will_dirty(dd->dd_dbuf, tx);
/*
* dsl_dataset_set_refreservation_sync_impl() calls this with
* dd_lock held, so that it can atomically update
@ -1525,36 +1530,28 @@ dsl_dir_diduse_space(dsl_dir_t *dd, dd_used_t type,
* consistently.
*/
boolean_t needlock = !MUTEX_HELD(&dd->dd_lock);
ASSERT(dmu_tx_is_syncing(tx));
ASSERT(type < DD_USED_NUM);
dmu_buf_will_dirty(dd->dd_dbuf, tx);
if (needlock)
mutex_enter(&dd->dd_lock);
accounted_delta =
parent_delta(dd, dsl_dir_phys(dd)->dd_used_bytes, used);
ASSERT(used >= 0 || dsl_dir_phys(dd)->dd_used_bytes >= -used);
ASSERT(compressed >= 0 ||
dsl_dir_phys(dd)->dd_compressed_bytes >= -compressed);
dsl_dir_phys_t *ddp = dsl_dir_phys(dd);
accounted_delta = parent_delta(dd, ddp->dd_used_bytes, used);
ASSERT(used >= 0 || ddp->dd_used_bytes >= -used);
ASSERT(compressed >= 0 || ddp->dd_compressed_bytes >= -compressed);
ASSERT(uncompressed >= 0 ||
dsl_dir_phys(dd)->dd_uncompressed_bytes >= -uncompressed);
dsl_dir_phys(dd)->dd_used_bytes += used;
dsl_dir_phys(dd)->dd_uncompressed_bytes += uncompressed;
dsl_dir_phys(dd)->dd_compressed_bytes += compressed;
ddp->dd_uncompressed_bytes >= -uncompressed);
ddp->dd_used_bytes += used;
ddp->dd_uncompressed_bytes += uncompressed;
ddp->dd_compressed_bytes += compressed;
if (dsl_dir_phys(dd)->dd_flags & DD_FLAG_USED_BREAKDOWN) {
ASSERT(used > 0 ||
dsl_dir_phys(dd)->dd_used_breakdown[type] >= -used);
dsl_dir_phys(dd)->dd_used_breakdown[type] += used;
if (ddp->dd_flags & DD_FLAG_USED_BREAKDOWN) {
ASSERT(used >= 0 || ddp->dd_used_breakdown[type] >= -used);
ddp->dd_used_breakdown[type] += used;
#ifdef ZFS_DEBUG
{
dd_used_t t;
uint64_t u = 0;
for (t = 0; t < DD_USED_NUM; t++)
u += dsl_dir_phys(dd)->dd_used_breakdown[t];
ASSERT3U(u, ==, dsl_dir_phys(dd)->dd_used_bytes);
u += ddp->dd_used_breakdown[t];
ASSERT3U(u, ==, ddp->dd_used_bytes);
}
#endif
}
@ -1562,11 +1559,9 @@ dsl_dir_diduse_space(dsl_dir_t *dd, dd_used_t type,
mutex_exit(&dd->dd_lock);
if (dd->dd_parent != NULL) {
dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD,
accounted_delta, compressed, uncompressed, tx);
dsl_dir_transfer_space(dd->dd_parent,
used - accounted_delta,
DD_USED_CHILD_RSRV, DD_USED_CHILD, tx);
dsl_dir_diduse_transfer_space(dd->dd_parent,
accounted_delta, compressed, uncompressed,
used, DD_USED_CHILD_RSRV, DD_USED_CHILD, tx);
}
}
@ -1578,21 +1573,72 @@ dsl_dir_transfer_space(dsl_dir_t *dd, int64_t delta,
ASSERT(oldtype < DD_USED_NUM);
ASSERT(newtype < DD_USED_NUM);
dsl_dir_phys_t *ddp = dsl_dir_phys(dd);
if (delta == 0 ||
!(dsl_dir_phys(dd)->dd_flags & DD_FLAG_USED_BREAKDOWN))
!(ddp->dd_flags & DD_FLAG_USED_BREAKDOWN))
return;
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 :
dsl_dir_phys(dd)->dd_used_breakdown[newtype] >= -delta);
ASSERT(dsl_dir_phys(dd)->dd_used_bytes >= ABS(delta));
dsl_dir_phys(dd)->dd_used_breakdown[oldtype] -= delta;
dsl_dir_phys(dd)->dd_used_breakdown[newtype] += delta;
ddp->dd_used_breakdown[oldtype] >= delta :
ddp->dd_used_breakdown[newtype] >= -delta);
ASSERT(ddp->dd_used_bytes >= ABS(delta));
ddp->dd_used_breakdown[oldtype] -= delta;
ddp->dd_used_breakdown[newtype] += delta;
mutex_exit(&dd->dd_lock);
}
void
dsl_dir_diduse_transfer_space(dsl_dir_t *dd, int64_t used,
int64_t compressed, int64_t uncompressed, int64_t tonew,
dd_used_t oldtype, dd_used_t newtype, dmu_tx_t *tx)
{
int64_t accounted_delta;
ASSERT(dmu_tx_is_syncing(tx));
ASSERT(oldtype < DD_USED_NUM);
ASSERT(newtype < DD_USED_NUM);
dmu_buf_will_dirty(dd->dd_dbuf, tx);
mutex_enter(&dd->dd_lock);
dsl_dir_phys_t *ddp = dsl_dir_phys(dd);
accounted_delta = parent_delta(dd, ddp->dd_used_bytes, used);
ASSERT(used >= 0 || ddp->dd_used_bytes >= -used);
ASSERT(compressed >= 0 || ddp->dd_compressed_bytes >= -compressed);
ASSERT(uncompressed >= 0 ||
ddp->dd_uncompressed_bytes >= -uncompressed);
ddp->dd_used_bytes += used;
ddp->dd_uncompressed_bytes += uncompressed;
ddp->dd_compressed_bytes += compressed;
if (ddp->dd_flags & DD_FLAG_USED_BREAKDOWN) {
ASSERT(tonew - used <= 0 ||
ddp->dd_used_breakdown[oldtype] >= tonew - used);
ASSERT(tonew >= 0 ||
ddp->dd_used_breakdown[newtype] >= -tonew);
ddp->dd_used_breakdown[oldtype] -= tonew - used;
ddp->dd_used_breakdown[newtype] += tonew;
#ifdef ZFS_DEBUG
{
dd_used_t t;
uint64_t u = 0;
for (t = 0; t < DD_USED_NUM; t++)
u += ddp->dd_used_breakdown[t];
ASSERT3U(u, ==, ddp->dd_used_bytes);
}
#endif
}
mutex_exit(&dd->dd_lock);
if (dd->dd_parent != NULL) {
dsl_dir_diduse_transfer_space(dd->dd_parent,
accounted_delta, compressed, uncompressed,
used, DD_USED_CHILD_RSRV, DD_USED_CHILD, tx);
}
}
typedef struct dsl_dir_set_qr_arg {
const char *ddsqra_name;
zprop_source_t ddsqra_source;