OpenZFS 7968 - multi-threaded spa_sync()

Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Saso Kiselkov <saso.kiselkov@nexenta.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: Matthew Ahrens <mahrens@delphix.com>

spa_sync() iterates over all the dirty dnodes and processes each of them
by calling dnode_sync(). If there are many dirty dnodes (e.g. because we
created or removed a lot of files), the single thread of spa_sync()
calling dnode_sync() can become a bottleneck. Additionally, if many
dnodes are dirtied concurrently in open context (e.g. due to concurrent
file creation), the os_lock will experience lock contention via
dnode_setdirty().

The solution is to track dirty dnodes on a multilist_t, and for
spa_sync() to use separate threads to process each of the sublists in
the multilist.

OpenZFS-issue: https://www.illumos.org/issues/7968
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/4a2a54c
Closes #5752
This commit is contained in:
Matthew Ahrens
2017-03-20 18:36:00 -07:00
committed by Brian Behlendorf
parent a3478c0747
commit 64fc776208
16 changed files with 303 additions and 159 deletions
+6 -4
View File
@@ -20,7 +20,7 @@
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2016 by Delphix. All rights reserved.
* Copyright (c) 2012, 2017 by Delphix. All rights reserved.
* Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
* Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
*/
@@ -113,7 +113,7 @@ struct objset {
/* no lock needed: */
struct dmu_tx *os_synctx; /* XXX sketchy */
zil_header_t os_zil_header;
list_t os_synced_dnodes;
multilist_t *os_synced_dnodes;
uint64_t os_flags;
uint64_t os_freed_dnodes;
boolean_t os_rescan_dnodes;
@@ -124,11 +124,13 @@ struct objset {
/* Protected by os_lock */
kmutex_t os_lock;
list_t os_dirty_dnodes[TXG_SIZE];
list_t os_free_dnodes[TXG_SIZE];
multilist_t *os_dirty_dnodes[TXG_SIZE];
list_t os_dnodes;
list_t os_downgraded_dbufs;
/* Protects changes to DMU_{USER,GROUP}USED_OBJECT */
kmutex_t os_userused_lock;
/* stuff we store for the user */
kmutex_t os_user_ptr_lock;
void *os_user_ptr;