freebsd-nq/include/sys/multilist.h
Matthew Ahrens 64fc776208 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
2017-03-20 18:36:00 -07:00

106 lines
3.1 KiB
C

/*
* CDDL HEADER START
*
* This file and its contents are supplied under the terms of the
* Common Development and Distribution License ("CDDL"), version 1.0.
* You may only use this file in accordance with the terms of version
* 1.0 of the CDDL.
*
* A full copy of the text of the CDDL should have accompanied this
* source. A copy of the CDDL is also available via the Internet at
* http://www.illumos.org/license/CDDL.
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2013, 2017 by Delphix. All rights reserved.
*/
#ifndef _SYS_MULTILIST_H
#define _SYS_MULTILIST_H
#include <sys/zfs_context.h>
#ifdef __cplusplus
extern "C" {
#endif
typedef list_node_t multilist_node_t;
typedef struct multilist multilist_t;
typedef struct multilist_sublist multilist_sublist_t;
typedef unsigned int multilist_sublist_index_func_t(multilist_t *, void *);
struct multilist_sublist {
/*
* The mutex used internally to implement thread safe insertions
* and removals to this individual sublist. It can also be locked
* by a consumer using multilist_sublist_{lock,unlock}, which is
* useful if a consumer needs to traverse the list in a thread
* safe manner.
*/
kmutex_t mls_lock;
/*
* The actual list object containing all objects in this sublist.
*/
list_t mls_list;
/*
* Pad to cache line, in an effort to try and prevent cache line
* contention.
*/
} ____cacheline_aligned;
struct multilist {
/*
* This is used to get to the multilist_node_t structure given
* the void *object contained on the list.
*/
size_t ml_offset;
/*
* The number of sublists used internally by this multilist.
*/
uint64_t ml_num_sublists;
/*
* The array of pointers to the actual sublists.
*/
multilist_sublist_t *ml_sublists;
/*
* Pointer to function which determines the sublist to use
* when inserting and removing objects from this multilist.
* Please see the comment above multilist_create for details.
*/
multilist_sublist_index_func_t *ml_index_func;
};
void multilist_destroy(multilist_t *);
multilist_t *multilist_create(size_t, size_t, multilist_sublist_index_func_t *);
void multilist_insert(multilist_t *, void *);
void multilist_remove(multilist_t *, void *);
int multilist_is_empty(multilist_t *);
unsigned int multilist_get_num_sublists(multilist_t *);
unsigned int multilist_get_random_index(multilist_t *);
multilist_sublist_t *multilist_sublist_lock(multilist_t *, unsigned int);
multilist_sublist_t *multilist_sublist_lock_obj(multilist_t *, void *);
void multilist_sublist_unlock(multilist_sublist_t *);
void multilist_sublist_insert_head(multilist_sublist_t *, void *);
void multilist_sublist_insert_tail(multilist_sublist_t *, void *);
void multilist_sublist_move_forward(multilist_sublist_t *mls, void *obj);
void multilist_sublist_remove(multilist_sublist_t *, void *);
void *multilist_sublist_head(multilist_sublist_t *);
void *multilist_sublist_tail(multilist_sublist_t *);
void *multilist_sublist_next(multilist_sublist_t *, void *);
void *multilist_sublist_prev(multilist_sublist_t *, void *);
void multilist_link_init(multilist_node_t *);
int multilist_link_active(multilist_node_t *);
#ifdef __cplusplus
}
#endif
#endif /* _SYS_MULTILIST_H */