mirror_zfs/include/sys/metaslab_impl.h
George Wilson e51be06697 Illumos #3552, #3564
3552 condensing one space map burns 3 seconds of CPU in spa_sync() thread
3564 spa_sync() spends 5-10% of its time in metaslab_sync() (when not condensing)
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

References:
  illumos/illumos-gate@16a4a80742
  https://www.illumos.org/issues/3552
  https://www.illumos.org/issues/3564

Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1513
2013-06-19 16:22:39 -07:00

114 lines
3.9 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
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* CDDL HEADER END
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Copyright (c) 2012 by Delphix. All rights reserved.
*/
#ifndef _SYS_METASLAB_IMPL_H
#define _SYS_METASLAB_IMPL_H
#include <sys/metaslab.h>
#include <sys/space_map.h>
#include <sys/vdev.h>
#include <sys/txg.h>
#include <sys/avl.h>
#ifdef __cplusplus
extern "C" {
#endif
struct metaslab_class {
spa_t *mc_spa;
metaslab_group_t *mc_rotor;
space_map_ops_t *mc_ops;
uint64_t mc_aliquot;
uint64_t mc_alloc; /* total allocated space */
uint64_t mc_deferred; /* total deferred frees */
uint64_t mc_space; /* total space (alloc + free) */
uint64_t mc_dspace; /* total deflated space */
kmutex_t mc_fastwrite_lock;
};
struct metaslab_group {
kmutex_t mg_lock;
avl_tree_t mg_metaslab_tree;
uint64_t mg_aliquot;
uint64_t mg_bonus_area;
uint64_t mg_alloc_failures;
int64_t mg_bias;
int64_t mg_activation_count;
metaslab_class_t *mg_class;
vdev_t *mg_vd;
metaslab_group_t *mg_prev;
metaslab_group_t *mg_next;
};
/*
* Each metaslab maintains an in-core free map (ms_map) that contains the
* current list of free segments. As blocks are allocated, the allocated
* segment is removed from the ms_map and added to a per txg allocation map.
* As blocks are freed, they are added to the per txg free map. These per
* txg maps allow us to process all allocations and frees in syncing context
* where it is safe to update the on-disk space maps.
*
* Each metaslab's free space is tracked in a space map object in the MOS,
* which is only updated in syncing context. Each time we sync a txg,
* we append the allocs and frees from that txg to the space map object.
* When the txg is done syncing, metaslab_sync_done() updates ms_smo
* to ms_smo_syncing. Everything in ms_smo is always safe to allocate.
*
* To load the in-core free map we read the space map object from disk.
* This object contains a series of alloc and free records that are
* combined to make up the list of all free segments in this metaslab. These
* segments are represented in-core by the ms_map and are stored in an
* AVL tree.
*
* As the space map objects grows (as a result of the appends) it will
* eventually become space-inefficient. When the space map object is
* zfs_condense_pct/100 times the size of the minimal on-disk representation,
* we rewrite it in its minimized form.
*/
struct metaslab {
kmutex_t ms_lock; /* metaslab lock */
space_map_obj_t ms_smo; /* synced space map object */
space_map_obj_t ms_smo_syncing; /* syncing space map object */
space_map_t *ms_allocmap[TXG_SIZE]; /* allocated this txg */
space_map_t *ms_freemap[TXG_SIZE]; /* freed this txg */
space_map_t *ms_defermap[TXG_DEFER_SIZE]; /* deferred frees */
space_map_t *ms_map; /* in-core free space map */
int64_t ms_deferspace; /* sum of ms_defermap[] space */
uint64_t ms_weight; /* weight vs. others in group */
metaslab_group_t *ms_group; /* metaslab group */
avl_node_t ms_group_node; /* node in metaslab group tree */
txg_node_t ms_txg_node; /* per-txg dirty metaslab links */
};
#ifdef __cplusplus
}
#endif
#endif /* _SYS_METASLAB_IMPL_H */