freebsd-dev/include/sys/bpobj.h
Alexander Motin dc5c8006f6
Prefetch on deadlists merge
During snapshot deletion ZFS may issue several reads for each deadlist
to merge them into next snapshot's or pool's bpobj.  Number of the dead
lists increases with number of snapshots.  On HDD pools it may take
significant time during which sync thread is blocked.

This patch introduces prescient prefetch of required blocks for up to
128 deadlists ahead.  Tests show reduction of time required to delete
dataset with 720 snapshots with randomly overwritten file on wide HDD
pool from 75-85 to 22-28 seconds.

Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Issue #14276 
Closes #14402
2023-01-25 11:30:24 -08:00

108 lines
3.3 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 https://opensource.org/licenses/CDDL-1.0.
* 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]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2015, 2019 by Delphix. All rights reserved.
*/
#ifndef _SYS_BPOBJ_H
#define _SYS_BPOBJ_H
#include <sys/dmu.h>
#include <sys/spa.h>
#include <sys/txg.h>
#include <sys/zio.h>
#include <sys/zfs_context.h>
#include <sys/bplist.h>
#ifdef __cplusplus
extern "C" {
#endif
typedef struct bpobj_phys {
/*
* This is the bonus buffer for the dead lists. The object's
* contents is an array of bpo_entries blkptr_t's, representing
* a total of bpo_bytes physical space.
*/
uint64_t bpo_num_blkptrs;
uint64_t bpo_bytes;
uint64_t bpo_comp;
uint64_t bpo_uncomp;
uint64_t bpo_subobjs;
uint64_t bpo_num_subobjs;
uint64_t bpo_num_freed;
} bpobj_phys_t;
#define BPOBJ_SIZE_V0 (2 * sizeof (uint64_t))
#define BPOBJ_SIZE_V1 (4 * sizeof (uint64_t))
#define BPOBJ_SIZE_V2 (6 * sizeof (uint64_t))
typedef struct bpobj {
kmutex_t bpo_lock;
objset_t *bpo_os;
uint64_t bpo_object;
int bpo_epb;
uint8_t bpo_havecomp;
uint8_t bpo_havesubobj;
uint8_t bpo_havefreed;
bpobj_phys_t *bpo_phys;
dmu_buf_t *bpo_dbuf;
dmu_buf_t *bpo_cached_dbuf;
} bpobj_t;
typedef int bpobj_itor_t(void *arg, const blkptr_t *bp, boolean_t bp_freed,
dmu_tx_t *tx);
uint64_t bpobj_alloc(objset_t *mos, int blocksize, dmu_tx_t *tx);
uint64_t bpobj_alloc_empty(objset_t *os, int blocksize, dmu_tx_t *tx);
void bpobj_free(objset_t *os, uint64_t obj, dmu_tx_t *tx);
void bpobj_decr_empty(objset_t *os, dmu_tx_t *tx);
int bpobj_open(bpobj_t *bpo, objset_t *mos, uint64_t object);
void bpobj_close(bpobj_t *bpo);
boolean_t bpobj_is_open(const bpobj_t *bpo);
int bpobj_iterate(bpobj_t *bpo, bpobj_itor_t func, void *arg, dmu_tx_t *tx);
int bpobj_iterate_nofree(bpobj_t *bpo, bpobj_itor_t func, void *, uint64_t *);
int livelist_bpobj_iterate_from_nofree(bpobj_t *bpo, bpobj_itor_t func,
void *arg, int64_t start);
void bpobj_enqueue_subobj(bpobj_t *bpo, uint64_t subobj, dmu_tx_t *tx);
void bpobj_prefetch_subobj(bpobj_t *bpo, uint64_t subobj);
void bpobj_enqueue(bpobj_t *bpo, const blkptr_t *bp, boolean_t bp_freed,
dmu_tx_t *tx);
int bpobj_space(bpobj_t *bpo,
uint64_t *usedp, uint64_t *compp, uint64_t *uncompp);
int bpobj_space_range(bpobj_t *bpo, uint64_t mintxg, uint64_t maxtxg,
uint64_t *usedp, uint64_t *compp, uint64_t *uncompp);
boolean_t bpobj_is_empty(bpobj_t *bpo);
int bplist_append_cb(void *arg, const blkptr_t *bp, boolean_t bp_freed,
dmu_tx_t *tx);
#ifdef __cplusplus
}
#endif
#endif /* _SYS_BPOBJ_H */