zio_compress.c revision 288542 
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26/*
27 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
28 */
29
30/*
31 * Copyright (c) 2013 by Delphix. All rights reserved.
32 */
33
34#include <sys/zfs_context.h>
35#include <sys/compress.h>
36#include <sys/kstat.h>
37#include <sys/spa.h>
38#include <sys/zfeature.h>
39#include <sys/zio.h>
40#include <sys/zio_compress.h>
41
42typedef struct zcomp_stats {
43	kstat_named_t zcompstat_attempts;
44	kstat_named_t zcompstat_empty;
45	kstat_named_t zcompstat_skipped_insufficient_gain;
46} zcomp_stats_t;
47
48static zcomp_stats_t zcomp_stats = {
49	{ "attempts",			KSTAT_DATA_UINT64 },
50	{ "empty",			KSTAT_DATA_UINT64 },
51	{ "skipped_insufficient_gain",	KSTAT_DATA_UINT64 }
52};
53
54#define	ZCOMPSTAT_INCR(stat, val) \
55	atomic_add_64(&zcomp_stats.stat.value.ui64, (val));
56
57#define	ZCOMPSTAT_BUMP(stat)		ZCOMPSTAT_INCR(stat, 1);
58
59kstat_t		*zcomp_ksp;
60
61/*
62 * Compression vectors.
63 */
64
65zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
66	{NULL,			NULL,			0,	"inherit"},
67	{NULL,			NULL,			0,	"on"},
68	{NULL,			NULL,			0,	"uncompressed"},
69	{lzjb_compress,		lzjb_decompress,	0,	"lzjb"},
70	{NULL,			NULL,			0,	"empty"},
71	{gzip_compress,		gzip_decompress,	1,	"gzip-1"},
72	{gzip_compress,		gzip_decompress,	2,	"gzip-2"},
73	{gzip_compress,		gzip_decompress,	3,	"gzip-3"},
74	{gzip_compress,		gzip_decompress,	4,	"gzip-4"},
75	{gzip_compress,		gzip_decompress,	5,	"gzip-5"},
76	{gzip_compress,		gzip_decompress,	6,	"gzip-6"},
77	{gzip_compress,		gzip_decompress,	7,	"gzip-7"},
78	{gzip_compress,		gzip_decompress,	8,	"gzip-8"},
79	{gzip_compress,		gzip_decompress,	9,	"gzip-9"},
80	{zle_compress,		zle_decompress,		64,	"zle"},
81	{lz4_compress,		lz4_decompress,		0,	"lz4"},
82};
83
84enum zio_compress
85zio_compress_select(spa_t *spa, enum zio_compress child,
86    enum zio_compress parent)
87{
88	enum zio_compress result;
89
90	ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
91	ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
92	ASSERT(parent != ZIO_COMPRESS_INHERIT);
93
94	result = child;
95	if (result == ZIO_COMPRESS_INHERIT)
96		result = parent;
97
98	if (result == ZIO_COMPRESS_ON) {
99		if (spa_feature_is_active(spa, SPA_FEATURE_LZ4_COMPRESS))
100			result = ZIO_COMPRESS_LZ4_ON_VALUE;
101		else
102			result = ZIO_COMPRESS_LEGACY_ON_VALUE;
103	}
104
105	return (result);
106}
107
108size_t
109zio_compress_data(enum zio_compress c, void *src, void *dst, size_t s_len)
110{
111	uint64_t *word, *word_end;
112	size_t c_len, d_len;
113	zio_compress_info_t *ci = &zio_compress_table[c];
114
115	ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
116	ASSERT((uint_t)c == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
117
118	ZCOMPSTAT_BUMP(zcompstat_attempts);
119
120	/*
121	 * If the data is all zeroes, we don't even need to allocate
122	 * a block for it.  We indicate this by returning zero size.
123	 */
124	word_end = (uint64_t *)((char *)src + s_len);
125	for (word = src; word < word_end; word++)
126		if (*word != 0)
127			break;
128
129	if (word == word_end) {
130		ZCOMPSTAT_BUMP(zcompstat_empty);
131 		return (0);
132	}
133
134	if (c == ZIO_COMPRESS_EMPTY)
135		return (s_len);
136
137	/* Compress at least 12.5% */
138	d_len = s_len - (s_len >> 3);
139	c_len = ci->ci_compress(src, dst, s_len, d_len, ci->ci_level);
140
141	if (c_len > d_len) {
142		ZCOMPSTAT_BUMP(zcompstat_skipped_insufficient_gain);
143		return (s_len);
144	}
145
146	ASSERT3U(c_len, <=, d_len);
147	return (c_len);
148}
149
150int
151zio_decompress_data(enum zio_compress c, void *src, void *dst,
152    size_t s_len, size_t d_len)
153{
154	zio_compress_info_t *ci = &zio_compress_table[c];
155
156	if ((uint_t)c >= ZIO_COMPRESS_FUNCTIONS || ci->ci_decompress == NULL)
157		return (SET_ERROR(EINVAL));
158
159	return (ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level));
160}
161
162void
163zio_compress_init(void)
164{
165
166	zcomp_ksp = kstat_create("zfs", 0, "zcompstats", "misc",
167	    KSTAT_TYPE_NAMED, sizeof (zcomp_stats) / sizeof (kstat_named_t),
168	    KSTAT_FLAG_VIRTUAL);
169
170	if (zcomp_ksp != NULL) {
171		zcomp_ksp->ks_data = &zcomp_stats;
172		kstat_install(zcomp_ksp);
173	}
174}
175
176void
177zio_compress_fini(void)
178{
179	if (zcomp_ksp != NULL) {
180		kstat_delete(zcomp_ksp);
181		zcomp_ksp = NULL;
182	}
183}
184