zio_compress.c revision 268649 
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/zio.h>
39#include <sys/zio_compress.h>
40
41typedef struct zcomp_stats {
42	kstat_named_t zcompstat_attempts;
43	kstat_named_t zcompstat_empty;
44	kstat_named_t zcompstat_skipped_insufficient_gain;
45} zcomp_stats_t;
46
47static zcomp_stats_t zcomp_stats = {
48	{ "attempts",			KSTAT_DATA_UINT64 },
49	{ "empty",			KSTAT_DATA_UINT64 },
50	{ "skipped_insufficient_gain",	KSTAT_DATA_UINT64 }
51};
52
53#define	ZCOMPSTAT_INCR(stat, val) \
54	atomic_add_64(&zcomp_stats.stat.value.ui64, (val));
55
56#define	ZCOMPSTAT_BUMP(stat)		ZCOMPSTAT_INCR(stat, 1);
57
58kstat_t		*zcomp_ksp;
59
60/*
61 * Compression vectors.
62 */
63
64zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
65	{NULL,			NULL,			0,	"inherit"},
66	{NULL,			NULL,			0,	"on"},
67	{NULL,			NULL,			0,	"uncompressed"},
68	{lzjb_compress,		lzjb_decompress,	0,	"lzjb"},
69	{NULL,			NULL,			0,	"empty"},
70	{gzip_compress,		gzip_decompress,	1,	"gzip-1"},
71	{gzip_compress,		gzip_decompress,	2,	"gzip-2"},
72	{gzip_compress,		gzip_decompress,	3,	"gzip-3"},
73	{gzip_compress,		gzip_decompress,	4,	"gzip-4"},
74	{gzip_compress,		gzip_decompress,	5,	"gzip-5"},
75	{gzip_compress,		gzip_decompress,	6,	"gzip-6"},
76	{gzip_compress,		gzip_decompress,	7,	"gzip-7"},
77	{gzip_compress,		gzip_decompress,	8,	"gzip-8"},
78	{gzip_compress,		gzip_decompress,	9,	"gzip-9"},
79	{zle_compress,		zle_decompress,		64,	"zle"},
80	{lz4_compress,		lz4_decompress,		0,	"lz4"},
81};
82
83enum zio_compress
84zio_compress_select(enum zio_compress child, enum zio_compress parent)
85{
86	ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
87	ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
88	ASSERT(parent != ZIO_COMPRESS_INHERIT && parent != ZIO_COMPRESS_ON);
89
90	if (child == ZIO_COMPRESS_INHERIT)
91		return (parent);
92
93	if (child == ZIO_COMPRESS_ON)
94		return (ZIO_COMPRESS_ON_VALUE);
95
96	return (child);
97}
98
99size_t
100zio_compress_data(enum zio_compress c, void *src, void *dst, size_t s_len,
101    size_t minblocksize)
102{
103	uint64_t *word, *word_end;
104	size_t c_len, d_len;
105	zio_compress_info_t *ci = &zio_compress_table[c];
106
107	ASSERT((uint_t)c < ZIO_COMPRESS_FUNCTIONS);
108	ASSERT((uint_t)c == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL);
109
110	ZCOMPSTAT_BUMP(zcompstat_attempts);
111
112	/*
113	 * If the data is all zeroes, we don't even need to allocate
114	 * a block for it.  We indicate this by returning zero size.
115	 */
116	word_end = (uint64_t *)((char *)src + s_len);
117	for (word = src; word < word_end; word++)
118		if (*word != 0)
119			break;
120
121	if (word == word_end) {
122		ZCOMPSTAT_BUMP(zcompstat_empty);
123 		return (0);
124	}
125
126	if (c == ZIO_COMPRESS_EMPTY)
127		return (s_len);
128
129	/* Compress at least 12.5% */
130	d_len = s_len - (s_len >> 3);
131	c_len = ci->ci_compress(src, dst, s_len, d_len, ci->ci_level);
132
133	if (c_len > d_len) {
134		ZCOMPSTAT_BUMP(zcompstat_skipped_insufficient_gain);
135		return (s_len);
136	}
137
138	ASSERT3U(c_len, <=, d_len);
139	return (c_len);
140}
141
142int
143zio_decompress_data(enum zio_compress c, void *src, void *dst,
144    size_t s_len, size_t d_len)
145{
146	zio_compress_info_t *ci = &zio_compress_table[c];
147
148	if ((uint_t)c >= ZIO_COMPRESS_FUNCTIONS || ci->ci_decompress == NULL)
149		return (SET_ERROR(EINVAL));
150
151	return (ci->ci_decompress(src, dst, s_len, d_len, ci->ci_level));
152}
153
154void
155zio_compress_init(void)
156{
157
158	zcomp_ksp = kstat_create("zfs", 0, "zcompstats", "misc",
159	    KSTAT_TYPE_NAMED, sizeof (zcomp_stats) / sizeof (kstat_named_t),
160	    KSTAT_FLAG_VIRTUAL);
161
162	if (zcomp_ksp != NULL) {
163		zcomp_ksp->ks_data = &zcomp_stats;
164		kstat_install(zcomp_ksp);
165	}
166}
167
168void
169zio_compress_fini(void)
170{
171	if (zcomp_ksp != NULL) {
172		kstat_delete(zcomp_ksp);
173		zcomp_ksp = NULL;
174	}
175}
176