Add strong madvise() hint for cache pruning
[fio.git] / engines / mmap.c
CommitLineData
2866c82d 1/*
da751ca9
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2 * mmap engine
3 *
4 * IO engine that reads/writes from files by doing memcpy to/from
5 * a memory mapped region of the file.
2866c82d
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6 *
7 */
8#include <stdio.h>
9#include <stdlib.h>
10#include <unistd.h>
11#include <errno.h>
2866c82d 12#include <sys/mman.h>
5f350952
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13
14#include "../fio.h"
4f5af7b2 15#include "../verify.h"
2866c82d 16
ac893112 17/*
ff455a04 18 * Limits us to 1GB of mapped files in total
ac893112 19 */
ff455a04 20#define MMAP_TOTAL_SZ (1 * 1024 * 1024 * 1024UL)
2866c82d 21
ac893112
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22static unsigned long mmap_map_size;
23static unsigned long mmap_map_mask;
2866c82d 24
ac893112
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25static int fio_mmap_file(struct thread_data *td, struct fio_file *f,
26 size_t length, off_t off)
b5af8293 27{
ac893112 28 int flags = 0;
c97d8369 29
b5af8293
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30 if (td_rw(td))
31 flags = PROT_READ | PROT_WRITE;
32 else if (td_write(td)) {
33 flags = PROT_WRITE;
34
2dc1bbeb 35 if (td->o.verify != VERIFY_NONE)
b5af8293
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36 flags |= PROT_READ;
37 } else
38 flags = PROT_READ;
39
ac893112
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40 f->mmap_ptr = mmap(NULL, length, flags, MAP_SHARED, f->fd, off);
41 if (f->mmap_ptr == MAP_FAILED) {
ac893112 42 f->mmap_ptr = NULL;
ed47cbf7 43 td_verror(td, errno, "mmap");
b5af8293
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44 goto err;
45 }
46
b5af8293 47 if (!td_random(td)) {
ac893112 48 if (madvise(f->mmap_ptr, length, MADV_SEQUENTIAL) < 0) {
b5af8293
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49 td_verror(td, errno, "madvise");
50 goto err;
51 }
52 } else {
ac893112 53 if (madvise(f->mmap_ptr, length, MADV_RANDOM) < 0) {
b5af8293
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54 td_verror(td, errno, "madvise");
55 goto err;
56 }
57 }
58
b5af8293 59err:
ed47cbf7
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60 if (td->error && f->mmap_ptr)
61 munmap(f->mmap_ptr, length);
62
63 return td->error;
b5af8293
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64}
65
ed47cbf7
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66/*
67 * Just mmap an appropriate portion, we cannot mmap the full extent
68 */
69static int fio_mmapio_prep_limited(struct thread_data *td, struct io_u *io_u)
b5af8293 70{
ac893112 71 struct fio_file *f = io_u->file;
6977bcd0 72
ac893112
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73 if (io_u->buflen > mmap_map_size) {
74 log_err("fio: bs too big for mmap engine\n");
ed47cbf7 75 return EIO;
ac893112
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76 }
77
ac893112
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78 f->mmap_sz = mmap_map_size;
79 if (f->mmap_sz > f->io_size)
80 f->mmap_sz = f->io_size;
6977bcd0 81
ff455a04 82 f->mmap_off = io_u->offset;
ac893112 83
ed47cbf7
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84 return fio_mmap_file(td, f, f->mmap_sz, f->mmap_off);
85}
86
87/*
88 * Attempt to mmap the entire file
89 */
90static int fio_mmapio_prep_full(struct thread_data *td, struct io_u *io_u)
91{
92 struct fio_file *f = io_u->file;
93 int ret;
94
95 if (fio_file_partial_mmap(f))
96 return EINVAL;
97
ed47cbf7
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98 f->mmap_sz = f->io_size;
99 f->mmap_off = 0;
100
ac893112 101 ret = fio_mmap_file(td, f, f->mmap_sz, f->mmap_off);
ed47cbf7
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102 if (ret)
103 fio_file_set_partial_mmap(f);
104
6977bcd0 105 return ret;
b5af8293
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106}
107
ed47cbf7
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108static int fio_mmapio_prep(struct thread_data *td, struct io_u *io_u)
109{
110 struct fio_file *f = io_u->file;
111 int ret;
112
8f933cae
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113 /*
114 * It fits within existing mapping, use it
115 */
ed47cbf7
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116 if (io_u->offset >= f->mmap_off &&
117 io_u->offset + io_u->buflen < f->mmap_off + f->mmap_sz)
118 goto done;
119
8f933cae
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120 /*
121 * unmap any existing mapping
122 */
123 if (f->mmap_ptr) {
124 if (munmap(f->mmap_ptr, f->mmap_sz) < 0)
125 return errno;
126 f->mmap_ptr = NULL;
127 }
128
ed47cbf7
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129 if (fio_mmapio_prep_full(td, io_u)) {
130 td_clear_error(td);
131 ret = fio_mmapio_prep_limited(td, io_u);
132 if (ret)
133 return ret;
134 }
135
136done:
137 io_u->mmap_data = f->mmap_ptr + io_u->offset - f->mmap_off -
138 f->file_offset;
139 return 0;
140}
141
ac893112
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142static int fio_mmapio_queue(struct thread_data *td, struct io_u *io_u)
143{
144 struct fio_file *f = io_u->file;
145
146 fio_ro_check(td, io_u);
147
148 if (io_u->ddir == DDIR_READ)
149 memcpy(io_u->xfer_buf, io_u->mmap_data, io_u->xfer_buflen);
150 else if (io_u->ddir == DDIR_WRITE)
151 memcpy(io_u->mmap_data, io_u->xfer_buf, io_u->xfer_buflen);
5f9099ea 152 else if (ddir_sync(io_u->ddir)) {
ac893112
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153 if (msync(f->mmap_ptr, f->mmap_sz, MS_SYNC)) {
154 io_u->error = errno;
155 td_verror(td, io_u->error, "msync");
156 }
157 }
158
159 /*
160 * not really direct, but should drop the pages from the cache
161 */
5f9099ea 162 if (td->o.odirect && !ddir_sync(io_u->ddir)) {
ac893112
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163 if (msync(io_u->mmap_data, io_u->xfer_buflen, MS_SYNC) < 0) {
164 io_u->error = errno;
165 td_verror(td, io_u->error, "msync");
166 }
167 if (madvise(io_u->mmap_data, io_u->xfer_buflen, MADV_DONTNEED) < 0) {
168 io_u->error = errno;
169 td_verror(td, io_u->error, "madvise");
170 }
171 }
172
173 return FIO_Q_COMPLETED;
174}
175
176static int fio_mmapio_init(struct thread_data *td)
177{
178 unsigned long shift, mask;
179
180 mmap_map_size = MMAP_TOTAL_SZ / td->o.nr_files;
181 mask = mmap_map_size;
182 shift = 0;
183 do {
184 mask >>= 1;
185 if (!mask)
186 break;
187 shift++;
188 } while (1);
189
190 mmap_map_mask = 1UL << shift;
191 return 0;
192}
193
5f350952 194static struct ioengine_ops ioengine = {
2866c82d
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195 .name = "mmap",
196 .version = FIO_IOOPS_VERSION,
ac893112
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197 .init = fio_mmapio_init,
198 .prep = fio_mmapio_prep,
2866c82d 199 .queue = fio_mmapio_queue,
ac893112
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200 .open_file = generic_open_file,
201 .close_file = generic_close_file,
df9c26b1 202 .get_file_size = generic_get_file_size,
0263882a 203 .flags = FIO_SYNCIO | FIO_NOEXTEND,
2866c82d 204};
5f350952
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205
206static void fio_init fio_mmapio_register(void)
207{
208 register_ioengine(&ioengine);
209}
210
211static void fio_exit fio_mmapio_unregister(void)
212{
213 unregister_ioengine(&ioengine);
214}