1 /*
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.
6 *
7 */
8 #include <stdio.h>
9 #include <stdlib.h>
10 #include <unistd.h>
11 #include <errno.h>
12 #include <sys/mman.h>
13
14 #include "../fio.h"
15 #include "../verify.h"
16
17 /*
18 * Limits us to 1GB of mapped files in total
19 */
20 #define MMAP_TOTAL_SZ (1 * 1024 * 1024 * 1024UL)
21
22 static unsigned long mmap_map_size;
23 static unsigned long mmap_map_mask;
24
fio_mmap_file(struct thread_data * td,struct fio_file * f,size_t length,off_t off)25 static int fio_mmap_file(struct thread_data *td, struct fio_file *f,
26 size_t length, off_t off)
27 {
28 int flags = 0;
29
30 if (td_rw(td))
31 flags = PROT_READ | PROT_WRITE;
32 else if (td_write(td)) {
33 flags = PROT_WRITE;
34
35 if (td->o.verify != VERIFY_NONE)
36 flags |= PROT_READ;
37 } else
38 flags = PROT_READ;
39
40 f->mmap_ptr = mmap(NULL, length, flags, MAP_SHARED, f->fd, off);
41 if (f->mmap_ptr == MAP_FAILED) {
42 f->mmap_ptr = NULL;
43 td_verror(td, errno, "mmap");
44 goto err;
45 }
46
47 if (!td_random(td)) {
48 if (posix_madvise(f->mmap_ptr, length, POSIX_MADV_SEQUENTIAL) < 0) {
49 td_verror(td, errno, "madvise");
50 goto err;
51 }
52 } else {
53 if (posix_madvise(f->mmap_ptr, length, POSIX_MADV_RANDOM) < 0) {
54 td_verror(td, errno, "madvise");
55 goto err;
56 }
57 }
58
59 err:
60 if (td->error && f->mmap_ptr)
61 munmap(f->mmap_ptr, length);
62
63 return td->error;
64 }
65
66 /*
67 * Just mmap an appropriate portion, we cannot mmap the full extent
68 */
fio_mmapio_prep_limited(struct thread_data * td,struct io_u * io_u)69 static int fio_mmapio_prep_limited(struct thread_data *td, struct io_u *io_u)
70 {
71 struct fio_file *f = io_u->file;
72
73 if (io_u->buflen > mmap_map_size) {
74 log_err("fio: bs too big for mmap engine\n");
75 return EIO;
76 }
77
78 f->mmap_sz = mmap_map_size;
79 if (f->mmap_sz > f->io_size)
80 f->mmap_sz = f->io_size;
81
82 f->mmap_off = io_u->offset;
83
84 return fio_mmap_file(td, f, f->mmap_sz, f->mmap_off);
85 }
86
87 /*
88 * Attempt to mmap the entire file
89 */
fio_mmapio_prep_full(struct thread_data * td,struct io_u * io_u)90 static 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
98 f->mmap_sz = f->io_size;
99 f->mmap_off = 0;
100
101 ret = fio_mmap_file(td, f, f->mmap_sz, f->mmap_off);
102 if (ret)
103 fio_file_set_partial_mmap(f);
104
105 return ret;
106 }
107
fio_mmapio_prep(struct thread_data * td,struct io_u * io_u)108 static 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
113 /*
114 * It fits within existing mapping, use it
115 */
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
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
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
136 done:
137 io_u->mmap_data = f->mmap_ptr + io_u->offset - f->mmap_off -
138 f->file_offset;
139 return 0;
140 }
141
fio_mmapio_queue(struct thread_data * td,struct io_u * io_u)142 static 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);
152 else if (ddir_sync(io_u->ddir)) {
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 } else if (io_u->ddir == DDIR_TRIM) {
158 int ret = do_io_u_trim(td, io_u);
159
160 if (!ret)
161 td_verror(td, io_u->error, "trim");
162 }
163
164
165 /*
166 * not really direct, but should drop the pages from the cache
167 */
168 if (td->o.odirect && ddir_rw(io_u->ddir)) {
169 if (msync(io_u->mmap_data, io_u->xfer_buflen, MS_SYNC) < 0) {
170 io_u->error = errno;
171 td_verror(td, io_u->error, "msync");
172 }
173 if (posix_madvise(io_u->mmap_data, io_u->xfer_buflen, POSIX_MADV_DONTNEED) < 0) {
174 io_u->error = errno;
175 td_verror(td, io_u->error, "madvise");
176 }
177 }
178
179 return FIO_Q_COMPLETED;
180 }
181
fio_mmapio_init(struct thread_data * td)182 static int fio_mmapio_init(struct thread_data *td)
183 {
184 struct thread_options *o = &td->o;
185 unsigned long shift, mask;
186
187 if ((td->o.rw_min_bs & page_mask) &&
188 (o->odirect || o->fsync_blocks || o->fdatasync_blocks)) {
189 log_err("fio: mmap options dictate a minimum block size of "
190 "%llu bytes\n", (unsigned long long) page_size);
191 return 1;
192 }
193
194 mmap_map_size = MMAP_TOTAL_SZ / td->o.nr_files;
195 mask = mmap_map_size;
196 shift = 0;
197 do {
198 mask >>= 1;
199 if (!mask)
200 break;
201 shift++;
202 } while (1);
203
204 mmap_map_mask = 1UL << shift;
205 return 0;
206 }
207
208 static struct ioengine_ops ioengine = {
209 .name = "mmap",
210 .version = FIO_IOOPS_VERSION,
211 .init = fio_mmapio_init,
212 .prep = fio_mmapio_prep,
213 .queue = fio_mmapio_queue,
214 .open_file = generic_open_file,
215 .close_file = generic_close_file,
216 .get_file_size = generic_get_file_size,
217 .flags = FIO_SYNCIO | FIO_NOEXTEND,
218 };
219
fio_mmapio_register(void)220 static void fio_init fio_mmapio_register(void)
221 {
222 register_ioengine(&ioengine);
223 }
224
fio_mmapio_unregister(void)225 static void fio_exit fio_mmapio_unregister(void)
226 {
227 unregister_ioengine(&ioengine);
228 }
229