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
25 struct fio_mmap_data {
26 void *mmap_ptr;
27 size_t mmap_sz;
28 off_t mmap_off;
29 };
30
fio_mmap_file(struct thread_data * td,struct fio_file * f,size_t length,off_t off)31 static int fio_mmap_file(struct thread_data *td, struct fio_file *f,
32 size_t length, off_t off)
33 {
34 struct fio_mmap_data *fmd = FILE_ENG_DATA(f);
35 int flags = 0;
36
37 if (td_rw(td))
38 flags = PROT_READ | PROT_WRITE;
39 else if (td_write(td)) {
40 flags = PROT_WRITE;
41
42 if (td->o.verify != VERIFY_NONE)
43 flags |= PROT_READ;
44 } else
45 flags = PROT_READ;
46
47 fmd->mmap_ptr = mmap(NULL, length, flags, MAP_SHARED, f->fd, off);
48 if (fmd->mmap_ptr == MAP_FAILED) {
49 fmd->mmap_ptr = NULL;
50 td_verror(td, errno, "mmap");
51 goto err;
52 }
53
54 if (!td_random(td)) {
55 if (posix_madvise(fmd->mmap_ptr, length, POSIX_MADV_SEQUENTIAL) < 0) {
56 td_verror(td, errno, "madvise");
57 goto err;
58 }
59 } else {
60 if (posix_madvise(fmd->mmap_ptr, length, POSIX_MADV_RANDOM) < 0) {
61 td_verror(td, errno, "madvise");
62 goto err;
63 }
64 }
65 if (posix_madvise(fmd->mmap_ptr, length, POSIX_MADV_DONTNEED) < 0) {
66 td_verror(td, errno, "madvise");
67 goto err;
68 }
69
70 #ifdef FIO_MADV_FREE
71 if (f->filetype == FIO_TYPE_BD)
72 (void) posix_madvise(fmd->mmap_ptr, fmd->mmap_sz, FIO_MADV_FREE);
73 #endif
74
75
76 err:
77 if (td->error && fmd->mmap_ptr)
78 munmap(fmd->mmap_ptr, length);
79
80 return td->error;
81 }
82
83 /*
84 * Just mmap an appropriate portion, we cannot mmap the full extent
85 */
fio_mmapio_prep_limited(struct thread_data * td,struct io_u * io_u)86 static int fio_mmapio_prep_limited(struct thread_data *td, struct io_u *io_u)
87 {
88 struct fio_file *f = io_u->file;
89 struct fio_mmap_data *fmd = FILE_ENG_DATA(f);
90
91 if (io_u->buflen > mmap_map_size) {
92 log_err("fio: bs too big for mmap engine\n");
93 return EIO;
94 }
95
96 fmd->mmap_sz = mmap_map_size;
97 if (fmd->mmap_sz > f->io_size)
98 fmd->mmap_sz = f->io_size;
99
100 fmd->mmap_off = io_u->offset;
101
102 return fio_mmap_file(td, f, fmd->mmap_sz, fmd->mmap_off);
103 }
104
105 /*
106 * Attempt to mmap the entire file
107 */
fio_mmapio_prep_full(struct thread_data * td,struct io_u * io_u)108 static int fio_mmapio_prep_full(struct thread_data *td, struct io_u *io_u)
109 {
110 struct fio_file *f = io_u->file;
111 struct fio_mmap_data *fmd = FILE_ENG_DATA(f);
112 int ret;
113
114 if (fio_file_partial_mmap(f))
115 return EINVAL;
116 if (io_u->offset != (size_t) io_u->offset ||
117 f->io_size != (size_t) f->io_size) {
118 fio_file_set_partial_mmap(f);
119 return EINVAL;
120 }
121
122 fmd->mmap_sz = f->io_size;
123 fmd->mmap_off = 0;
124
125 ret = fio_mmap_file(td, f, fmd->mmap_sz, fmd->mmap_off);
126 if (ret)
127 fio_file_set_partial_mmap(f);
128
129 return ret;
130 }
131
fio_mmapio_prep(struct thread_data * td,struct io_u * io_u)132 static int fio_mmapio_prep(struct thread_data *td, struct io_u *io_u)
133 {
134 struct fio_file *f = io_u->file;
135 struct fio_mmap_data *fmd = FILE_ENG_DATA(f);
136 int ret;
137
138 /*
139 * It fits within existing mapping, use it
140 */
141 if (io_u->offset >= fmd->mmap_off &&
142 io_u->offset + io_u->buflen < fmd->mmap_off + fmd->mmap_sz)
143 goto done;
144
145 /*
146 * unmap any existing mapping
147 */
148 if (fmd->mmap_ptr) {
149 if (munmap(fmd->mmap_ptr, fmd->mmap_sz) < 0)
150 return errno;
151 fmd->mmap_ptr = NULL;
152 }
153
154 if (fio_mmapio_prep_full(td, io_u)) {
155 td_clear_error(td);
156 ret = fio_mmapio_prep_limited(td, io_u);
157 if (ret)
158 return ret;
159 }
160
161 done:
162 io_u->mmap_data = fmd->mmap_ptr + io_u->offset - fmd->mmap_off -
163 f->file_offset;
164 return 0;
165 }
166
fio_mmapio_queue(struct thread_data * td,struct io_u * io_u)167 static int fio_mmapio_queue(struct thread_data *td, struct io_u *io_u)
168 {
169 struct fio_file *f = io_u->file;
170 struct fio_mmap_data *fmd = FILE_ENG_DATA(f);
171
172 fio_ro_check(td, io_u);
173
174 if (io_u->ddir == DDIR_READ)
175 memcpy(io_u->xfer_buf, io_u->mmap_data, io_u->xfer_buflen);
176 else if (io_u->ddir == DDIR_WRITE)
177 memcpy(io_u->mmap_data, io_u->xfer_buf, io_u->xfer_buflen);
178 else if (ddir_sync(io_u->ddir)) {
179 if (msync(fmd->mmap_ptr, fmd->mmap_sz, MS_SYNC)) {
180 io_u->error = errno;
181 td_verror(td, io_u->error, "msync");
182 }
183 } else if (io_u->ddir == DDIR_TRIM) {
184 int ret = do_io_u_trim(td, io_u);
185
186 if (!ret)
187 td_verror(td, io_u->error, "trim");
188 }
189
190
191 /*
192 * not really direct, but should drop the pages from the cache
193 */
194 if (td->o.odirect && ddir_rw(io_u->ddir)) {
195 if (msync(io_u->mmap_data, io_u->xfer_buflen, MS_SYNC) < 0) {
196 io_u->error = errno;
197 td_verror(td, io_u->error, "msync");
198 }
199 if (posix_madvise(io_u->mmap_data, io_u->xfer_buflen, POSIX_MADV_DONTNEED) < 0) {
200 io_u->error = errno;
201 td_verror(td, io_u->error, "madvise");
202 }
203 }
204
205 return FIO_Q_COMPLETED;
206 }
207
fio_mmapio_init(struct thread_data * td)208 static int fio_mmapio_init(struct thread_data *td)
209 {
210 struct thread_options *o = &td->o;
211 unsigned long shift, mask;
212
213 if ((td->o.rw_min_bs & page_mask) &&
214 (o->odirect || o->fsync_blocks || o->fdatasync_blocks)) {
215 log_err("fio: mmap options dictate a minimum block size of "
216 "%llu bytes\n", (unsigned long long) page_size);
217 return 1;
218 }
219
220 mmap_map_size = MMAP_TOTAL_SZ / td->o.nr_files;
221 mask = mmap_map_size;
222 shift = 0;
223 do {
224 mask >>= 1;
225 if (!mask)
226 break;
227 shift++;
228 } while (1);
229
230 mmap_map_mask = 1UL << shift;
231 return 0;
232 }
233
fio_mmapio_open_file(struct thread_data * td,struct fio_file * f)234 static int fio_mmapio_open_file(struct thread_data *td, struct fio_file *f)
235 {
236 struct fio_mmap_data *fmd;
237 int ret;
238
239 ret = generic_open_file(td, f);
240 if (ret)
241 return ret;
242
243 fmd = calloc(1, sizeof(*fmd));
244 if (!fmd) {
245 int fio_unused ret;
246 ret = generic_close_file(td, f);
247 return 1;
248 }
249
250 FILE_SET_ENG_DATA(f, fmd);
251 return 0;
252 }
253
fio_mmapio_close_file(struct thread_data * td,struct fio_file * f)254 static int fio_mmapio_close_file(struct thread_data *td, struct fio_file *f)
255 {
256 struct fio_mmap_data *fmd = FILE_ENG_DATA(f);
257
258 FILE_SET_ENG_DATA(f, NULL);
259 free(fmd);
260 fio_file_clear_partial_mmap(f);
261
262 return generic_close_file(td, f);
263 }
264
265 static struct ioengine_ops ioengine = {
266 .name = "mmap",
267 .version = FIO_IOOPS_VERSION,
268 .init = fio_mmapio_init,
269 .prep = fio_mmapio_prep,
270 .queue = fio_mmapio_queue,
271 .open_file = fio_mmapio_open_file,
272 .close_file = fio_mmapio_close_file,
273 .get_file_size = generic_get_file_size,
274 .flags = FIO_SYNCIO | FIO_NOEXTEND,
275 };
276
fio_mmapio_register(void)277 static void fio_init fio_mmapio_register(void)
278 {
279 register_ioengine(&ioengine);
280 }
281
fio_mmapio_unregister(void)282 static void fio_exit fio_mmapio_unregister(void)
283 {
284 unregister_ioengine(&ioengine);
285 }
286