| 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 | 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 | int ret = 0; |
| 30 | |
| 31 | if (td_rw(td)) |
| 32 | flags = PROT_READ | PROT_WRITE; |
| 33 | else if (td_write(td)) { |
| 34 | flags = PROT_WRITE; |
| 35 | |
| 36 | if (td->o.verify != VERIFY_NONE) |
| 37 | flags |= PROT_READ; |
| 38 | } else |
| 39 | flags = PROT_READ; |
| 40 | |
| 41 | f->mmap_ptr = mmap(NULL, length, flags, MAP_SHARED, f->fd, off); |
| 42 | if (f->mmap_ptr == MAP_FAILED) { |
| 43 | int err = errno; |
| 44 | |
| 45 | f->mmap_ptr = NULL; |
| 46 | td_verror(td, err, "mmap"); |
| 47 | goto err; |
| 48 | } |
| 49 | |
| 50 | if (!td_random(td)) { |
| 51 | if (madvise(f->mmap_ptr, length, MADV_SEQUENTIAL) < 0) { |
| 52 | td_verror(td, errno, "madvise"); |
| 53 | goto err; |
| 54 | } |
| 55 | } else { |
| 56 | if (madvise(f->mmap_ptr, length, MADV_RANDOM) < 0) { |
| 57 | td_verror(td, errno, "madvise"); |
| 58 | goto err; |
| 59 | } |
| 60 | } |
| 61 | |
| 62 | err: |
| 63 | return ret; |
| 64 | } |
| 65 | |
| 66 | static int fio_mmapio_prep(struct thread_data *td, struct io_u *io_u) |
| 67 | { |
| 68 | struct fio_file *f = io_u->file; |
| 69 | int ret = 0; |
| 70 | |
| 71 | if (io_u->buflen > mmap_map_size) { |
| 72 | log_err("fio: bs too big for mmap engine\n"); |
| 73 | ret = EIO; |
| 74 | goto err; |
| 75 | } |
| 76 | |
| 77 | if (io_u->offset >= f->mmap_off && |
| 78 | io_u->offset + io_u->buflen < f->mmap_off + f->mmap_sz) |
| 79 | goto done; |
| 80 | |
| 81 | if (f->mmap_ptr) { |
| 82 | if (munmap(f->mmap_ptr, f->mmap_sz) < 0) { |
| 83 | ret = errno; |
| 84 | goto err; |
| 85 | } |
| 86 | f->mmap_ptr = NULL; |
| 87 | } |
| 88 | |
| 89 | f->mmap_sz = mmap_map_size; |
| 90 | if (f->mmap_sz > f->io_size) |
| 91 | f->mmap_sz = f->io_size; |
| 92 | |
| 93 | f->mmap_off = io_u->offset; |
| 94 | |
| 95 | ret = fio_mmap_file(td, f, f->mmap_sz, f->mmap_off); |
| 96 | done: |
| 97 | if (!ret) |
| 98 | io_u->mmap_data = f->mmap_ptr + io_u->offset - f->mmap_off - |
| 99 | f->file_offset; |
| 100 | err: |
| 101 | return ret; |
| 102 | } |
| 103 | |
| 104 | static int fio_mmapio_queue(struct thread_data *td, struct io_u *io_u) |
| 105 | { |
| 106 | struct fio_file *f = io_u->file; |
| 107 | |
| 108 | fio_ro_check(td, io_u); |
| 109 | |
| 110 | if (io_u->ddir == DDIR_READ) |
| 111 | memcpy(io_u->xfer_buf, io_u->mmap_data, io_u->xfer_buflen); |
| 112 | else if (io_u->ddir == DDIR_WRITE) |
| 113 | memcpy(io_u->mmap_data, io_u->xfer_buf, io_u->xfer_buflen); |
| 114 | else if (ddir_sync(io_u->ddir)) { |
| 115 | if (msync(f->mmap_ptr, f->mmap_sz, MS_SYNC)) { |
| 116 | io_u->error = errno; |
| 117 | td_verror(td, io_u->error, "msync"); |
| 118 | } |
| 119 | } |
| 120 | |
| 121 | /* |
| 122 | * not really direct, but should drop the pages from the cache |
| 123 | */ |
| 124 | if (td->o.odirect && !ddir_sync(io_u->ddir)) { |
| 125 | if (msync(io_u->mmap_data, io_u->xfer_buflen, MS_SYNC) < 0) { |
| 126 | io_u->error = errno; |
| 127 | td_verror(td, io_u->error, "msync"); |
| 128 | } |
| 129 | if (madvise(io_u->mmap_data, io_u->xfer_buflen, MADV_DONTNEED) < 0) { |
| 130 | io_u->error = errno; |
| 131 | td_verror(td, io_u->error, "madvise"); |
| 132 | } |
| 133 | } |
| 134 | |
| 135 | return FIO_Q_COMPLETED; |
| 136 | } |
| 137 | |
| 138 | static int fio_mmapio_init(struct thread_data *td) |
| 139 | { |
| 140 | unsigned long shift, mask; |
| 141 | |
| 142 | mmap_map_size = MMAP_TOTAL_SZ / td->o.nr_files; |
| 143 | mask = mmap_map_size; |
| 144 | shift = 0; |
| 145 | do { |
| 146 | mask >>= 1; |
| 147 | if (!mask) |
| 148 | break; |
| 149 | shift++; |
| 150 | } while (1); |
| 151 | |
| 152 | mmap_map_mask = 1UL << shift; |
| 153 | return 0; |
| 154 | } |
| 155 | |
| 156 | static struct ioengine_ops ioengine = { |
| 157 | .name = "mmap", |
| 158 | .version = FIO_IOOPS_VERSION, |
| 159 | .init = fio_mmapio_init, |
| 160 | .prep = fio_mmapio_prep, |
| 161 | .queue = fio_mmapio_queue, |
| 162 | .open_file = generic_open_file, |
| 163 | .close_file = generic_close_file, |
| 164 | .get_file_size = generic_get_file_size, |
| 165 | .flags = FIO_SYNCIO | FIO_NOEXTEND, |
| 166 | }; |
| 167 | |
| 168 | static void fio_init fio_mmapio_register(void) |
| 169 | { |
| 170 | register_ioengine(&ioengine); |
| 171 | } |
| 172 | |
| 173 | static void fio_exit fio_mmapio_unregister(void) |
| 174 | { |
| 175 | unregister_ioengine(&ioengine); |
| 176 | } |