1 /* 2 * QEMU block throttling filter driver infrastructure 3 * 4 * Copyright (c) 2017 Manos Pitsidianakis 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation; either version 2 or 9 * (at your option) version 3 of the License. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include "qemu/osdep.h" 21 #include "block/throttle-groups.h" 22 #include "qemu/option.h" 23 #include "qemu/throttle-options.h" 24 #include "qapi/error.h" 25 26 static QemuOptsList throttle_opts = { 27 .name = "throttle", 28 .head = QTAILQ_HEAD_INITIALIZER(throttle_opts.head), 29 .desc = { 30 { 31 .name = QEMU_OPT_THROTTLE_GROUP_NAME, 32 .type = QEMU_OPT_STRING, 33 .help = "Name of the throttle group", 34 }, 35 { /* end of list */ } 36 }, 37 }; 38 39 static int throttle_configure_tgm(BlockDriverState *bs, 40 ThrottleGroupMember *tgm, 41 QDict *options, Error **errp) 42 { 43 int ret; 44 const char *group_name; 45 Error *local_err = NULL; 46 QemuOpts *opts = qemu_opts_create(&throttle_opts, NULL, 0, &error_abort); 47 48 qemu_opts_absorb_qdict(opts, options, &local_err); 49 if (local_err) { 50 error_propagate(errp, local_err); 51 ret = -EINVAL; 52 goto fin; 53 } 54 55 group_name = qemu_opt_get(opts, QEMU_OPT_THROTTLE_GROUP_NAME); 56 if (!group_name) { 57 error_setg(errp, "Please specify a throttle group"); 58 ret = -EINVAL; 59 goto fin; 60 } else if (!throttle_group_exists(group_name)) { 61 error_setg(errp, "Throttle group '%s' does not exist", group_name); 62 ret = -EINVAL; 63 goto fin; 64 } 65 66 /* Register membership to group with name group_name */ 67 throttle_group_register_tgm(tgm, group_name, bdrv_get_aio_context(bs)); 68 ret = 0; 69 fin: 70 qemu_opts_del(opts); 71 return ret; 72 } 73 74 static int throttle_open(BlockDriverState *bs, QDict *options, 75 int flags, Error **errp) 76 { 77 ThrottleGroupMember *tgm = bs->opaque; 78 79 bs->file = bdrv_open_child(NULL, options, "file", bs, 80 &child_file, false, errp); 81 if (!bs->file) { 82 return -EINVAL; 83 } 84 bs->supported_write_flags = bs->file->bs->supported_write_flags; 85 bs->supported_zero_flags = bs->file->bs->supported_zero_flags; 86 87 return throttle_configure_tgm(bs, tgm, options, errp); 88 } 89 90 static void throttle_close(BlockDriverState *bs) 91 { 92 ThrottleGroupMember *tgm = bs->opaque; 93 throttle_group_unregister_tgm(tgm); 94 } 95 96 97 static int64_t throttle_getlength(BlockDriverState *bs) 98 { 99 return bdrv_getlength(bs->file->bs); 100 } 101 102 static int coroutine_fn throttle_co_preadv(BlockDriverState *bs, 103 uint64_t offset, uint64_t bytes, 104 QEMUIOVector *qiov, int flags) 105 { 106 107 ThrottleGroupMember *tgm = bs->opaque; 108 throttle_group_co_io_limits_intercept(tgm, bytes, false); 109 110 return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags); 111 } 112 113 static int coroutine_fn throttle_co_pwritev(BlockDriverState *bs, 114 uint64_t offset, uint64_t bytes, 115 QEMUIOVector *qiov, int flags) 116 { 117 ThrottleGroupMember *tgm = bs->opaque; 118 throttle_group_co_io_limits_intercept(tgm, bytes, true); 119 120 return bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags); 121 } 122 123 static int coroutine_fn throttle_co_pwrite_zeroes(BlockDriverState *bs, 124 int64_t offset, int bytes, 125 BdrvRequestFlags flags) 126 { 127 ThrottleGroupMember *tgm = bs->opaque; 128 throttle_group_co_io_limits_intercept(tgm, bytes, true); 129 130 return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags); 131 } 132 133 static int coroutine_fn throttle_co_pdiscard(BlockDriverState *bs, 134 int64_t offset, int bytes) 135 { 136 ThrottleGroupMember *tgm = bs->opaque; 137 throttle_group_co_io_limits_intercept(tgm, bytes, true); 138 139 return bdrv_co_pdiscard(bs->file->bs, offset, bytes); 140 } 141 142 static int throttle_co_flush(BlockDriverState *bs) 143 { 144 return bdrv_co_flush(bs->file->bs); 145 } 146 147 static void throttle_detach_aio_context(BlockDriverState *bs) 148 { 149 ThrottleGroupMember *tgm = bs->opaque; 150 throttle_group_detach_aio_context(tgm); 151 } 152 153 static void throttle_attach_aio_context(BlockDriverState *bs, 154 AioContext *new_context) 155 { 156 ThrottleGroupMember *tgm = bs->opaque; 157 throttle_group_attach_aio_context(tgm, new_context); 158 } 159 160 static int throttle_reopen_prepare(BDRVReopenState *reopen_state, 161 BlockReopenQueue *queue, Error **errp) 162 { 163 ThrottleGroupMember *tgm; 164 165 assert(reopen_state != NULL); 166 assert(reopen_state->bs != NULL); 167 168 reopen_state->opaque = g_new0(ThrottleGroupMember, 1); 169 tgm = reopen_state->opaque; 170 171 return throttle_configure_tgm(reopen_state->bs, tgm, reopen_state->options, 172 errp); 173 } 174 175 static void throttle_reopen_commit(BDRVReopenState *reopen_state) 176 { 177 ThrottleGroupMember *old_tgm = reopen_state->bs->opaque; 178 ThrottleGroupMember *new_tgm = reopen_state->opaque; 179 180 throttle_group_unregister_tgm(old_tgm); 181 g_free(old_tgm); 182 reopen_state->bs->opaque = new_tgm; 183 reopen_state->opaque = NULL; 184 } 185 186 static void throttle_reopen_abort(BDRVReopenState *reopen_state) 187 { 188 ThrottleGroupMember *tgm = reopen_state->opaque; 189 190 throttle_group_unregister_tgm(tgm); 191 g_free(tgm); 192 reopen_state->opaque = NULL; 193 } 194 195 static bool throttle_recurse_is_first_non_filter(BlockDriverState *bs, 196 BlockDriverState *candidate) 197 { 198 return bdrv_recurse_is_first_non_filter(bs->file->bs, candidate); 199 } 200 201 static void coroutine_fn throttle_co_drain_begin(BlockDriverState *bs) 202 { 203 ThrottleGroupMember *tgm = bs->opaque; 204 if (atomic_fetch_inc(&tgm->io_limits_disabled) == 0) { 205 throttle_group_restart_tgm(tgm); 206 } 207 } 208 209 static void coroutine_fn throttle_co_drain_end(BlockDriverState *bs) 210 { 211 ThrottleGroupMember *tgm = bs->opaque; 212 assert(tgm->io_limits_disabled); 213 atomic_dec(&tgm->io_limits_disabled); 214 } 215 216 static BlockDriver bdrv_throttle = { 217 .format_name = "throttle", 218 .protocol_name = "throttle", 219 .instance_size = sizeof(ThrottleGroupMember), 220 221 .bdrv_file_open = throttle_open, 222 .bdrv_close = throttle_close, 223 .bdrv_co_flush = throttle_co_flush, 224 225 .bdrv_child_perm = bdrv_filter_default_perms, 226 227 .bdrv_getlength = throttle_getlength, 228 229 .bdrv_co_preadv = throttle_co_preadv, 230 .bdrv_co_pwritev = throttle_co_pwritev, 231 232 .bdrv_co_pwrite_zeroes = throttle_co_pwrite_zeroes, 233 .bdrv_co_pdiscard = throttle_co_pdiscard, 234 235 .bdrv_recurse_is_first_non_filter = throttle_recurse_is_first_non_filter, 236 237 .bdrv_attach_aio_context = throttle_attach_aio_context, 238 .bdrv_detach_aio_context = throttle_detach_aio_context, 239 240 .bdrv_reopen_prepare = throttle_reopen_prepare, 241 .bdrv_reopen_commit = throttle_reopen_commit, 242 .bdrv_reopen_abort = throttle_reopen_abort, 243 .bdrv_co_block_status = bdrv_co_block_status_from_file, 244 245 .bdrv_co_drain_begin = throttle_co_drain_begin, 246 .bdrv_co_drain_end = throttle_co_drain_end, 247 248 .is_filter = true, 249 }; 250 251 static void bdrv_throttle_init(void) 252 { 253 bdrv_register(&bdrv_throttle); 254 } 255 256 block_init(bdrv_throttle_init); 257