qapi: Require descriptions and tagged sections to be indented
[qemu/kevin.git] / block / throttle.c
blob97972d1f15e9ae58780ee9ac6298ec60754d1a24
1 /*
2 * QEMU block throttling filter driver infrastructure
4 * Copyright (c) 2017 Manos Pitsidianakis
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.
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.
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/>.
20 #include "qemu/osdep.h"
21 #include "block/block-io.h"
22 #include "block/block_int.h"
23 #include "block/throttle-groups.h"
24 #include "qemu/module.h"
25 #include "qemu/option.h"
26 #include "qemu/throttle-options.h"
27 #include "qapi/error.h"
29 static QemuOptsList throttle_opts = {
30 .name = "throttle",
31 .head = QTAILQ_HEAD_INITIALIZER(throttle_opts.head),
32 .desc = {
34 .name = QEMU_OPT_THROTTLE_GROUP_NAME,
35 .type = QEMU_OPT_STRING,
36 .help = "Name of the throttle group",
38 { /* end of list */ }
43 * If this function succeeds then the throttle group name is stored in
44 * @group and must be freed by the caller.
45 * If there's an error then @group remains unmodified.
47 static int throttle_parse_options(QDict *options, char **group, Error **errp)
49 int ret;
50 const char *group_name;
51 QemuOpts *opts = qemu_opts_create(&throttle_opts, NULL, 0, &error_abort);
53 if (!qemu_opts_absorb_qdict(opts, options, errp)) {
54 ret = -EINVAL;
55 goto fin;
58 group_name = qemu_opt_get(opts, QEMU_OPT_THROTTLE_GROUP_NAME);
59 if (!group_name) {
60 error_setg(errp, "Please specify a throttle group");
61 ret = -EINVAL;
62 goto fin;
63 } else if (!throttle_group_exists(group_name)) {
64 error_setg(errp, "Throttle group '%s' does not exist", group_name);
65 ret = -EINVAL;
66 goto fin;
69 *group = g_strdup(group_name);
70 ret = 0;
71 fin:
72 qemu_opts_del(opts);
73 return ret;
76 static int throttle_open(BlockDriverState *bs, QDict *options,
77 int flags, Error **errp)
79 ThrottleGroupMember *tgm = bs->opaque;
80 char *group;
81 int ret;
83 ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
84 if (ret < 0) {
85 return ret;
88 GRAPH_RDLOCK_GUARD_MAINLOOP();
90 bs->supported_write_flags = bs->file->bs->supported_write_flags |
91 BDRV_REQ_WRITE_UNCHANGED;
92 bs->supported_zero_flags = bs->file->bs->supported_zero_flags |
93 BDRV_REQ_WRITE_UNCHANGED;
95 ret = throttle_parse_options(options, &group, errp);
96 if (ret == 0) {
97 /* Register membership to group with name group_name */
98 throttle_group_register_tgm(tgm, group, bdrv_get_aio_context(bs));
99 g_free(group);
102 return ret;
105 static void throttle_close(BlockDriverState *bs)
107 ThrottleGroupMember *tgm = bs->opaque;
108 throttle_group_unregister_tgm(tgm);
112 static int64_t coroutine_fn GRAPH_RDLOCK
113 throttle_co_getlength(BlockDriverState *bs)
115 return bdrv_co_getlength(bs->file->bs);
118 static int coroutine_fn GRAPH_RDLOCK
119 throttle_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
120 QEMUIOVector *qiov, BdrvRequestFlags flags)
123 ThrottleGroupMember *tgm = bs->opaque;
124 throttle_group_co_io_limits_intercept(tgm, bytes, THROTTLE_READ);
126 return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
129 static int coroutine_fn GRAPH_RDLOCK
130 throttle_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
131 QEMUIOVector *qiov, BdrvRequestFlags flags)
133 ThrottleGroupMember *tgm = bs->opaque;
134 throttle_group_co_io_limits_intercept(tgm, bytes, THROTTLE_WRITE);
136 return bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
139 static int coroutine_fn GRAPH_RDLOCK
140 throttle_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int64_t bytes,
141 BdrvRequestFlags flags)
143 ThrottleGroupMember *tgm = bs->opaque;
144 throttle_group_co_io_limits_intercept(tgm, bytes, THROTTLE_WRITE);
146 return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
149 static int coroutine_fn GRAPH_RDLOCK
150 throttle_co_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes)
152 ThrottleGroupMember *tgm = bs->opaque;
153 throttle_group_co_io_limits_intercept(tgm, bytes, THROTTLE_WRITE);
155 return bdrv_co_pdiscard(bs->file, offset, bytes);
158 static int coroutine_fn GRAPH_RDLOCK
159 throttle_co_pwritev_compressed(BlockDriverState *bs, int64_t offset,
160 int64_t bytes, QEMUIOVector *qiov)
162 return throttle_co_pwritev(bs, offset, bytes, qiov,
163 BDRV_REQ_WRITE_COMPRESSED);
166 static int coroutine_fn GRAPH_RDLOCK throttle_co_flush(BlockDriverState *bs)
168 return bdrv_co_flush(bs->file->bs);
171 static void throttle_detach_aio_context(BlockDriverState *bs)
173 ThrottleGroupMember *tgm = bs->opaque;
174 throttle_group_detach_aio_context(tgm);
177 static void throttle_attach_aio_context(BlockDriverState *bs,
178 AioContext *new_context)
180 ThrottleGroupMember *tgm = bs->opaque;
181 throttle_group_attach_aio_context(tgm, new_context);
184 static int throttle_reopen_prepare(BDRVReopenState *reopen_state,
185 BlockReopenQueue *queue, Error **errp)
187 int ret;
188 char *group = NULL;
190 assert(reopen_state != NULL);
191 assert(reopen_state->bs != NULL);
193 ret = throttle_parse_options(reopen_state->options, &group, errp);
194 reopen_state->opaque = group;
195 return ret;
198 static void throttle_reopen_commit(BDRVReopenState *reopen_state)
200 BlockDriverState *bs = reopen_state->bs;
201 ThrottleGroupMember *tgm = bs->opaque;
202 char *group = reopen_state->opaque;
204 assert(group);
206 if (strcmp(group, throttle_group_get_name(tgm))) {
207 throttle_group_unregister_tgm(tgm);
208 throttle_group_register_tgm(tgm, group, bdrv_get_aio_context(bs));
210 g_free(reopen_state->opaque);
211 reopen_state->opaque = NULL;
214 static void throttle_reopen_abort(BDRVReopenState *reopen_state)
216 g_free(reopen_state->opaque);
217 reopen_state->opaque = NULL;
220 static void throttle_drain_begin(BlockDriverState *bs)
222 ThrottleGroupMember *tgm = bs->opaque;
223 if (qatomic_fetch_inc(&tgm->io_limits_disabled) == 0) {
224 throttle_group_restart_tgm(tgm);
228 static void throttle_drain_end(BlockDriverState *bs)
230 ThrottleGroupMember *tgm = bs->opaque;
231 assert(tgm->io_limits_disabled);
232 qatomic_dec(&tgm->io_limits_disabled);
235 static const char *const throttle_strong_runtime_opts[] = {
236 QEMU_OPT_THROTTLE_GROUP_NAME,
238 NULL
241 static BlockDriver bdrv_throttle = {
242 .format_name = "throttle",
243 .instance_size = sizeof(ThrottleGroupMember),
245 .bdrv_open = throttle_open,
246 .bdrv_close = throttle_close,
247 .bdrv_co_flush = throttle_co_flush,
249 .bdrv_child_perm = bdrv_default_perms,
251 .bdrv_co_getlength = throttle_co_getlength,
253 .bdrv_co_preadv = throttle_co_preadv,
254 .bdrv_co_pwritev = throttle_co_pwritev,
256 .bdrv_co_pwrite_zeroes = throttle_co_pwrite_zeroes,
257 .bdrv_co_pdiscard = throttle_co_pdiscard,
258 .bdrv_co_pwritev_compressed = throttle_co_pwritev_compressed,
260 .bdrv_attach_aio_context = throttle_attach_aio_context,
261 .bdrv_detach_aio_context = throttle_detach_aio_context,
263 .bdrv_reopen_prepare = throttle_reopen_prepare,
264 .bdrv_reopen_commit = throttle_reopen_commit,
265 .bdrv_reopen_abort = throttle_reopen_abort,
267 .bdrv_drain_begin = throttle_drain_begin,
268 .bdrv_drain_end = throttle_drain_end,
270 .is_filter = true,
271 .strong_runtime_opts = throttle_strong_runtime_opts,
274 static void bdrv_throttle_init(void)
276 bdrv_register(&bdrv_throttle);
279 block_init(bdrv_throttle_init);