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/throttle-groups.h"
22 #include "qemu/module.h"
23 #include "qemu/option.h"
24 #include "qemu/throttle-options.h"
25 #include "qapi/error.h"
27 static QemuOptsList throttle_opts
= {
29 .head
= QTAILQ_HEAD_INITIALIZER(throttle_opts
.head
),
32 .name
= QEMU_OPT_THROTTLE_GROUP_NAME
,
33 .type
= QEMU_OPT_STRING
,
34 .help
= "Name of the throttle group",
41 * If this function succeeds then the throttle group name is stored in
42 * @group and must be freed by the caller.
43 * If there's an error then @group remains unmodified.
45 static int throttle_parse_options(QDict
*options
, char **group
, Error
**errp
)
48 const char *group_name
;
49 Error
*local_err
= NULL
;
50 QemuOpts
*opts
= qemu_opts_create(&throttle_opts
, NULL
, 0, &error_abort
);
52 qemu_opts_absorb_qdict(opts
, options
, &local_err
);
54 error_propagate(errp
, local_err
);
59 group_name
= qemu_opt_get(opts
, QEMU_OPT_THROTTLE_GROUP_NAME
);
61 error_setg(errp
, "Please specify a throttle group");
64 } else if (!throttle_group_exists(group_name
)) {
65 error_setg(errp
, "Throttle group '%s' does not exist", group_name
);
70 *group
= g_strdup(group_name
);
77 static int throttle_open(BlockDriverState
*bs
, QDict
*options
,
78 int flags
, Error
**errp
)
80 ThrottleGroupMember
*tgm
= bs
->opaque
;
84 bs
->file
= bdrv_open_child(NULL
, options
, "file", bs
,
85 &child_file
, 0, false, errp
);
89 bs
->supported_write_flags
= bs
->file
->bs
->supported_write_flags
|
90 BDRV_REQ_WRITE_UNCHANGED
;
91 bs
->supported_zero_flags
= bs
->file
->bs
->supported_zero_flags
|
92 BDRV_REQ_WRITE_UNCHANGED
;
94 ret
= throttle_parse_options(options
, &group
, errp
);
96 /* Register membership to group with name group_name */
97 throttle_group_register_tgm(tgm
, group
, bdrv_get_aio_context(bs
));
104 static void throttle_close(BlockDriverState
*bs
)
106 ThrottleGroupMember
*tgm
= bs
->opaque
;
107 throttle_group_unregister_tgm(tgm
);
111 static int64_t throttle_getlength(BlockDriverState
*bs
)
113 return bdrv_getlength(bs
->file
->bs
);
116 static int coroutine_fn
throttle_co_preadv(BlockDriverState
*bs
,
117 uint64_t offset
, uint64_t bytes
,
118 QEMUIOVector
*qiov
, int flags
)
121 ThrottleGroupMember
*tgm
= bs
->opaque
;
122 throttle_group_co_io_limits_intercept(tgm
, bytes
, false);
124 return bdrv_co_preadv(bs
->file
, offset
, bytes
, qiov
, flags
);
127 static int coroutine_fn
throttle_co_pwritev(BlockDriverState
*bs
,
128 uint64_t offset
, uint64_t bytes
,
129 QEMUIOVector
*qiov
, int flags
)
131 ThrottleGroupMember
*tgm
= bs
->opaque
;
132 throttle_group_co_io_limits_intercept(tgm
, bytes
, true);
134 return bdrv_co_pwritev(bs
->file
, offset
, bytes
, qiov
, flags
);
137 static int coroutine_fn
throttle_co_pwrite_zeroes(BlockDriverState
*bs
,
138 int64_t offset
, int bytes
,
139 BdrvRequestFlags flags
)
141 ThrottleGroupMember
*tgm
= bs
->opaque
;
142 throttle_group_co_io_limits_intercept(tgm
, bytes
, true);
144 return bdrv_co_pwrite_zeroes(bs
->file
, offset
, bytes
, flags
);
147 static int coroutine_fn
throttle_co_pdiscard(BlockDriverState
*bs
,
148 int64_t offset
, int bytes
)
150 ThrottleGroupMember
*tgm
= bs
->opaque
;
151 throttle_group_co_io_limits_intercept(tgm
, bytes
, true);
153 return bdrv_co_pdiscard(bs
->file
, offset
, bytes
);
156 static int throttle_co_flush(BlockDriverState
*bs
)
158 return bdrv_co_flush(bs
->file
->bs
);
161 static void throttle_detach_aio_context(BlockDriverState
*bs
)
163 ThrottleGroupMember
*tgm
= bs
->opaque
;
164 throttle_group_detach_aio_context(tgm
);
167 static void throttle_attach_aio_context(BlockDriverState
*bs
,
168 AioContext
*new_context
)
170 ThrottleGroupMember
*tgm
= bs
->opaque
;
171 throttle_group_attach_aio_context(tgm
, new_context
);
174 static int throttle_reopen_prepare(BDRVReopenState
*reopen_state
,
175 BlockReopenQueue
*queue
, Error
**errp
)
180 assert(reopen_state
!= NULL
);
181 assert(reopen_state
->bs
!= NULL
);
183 ret
= throttle_parse_options(reopen_state
->options
, &group
, errp
);
184 reopen_state
->opaque
= group
;
188 static void throttle_reopen_commit(BDRVReopenState
*reopen_state
)
190 BlockDriverState
*bs
= reopen_state
->bs
;
191 ThrottleGroupMember
*tgm
= bs
->opaque
;
192 char *group
= reopen_state
->opaque
;
196 if (strcmp(group
, throttle_group_get_name(tgm
))) {
197 throttle_group_unregister_tgm(tgm
);
198 throttle_group_register_tgm(tgm
, group
, bdrv_get_aio_context(bs
));
200 g_free(reopen_state
->opaque
);
201 reopen_state
->opaque
= NULL
;
204 static void throttle_reopen_abort(BDRVReopenState
*reopen_state
)
206 g_free(reopen_state
->opaque
);
207 reopen_state
->opaque
= NULL
;
210 static void coroutine_fn
throttle_co_drain_begin(BlockDriverState
*bs
)
212 ThrottleGroupMember
*tgm
= bs
->opaque
;
213 if (atomic_fetch_inc(&tgm
->io_limits_disabled
) == 0) {
214 throttle_group_restart_tgm(tgm
);
218 static void coroutine_fn
throttle_co_drain_end(BlockDriverState
*bs
)
220 ThrottleGroupMember
*tgm
= bs
->opaque
;
221 assert(tgm
->io_limits_disabled
);
222 atomic_dec(&tgm
->io_limits_disabled
);
225 static const char *const throttle_strong_runtime_opts
[] = {
226 QEMU_OPT_THROTTLE_GROUP_NAME
,
231 static BlockDriver bdrv_throttle
= {
232 .format_name
= "throttle",
233 .instance_size
= sizeof(ThrottleGroupMember
),
235 .bdrv_open
= throttle_open
,
236 .bdrv_close
= throttle_close
,
237 .bdrv_co_flush
= throttle_co_flush
,
239 .bdrv_child_perm
= bdrv_filter_default_perms
,
241 .bdrv_getlength
= throttle_getlength
,
243 .bdrv_co_preadv
= throttle_co_preadv
,
244 .bdrv_co_pwritev
= throttle_co_pwritev
,
246 .bdrv_co_pwrite_zeroes
= throttle_co_pwrite_zeroes
,
247 .bdrv_co_pdiscard
= throttle_co_pdiscard
,
249 .bdrv_attach_aio_context
= throttle_attach_aio_context
,
250 .bdrv_detach_aio_context
= throttle_detach_aio_context
,
252 .bdrv_reopen_prepare
= throttle_reopen_prepare
,
253 .bdrv_reopen_commit
= throttle_reopen_commit
,
254 .bdrv_reopen_abort
= throttle_reopen_abort
,
255 .bdrv_co_block_status
= bdrv_co_block_status_from_file
,
257 .bdrv_co_drain_begin
= throttle_co_drain_begin
,
258 .bdrv_co_drain_end
= throttle_co_drain_end
,
261 .strong_runtime_opts
= throttle_strong_runtime_opts
,
264 static void bdrv_throttle_init(void)
266 bdrv_register(&bdrv_throttle
);
269 block_init(bdrv_throttle_init
);