include/block/throttle-groups.h

   1 /*
   2  * QEMU block throttling group infrastructure
   3  *
   4  * Copyright (C) Nodalink, EURL. 2014
   5  * Copyright (C) Igalia, S.L. 2015
   6  *
   7  * Authors:
   8  *   Benoît Canet <benoit.canet@nodalink.com>
   9  *   Alberto Garcia <berto@igalia.com>
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License as
  13  * published by the Free Software Foundation; either version 2 or
  14  * (at your option) version 3 of the License.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  23  */
  24
  25 #ifndef THROTTLE_GROUPS_H
  26 #define THROTTLE_GROUPS_H
  27
  28 #include "qemu/coroutine.h"
  29 #include "qemu/throttle.h"
  30 #include "qom/object.h"
  31
  32 /* The ThrottleGroupMember structure indicates membership in a ThrottleGroup
  33  * and holds related data.
  34  */
  35
  36 typedef struct ThrottleGroupMember {
  37     AioContext   *aio_context;
  38     /* throttled_reqs_lock protects the CoQueues for throttled requests.  */
  39     CoMutex      throttled_reqs_lock;
  40     CoQueue      throttled_reqs[2];
  41
  42     /* Nonzero if the I/O limits are currently being ignored; generally
  43      * it is zero.  Accessed with atomic operations.
  44      */
  45     unsigned int io_limits_disabled;
  46
  47     /* Number of pending throttle_group_restart_queue_entry() coroutines.
  48      * Accessed with atomic operations.
  49      */
  50     unsigned int restart_pending;
  51
  52     /* The following fields are protected by the ThrottleGroup lock.
  53      * See the ThrottleGroup documentation for details.
  54      * throttle_state tells us if I/O limits are configured. */
  55     ThrottleState *throttle_state;
  56     ThrottleTimers throttle_timers;
  57     unsigned       pending_reqs[2];
  58     QLIST_ENTRY(ThrottleGroupMember) round_robin;
  59
  60 } ThrottleGroupMember;
  61
  62 #define TYPE_THROTTLE_GROUP "throttle-group"
  63 OBJECT_DECLARE_SIMPLE_TYPE(ThrottleGroup, THROTTLE_GROUP)
  64
  65 const char *throttle_group_get_name(ThrottleGroupMember *tgm);
  66
  67 ThrottleState *throttle_group_incref(const char *name);
  68 void throttle_group_unref(ThrottleState *ts);
  69
  70 void throttle_group_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg);
  71 void throttle_group_get_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg);
  72
  73 void throttle_group_register_tgm(ThrottleGroupMember *tgm,
  74                                 const char *groupname,
  75                                 AioContext *ctx);
  76 void throttle_group_unregister_tgm(ThrottleGroupMember *tgm);
  77 void throttle_group_restart_tgm(ThrottleGroupMember *tgm);
  78
  79 void coroutine_fn throttle_group_co_io_limits_intercept(ThrottleGroupMember *tgm,
  80                                                         int64_t bytes,
  81                                                         bool is_write);
  82 void throttle_group_attach_aio_context(ThrottleGroupMember *tgm,
  83                                        AioContext *new_context);
  84 void throttle_group_detach_aio_context(ThrottleGroupMember *tgm);
  85 /*
  86  * throttle_group_exists() must be called under the global
  87  * mutex.
  88  */
  89 bool throttle_group_exists(const char *name);
  90
  91 #endif