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/throttle.h"
  29 #include "block/block_int.h"
  30
  31 /* The ThrottleGroupMember structure indicates membership in a ThrottleGroup
  32  * and holds related data.
  33  */
  34
  35 typedef struct ThrottleGroupMember {
  36     AioContext   *aio_context;
  37     /* throttled_reqs_lock protects the CoQueues for throttled requests.  */
  38     CoMutex      throttled_reqs_lock;
  39     CoQueue      throttled_reqs[2];
  40
  41     /* Nonzero if the I/O limits are currently being ignored; generally
  42      * it is zero.  Accessed with atomic operations.
  43      */
  44     unsigned int io_limits_disabled;
  45
  46     /* Number of pending throttle_group_restart_queue_entry() coroutines.
  47      * Accessed with atomic operations.
  48      */
  49     unsigned int restart_pending;
  50
  51     /* The following fields are protected by the ThrottleGroup lock.
  52      * See the ThrottleGroup documentation for details.
  53      * throttle_state tells us if I/O limits are configured. */
  54     ThrottleState *throttle_state;
  55     ThrottleTimers throttle_timers;
  56     unsigned       pending_reqs[2];
  57     QLIST_ENTRY(ThrottleGroupMember) round_robin;
  58
  59 } ThrottleGroupMember;
  60
  61 #define TYPE_THROTTLE_GROUP "throttle-group"
  62 #define THROTTLE_GROUP(obj) OBJECT_CHECK(ThrottleGroup, (obj), TYPE_THROTTLE_GROUP)
  63
  64 const char *throttle_group_get_name(ThrottleGroupMember *tgm);
  65
  66 ThrottleState *throttle_group_incref(const char *name);
  67 void throttle_group_unref(ThrottleState *ts);
  68
  69 void throttle_group_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg);
  70 void throttle_group_get_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg);
  71
  72 void throttle_group_register_tgm(ThrottleGroupMember *tgm,
  73                                 const char *groupname,
  74                                 AioContext *ctx);
  75 void throttle_group_unregister_tgm(ThrottleGroupMember *tgm);
  76 void throttle_group_restart_tgm(ThrottleGroupMember *tgm);
  77
  78 void coroutine_fn throttle_group_co_io_limits_intercept(ThrottleGroupMember *tgm,
  79                                                         unsigned int bytes,
  80                                                         bool is_write);
  81 void throttle_group_attach_aio_context(ThrottleGroupMember *tgm,
  82                                        AioContext *new_context);
  83 void throttle_group_detach_aio_context(ThrottleGroupMember *tgm);
  84 /*
  85  * throttle_group_exists() must be called under the global
  86  * mutex.
  87  */
  88 bool throttle_group_exists(const char *name);
  89
  90 #endif