LXR qemu/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
  35typedef 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
  64const char *throttle_group_get_name(ThrottleGroupMember *tgm);
  65
  66ThrottleState *throttle_group_incref(const char *name);
  67void throttle_group_unref(ThrottleState *ts);
  68
  69void throttle_group_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg);
  70void throttle_group_get_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg);
  71
  72void throttle_group_register_tgm(ThrottleGroupMember *tgm,
  73                                const char *groupname,
  74                                AioContext *ctx);
  75void throttle_group_unregister_tgm(ThrottleGroupMember *tgm);
  76void throttle_group_restart_tgm(ThrottleGroupMember *tgm);
  77
  78void coroutine_fn throttle_group_co_io_limits_intercept(ThrottleGroupMember *tgm,
  79                                                        unsigned int bytes,
  80                                                        bool is_write);
  81void throttle_group_attach_aio_context(ThrottleGroupMember *tgm,
  82                                       AioContext *new_context);
  83void throttle_group_detach_aio_context(ThrottleGroupMember *tgm);
  84/*
  85 * throttle_group_exists() must be called under the global
  86 * mutex.
  87 */
  88bool throttle_group_exists(const char *name);
  89
  90#endif
  91