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#include "qom/object.h"
  31
  32/* The ThrottleGroupMember structure indicates membership in a ThrottleGroup
  33 * and holds related data.
  34 */
  35
  36typedef 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"
  63OBJECT_DECLARE_SIMPLE_TYPE(ThrottleGroup, THROTTLE_GROUP)
  64
  65const char *throttle_group_get_name(ThrottleGroupMember *tgm);
  66
  67ThrottleState *throttle_group_incref(const char *name);
  68void throttle_group_unref(ThrottleState *ts);
  69
  70void throttle_group_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg);
  71void throttle_group_get_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg);
  72
  73void throttle_group_register_tgm(ThrottleGroupMember *tgm,
  74                                const char *groupname,
  75                                AioContext *ctx);
  76void throttle_group_unregister_tgm(ThrottleGroupMember *tgm);
  77void throttle_group_restart_tgm(ThrottleGroupMember *tgm);
  78
  79void coroutine_fn throttle_group_co_io_limits_intercept(ThrottleGroupMember *tgm,
  80                                                        int64_t bytes,
  81                                                        bool is_write);
  82void throttle_group_attach_aio_context(ThrottleGroupMember *tgm,
  83                                       AioContext *new_context);
  84void throttle_group_detach_aio_context(ThrottleGroupMember *tgm);
  85/*
  86 * throttle_group_exists() must be called under the global
  87 * mutex.
  88 */
  89bool throttle_group_exists(const char *name);
  90
  91#endif
  92