qemu/include/block/throttle-groups.h
Manos Pitsidianakis d8e7d87ec4 block: add throttle block filter driver
block/throttle.c uses existing I/O throttle infrastructure inside a
block filter driver. I/O operations are intercepted in the filter's
read/write coroutines, and referred to block/throttle-groups.c

The driver can be used with the syntax
-drive driver=throttle,file.filename=foo.qcow2,throttle-group=bar

which registers the throttle filter node with the ThrottleGroup 'bar'. The
given group must be created beforehand with object-add or -object.

Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-09-06 10:12:02 +02:00

86 lines
3.1 KiB
C

/*
* QEMU block throttling group infrastructure
*
* Copyright (C) Nodalink, EURL. 2014
* Copyright (C) Igalia, S.L. 2015
*
* Authors:
* Benoît Canet <benoit.canet@nodalink.com>
* Alberto Garcia <berto@igalia.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 or
* (at your option) version 3 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#ifndef THROTTLE_GROUPS_H
#define THROTTLE_GROUPS_H
#include "qemu/throttle.h"
#include "block/block_int.h"
/* The ThrottleGroupMember structure indicates membership in a ThrottleGroup
* and holds related data.
*/
typedef struct ThrottleGroupMember {
AioContext *aio_context;
/* throttled_reqs_lock protects the CoQueues for throttled requests. */
CoMutex throttled_reqs_lock;
CoQueue throttled_reqs[2];
/* Nonzero if the I/O limits are currently being ignored; generally
* it is zero. Accessed with atomic operations.
*/
unsigned int io_limits_disabled;
/* The following fields are protected by the ThrottleGroup lock.
* See the ThrottleGroup documentation for details.
* throttle_state tells us if I/O limits are configured. */
ThrottleState *throttle_state;
ThrottleTimers throttle_timers;
unsigned pending_reqs[2];
QLIST_ENTRY(ThrottleGroupMember) round_robin;
} ThrottleGroupMember;
#define TYPE_THROTTLE_GROUP "throttle-group"
#define THROTTLE_GROUP(obj) OBJECT_CHECK(ThrottleGroup, (obj), TYPE_THROTTLE_GROUP)
const char *throttle_group_get_name(ThrottleGroupMember *tgm);
ThrottleState *throttle_group_incref(const char *name);
void throttle_group_unref(ThrottleState *ts);
void throttle_group_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg);
void throttle_group_get_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg);
void throttle_group_register_tgm(ThrottleGroupMember *tgm,
const char *groupname,
AioContext *ctx);
void throttle_group_unregister_tgm(ThrottleGroupMember *tgm);
void throttle_group_restart_tgm(ThrottleGroupMember *tgm);
void coroutine_fn throttle_group_co_io_limits_intercept(ThrottleGroupMember *tgm,
unsigned int bytes,
bool is_write);
void throttle_group_attach_aio_context(ThrottleGroupMember *tgm,
AioContext *new_context);
void throttle_group_detach_aio_context(ThrottleGroupMember *tgm);
/*
* throttle_group_exists() must be called under the global
* mutex.
*/
bool throttle_group_exists(const char *name);
#endif