qemu-patch-raspberry4/include/qemu/throttle.h
Benoît Canet 0e5b0a2d54 throttle: Extract timers from ThrottleState into a separate structure
Group throttling will share ThrottleState between multiple bs.
As a consequence the ThrottleState will be accessed by multiple aio
context.

Timers are tied to their aio context so they must go out of the
ThrottleState structure.

This commit paves the way for each bs of a common ThrottleState to
have its own timer.

Signed-off-by: Benoit Canet <benoit.canet@nodalink.com>
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 6cf9ea96d8b32ae2f8769cead38f68a6a0c8c909.1433779731.git.berto@igalia.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-06-12 14:00:00 +01:00

131 lines
4.1 KiB
C

/*
* QEMU throttling infrastructure
*
* Copyright (C) Nodalink, SARL. 2013
*
* Author:
* Benoît Canet <benoit.canet@irqsave.net>
*
* 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_H
#define THROTTLE_H
#include <stdint.h>
#include "qemu-common.h"
#include "qemu/timer.h"
#define NANOSECONDS_PER_SECOND 1000000000.0
typedef enum {
THROTTLE_BPS_TOTAL,
THROTTLE_BPS_READ,
THROTTLE_BPS_WRITE,
THROTTLE_OPS_TOTAL,
THROTTLE_OPS_READ,
THROTTLE_OPS_WRITE,
BUCKETS_COUNT,
} BucketType;
/*
* The max parameter of the leaky bucket throttling algorithm can be used to
* allow the guest to do bursts.
* The max value is a pool of I/O that the guest can use without being throttled
* at all. Throttling is triggered once this pool is empty.
*/
typedef struct LeakyBucket {
double avg; /* average goal in units per second */
double max; /* leaky bucket max burst in units */
double level; /* bucket level in units */
} LeakyBucket;
/* The following structure is used to configure a ThrottleState
* It contains a bit of state: the bucket field of the LeakyBucket structure.
* However it allows to keep the code clean and the bucket field is reset to
* zero at the right time.
*/
typedef struct ThrottleConfig {
LeakyBucket buckets[BUCKETS_COUNT]; /* leaky buckets */
uint64_t op_size; /* size of an operation in bytes */
} ThrottleConfig;
typedef struct ThrottleState {
ThrottleConfig cfg; /* configuration */
int64_t previous_leak; /* timestamp of the last leak done */
} ThrottleState;
typedef struct ThrottleTimers {
QEMUTimer *timers[2]; /* timers used to do the throttling */
QEMUClockType clock_type; /* the clock used */
/* Callbacks */
QEMUTimerCB *read_timer_cb;
QEMUTimerCB *write_timer_cb;
void *timer_opaque;
} ThrottleTimers;
/* operations on single leaky buckets */
void throttle_leak_bucket(LeakyBucket *bkt, int64_t delta);
int64_t throttle_compute_wait(LeakyBucket *bkt);
/* expose timer computation function for unit tests */
bool throttle_compute_timer(ThrottleState *ts,
bool is_write,
int64_t now,
int64_t *next_timestamp);
/* init/destroy cycle */
void throttle_init(ThrottleState *ts);
void throttle_timers_init(ThrottleTimers *tt,
AioContext *aio_context,
QEMUClockType clock_type,
QEMUTimerCB *read_timer_cb,
QEMUTimerCB *write_timer_cb,
void *timer_opaque);
void throttle_timers_destroy(ThrottleTimers *tt);
void throttle_timers_detach_aio_context(ThrottleTimers *tt);
void throttle_timers_attach_aio_context(ThrottleTimers *tt,
AioContext *new_context);
bool throttle_timers_are_initialized(ThrottleTimers *tt);
/* configuration */
bool throttle_enabled(ThrottleConfig *cfg);
bool throttle_conflicting(ThrottleConfig *cfg);
bool throttle_is_valid(ThrottleConfig *cfg);
void throttle_config(ThrottleState *ts,
ThrottleTimers *tt,
ThrottleConfig *cfg);
void throttle_get_config(ThrottleState *ts, ThrottleConfig *cfg);
/* usage */
bool throttle_schedule_timer(ThrottleState *ts,
ThrottleTimers *tt,
bool is_write);
void throttle_account(ThrottleState *ts, bool is_write, uint64_t size);
#endif