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qemu/block/throttle-groups.c

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/*
* 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/>.
*/
#include "qemu/osdep.h"
#include "sysemu/block-backend.h"
#include "block/throttle-groups.h"
#include "qemu/throttle-options.h"
#include "qemu/main-loop.h"
#include "qemu/queue.h"
#include "qemu/thread.h"
#include "sysemu/qtest.h"
#include "qapi/error.h"
#include "qapi/qapi-visit-block-core.h"
#include "qom/object.h"
#include "qom/object_interfaces.h"
static void throttle_group_obj_init(Object *obj);
static void throttle_group_obj_complete(UserCreatable *obj, Error **errp);
static void timer_cb(ThrottleGroupMember *tgm, bool is_write);
/* The ThrottleGroup structure (with its ThrottleState) is shared
* among different ThrottleGroupMembers and it's independent from
* AioContext, so in order to use it from different threads it needs
* its own locking.
*
* This locking is however handled internally in this file, so it's
* transparent to outside users.
*
* The whole ThrottleGroup structure is private and invisible to
* outside users, that only use it through its ThrottleState.
*
* In addition to the ThrottleGroup structure, ThrottleGroupMember has
* fields that need to be accessed by other members of the group and
* therefore also need to be protected by this lock. Once a
* ThrottleGroupMember is registered in a group those fields can be accessed
* by other threads any time.
*
* Again, all this is handled internally and is mostly transparent to
* the outside. The 'throttle_timers' field however has an additional
* constraint because it may be temporarily invalid (see for example
* blk_set_aio_context()). Therefore in this file a thread will
* access some other ThrottleGroupMember's timers only after verifying that
* that ThrottleGroupMember has throttled requests in the queue.
*/
struct ThrottleGroup {
Object parent_obj;
/* refuse individual property change if initialization is complete */
bool is_initialized;
char *name; /* This is constant during the lifetime of the group */
QemuMutex lock; /* This lock protects the following four fields */
ThrottleState ts;
QLIST_HEAD(, ThrottleGroupMember) head;
ThrottleGroupMember *tokens[2];
bool any_timer_armed[2];
QEMUClockType clock_type;
/* This field is protected by the global QEMU mutex */
QTAILQ_ENTRY(ThrottleGroup) list;
};
/* This is protected by the global QEMU mutex */
static QTAILQ_HEAD(, ThrottleGroup) throttle_groups =
QTAILQ_HEAD_INITIALIZER(throttle_groups);
/* This function reads throttle_groups and must be called under the global
* mutex.
*/
static ThrottleGroup *throttle_group_by_name(const char *name)
{
ThrottleGroup *iter;
/* Look for an existing group with that name */
QTAILQ_FOREACH(iter, &throttle_groups, list) {
if (!g_strcmp0(name, iter->name)) {
return iter;
}
}
return NULL;
}
/* This function reads throttle_groups and must be called under the global
* mutex.
*/
bool throttle_group_exists(const char *name)
{
return throttle_group_by_name(name) != NULL;
}
/* Increments the reference count of a ThrottleGroup given its name.
*
* If no ThrottleGroup is found with the given name a new one is
* created.
*
* This function edits throttle_groups and must be called under the global
* mutex.
*
* @name: the name of the ThrottleGroup
* @ret: the ThrottleState member of the ThrottleGroup
*/
ThrottleState *throttle_group_incref(const char *name)
{
ThrottleGroup *tg = NULL;
/* Look for an existing group with that name */
tg = throttle_group_by_name(name);
if (tg) {
object_ref(OBJECT(tg));
} else {
/* Create a new one if not found */
/* new ThrottleGroup obj will have a refcnt = 1 */
tg = THROTTLE_GROUP(object_new(TYPE_THROTTLE_GROUP));
tg->name = g_strdup(name);
throttle_group_obj_complete(USER_CREATABLE(tg), &error_abort);
}
return &tg->ts;
}
/* Decrease the reference count of a ThrottleGroup.
*
* When the reference count reaches zero the ThrottleGroup is
* destroyed.
*
* This function edits throttle_groups and must be called under the global
* mutex.
*
* @ts: The ThrottleGroup to unref, given by its ThrottleState member
*/
void throttle_group_unref(ThrottleState *ts)
{
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
object_unref(OBJECT(tg));
}
/* Get the name from a ThrottleGroupMember's group. The name (and the pointer)
* is guaranteed to remain constant during the lifetime of the group.
*
* @tgm: a ThrottleGroupMember
* @ret: the name of the group.
*/
const char *throttle_group_get_name(ThrottleGroupMember *tgm)
{
ThrottleGroup *tg = container_of(tgm->throttle_state, ThrottleGroup, ts);
return tg->name;
}
/* Return the next ThrottleGroupMember in the round-robin sequence, simulating
* a circular list.
*
* This assumes that tg->lock is held.
*
* @tgm: the current ThrottleGroupMember
* @ret: the next ThrottleGroupMember in the sequence
*/
static ThrottleGroupMember *throttle_group_next_tgm(ThrottleGroupMember *tgm)
{
ThrottleState *ts = tgm->throttle_state;
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
ThrottleGroupMember *next = QLIST_NEXT(tgm, round_robin);
if (!next) {
next = QLIST_FIRST(&tg->head);
}
return next;
}
/*
* Return whether a ThrottleGroupMember has pending requests.
*
* This assumes that tg->lock is held.
*
* @tgm: the ThrottleGroupMember
* @is_write: the type of operation (read/write)
* @ret: whether the ThrottleGroupMember has pending requests.
*/
static inline bool tgm_has_pending_reqs(ThrottleGroupMember *tgm,
bool is_write)
{
return tgm->pending_reqs[is_write];
}
/* Return the next ThrottleGroupMember in the round-robin sequence with pending
* I/O requests.
*
* This assumes that tg->lock is held.
*
* @tgm: the current ThrottleGroupMember
* @is_write: the type of operation (read/write)
* @ret: the next ThrottleGroupMember with pending requests, or tgm if
* there is none.
*/
static ThrottleGroupMember *next_throttle_token(ThrottleGroupMember *tgm,
bool is_write)
{
ThrottleState *ts = tgm->throttle_state;
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
ThrottleGroupMember *token, *start;
/* If this member has its I/O limits disabled then it means that
* it's being drained. Skip the round-robin search and return tgm
* immediately if it has pending requests. Otherwise we could be
* forcing it to wait for other member's throttled requests. */
if (tgm_has_pending_reqs(tgm, is_write) &&
qatomic_read(&tgm->io_limits_disabled)) {
return tgm;
}
start = token = tg->tokens[is_write];
/* get next bs round in round robin style */
token = throttle_group_next_tgm(token);
while (token != start && !tgm_has_pending_reqs(token, is_write)) {
token = throttle_group_next_tgm(token);
}
/* If no IO are queued for scheduling on the next round robin token
* then decide the token is the current tgm because chances are
* the current tgm got the current request queued.
*/
if (token == start && !tgm_has_pending_reqs(token, is_write)) {
token = tgm;
}
/* Either we return the original TGM, or one with pending requests */
assert(token == tgm || tgm_has_pending_reqs(token, is_write));
return token;
}
/* Check if the next I/O request for a ThrottleGroupMember needs to be
* throttled or not. If there's no timer set in this group, set one and update
* the token accordingly.
*
* This assumes that tg->lock is held.
*
* @tgm: the current ThrottleGroupMember
* @is_write: the type of operation (read/write)
* @ret: whether the I/O request needs to be throttled or not
*/
static bool throttle_group_schedule_timer(ThrottleGroupMember *tgm,
bool is_write)
{
ThrottleState *ts = tgm->throttle_state;
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
ThrottleTimers *tt = &tgm->throttle_timers;
bool must_wait;
if (qatomic_read(&tgm->io_limits_disabled)) {
return false;
}
/* Check if any of the timers in this group is already armed */
if (tg->any_timer_armed[is_write]) {
return true;
}
must_wait = throttle_schedule_timer(ts, tt, is_write);
/* If a timer just got armed, set tgm as the current token */
if (must_wait) {
tg->tokens[is_write] = tgm;
tg->any_timer_armed[is_write] = true;
}
return must_wait;
}
/* Start the next pending I/O request for a ThrottleGroupMember. Return whether
* any request was actually pending.
*
* @tgm: the current ThrottleGroupMember
* @is_write: the type of operation (read/write)
*/
static bool coroutine_fn throttle_group_co_restart_queue(ThrottleGroupMember *tgm,
bool is_write)
{
bool ret;
qemu_co_mutex_lock(&tgm->throttled_reqs_lock);
ret = qemu_co_queue_next(&tgm->throttled_reqs[is_write]);
qemu_co_mutex_unlock(&tgm->throttled_reqs_lock);
return ret;
}
/* Look for the next pending I/O request and schedule it.
*
* This assumes that tg->lock is held.
*
* @tgm: the current ThrottleGroupMember
* @is_write: the type of operation (read/write)
*/
static void schedule_next_request(ThrottleGroupMember *tgm, bool is_write)
{
ThrottleState *ts = tgm->throttle_state;
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
bool must_wait;
ThrottleGroupMember *token;
/* Check if there's any pending request to schedule next */
token = next_throttle_token(tgm, is_write);
if (!tgm_has_pending_reqs(token, is_write)) {
return;
}
/* Set a timer for the request if it needs to be throttled */
must_wait = throttle_group_schedule_timer(token, is_write);
/* If it doesn't have to wait, queue it for immediate execution */
if (!must_wait) {
/* Give preference to requests from the current tgm */
if (qemu_in_coroutine() &&
throttle_group_co_restart_queue(tgm, is_write)) {
token = tgm;
} else {
ThrottleTimers *tt = &token->throttle_timers;
int64_t now = qemu_clock_get_ns(tg->clock_type);
timer_mod(tt->timers[is_write], now);
tg->any_timer_armed[is_write] = true;
}
tg->tokens[is_write] = token;
}
}
/* Check if an I/O request needs to be throttled, wait and set a timer
* if necessary, and schedule the next request using a round robin
* algorithm.
*
* @tgm: the current ThrottleGroupMember
* @bytes: the number of bytes for this I/O
* @is_write: the type of operation (read/write)
*/
void coroutine_fn throttle_group_co_io_limits_intercept(ThrottleGroupMember *tgm,
int64_t bytes,
bool is_write)
{
bool must_wait;
ThrottleGroupMember *token;
ThrottleGroup *tg = container_of(tgm->throttle_state, ThrottleGroup, ts);
assert(bytes >= 0);
qemu_mutex_lock(&tg->lock);
/* First we check if this I/O has to be throttled. */
token = next_throttle_token(tgm, is_write);
must_wait = throttle_group_schedule_timer(token, is_write);
/* Wait if there's a timer set or queued requests of this type */
if (must_wait || tgm->pending_reqs[is_write]) {
tgm->pending_reqs[is_write]++;
qemu_mutex_unlock(&tg->lock);
qemu_co_mutex_lock(&tgm->throttled_reqs_lock);
qemu_co_queue_wait(&tgm->throttled_reqs[is_write],
&tgm->throttled_reqs_lock);
qemu_co_mutex_unlock(&tgm->throttled_reqs_lock);
qemu_mutex_lock(&tg->lock);
tgm->pending_reqs[is_write]--;
}
/* The I/O will be executed, so do the accounting */
throttle_account(tgm->throttle_state, is_write, bytes);
/* Schedule the next request */
schedule_next_request(tgm, is_write);
qemu_mutex_unlock(&tg->lock);
}
typedef struct {
ThrottleGroupMember *tgm;
bool is_write;
} RestartData;
static void coroutine_fn throttle_group_restart_queue_entry(void *opaque)
{
RestartData *data = opaque;
ThrottleGroupMember *tgm = data->tgm;
ThrottleState *ts = tgm->throttle_state;
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
bool is_write = data->is_write;
bool empty_queue;
empty_queue = !throttle_group_co_restart_queue(tgm, is_write);
/* If the request queue was empty then we have to take care of
* scheduling the next one */
if (empty_queue) {
qemu_mutex_lock(&tg->lock);
schedule_next_request(tgm, is_write);
qemu_mutex_unlock(&tg->lock);
}
g_free(data);
qatomic_dec(&tgm->restart_pending);
aio_wait_kick();
}
static void throttle_group_restart_queue(ThrottleGroupMember *tgm, bool is_write)
{
Coroutine *co;
RestartData *rd = g_new0(RestartData, 1);
rd->tgm = tgm;
rd->is_write = is_write;
/* This function is called when a timer is fired or when
* throttle_group_restart_tgm() is called. Either way, there can
* be no timer pending on this tgm at this point */
assert(!timer_pending(tgm->throttle_timers.timers[is_write]));
qatomic_inc(&tgm->restart_pending);
co = qemu_coroutine_create(throttle_group_restart_queue_entry, rd);
aio_co_enter(tgm->aio_context, co);
}
void throttle_group_restart_tgm(ThrottleGroupMember *tgm)
{
int i;
if (tgm->throttle_state) {
for (i = 0; i < 2; i++) {
QEMUTimer *t = tgm->throttle_timers.timers[i];
if (timer_pending(t)) {
/* If there's a pending timer on this tgm, fire it now */
timer_del(t);
timer_cb(tgm, i);
} else {
/* Else run the next request from the queue manually */
throttle_group_restart_queue(tgm, i);
}
}
}
}
/* Update the throttle configuration for a particular group. Similar
* to throttle_config(), but guarantees atomicity within the
* throttling group.
*
* @tgm: a ThrottleGroupMember that is a member of the group
* @cfg: the configuration to set
*/
void throttle_group_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg)
{
ThrottleState *ts = tgm->throttle_state;
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
qemu_mutex_lock(&tg->lock);
throttle_config(ts, tg->clock_type, cfg);
qemu_mutex_unlock(&tg->lock);
throttle_group_restart_tgm(tgm);
}
/* Get the throttle configuration from a particular group. Similar to
* throttle_get_config(), but guarantees atomicity within the
* throttling group.
*
* @tgm: a ThrottleGroupMember that is a member of the group
* @cfg: the configuration will be written here
*/
void throttle_group_get_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg)
{
ThrottleState *ts = tgm->throttle_state;
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
qemu_mutex_lock(&tg->lock);
throttle_get_config(ts, cfg);
qemu_mutex_unlock(&tg->lock);
}
/* ThrottleTimers callback. This wakes up a request that was waiting
* because it had been throttled.
*
* @tgm: the ThrottleGroupMember whose request had been throttled
* @is_write: the type of operation (read/write)
*/
static void timer_cb(ThrottleGroupMember *tgm, bool is_write)
{
ThrottleState *ts = tgm->throttle_state;
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
/* The timer has just been fired, so we can update the flag */
qemu_mutex_lock(&tg->lock);
tg->any_timer_armed[is_write] = false;
qemu_mutex_unlock(&tg->lock);
/* Run the request that was waiting for this timer */
throttle_group_restart_queue(tgm, is_write);
}
static void read_timer_cb(void *opaque)
{
timer_cb(opaque, false);
}
static void write_timer_cb(void *opaque)
{
timer_cb(opaque, true);
}
/* Register a ThrottleGroupMember from the throttling group, also initializing
* its timers and updating its throttle_state pointer to point to it. If a
* throttling group with that name does not exist yet, it will be created.
*
* This function edits throttle_groups and must be called under the global
* mutex.
*
* @tgm: the ThrottleGroupMember to insert
* @groupname: the name of the group
* @ctx: the AioContext to use
*/
void throttle_group_register_tgm(ThrottleGroupMember *tgm,
const char *groupname,
AioContext *ctx)
{
int i;
ThrottleState *ts = throttle_group_incref(groupname);
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
tgm->throttle_state = ts;
tgm->aio_context = ctx;
qatomic_set(&tgm->restart_pending, 0);
QEMU_LOCK_GUARD(&tg->lock);
/* If the ThrottleGroup is new set this ThrottleGroupMember as the token */
for (i = 0; i < 2; i++) {
if (!tg->tokens[i]) {
tg->tokens[i] = tgm;
}
}
QLIST_INSERT_HEAD(&tg->head, tgm, round_robin);
throttle_timers_init(&tgm->throttle_timers,
tgm->aio_context,
tg->clock_type,
read_timer_cb,
write_timer_cb,
tgm);
qemu_co_mutex_init(&tgm->throttled_reqs_lock);
qemu_co_queue_init(&tgm->throttled_reqs[0]);
qemu_co_queue_init(&tgm->throttled_reqs[1]);
}
/* Unregister a ThrottleGroupMember from its group, removing it from the list,
* destroying the timers and setting the throttle_state pointer to NULL.
*
* The ThrottleGroupMember must not have pending throttled requests, so the
* caller has to drain them first.
*
* The group will be destroyed if it's empty after this operation.
*
* @tgm the ThrottleGroupMember to remove
*/
void throttle_group_unregister_tgm(ThrottleGroupMember *tgm)
{
ThrottleState *ts = tgm->throttle_state;
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
ThrottleGroupMember *token;
int i;
if (!ts) {
/* Discard already unregistered tgm */
return;
}
/* Wait for throttle_group_restart_queue_entry() coroutines to finish */
AIO_WAIT_WHILE(tgm->aio_context, qatomic_read(&tgm->restart_pending) > 0);
WITH_QEMU_LOCK_GUARD(&tg->lock) {
for (i = 0; i < 2; i++) {
assert(tgm->pending_reqs[i] == 0);
assert(qemu_co_queue_empty(&tgm->throttled_reqs[i]));
assert(!timer_pending(tgm->throttle_timers.timers[i]));
if (tg->tokens[i] == tgm) {
token = throttle_group_next_tgm(tgm);
/* Take care of the case where this is the last tgm in the group */
if (token == tgm) {
token = NULL;
}
tg->tokens[i] = token;
}
}
/* remove the current tgm from the list */
QLIST_REMOVE(tgm, round_robin);
throttle_timers_destroy(&tgm->throttle_timers);
}
throttle_group_unref(&tg->ts);
tgm->throttle_state = NULL;
}
void throttle_group_attach_aio_context(ThrottleGroupMember *tgm,
AioContext *new_context)
{
ThrottleTimers *tt = &tgm->throttle_timers;
throttle_timers_attach_aio_context(tt, new_context);
tgm->aio_context = new_context;
}
void throttle_group_detach_aio_context(ThrottleGroupMember *tgm)
{
ThrottleGroup *tg = container_of(tgm->throttle_state, ThrottleGroup, ts);
ThrottleTimers *tt = &tgm->throttle_timers;
int i;
/* Requests must have been drained */
assert(tgm->pending_reqs[0] == 0 && tgm->pending_reqs[1] == 0);
assert(qemu_co_queue_empty(&tgm->throttled_reqs[0]));
assert(qemu_co_queue_empty(&tgm->throttled_reqs[1]));
/* Kick off next ThrottleGroupMember, if necessary */
WITH_QEMU_LOCK_GUARD(&tg->lock) {
for (i = 0; i < 2; i++) {
if (timer_pending(tt->timers[i])) {
tg->any_timer_armed[i] = false;
schedule_next_request(tgm, i);
}
}
}
throttle_timers_detach_aio_context(tt);
tgm->aio_context = NULL;
}
#undef THROTTLE_OPT_PREFIX
#define THROTTLE_OPT_PREFIX "x-"
/* Helper struct and array for QOM property setter/getter */
typedef struct {
const char *name;
BucketType type;
enum {
AVG,
MAX,
BURST_LENGTH,
IOPS_SIZE,
} category;
} ThrottleParamInfo;
static ThrottleParamInfo properties[] = {
{
THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_TOTAL,
THROTTLE_OPS_TOTAL, AVG,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_TOTAL_MAX,
THROTTLE_OPS_TOTAL, MAX,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_TOTAL_MAX_LENGTH,
THROTTLE_OPS_TOTAL, BURST_LENGTH,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_READ,
THROTTLE_OPS_READ, AVG,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_READ_MAX,
THROTTLE_OPS_READ, MAX,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_READ_MAX_LENGTH,
THROTTLE_OPS_READ, BURST_LENGTH,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_WRITE,
THROTTLE_OPS_WRITE, AVG,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_WRITE_MAX,
THROTTLE_OPS_WRITE, MAX,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_WRITE_MAX_LENGTH,
THROTTLE_OPS_WRITE, BURST_LENGTH,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_BPS_TOTAL,
THROTTLE_BPS_TOTAL, AVG,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_BPS_TOTAL_MAX,
THROTTLE_BPS_TOTAL, MAX,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_BPS_TOTAL_MAX_LENGTH,
THROTTLE_BPS_TOTAL, BURST_LENGTH,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_BPS_READ,
THROTTLE_BPS_READ, AVG,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_BPS_READ_MAX,
THROTTLE_BPS_READ, MAX,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_BPS_READ_MAX_LENGTH,
THROTTLE_BPS_READ, BURST_LENGTH,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_BPS_WRITE,
THROTTLE_BPS_WRITE, AVG,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_BPS_WRITE_MAX,
THROTTLE_BPS_WRITE, MAX,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_BPS_WRITE_MAX_LENGTH,
THROTTLE_BPS_WRITE, BURST_LENGTH,
},
{
THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_SIZE,
0, IOPS_SIZE,
}
};
/* This function edits throttle_groups and must be called under the global
* mutex */
static void throttle_group_obj_init(Object *obj)
{
ThrottleGroup *tg = THROTTLE_GROUP(obj);
tg->clock_type = QEMU_CLOCK_REALTIME;
if (qtest_enabled()) {
/* For testing block IO throttling only */
tg->clock_type = QEMU_CLOCK_VIRTUAL;
}
tg->is_initialized = false;
qemu_mutex_init(&tg->lock);
throttle_init(&tg->ts);
QLIST_INIT(&tg->head);
}
/* This function edits throttle_groups and must be called under the global
* mutex */
static void throttle_group_obj_complete(UserCreatable *obj, Error **errp)
{
ThrottleGroup *tg = THROTTLE_GROUP(obj);
ThrottleConfig cfg;
/* set group name to object id if it exists */
if (!tg->name && tg->parent_obj.parent) {
tg->name = g_strdup(object_get_canonical_path_component(OBJECT(obj)));
}
/* We must have a group name at this point */
assert(tg->name);
/* error if name is duplicate */
if (throttle_group_exists(tg->name)) {
error_setg(errp, "A group with this name already exists");
return;
}
/* check validity */
throttle_get_config(&tg->ts, &cfg);
if (!throttle_is_valid(&cfg, errp)) {
return;
}
throttle_config(&tg->ts, tg->clock_type, &cfg);
QTAILQ_INSERT_TAIL(&throttle_groups, tg, list);
tg->is_initialized = true;
}
/* This function edits throttle_groups and must be called under the global
* mutex */
static void throttle_group_obj_finalize(Object *obj)
{
ThrottleGroup *tg = THROTTLE_GROUP(obj);
if (tg->is_initialized) {
QTAILQ_REMOVE(&throttle_groups, tg, list);
}
qemu_mutex_destroy(&tg->lock);
g_free(tg->name);
}
static void throttle_group_set(Object *obj, Visitor *v, const char * name,
void *opaque, Error **errp)
{
ThrottleGroup *tg = THROTTLE_GROUP(obj);
ThrottleConfig *cfg;
ThrottleParamInfo *info = opaque;
int64_t value;
/* If we have finished initialization, don't accept individual property
* changes through QOM. Throttle configuration limits must be set in one
* transaction, as certain combinations are invalid.
*/
if (tg->is_initialized) {
error_setg(errp, "Property cannot be set after initialization");
return;
}
if (!visit_type_int64(v, name, &value, errp)) {
return;
}
if (value < 0) {
error_setg(errp, "Property values cannot be negative");
return;
}
cfg = &tg->ts.cfg;
switch (info->category) {
case AVG:
cfg->buckets[info->type].avg = value;
break;
case MAX:
cfg->buckets[info->type].max = value;
break;
case BURST_LENGTH:
if (value > UINT_MAX) {
error_setg(errp, "%s value must be in the" "range [0, %u]",
info->name, UINT_MAX);
return;
}
cfg->buckets[info->type].burst_length = value;
break;
case IOPS_SIZE:
cfg->op_size = value;
break;
}
}
static void throttle_group_get(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
ThrottleGroup *tg = THROTTLE_GROUP(obj);
ThrottleConfig cfg;
ThrottleParamInfo *info = opaque;
int64_t value;
throttle_get_config(&tg->ts, &cfg);
switch (info->category) {
case AVG:
value = cfg.buckets[info->type].avg;
break;
case MAX:
value = cfg.buckets[info->type].max;
break;
case BURST_LENGTH:
value = cfg.buckets[info->type].burst_length;
break;
case IOPS_SIZE:
value = cfg.op_size;
break;
}
visit_type_int64(v, name, &value, errp);
}
static void throttle_group_set_limits(Object *obj, Visitor *v,
const char *name, void *opaque,
Error **errp)
{
ThrottleGroup *tg = THROTTLE_GROUP(obj);
ThrottleConfig cfg;
ThrottleLimits *argp;
Error *local_err = NULL;
if (!visit_type_ThrottleLimits(v, name, &argp, errp)) {
return;
}
qemu_mutex_lock(&tg->lock);
throttle_get_config(&tg->ts, &cfg);
throttle_limits_to_config(argp, &cfg, &local_err);
if (local_err) {
goto unlock;
}
throttle_config(&tg->ts, tg->clock_type, &cfg);
unlock:
qemu_mutex_unlock(&tg->lock);
qapi_free_ThrottleLimits(argp);
error_propagate(errp, local_err);
return;
}
static void throttle_group_get_limits(Object *obj, Visitor *v,
const char *name, void *opaque,
Error **errp)
{
ThrottleGroup *tg = THROTTLE_GROUP(obj);
ThrottleConfig cfg;
ThrottleLimits arg = { 0 };
ThrottleLimits *argp = &arg;
qemu_mutex_lock(&tg->lock);
throttle_get_config(&tg->ts, &cfg);
qemu_mutex_unlock(&tg->lock);
throttle_config_to_limits(&cfg, argp);
visit_type_ThrottleLimits(v, name, &argp, errp);
}
static bool throttle_group_can_be_deleted(UserCreatable *uc)
{
return OBJECT(uc)->ref == 1;
}
static void throttle_group_obj_class_init(ObjectClass *klass, void *class_data)
{
size_t i = 0;
UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass);
ucc->complete = throttle_group_obj_complete;
ucc->can_be_deleted = throttle_group_can_be_deleted;
/* individual properties */
for (i = 0; i < sizeof(properties) / sizeof(ThrottleParamInfo); i++) {
object_class_property_add(klass,
properties[i].name,
"int",
throttle_group_get,
throttle_group_set,
NULL, &properties[i]);
}
/* ThrottleLimits */
object_class_property_add(klass,
"limits", "ThrottleLimits",
throttle_group_get_limits,
throttle_group_set_limits,
NULL, NULL);
}
static const TypeInfo throttle_group_info = {
.name = TYPE_THROTTLE_GROUP,
.parent = TYPE_OBJECT,
.class_init = throttle_group_obj_class_init,
.instance_size = sizeof(ThrottleGroup),
.instance_init = throttle_group_obj_init,
.instance_finalize = throttle_group_obj_finalize,
.interfaces = (InterfaceInfo[]) {
{ TYPE_USER_CREATABLE },
{ }
},
};
static void throttle_groups_init(void)
{
type_register_static(&throttle_group_info);
}
type_init(throttle_groups_init);
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