From 0e5b0a2d54f4dca2f6d1a676da8ec089dc143001 Mon Sep 17 00:00:00 2001 From: Benoît Canet Date: Mon, 8 Jun 2015 18:17:41 +0200 Subject: 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 Signed-off-by: Alberto Garcia Reviewed-by: Stefan Hajnoczi Message-id: 6cf9ea96d8b32ae2f8769cead38f68a6a0c8c909.1433779731.git.berto@igalia.com Signed-off-by: Stefan Hajnoczi --- include/block/block_int.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/block') diff --git a/include/block/block_int.h b/include/block/block_int.h index f004378d58..02b312fea9 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -380,6 +380,7 @@ struct BlockDriverState { /* I/O throttling */ ThrottleState throttle_state; + ThrottleTimers throttle_timers; CoQueue throttled_reqs[2]; bool io_limits_enabled; -- cgit v1.2.3-55-g7522 From 2ff1f2e3a39daf4a401a8904d00b29ea8c450463 Mon Sep 17 00:00:00 2001 From: Alberto Garcia Date: Mon, 8 Jun 2015 18:17:42 +0200 Subject: throttle: Add throttle group infrastructure Signed-off-by: Alberto Garcia Reviewed-by: Stefan Hajnoczi Message-id: 2fdb4de17210b733a13eb472c33cd08b45f8fd21.1433779731.git.berto@igalia.com Signed-off-by: Stefan Hajnoczi --- block/Makefile.objs | 1 + block/throttle-groups.c | 261 ++++++++++++++++++++++++++++++++++++++++ include/block/block_int.h | 1 + include/block/throttle-groups.h | 39 ++++++ 4 files changed, 302 insertions(+) create mode 100644 block/throttle-groups.c create mode 100644 include/block/throttle-groups.h (limited to 'include/block') diff --git a/block/Makefile.objs b/block/Makefile.objs index 0d8c2a4ab6..c34fd7cdc2 100644 --- a/block/Makefile.objs +++ b/block/Makefile.objs @@ -10,6 +10,7 @@ block-obj-$(CONFIG_WIN32) += raw-win32.o win32-aio.o block-obj-$(CONFIG_POSIX) += raw-posix.o block-obj-$(CONFIG_LINUX_AIO) += linux-aio.o block-obj-y += null.o mirror.o io.o +block-obj-y += throttle-groups.o block-obj-y += nbd.o nbd-client.o sheepdog.o block-obj-$(CONFIG_LIBISCSI) += iscsi.o diff --git a/block/throttle-groups.c b/block/throttle-groups.c new file mode 100644 index 0000000000..352077f98c --- /dev/null +++ b/block/throttle-groups.c @@ -0,0 +1,261 @@ +/* + * QEMU block throttling group infrastructure + * + * Copyright (C) Nodalink, EURL. 2014 + * Copyright (C) Igalia, S.L. 2015 + * + * Authors: + * Benoît Canet + * Alberto Garcia + * + * 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 . + */ + +#include "block/throttle-groups.h" + +/* The ThrottleGroup structure (with its ThrottleState) is shared + * among different BlockDriverState 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, BlockDriverState 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 BDS 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 + * bdrv_set_aio_context()). Therefore in this file a thread will + * access some other BDS's timers only after verifying that that BDS + * has throttled requests in the queue. + */ +typedef struct ThrottleGroup { + char *name; /* This is constant during the lifetime of the group */ + + QemuMutex lock; /* This lock protects the following four fields */ + ThrottleState ts; + QLIST_HEAD(, BlockDriverState) head; + BlockDriverState *tokens[2]; + bool any_timer_armed[2]; + + /* These two are protected by the global throttle_groups_lock */ + unsigned refcount; + QTAILQ_ENTRY(ThrottleGroup) list; +} ThrottleGroup; + +static QemuMutex throttle_groups_lock; +static QTAILQ_HEAD(, ThrottleGroup) throttle_groups = + QTAILQ_HEAD_INITIALIZER(throttle_groups); + +/* Increments the reference count of a ThrottleGroup given its name. + * + * If no ThrottleGroup is found with the given name a new one is + * created. + * + * @name: the name of the ThrottleGroup + * @ret: the ThrottleGroup + */ +static ThrottleGroup *throttle_group_incref(const char *name) +{ + ThrottleGroup *tg = NULL; + ThrottleGroup *iter; + + qemu_mutex_lock(&throttle_groups_lock); + + /* Look for an existing group with that name */ + QTAILQ_FOREACH(iter, &throttle_groups, list) { + if (!strcmp(name, iter->name)) { + tg = iter; + break; + } + } + + /* Create a new one if not found */ + if (!tg) { + tg = g_new0(ThrottleGroup, 1); + tg->name = g_strdup(name); + qemu_mutex_init(&tg->lock); + throttle_init(&tg->ts); + QLIST_INIT(&tg->head); + + QTAILQ_INSERT_TAIL(&throttle_groups, tg, list); + } + + tg->refcount++; + + qemu_mutex_unlock(&throttle_groups_lock); + + return tg; +} + +/* Decrease the reference count of a ThrottleGroup. + * + * When the reference count reaches zero the ThrottleGroup is + * destroyed. + * + * @tg: The ThrottleGroup to unref + */ +static void throttle_group_unref(ThrottleGroup *tg) +{ + qemu_mutex_lock(&throttle_groups_lock); + if (--tg->refcount == 0) { + QTAILQ_REMOVE(&throttle_groups, tg, list); + qemu_mutex_destroy(&tg->lock); + g_free(tg->name); + g_free(tg); + } + qemu_mutex_unlock(&throttle_groups_lock); +} + +/* Get the name from a BlockDriverState's ThrottleGroup. The name (and + * the pointer) is guaranteed to remain constant during the lifetime + * of the group. + * + * @bs: a BlockDriverState that is member of a throttling group + * @ret: the name of the group. + */ +const char *throttle_group_get_name(BlockDriverState *bs) +{ + ThrottleGroup *tg = container_of(bs->throttle_state, ThrottleGroup, ts); + return tg->name; +} + +/* Return the next BlockDriverState in the round-robin sequence, + * simulating a circular list. + * + * This assumes that tg->lock is held. + * + * @bs: the current BlockDriverState + * @ret: the next BlockDriverState in the sequence + */ +static BlockDriverState *throttle_group_next_bs(BlockDriverState *bs) +{ + ThrottleState *ts = bs->throttle_state; + ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts); + BlockDriverState *next = QLIST_NEXT(bs, round_robin); + + if (!next) { + return QLIST_FIRST(&tg->head); + } + + return next; +} + +/* Update the throttle configuration for a particular group. Similar + * to throttle_config(), but guarantees atomicity within the + * throttling group. + * + * @bs: a BlockDriverState that is member of the group + * @cfg: the configuration to set + */ +void throttle_group_config(BlockDriverState *bs, ThrottleConfig *cfg) +{ + ThrottleTimers *tt = &bs->throttle_timers; + ThrottleState *ts = bs->throttle_state; + ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts); + qemu_mutex_lock(&tg->lock); + throttle_config(ts, tt, cfg); + /* throttle_config() cancels the timers */ + tg->any_timer_armed[0] = tg->any_timer_armed[1] = false; + qemu_mutex_unlock(&tg->lock); +} + +/* Get the throttle configuration from a particular group. Similar to + * throttle_get_config(), but guarantees atomicity within the + * throttling group. + * + * @bs: a BlockDriverState that is member of the group + * @cfg: the configuration will be written here + */ +void throttle_group_get_config(BlockDriverState *bs, ThrottleConfig *cfg) +{ + ThrottleState *ts = bs->throttle_state; + ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts); + qemu_mutex_lock(&tg->lock); + throttle_get_config(ts, cfg); + qemu_mutex_unlock(&tg->lock); +} + +/* Register a BlockDriverState in the throttling group, also updating + * its throttle_state pointer to point to it. If a throttling group + * with that name does not exist yet, it will be created. + * + * @bs: the BlockDriverState to insert + * @groupname: the name of the group + */ +void throttle_group_register_bs(BlockDriverState *bs, const char *groupname) +{ + int i; + ThrottleGroup *tg = throttle_group_incref(groupname); + + bs->throttle_state = &tg->ts; + + qemu_mutex_lock(&tg->lock); + /* If the ThrottleGroup is new set this BlockDriverState as the token */ + for (i = 0; i < 2; i++) { + if (!tg->tokens[i]) { + tg->tokens[i] = bs; + } + } + + QLIST_INSERT_HEAD(&tg->head, bs, round_robin); + qemu_mutex_unlock(&tg->lock); +} + +/* Unregister a BlockDriverState from its group, removing it from the + * list and setting the throttle_state pointer to NULL. + * + * The group will be destroyed if it's empty after this operation. + * + * @bs: the BlockDriverState to remove + */ +void throttle_group_unregister_bs(BlockDriverState *bs) +{ + ThrottleGroup *tg = container_of(bs->throttle_state, ThrottleGroup, ts); + int i; + + qemu_mutex_lock(&tg->lock); + for (i = 0; i < 2; i++) { + if (tg->tokens[i] == bs) { + BlockDriverState *token = throttle_group_next_bs(bs); + /* Take care of the case where this is the last bs in the group */ + if (token == bs) { + token = NULL; + } + tg->tokens[i] = token; + } + } + + /* remove the current bs from the list */ + QLIST_REMOVE(bs, round_robin); + qemu_mutex_unlock(&tg->lock); + + throttle_group_unref(tg); + bs->throttle_state = NULL; +} + +static void throttle_groups_init(void) +{ + qemu_mutex_init(&throttle_groups_lock); +} + +block_init(throttle_groups_init); diff --git a/include/block/block_int.h b/include/block/block_int.h index 02b312fea9..8d15c7b680 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -383,6 +383,7 @@ struct BlockDriverState { ThrottleTimers throttle_timers; CoQueue throttled_reqs[2]; bool io_limits_enabled; + QLIST_ENTRY(BlockDriverState) round_robin; /* I/O stats (display with "info blockstats"). */ BlockAcctStats stats; diff --git a/include/block/throttle-groups.h b/include/block/throttle-groups.h new file mode 100644 index 0000000000..b966ec793c --- /dev/null +++ b/include/block/throttle-groups.h @@ -0,0 +1,39 @@ +/* + * QEMU block throttling group infrastructure + * + * Copyright (C) Nodalink, EURL. 2014 + * Copyright (C) Igalia, S.L. 2015 + * + * Authors: + * Benoît Canet + * Alberto Garcia + * + * 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 . + */ + +#ifndef THROTTLE_GROUPS_H +#define THROTTLE_GROUPS_H + +#include "qemu/throttle.h" +#include "block/block_int.h" + +const char *throttle_group_get_name(BlockDriverState *bs); + +void throttle_group_config(BlockDriverState *bs, ThrottleConfig *cfg); +void throttle_group_get_config(BlockDriverState *bs, ThrottleConfig *cfg); + +void throttle_group_register_bs(BlockDriverState *bs, const char *groupname); +void throttle_group_unregister_bs(BlockDriverState *bs); + +#endif -- cgit v1.2.3-55-g7522 From 76f4afb40fa076ed23fe0ab42c7a768ddb71123f Mon Sep 17 00:00:00 2001 From: Alberto Garcia Date: Mon, 8 Jun 2015 18:17:44 +0200 Subject: throttle: Add throttle group support The throttle group support use a cooperative round robin scheduling algorithm. The principles of the algorithm are simple: - Each BDS of the group is used as a token in a circular way. - The active BDS computes if a wait must be done and arms the right timer. - If a wait must be done the token timer will be armed so the token will become the next active BDS. Signed-off-by: Alberto Garcia Reviewed-by: Stefan Hajnoczi Message-id: f0082a86f3ac01c46170f7eafe2101a92e8fde39.1433779731.git.berto@igalia.com Signed-off-by: Stefan Hajnoczi --- block.c | 15 +-- block/io.c | 75 +++----------- block/qapi.c | 5 +- block/throttle-groups.c | 214 +++++++++++++++++++++++++++++++++++++++- blockdev.c | 38 +++++-- hmp.c | 4 +- include/block/block.h | 3 +- include/block/block_int.h | 7 +- include/block/throttle-groups.h | 4 + qapi/block-core.json | 25 ++++- qemu-options.hx | 1 + qmp-commands.hx | 3 +- 12 files changed, 309 insertions(+), 85 deletions(-) (limited to 'include/block') diff --git a/block.c b/block.c index f9c6bb7404..1bc0e7394b 100644 --- a/block.c +++ b/block.c @@ -1822,15 +1822,18 @@ static void bdrv_move_feature_fields(BlockDriverState *bs_dest, bs_dest->enable_write_cache = bs_src->enable_write_cache; /* i/o throttled req */ - memcpy(&bs_dest->throttle_state, - &bs_src->throttle_state, - sizeof(ThrottleState)); + bs_dest->throttle_state = bs_src->throttle_state, + bs_dest->io_limits_enabled = bs_src->io_limits_enabled; + bs_dest->pending_reqs[0] = bs_src->pending_reqs[0]; + bs_dest->pending_reqs[1] = bs_src->pending_reqs[1]; + bs_dest->throttled_reqs[0] = bs_src->throttled_reqs[0]; + bs_dest->throttled_reqs[1] = bs_src->throttled_reqs[1]; + memcpy(&bs_dest->round_robin, + &bs_src->round_robin, + sizeof(bs_dest->round_robin)); memcpy(&bs_dest->throttle_timers, &bs_src->throttle_timers, sizeof(ThrottleTimers)); - bs_dest->throttled_reqs[0] = bs_src->throttled_reqs[0]; - bs_dest->throttled_reqs[1] = bs_src->throttled_reqs[1]; - bs_dest->io_limits_enabled = bs_src->io_limits_enabled; /* r/w error */ bs_dest->on_read_error = bs_src->on_read_error; diff --git a/block/io.c b/block/io.c index 61a9d1da28..bb4f78784e 100644 --- a/block/io.c +++ b/block/io.c @@ -23,9 +23,9 @@ */ #include "trace.h" -#include "sysemu/qtest.h" #include "block/blockjob.h" #include "block/block_int.h" +#include "block/throttle-groups.h" #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ @@ -65,7 +65,7 @@ void bdrv_set_io_limits(BlockDriverState *bs, { int i; - throttle_config(&bs->throttle_state, &bs->throttle_timers, cfg); + throttle_group_config(bs, cfg); for (i = 0; i < 2; i++) { qemu_co_enter_next(&bs->throttled_reqs[i]); @@ -95,76 +95,33 @@ static bool bdrv_start_throttled_reqs(BlockDriverState *bs) void bdrv_io_limits_disable(BlockDriverState *bs) { bs->io_limits_enabled = false; - bdrv_start_throttled_reqs(bs); - - throttle_timers_destroy(&bs->throttle_timers); -} - -static void bdrv_throttle_read_timer_cb(void *opaque) -{ - BlockDriverState *bs = opaque; - qemu_co_enter_next(&bs->throttled_reqs[0]); -} - -static void bdrv_throttle_write_timer_cb(void *opaque) -{ - BlockDriverState *bs = opaque; - qemu_co_enter_next(&bs->throttled_reqs[1]); + throttle_group_unregister_bs(bs); } /* should be called before bdrv_set_io_limits if a limit is set */ -void bdrv_io_limits_enable(BlockDriverState *bs) +void bdrv_io_limits_enable(BlockDriverState *bs, const char *group) { - int clock_type = QEMU_CLOCK_REALTIME; - - if (qtest_enabled()) { - /* For testing block IO throttling only */ - clock_type = QEMU_CLOCK_VIRTUAL; - } assert(!bs->io_limits_enabled); - throttle_init(&bs->throttle_state); - throttle_timers_init(&bs->throttle_timers, - bdrv_get_aio_context(bs), - clock_type, - bdrv_throttle_read_timer_cb, - bdrv_throttle_write_timer_cb, - bs); + throttle_group_register_bs(bs, group); bs->io_limits_enabled = true; } -/* This function makes an IO wait if needed - * - * @nb_sectors: the number of sectors of the IO - * @is_write: is the IO a write - */ -static void bdrv_io_limits_intercept(BlockDriverState *bs, - unsigned int bytes, - bool is_write) +void bdrv_io_limits_update_group(BlockDriverState *bs, const char *group) { - /* does this io must wait */ - bool must_wait = throttle_schedule_timer(&bs->throttle_state, - &bs->throttle_timers, - is_write); - - /* if must wait or any request of this type throttled queue the IO */ - if (must_wait || - !qemu_co_queue_empty(&bs->throttled_reqs[is_write])) { - qemu_co_queue_wait(&bs->throttled_reqs[is_write]); + /* this bs is not part of any group */ + if (!bs->throttle_state) { + return; } - /* the IO will be executed, do the accounting */ - throttle_account(&bs->throttle_state, is_write, bytes); - - - /* if the next request must wait -> do nothing */ - if (throttle_schedule_timer(&bs->throttle_state, &bs->throttle_timers, - is_write)) { + /* this bs is a part of the same group than the one we want */ + if (!g_strcmp0(throttle_group_get_name(bs), group)) { return; } - /* else queue next request for execution */ - qemu_co_queue_next(&bs->throttled_reqs[is_write]); + /* need to change the group this bs belong to */ + bdrv_io_limits_disable(bs); + bdrv_io_limits_enable(bs, group); } void bdrv_setup_io_funcs(BlockDriver *bdrv) @@ -971,7 +928,7 @@ static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs, /* throttling disk I/O */ if (bs->io_limits_enabled) { - bdrv_io_limits_intercept(bs, bytes, false); + throttle_group_co_io_limits_intercept(bs, bytes, false); } /* Align read if necessary by padding qiov */ @@ -1301,7 +1258,7 @@ static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs, /* throttling disk I/O */ if (bs->io_limits_enabled) { - bdrv_io_limits_intercept(bs, bytes, true); + throttle_group_co_io_limits_intercept(bs, bytes, true); } /* diff --git a/block/qapi.c b/block/qapi.c index 18d2b95f54..a5ac31268d 100644 --- a/block/qapi.c +++ b/block/qapi.c @@ -24,6 +24,7 @@ #include "block/qapi.h" #include "block/block_int.h" +#include "block/throttle-groups.h" #include "block/write-threshold.h" #include "qmp-commands.h" #include "qapi-visit.h" @@ -65,7 +66,9 @@ BlockDeviceInfo *bdrv_block_device_info(BlockDriverState *bs, Error **errp) if (bs->io_limits_enabled) { ThrottleConfig cfg; - throttle_get_config(&bs->throttle_state, &cfg); + + throttle_group_get_config(bs, &cfg); + info->bps = cfg.buckets[THROTTLE_BPS_TOTAL].avg; info->bps_rd = cfg.buckets[THROTTLE_BPS_READ].avg; info->bps_wr = cfg.buckets[THROTTLE_BPS_WRITE].avg; diff --git a/block/throttle-groups.c b/block/throttle-groups.c index 352077f98c..da8c70c4a6 100644 --- a/block/throttle-groups.c +++ b/block/throttle-groups.c @@ -23,6 +23,9 @@ */ #include "block/throttle-groups.h" +#include "qemu/queue.h" +#include "qemu/thread.h" +#include "sysemu/qtest.h" /* The ThrottleGroup structure (with its ThrottleState) is shared * among different BlockDriverState and it's independent from @@ -160,6 +163,153 @@ static BlockDriverState *throttle_group_next_bs(BlockDriverState *bs) return next; } +/* Return the next BlockDriverState in the round-robin sequence with + * pending I/O requests. + * + * This assumes that tg->lock is held. + * + * @bs: the current BlockDriverState + * @is_write: the type of operation (read/write) + * @ret: the next BlockDriverState with pending requests, or bs + * if there is none. + */ +static BlockDriverState *next_throttle_token(BlockDriverState *bs, + bool is_write) +{ + ThrottleGroup *tg = container_of(bs->throttle_state, ThrottleGroup, ts); + BlockDriverState *token, *start; + + start = token = tg->tokens[is_write]; + + /* get next bs round in round robin style */ + token = throttle_group_next_bs(token); + while (token != start && !token->pending_reqs[is_write]) { + token = throttle_group_next_bs(token); + } + + /* If no IO are queued for scheduling on the next round robin token + * then decide the token is the current bs because chances are + * the current bs get the current request queued. + */ + if (token == start && !token->pending_reqs[is_write]) { + token = bs; + } + + return token; +} + +/* Check if the next I/O request for a BlockDriverState 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. + * + * @bs: the current BlockDriverState + * @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(BlockDriverState *bs, + bool is_write) +{ + ThrottleState *ts = bs->throttle_state; + ThrottleTimers *tt = &bs->throttle_timers; + ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts); + bool must_wait; + + /* 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 bs as the current token */ + if (must_wait) { + tg->tokens[is_write] = bs; + tg->any_timer_armed[is_write] = true; + } + + return must_wait; +} + +/* Look for the next pending I/O request and schedule it. + * + * This assumes that tg->lock is held. + * + * @bs: the current BlockDriverState + * @is_write: the type of operation (read/write) + */ +static void schedule_next_request(BlockDriverState *bs, bool is_write) +{ + ThrottleGroup *tg = container_of(bs->throttle_state, ThrottleGroup, ts); + bool must_wait; + BlockDriverState *token; + + /* Check if there's any pending request to schedule next */ + token = next_throttle_token(bs, is_write); + if (!token->pending_reqs[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 bs */ + if (qemu_in_coroutine() && + qemu_co_queue_next(&bs->throttled_reqs[is_write])) { + token = bs; + } else { + ThrottleTimers *tt = &token->throttle_timers; + int64_t now = qemu_clock_get_ns(tt->clock_type); + timer_mod(tt->timers[is_write], now + 1); + 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. + * + * @bs: the current BlockDriverState + * @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(BlockDriverState *bs, + unsigned int bytes, + bool is_write) +{ + bool must_wait; + BlockDriverState *token; + + ThrottleGroup *tg = container_of(bs->throttle_state, ThrottleGroup, ts); + qemu_mutex_lock(&tg->lock); + + /* First we check if this I/O has to be throttled. */ + token = next_throttle_token(bs, 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 || bs->pending_reqs[is_write]) { + bs->pending_reqs[is_write]++; + qemu_mutex_unlock(&tg->lock); + qemu_co_queue_wait(&bs->throttled_reqs[is_write]); + qemu_mutex_lock(&tg->lock); + bs->pending_reqs[is_write]--; + } + + /* The I/O will be executed, so do the accounting */ + throttle_account(bs->throttle_state, is_write, bytes); + + /* Schedule the next request */ + schedule_next_request(bs, is_write); + + qemu_mutex_unlock(&tg->lock); +} + /* Update the throttle configuration for a particular group. Similar * to throttle_config(), but guarantees atomicity within the * throttling group. @@ -195,9 +345,49 @@ void throttle_group_get_config(BlockDriverState *bs, ThrottleConfig *cfg) qemu_mutex_unlock(&tg->lock); } -/* Register a BlockDriverState in the throttling group, also updating - * its throttle_state pointer to point to it. If a throttling group - * with that name does not exist yet, it will be created. +/* ThrottleTimers callback. This wakes up a request that was waiting + * because it had been throttled. + * + * @bs: the BlockDriverState whose request had been throttled + * @is_write: the type of operation (read/write) + */ +static void timer_cb(BlockDriverState *bs, bool is_write) +{ + ThrottleState *ts = bs->throttle_state; + ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts); + bool empty_queue; + + /* 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 */ + empty_queue = !qemu_co_enter_next(&bs->throttled_reqs[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(bs, is_write); + qemu_mutex_unlock(&tg->lock); + } +} + +static void read_timer_cb(void *opaque) +{ + timer_cb(opaque, false); +} + +static void write_timer_cb(void *opaque) +{ + timer_cb(opaque, true); +} + +/* Register a BlockDriverState in 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. * * @bs: the BlockDriverState to insert * @groupname: the name of the group @@ -206,6 +396,12 @@ void throttle_group_register_bs(BlockDriverState *bs, const char *groupname) { int i; ThrottleGroup *tg = throttle_group_incref(groupname); + int clock_type = QEMU_CLOCK_REALTIME; + + if (qtest_enabled()) { + /* For testing block IO throttling only */ + clock_type = QEMU_CLOCK_VIRTUAL; + } bs->throttle_state = &tg->ts; @@ -218,11 +414,20 @@ void throttle_group_register_bs(BlockDriverState *bs, const char *groupname) } QLIST_INSERT_HEAD(&tg->head, bs, round_robin); + + throttle_timers_init(&bs->throttle_timers, + bdrv_get_aio_context(bs), + clock_type, + read_timer_cb, + write_timer_cb, + bs); + qemu_mutex_unlock(&tg->lock); } /* Unregister a BlockDriverState from its group, removing it from the - * list and setting the throttle_state pointer to NULL. + * list, destroying the timers and setting the throttle_state pointer + * to NULL. * * The group will be destroyed if it's empty after this operation. * @@ -247,6 +452,7 @@ void throttle_group_unregister_bs(BlockDriverState *bs) /* remove the current bs from the list */ QLIST_REMOVE(bs, round_robin); + throttle_timers_destroy(&bs->throttle_timers); qemu_mutex_unlock(&tg->lock); throttle_group_unref(tg); diff --git a/blockdev.c b/blockdev.c index de94a8bcb3..d4274efe55 100644 --- a/blockdev.c +++ b/blockdev.c @@ -34,6 +34,7 @@ #include "sysemu/blockdev.h" #include "hw/block/block.h" #include "block/blockjob.h" +#include "block/throttle-groups.h" #include "monitor/monitor.h" #include "qemu/option.h" #include "qemu/config-file.h" @@ -357,6 +358,7 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts, const char *id; bool has_driver_specific_opts; BlockdevDetectZeroesOptions detect_zeroes; + const char *throttling_group; /* Check common options by copying from bs_opts to opts, all other options * stay in bs_opts for processing by bdrv_open(). */ @@ -459,6 +461,8 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts, cfg.op_size = qemu_opt_get_number(opts, "throttling.iops-size", 0); + throttling_group = qemu_opt_get(opts, "throttling.group"); + if (!check_throttle_config(&cfg, &error)) { error_propagate(errp, error); goto early_err; @@ -547,7 +551,10 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts, /* disk I/O throttling */ if (throttle_enabled(&cfg)) { - bdrv_io_limits_enable(bs); + if (!throttling_group) { + throttling_group = blk_name(blk); + } + bdrv_io_limits_enable(bs, throttling_group); bdrv_set_io_limits(bs, &cfg); } @@ -711,6 +718,8 @@ DriveInfo *drive_new(QemuOpts *all_opts, BlockInterfaceType block_default_type) { "iops_size", "throttling.iops-size" }, + { "group", "throttling.group" }, + { "readonly", "read-only" }, }; @@ -1951,7 +1960,9 @@ void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd, bool has_iops_wr_max, int64_t iops_wr_max, bool has_iops_size, - int64_t iops_size, Error **errp) + int64_t iops_size, + bool has_group, + const char *group, Error **errp) { ThrottleConfig cfg; BlockDriverState *bs; @@ -2004,14 +2015,19 @@ void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd, aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); - if (!bs->io_limits_enabled && throttle_enabled(&cfg)) { - bdrv_io_limits_enable(bs); - } else if (bs->io_limits_enabled && !throttle_enabled(&cfg)) { - bdrv_io_limits_disable(bs); - } - - if (bs->io_limits_enabled) { + if (throttle_enabled(&cfg)) { + /* Enable I/O limits if they're not enabled yet, otherwise + * just update the throttling group. */ + if (!bs->io_limits_enabled) { + bdrv_io_limits_enable(bs, has_group ? group : device); + } else if (has_group) { + bdrv_io_limits_update_group(bs, group); + } + /* Set the new throttling configuration */ bdrv_set_io_limits(bs, &cfg); + } else if (bs->io_limits_enabled) { + /* If all throttling settings are set to 0, disable I/O limits */ + bdrv_io_limits_disable(bs); } aio_context_release(aio_context); @@ -3188,6 +3204,10 @@ QemuOptsList qemu_common_drive_opts = { .name = "throttling.iops-size", .type = QEMU_OPT_NUMBER, .help = "when limiting by iops max size of an I/O in bytes", + },{ + .name = "throttling.group", + .type = QEMU_OPT_STRING, + .help = "name of the block throttling group", },{ .name = "copy-on-read", .type = QEMU_OPT_BOOL, diff --git a/hmp.c b/hmp.c index 514f22fbfa..eb5ef61abe 100644 --- a/hmp.c +++ b/hmp.c @@ -1356,7 +1356,9 @@ void hmp_block_set_io_throttle(Monitor *mon, const QDict *qdict) false, 0, false, /* No default I/O size */ - 0, &err); + 0, + false, + NULL, &err); hmp_handle_error(mon, &err); } diff --git a/include/block/block.h b/include/block/block.h index f7680b6e68..f6fb8c497b 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -173,8 +173,9 @@ void bdrv_stats_print(Monitor *mon, const QObject *data); void bdrv_info_stats(Monitor *mon, QObject **ret_data); /* disk I/O throttling */ -void bdrv_io_limits_enable(BlockDriverState *bs); +void bdrv_io_limits_enable(BlockDriverState *bs, const char *group); void bdrv_io_limits_disable(BlockDriverState *bs); +void bdrv_io_limits_update_group(BlockDriverState *bs, const char *group); void bdrv_init(void); void bdrv_init_with_whitelist(void); diff --git a/include/block/block_int.h b/include/block/block_int.h index 8d15c7b680..b174852099 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -379,10 +379,13 @@ struct BlockDriverState { unsigned int serialising_in_flight; /* I/O throttling */ - ThrottleState throttle_state; - ThrottleTimers throttle_timers; CoQueue throttled_reqs[2]; bool io_limits_enabled; + /* The following fields are protected by the ThrottleGroup lock. + * See the ThrottleGroup documentation for details. */ + ThrottleState *throttle_state; + ThrottleTimers throttle_timers; + unsigned pending_reqs[2]; QLIST_ENTRY(BlockDriverState) round_robin; /* I/O stats (display with "info blockstats"). */ diff --git a/include/block/throttle-groups.h b/include/block/throttle-groups.h index b966ec793c..322139a7a2 100644 --- a/include/block/throttle-groups.h +++ b/include/block/throttle-groups.h @@ -36,4 +36,8 @@ void throttle_group_get_config(BlockDriverState *bs, ThrottleConfig *cfg); void throttle_group_register_bs(BlockDriverState *bs, const char *groupname); void throttle_group_unregister_bs(BlockDriverState *bs); +void coroutine_fn throttle_group_co_io_limits_intercept(BlockDriverState *bs, + unsigned int bytes, + bool is_write); + #endif diff --git a/qapi/block-core.json b/qapi/block-core.json index 8411d4f83a..30871546af 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -1062,6 +1062,27 @@ # # Change I/O throttle limits for a block drive. # +# Since QEMU 2.4, each device with I/O limits is member of a throttle +# group. +# +# If two or more devices are members of the same group, the limits +# will apply to the combined I/O of the whole group in a round-robin +# fashion. Therefore, setting new I/O limits to a device will affect +# the whole group. +# +# The name of the group can be specified using the 'group' parameter. +# If the parameter is unset, it is assumed to be the current group of +# that device. If it's not in any group yet, the name of the device +# will be used as the name for its group. +# +# The 'group' parameter can also be used to move a device to a +# different group. In this case the limits specified in the parameters +# will be applied to the new group only. +# +# I/O limits can be disabled by setting all of them to 0. In this case +# the device will be removed from its group and the rest of its +# members will no be affected. The 'group' parameter is ignored. +# # @device: The name of the device # # @bps: total throughput limit in bytes per second @@ -1090,6 +1111,8 @@ # # @iops_size: #optional an I/O size in bytes (Since 1.7) # +# @group: #optional throttle group name (Since 2.4) +# # Returns: Nothing on success # If @device is not a valid block device, DeviceNotFound # @@ -1101,7 +1124,7 @@ '*bps_max': 'int', '*bps_rd_max': 'int', '*bps_wr_max': 'int', '*iops_max': 'int', '*iops_rd_max': 'int', '*iops_wr_max': 'int', - '*iops_size': 'int' } } + '*iops_size': 'int', '*group': 'str' } } ## # @block-stream: diff --git a/qemu-options.hx b/qemu-options.hx index 1d281f6818..289ddcb944 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -468,6 +468,7 @@ DEF("drive", HAS_ARG, QEMU_OPTION_drive, " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" " [[,iops_size=is]]\n" + " [[,group=g]]\n" " use 'file' as a drive image\n", QEMU_ARCH_ALL) STEXI @item -drive @var{option}[,@var{option}[,@var{option}[,...]]] diff --git a/qmp-commands.hx b/qmp-commands.hx index 867a21fab6..a819160812 100644 --- a/qmp-commands.hx +++ b/qmp-commands.hx @@ -1853,7 +1853,7 @@ EQMP { .name = "block_set_io_throttle", - .args_type = "device:B,bps:l,bps_rd:l,bps_wr:l,iops:l,iops_rd:l,iops_wr:l,bps_max:l?,bps_rd_max:l?,bps_wr_max:l?,iops_max:l?,iops_rd_max:l?,iops_wr_max:l?,iops_size:l?", + .args_type = "device:B,bps:l,bps_rd:l,bps_wr:l,iops:l,iops_rd:l,iops_wr:l,bps_max:l?,bps_rd_max:l?,bps_wr_max:l?,iops_max:l?,iops_rd_max:l?,iops_wr_max:l?,iops_size:l?,group:s?", .mhandler.cmd_new = qmp_marshal_input_block_set_io_throttle, }, @@ -1879,6 +1879,7 @@ Arguments: - "iops_rd_max": read I/O operations max (json-int) - "iops_wr_max": write I/O operations max (json-int) - "iops_size": I/O size in bytes when limiting (json-int) +- "group": throttle group name (json-string) Example: -- cgit v1.2.3-55-g7522 From db6283385cb708b9d589e5b57e96eab4afd0269e Mon Sep 17 00:00:00 2001 From: Alberto Garcia Date: Mon, 8 Jun 2015 18:17:45 +0200 Subject: throttle: acquire the ThrottleGroup lock in bdrv_swap() bdrv_swap() touches the fields of a BlockDriverState that are protected by the ThrottleGroup lock. Although those fields end up in their original place, they are temporarily swapped in the process, so there's a chance that an operation on a member of the same group happening on a different thread can try to use them. Signed-off-by: Alberto Garcia Reviewed-by: Stefan Hajnoczi Message-id: d92dc40d7c4f1fc5cda5cbbf4ffb7a4670b79d17.1433779731.git.berto@igalia.com Signed-off-by: Stefan Hajnoczi --- block.c | 16 ++++++++++++++++ block/throttle-groups.c | 31 ++++++++++++++++++++++++++++++- include/block/throttle-groups.h | 3 +++ 3 files changed, 49 insertions(+), 1 deletion(-) (limited to 'include/block') diff --git a/block.c b/block.c index 1bc0e7394b..54d789a8e9 100644 --- a/block.c +++ b/block.c @@ -36,6 +36,7 @@ #include "qmp-commands.h" #include "qemu/timer.h" #include "qapi-event.h" +#include "block/throttle-groups.h" #ifdef CONFIG_BSD #include @@ -1887,11 +1888,20 @@ void bdrv_swap(BlockDriverState *bs_new, BlockDriverState *bs_old) QTAILQ_REMOVE(&graph_bdrv_states, bs_old, node_list); } + /* If the BlockDriverState is part of a throttling group acquire + * its lock since we're going to mess with the protected fields. + * Otherwise there's no need to worry since no one else can touch + * them. */ + if (bs_old->throttle_state) { + throttle_group_lock(bs_old); + } + /* bs_new must be unattached and shouldn't have anything fancy enabled */ assert(!bs_new->blk); assert(QLIST_EMPTY(&bs_new->dirty_bitmaps)); assert(bs_new->job == NULL); assert(bs_new->io_limits_enabled == false); + assert(bs_new->throttle_state == NULL); assert(!throttle_timers_are_initialized(&bs_new->throttle_timers)); tmp = *bs_new; @@ -1909,8 +1919,14 @@ void bdrv_swap(BlockDriverState *bs_new, BlockDriverState *bs_old) /* Check a few fields that should remain attached to the device */ assert(bs_new->job == NULL); assert(bs_new->io_limits_enabled == false); + assert(bs_new->throttle_state == NULL); assert(!throttle_timers_are_initialized(&bs_new->throttle_timers)); + /* Release the ThrottleGroup lock */ + if (bs_old->throttle_state) { + throttle_group_unlock(bs_old); + } + /* insert the nodes back into the graph node list if needed */ if (bs_new->node_name[0] != '\0') { QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs_new, node_list); diff --git a/block/throttle-groups.c b/block/throttle-groups.c index da8c70c4a6..efc462fbc5 100644 --- a/block/throttle-groups.c +++ b/block/throttle-groups.c @@ -33,7 +33,8 @@ * its own locking. * * This locking is however handled internally in this file, so it's - * transparent to outside users. + * mostly transparent to outside users (but see the documentation in + * throttle_groups_lock()). * * The whole ThrottleGroup structure is private and invisible to * outside users, that only use it through its ThrottleState. @@ -459,6 +460,34 @@ void throttle_group_unregister_bs(BlockDriverState *bs) bs->throttle_state = NULL; } +/* Acquire the lock of this throttling group. + * + * You won't normally need to use this. None of the functions from the + * ThrottleGroup API require you to acquire the lock since all of them + * deal with it internally. + * + * This should only be used in exceptional cases when you want to + * access the protected fields of a BlockDriverState directly + * (e.g. bdrv_swap()). + * + * @bs: a BlockDriverState that is member of the group + */ +void throttle_group_lock(BlockDriverState *bs) +{ + ThrottleGroup *tg = container_of(bs->throttle_state, ThrottleGroup, ts); + qemu_mutex_lock(&tg->lock); +} + +/* Release the lock of this throttling group. + * + * See the comments in throttle_group_lock(). + */ +void throttle_group_unlock(BlockDriverState *bs) +{ + ThrottleGroup *tg = container_of(bs->throttle_state, ThrottleGroup, ts); + qemu_mutex_unlock(&tg->lock); +} + static void throttle_groups_init(void) { qemu_mutex_init(&throttle_groups_lock); diff --git a/include/block/throttle-groups.h b/include/block/throttle-groups.h index 322139a7a2..fab113f6d1 100644 --- a/include/block/throttle-groups.h +++ b/include/block/throttle-groups.h @@ -40,4 +40,7 @@ void coroutine_fn throttle_group_co_io_limits_intercept(BlockDriverState *bs, unsigned int bytes, bool is_write); +void throttle_group_lock(BlockDriverState *bs); +void throttle_group_unlock(BlockDriverState *bs); + #endif -- cgit v1.2.3-55-g7522