From patchwork Wed Jun 7 13:06:19 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Manos Pitsidianakis X-Patchwork-Id: 9771501 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 691D56034B for ; Wed, 7 Jun 2017 13:09:52 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 723F526CFF for ; Wed, 7 Jun 2017 13:09:52 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 665CC28471; Wed, 7 Jun 2017 13:09:52 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 4B3CB26CFF for ; Wed, 7 Jun 2017 13:09:50 +0000 (UTC) Received: from localhost ([::1]:43448 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dIaib-0004r2-7p for patchwork-qemu-devel@patchwork.kernel.org; Wed, 07 Jun 2017 09:09:49 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48133) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dIagg-0003xZ-9R for qemu-devel@nongnu.org; Wed, 07 Jun 2017 09:07:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dIagc-0004CZ-SZ for qemu-devel@nongnu.org; Wed, 07 Jun 2017 09:07:50 -0400 Received: from smtp1.ntua.gr ([2001:648:2000:de::183]:35434) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dIagc-00046q-8q for qemu-devel@nongnu.org; Wed, 07 Jun 2017 09:07:46 -0400 Received: from mail.ntua.gr (ppp141255063244.access.hol.gr [141.255.63.244]) (authenticated bits=0) by smtp1.ntua.gr (8.15.2/8.15.2) with ESMTPSA id v57D6wBS074234 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 7 Jun 2017 16:06:59 +0300 (EEST) (envelope-from el13635@mail.ntua.gr) X-Authentication-Warning: smtp1.ntua.gr: Host ppp141255063244.access.hol.gr [141.255.63.244] claimed to be mail.ntua.gr From: Manos Pitsidianakis To: qemu-devel@nongnu.org Date: Wed, 7 Jun 2017 16:06:19 +0300 Message-Id: <20170607130619.1545-1-el13635@mail.ntua.gr> X-Mailer: git-send-email 2.11.0 MIME-Version: 1.0 X-MIME-Autoconverted: from 8bit to quoted-printable by smtp1.ntua.gr id v57D6wBS074234 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2001:648:2000:de::183 Subject: [Qemu-devel] [PATCH RFC] block: add throttle block filter driver X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, stefanha@gmail.com, berto@igalia.com, Manos Pitsidianakis Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP This is part of my work for my GSOC project this summer. I am not sure if the count parameter in bdrv_co_pwrite_zeros and bdrv_co_pdiscard refers to sectors or bytes. Should this be handled differently? The driver can only be instantiated in the command line for now like in the following examples: -drive driver=throttle,file.filename=foo.qcow2,iops-total=100, iops-total-max=2000,iops-total-max-length=60,throttle-group=foobar -drive driver=throttle,file.filename=foo.qcow2,iops-total=100, throttle-group=foobar This commit copies throttle group infrastructure from block/throttle-groups.c to block/throttle.c to be used as a block filter driver. Signed-off-by: Manos Pitsidianakis --- block/Makefile.objs | 1 + block/throttle.c | 747 +++++++++++++++++++++++++++++++++++++++++++++++ include/block/throttle.h | 59 ++++ 3 files changed, 807 insertions(+) create mode 100644 block/throttle.c create mode 100644 include/block/throttle.h diff --git a/block/Makefile.objs b/block/Makefile.objs index ea955302c8..bb811a4d01 100644 --- a/block/Makefile.objs +++ b/block/Makefile.objs @@ -25,6 +25,7 @@ block-obj-y += accounting.o dirty-bitmap.o block-obj-y += write-threshold.o block-obj-y += backup.o block-obj-$(CONFIG_REPLICATION) += replication.o +block-obj-y += throttle.o block-obj-y += crypto.o diff --git a/block/throttle.c b/block/throttle.c new file mode 100644 index 0000000000..e4536a09ed --- /dev/null +++ b/block/throttle.c @@ -0,0 +1,747 @@ +/* + * QEMU block throttling filter driver 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 "qemu/osdep.h" +#include "sysemu/block-backend.h" +#include "block/throttle-groups.h" +#include "qemu/queue.h" +#include "qemu/thread.h" +#include "sysemu/qtest.h" +#include "monitor/monitor.h" +#include "qapi/error.h" +#include "block/throttle.h" +#include "qapi/qmp/qdict.h" + +#define QEMU_OPT_IOPS_TOTAL "iops-total" +#define QEMU_OPT_IOPS_TOTAL_MAX "iops-total-max" +#define QEMU_OPT_IOPS_TOTAL_MAX_LENGTH "iops-total-max-length" +#define QEMU_OPT_IOPS_READ "iops-read" +#define QEMU_OPT_IOPS_READ_MAX "iops-read-max" +#define QEMU_OPT_IOPS_READ_MAX_LENGTH "iops-read-max-length" +#define QEMU_OPT_IOPS_WRITE "iops-write" +#define QEMU_OPT_IOPS_WRITE_MAX "iops-write-max" +#define QEMU_OPT_IOPS_WRITE_MAX_LENGTH "iops-write-max-length" +#define QEMU_OPT_BPS_TOTAL "bps-total" +#define QEMU_OPT_BPS_TOTAL_MAX "bps-total-max" +#define QEMU_OPT_BPS_TOTAL_MAX_LENGTH "bps-total-max-length" +#define QEMU_OPT_BPS_READ "bps-read" +#define QEMU_OPT_BPS_READ_MAX "bps-read-max" +#define QEMU_OPT_BPS_READ_MAX_LENGTH "bps-read-max-length" +#define QEMU_OPT_BPS_WRITE "bps-write" +#define QEMU_OPT_BPS_WRITE_MAX "bps-write-max" +#define QEMU_OPT_BPS_WRITE_MAX_LENGTH "bps-write-max-length" +#define QEMU_OPT_IOPS_SIZE "iops-size" +#define QEMU_OPT_THROTTLE_GROUP_NAME "throttle-group" + + +static QemuMutex throttle_groups_lock; +static QTAILQ_HEAD(, ThrottleGroup) throttle_groups = + QTAILQ_HEAD_INITIALIZER(throttle_groups); + +static QemuOptsList throttle_opts = { + .name = "throttle", + .head = QTAILQ_HEAD_INITIALIZER(throttle_opts.head), + .desc = { + { + .name = QEMU_OPT_IOPS_TOTAL, + .type = QEMU_OPT_NUMBER, + .help = "throttling.iops-total", + }, + { + .name = QEMU_OPT_IOPS_TOTAL_MAX, + .type = QEMU_OPT_NUMBER, + .help = "throttling.iops-total-max", + }, + { + .name = QEMU_OPT_IOPS_TOTAL_MAX_LENGTH, + .type = QEMU_OPT_NUMBER, + .help = "throttling.iops-total-max-length", + }, + { + .name = QEMU_OPT_IOPS_READ, + .type = QEMU_OPT_NUMBER, + .help = "throttling.iops-read", + }, + { + .name = QEMU_OPT_IOPS_READ_MAX, + .type = QEMU_OPT_NUMBER, + .help = "throttling.iops-read-max", + }, + { + .name = QEMU_OPT_IOPS_READ_MAX_LENGTH, + .type = QEMU_OPT_NUMBER, + .help = "throttling.iops-read-max-length", + }, + { + .name = QEMU_OPT_IOPS_WRITE, + .type = QEMU_OPT_NUMBER, + .help = "throttling.iops-write", + }, + { + .name = QEMU_OPT_IOPS_WRITE_MAX, + .type = QEMU_OPT_NUMBER, + .help = "throttling.iops-write-max", + }, + { + .name = QEMU_OPT_IOPS_WRITE_MAX_LENGTH, + .type = QEMU_OPT_NUMBER, + .help = "throttling.iops-write-max-length", + }, + { + .name = QEMU_OPT_BPS_TOTAL, + .type = QEMU_OPT_NUMBER, + .help = "trottling.bps-total", + }, + { + .name = QEMU_OPT_BPS_TOTAL_MAX, + .type = QEMU_OPT_NUMBER, + .help = "trottling.bps-total-max", + }, + { + .name = QEMU_OPT_BPS_TOTAL_MAX_LENGTH, + .type = QEMU_OPT_NUMBER, + .help = "trottling.bps-total-max-length", + }, + { + .name = QEMU_OPT_BPS_READ, + .type = QEMU_OPT_NUMBER, + .help = "throttling.bps-read", + }, + { + .name = QEMU_OPT_BPS_READ_MAX, + .type = QEMU_OPT_NUMBER, + .help = "throttling.bps-read-max", + }, + { + .name = QEMU_OPT_BPS_READ_MAX_LENGTH, + .type = QEMU_OPT_NUMBER, + .help = "throttling.bps-read-max-length", + }, + { + .name = QEMU_OPT_BPS_WRITE, + .type = QEMU_OPT_NUMBER, + .help = "throttling.bps-write", + }, + { + .name = QEMU_OPT_BPS_WRITE_MAX, + .type = QEMU_OPT_NUMBER, + .help = "throttling.bps-write-max", + }, + { + .name = QEMU_OPT_BPS_WRITE_MAX_LENGTH, + .type = QEMU_OPT_NUMBER, + .help = "throttling.bps-write-max-length", + }, + { + .name = QEMU_OPT_IOPS_SIZE, + .type = QEMU_OPT_NUMBER, + .help = "throttling.iops-size", + }, + { + .name = QEMU_OPT_THROTTLE_GROUP_NAME, + .type = QEMU_OPT_STRING, + .help = "Throttle group name", + }, + { /* end of list */ } + }, +}; + +/* Return the next BDRVThrottleNodeState in the round-robin sequence, + * simulating a circular list. + * + * This assumes that tg->lock is held. + * + * @s: the current BlockDriverstate's BDRVThrottleNodeState + * @ret: the next BDRVThrottleNodeState in the sequence + */ +static BDRVThrottleNodeState *throttle_group_next_bds(BDRVThrottleNodeState *s) +{ + ThrottleGroup *tg = s->throttle_group; + BDRVThrottleNodeState *next = QLIST_NEXT(s, round_robin); + + if (!next) { + next = QLIST_FIRST(&tg->head); + } + + return next; +} + +/* + * Return whether a BlockDriverState has pending requests. + * + * This assumes that tg->lock is held. + * + * @s: the BlockDriverState's BDRVThrottleNodeState + * @is_write: the type of operation (read/write) + * @ret: whether the BDRVThrottleNodeState has pending requests. + */ +static inline bool bds_has_pending_reqs(BDRVThrottleNodeState *s, + bool is_write) +{ + return s->pending_reqs[is_write]; +} + +/* 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's BDRVThrottleNodeState + * @is_write: the type of operation (read/write) + * @ret: the next BDRVThrottleNodeState with pending requests, or bs if + * there is none. + */ +static BDRVThrottleNodeState *next_throttle_token(BDRVThrottleNodeState *s, + bool is_write) +{ + ThrottleGroup *tg = s->throttle_group; + BDRVThrottleNodeState *token, *start; + + start = token = tg->tokens[is_write]; + + /* get next bs round in round robin style */ + token = throttle_group_next_bds(token); + while (token != start && !bds_has_pending_reqs(token, is_write)) { + token = throttle_group_next_bds(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 && !bds_has_pending_reqs(token, is_write)) { + token = s; + } + + /* Either we return the original BB, or one with pending requests */ + assert(token == s || bds_has_pending_reqs(token, is_write)); + + return token; +} + +/* 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 ThrottleState member of the ThrottleGroup + */ +static ThrottleState *bdrv_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->ts; +} + +/* Decrease the reference count of a ThrottleGroup. + * + * When the reference count reaches zero the ThrottleGroup is + * destroyed. + * + * @ts: The ThrottleGroup to unref, given by its ThrottleState member + */ +static void bdrv_throttle_group_unref(ThrottleState *ts) +{ + ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts); + + 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); +} + + +/* Check if the next I/O request for a BDRVThrottleNodeState 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. + * + * @s: the current BDRVThrottleNodeState + * @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(BDRVThrottleNodeState *s, + bool is_write) +{ + ThrottleGroup *tg = s->throttle_group; + ThrottleTimers *tt = &s->throttle_timers; + ThrottleState *ts = &tg->ts; + bool must_wait; + + if (s->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 s as the current token */ + if (must_wait) { + tg->tokens[is_write] = s; + 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) +{ + BDRVThrottleNodeState *s = bs->opaque, *token = NULL; + ThrottleGroup *tg = s->throttle_group; + bool must_wait; + + /* Check if there's any pending request to schedule next */ + token = next_throttle_token(s, is_write); + if (!bds_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 BDS */ + if (qemu_in_coroutine() && + qemu_co_queue_next(&s->throttled_reqs[is_write])) { + token = s; + } 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; + } +} + +/* 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) +{ + BDRVThrottleNodeState *s = bs->opaque; + ThrottleGroup *tg = s->throttle_group; + 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 */ + aio_context_acquire(bdrv_get_aio_context(bs)); + empty_queue = !qemu_co_enter_next(&s->throttled_reqs[is_write]); + aio_context_release(bdrv_get_aio_context(bs)); + + /* 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); +} + +/* Unregister a BlockDriverState from its group, removing it from the list, + * destroying the timers and setting the throttle_state pointer to NULL. + * + * The BlockDriverState 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. + * + * @bs: the BlockDriverState to remove + */ +static void throttle_node_unregister_bs(BlockDriverState *bs) +{ + BDRVThrottleNodeState *s = bs->opaque; + ThrottleGroup *tg = s->throttle_group; + int i; + + assert(s->pending_reqs[0] == 0 && s->pending_reqs[1] == 0); + assert(qemu_co_queue_empty(&s->throttled_reqs[0])); + assert(qemu_co_queue_empty(&s->throttled_reqs[1])); + + qemu_mutex_lock(&tg->lock); + for (i = 0; i < 2; i++) { + if (tg->tokens[i] == s) { + BDRVThrottleNodeState *token = throttle_group_next_bds(s); + /* Take care of the case where this is the last BlockDriverState in + * the group */ + if (token == s) { + token = NULL; + } + tg->tokens[i] = token; + } + } + + /* remove the current BDS from the list */ + QLIST_REMOVE(s, round_robin); + throttle_timers_destroy(&s->throttle_timers); + qemu_mutex_unlock(&tg->lock); + + bdrv_throttle_group_unref(&tg->ts); + s->throttle_state = NULL; +} + + +/* 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 + */ +static void throttle_node_register_bs(BlockDriverState *bs, + const char *groupname) +{ + int i; + BDRVThrottleNodeState *s = bs->opaque; + ThrottleState *ts = bdrv_throttle_group_incref(groupname); + ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts); + int clock_type = QEMU_CLOCK_REALTIME; + + if (qtest_enabled()) { + /* For testing block IO throttling only */ + clock_type = QEMU_CLOCK_VIRTUAL; + } + + s->throttle_state = ts; + s->throttle_group = tg; + + 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] = s; + } + } + + QLIST_INSERT_HEAD(&tg->head, s, round_robin); + throttle_timers_init(&s->throttle_timers, + bdrv_get_aio_context(bs), + clock_type, + read_timer_cb, + write_timer_cb, + bs); + qemu_mutex_unlock(&tg->lock); +} + +static int throttle_open(BlockDriverState *bs, QDict *options, + int flags, Error **errp) +{ + int ret = 0; + BDRVThrottleNodeState *s = bs->opaque; + Error *local_err = NULL; + QemuOpts *opts = NULL; + const char *groupname = NULL; + + bs->file = bdrv_open_child(NULL, options, "file", + bs, &child_file, false, &local_err); + + if (local_err) { + ret = -EINVAL; + error_propagate(errp, local_err); + return ret; + } + + qdict_flatten(options); + opts = qemu_opts_create(&throttle_opts, NULL, 0, &error_abort); + qemu_opts_absorb_qdict(opts, options, &local_err); + if (local_err) { + error_propagate(errp, local_err); + ret = -EINVAL; + goto open_ret; + } + + groupname = qemu_opt_get(opts, QEMU_OPT_THROTTLE_GROUP_NAME); + if (!groupname) { + groupname = bdrv_get_device_or_node_name(bs); + if (!groupname) { + error_setg(&local_err, + "A group name must be specified for this device."); + error_propagate(errp, local_err); + ret = -EINVAL; + goto open_ret; + } + } + + throttle_node_register_bs(bs, groupname); + ThrottleConfig *throttle_cfg = &s->throttle_state->cfg; + + throttle_config_init(throttle_cfg); + throttle_cfg->buckets[THROTTLE_BPS_TOTAL].avg = + qemu_opt_get_number(opts, QEMU_OPT_BPS_TOTAL, 0); + throttle_cfg->buckets[THROTTLE_BPS_READ].avg = + qemu_opt_get_number(opts, QEMU_OPT_BPS_READ, 0); + throttle_cfg->buckets[THROTTLE_BPS_WRITE].avg = + qemu_opt_get_number(opts, QEMU_OPT_BPS_WRITE, 0); + throttle_cfg->buckets[THROTTLE_OPS_TOTAL].avg = + qemu_opt_get_number(opts, QEMU_OPT_IOPS_TOTAL, 0); + throttle_cfg->buckets[THROTTLE_OPS_READ].avg = + qemu_opt_get_number(opts, QEMU_OPT_IOPS_READ, 0); + throttle_cfg->buckets[THROTTLE_OPS_WRITE].avg = + qemu_opt_get_number(opts, QEMU_OPT_IOPS_WRITE, 0); + + throttle_cfg->buckets[THROTTLE_BPS_TOTAL].max = + qemu_opt_get_number(opts, QEMU_OPT_BPS_TOTAL_MAX, 0); + throttle_cfg->buckets[THROTTLE_BPS_READ].max = + qemu_opt_get_number(opts, QEMU_OPT_BPS_READ_MAX, 0); + throttle_cfg->buckets[THROTTLE_BPS_WRITE].max = + qemu_opt_get_number(opts, QEMU_OPT_BPS_WRITE_MAX, 0); + throttle_cfg->buckets[THROTTLE_OPS_TOTAL].max = + qemu_opt_get_number(opts, QEMU_OPT_IOPS_TOTAL_MAX, 0); + throttle_cfg->buckets[THROTTLE_OPS_READ].max = + qemu_opt_get_number(opts, QEMU_OPT_IOPS_READ_MAX, 0); + throttle_cfg->buckets[THROTTLE_OPS_WRITE].max = + qemu_opt_get_number(opts, QEMU_OPT_IOPS_WRITE_MAX, 0); + + throttle_cfg->buckets[THROTTLE_BPS_TOTAL].burst_length = + qemu_opt_get_number(opts, QEMU_OPT_BPS_TOTAL_MAX_LENGTH, 1); + throttle_cfg->buckets[THROTTLE_BPS_READ].burst_length = + qemu_opt_get_number(opts, QEMU_OPT_BPS_READ_MAX_LENGTH, 1); + throttle_cfg->buckets[THROTTLE_BPS_WRITE].burst_length = + qemu_opt_get_number(opts, QEMU_OPT_BPS_WRITE_MAX_LENGTH, 1); + throttle_cfg->buckets[THROTTLE_OPS_TOTAL].burst_length = + qemu_opt_get_number(opts, QEMU_OPT_IOPS_TOTAL_MAX_LENGTH, 1); + throttle_cfg->buckets[THROTTLE_OPS_READ].burst_length = + qemu_opt_get_number(opts, QEMU_OPT_IOPS_READ_MAX_LENGTH, 1); + throttle_cfg->buckets[THROTTLE_OPS_WRITE].burst_length = + qemu_opt_get_number(opts, QEMU_OPT_IOPS_WRITE_MAX_LENGTH, 1); + + throttle_cfg->op_size = + qemu_opt_get_number(opts, QEMU_OPT_IOPS_SIZE, 0); + + if (!throttle_is_valid(throttle_cfg, &local_err)) { + error_propagate(errp, local_err); + throttle_node_unregister_bs(bs); + ret = -EINVAL; + goto open_ret; + } + + qemu_co_queue_init(&s->throttled_reqs[0]); + qemu_co_queue_init(&s->throttled_reqs[1]); + + throttle_timers_attach_aio_context(&s->throttle_timers, + bdrv_get_aio_context(bs)); + +open_ret: + qemu_opts_del(opts); + return ret; +} + +static void throttle_close(BlockDriverState *bs) +{ + throttle_node_unregister_bs(bs); + return; +} + + +static int64_t throttle_getlength(BlockDriverState *bs) +{ + return bdrv_getlength(bs->file->bs);; +} + +/* 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) + */ +static void coroutine_fn throttle_co_io_limits_intercept(BlockDriverState *bs, + unsigned int bytes, + bool is_write) +{ + bool must_wait; + BDRVThrottleNodeState *s = bs->opaque, *token; + ThrottleGroup *tg = s->throttle_group; + qemu_mutex_lock(&tg->lock); + + /* First we check if this I/O has to be throttled. */ + token = next_throttle_token(s, 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 || s->pending_reqs[is_write]) { + s->pending_reqs[is_write]++; + qemu_mutex_unlock(&tg->lock); + qemu_co_queue_wait(&s->throttled_reqs[is_write], NULL); + qemu_mutex_lock(&tg->lock); + s->pending_reqs[is_write]--; + } + + /* The I/O will be executed, so do the accounting */ + throttle_account(s->throttle_state, is_write, bytes); + + /* Schedule the next request */ + schedule_next_request(bs, is_write); + + qemu_mutex_unlock(&tg->lock); +} + +static int coroutine_fn throttle_co_preadv(BlockDriverState *bs, uint64_t offset, + uint64_t bytes, QEMUIOVector *qiov, + int flags) +{ + + throttle_co_io_limits_intercept(bs, bytes, false); + + return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags); +} + +static int coroutine_fn throttle_co_pwritev(BlockDriverState *bs, uint64_t offset, + uint64_t bytes, QEMUIOVector *qiov, + int flags) +{ + throttle_co_io_limits_intercept(bs, bytes, true); + + return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags); +} + +static int coroutine_fn throttle_co_pwrite_zeroes(BlockDriverState *bs, + int64_t offset, int count, BdrvRequestFlags flags) +{ + throttle_co_io_limits_intercept(bs, count, true); + + return bdrv_co_pwrite_zeroes(bs->file, offset, count, flags); +} + +static int coroutine_fn throttle_co_pdiscard(BlockDriverState *bs, + int64_t offset, int count) +{ + throttle_co_io_limits_intercept(bs, count, true); + + return bdrv_co_pdiscard(bs->file->bs, offset, count); +} + +static int throttle_co_flush(BlockDriverState *bs) +{ + return bdrv_co_flush(bs->file->bs); +} + +static void throttle_detach_aio_context(BlockDriverState *bs) +{ + BDRVThrottleNodeState *s = bs->opaque; + throttle_timers_detach_aio_context(&s->throttle_timers); +} + +static void throttle_attach_aio_context(BlockDriverState *bs, + AioContext *new_context) +{ + BDRVThrottleNodeState *s = bs->opaque; + throttle_timers_attach_aio_context(&s->throttle_timers, new_context); +} +static BlockDriver bdrv_throttle = { + .format_name = "throttle", + .protocol_name = "throttle", + .instance_size = sizeof(BDRVThrottleNodeState), + + .bdrv_file_open = throttle_open, + .bdrv_close = throttle_close, + .bdrv_co_flush = throttle_co_flush, + + .bdrv_child_perm = bdrv_filter_default_perms, + + .bdrv_getlength = throttle_getlength, + + .bdrv_co_preadv = throttle_co_preadv, + .bdrv_co_pwritev = throttle_co_pwritev, + + .bdrv_co_pwrite_zeroes = throttle_co_pwrite_zeroes, + .bdrv_co_pdiscard = throttle_co_pdiscard, + + .bdrv_recurse_is_first_non_filter = bdrv_recurse_is_first_non_filter, + + .bdrv_attach_aio_context = throttle_attach_aio_context, + .bdrv_detach_aio_context = throttle_detach_aio_context, + + .is_filter = true, +}; + +static void bdrv_throttle_init(void) +{ + qemu_mutex_init(&throttle_groups_lock); + bdrv_register(&bdrv_throttle); +} + +block_init(bdrv_throttle_init); diff --git a/include/block/throttle.h b/include/block/throttle.h new file mode 100644 index 0000000000..fed24f02a6 --- /dev/null +++ b/include/block/throttle.h @@ -0,0 +1,59 @@ +/* The ThrottleGroup structure (with its ThrottleState) is shared + * among different BlockDriverStates 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 block/throttle.c 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 + * BlockDriverState is registered in a group those fields can be accessed + * by other threads any time. + * + * Again, all this is handled internally in block/throttle.c 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 block/throttle.c will access some + * other BlockDriverState'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(, BDRVThrottleNodeState) head; + struct BDRVThrottleNodeState *tokens[2]; + bool any_timer_armed[2]; + + /* These two are protected by the global throttle_groups_lock */ + unsigned refcount; + QTAILQ_ENTRY(ThrottleGroup) list; +} ThrottleGroup; + +typedef struct BDRVThrottleNodeState { + ThrottleGroup *throttle_group; + + /* I/O throttling has its own locking, but also some fields are + * protected by the AioContext lock. + */ + + /* Protected by AioContext lock. */ + CoQueue throttled_reqs[2]; + + /* Nonzero if the I/O limits are currently being ignored; generally + * it is zero. */ + unsigned int io_limits_disabled; + + ThrottleState *throttle_state; + ThrottleTimers throttle_timers; + unsigned pending_reqs[2]; + QLIST_ENTRY(BDRVThrottleNodeState) round_robin; + +} BDRVThrottleNodeState;