From patchwork Thu Dec 2 13:04:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 12652563 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D12D0C433F5 for ; Thu, 2 Dec 2021 12:52:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358119AbhLBM4L (ORCPT ); Thu, 2 Dec 2021 07:56:11 -0500 Received: from szxga08-in.huawei.com ([45.249.212.255]:29082 "EHLO szxga08-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358143AbhLBM4J (ORCPT ); Thu, 2 Dec 2021 07:56:09 -0500 Received: from kwepemi100004.china.huawei.com (unknown [172.30.72.53]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4J4bQK1FZCz1DJn3; Thu, 2 Dec 2021 20:50:01 +0800 (CST) Received: from kwepemm600009.china.huawei.com (7.193.23.164) by kwepemi100004.china.huawei.com (7.221.188.70) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Thu, 2 Dec 2021 20:52:43 +0800 Received: from huawei.com (10.175.127.227) by kwepemm600009.china.huawei.com (7.193.23.164) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Thu, 2 Dec 2021 20:52:43 +0800 From: Yu Kuai To: , , CC: , , , , Subject: [PATCH v4 1/2] blk-throtl: move WARN_ON_ONCE() from throtl_rb_first() to it's caller Date: Thu, 2 Dec 2021 21:04:39 +0800 Message-ID: <20211202130440.1943847-2-yukuai3@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211202130440.1943847-1-yukuai3@huawei.com> References: <20211202130440.1943847-1-yukuai3@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemm600009.china.huawei.com (7.193.23.164) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Prepare to reintroduce tg_drain_bios(), which will iterate until throtl_rb_first() return NULL. Signed-off-by: Yu Kuai --- block/blk-throttle.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 39bb6e68a9a2..fdd57878e862 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -502,7 +502,6 @@ throtl_rb_first(struct throtl_service_queue *parent_sq) struct rb_node *n; n = rb_first_cached(&parent_sq->pending_tree); - WARN_ON_ONCE(!n); if (!n) return NULL; return rb_entry_tg(n); @@ -521,7 +520,7 @@ static void update_min_dispatch_time(struct throtl_service_queue *parent_sq) struct throtl_grp *tg; tg = throtl_rb_first(parent_sq); - if (!tg) + if (WARN_ON_ONCE(!tg)) return; parent_sq->first_pending_disptime = tg->disptime; @@ -1090,7 +1089,7 @@ static int throtl_select_dispatch(struct throtl_service_queue *parent_sq) break; tg = throtl_rb_first(parent_sq); - if (!tg) + if (WARN_ON_ONCE(!tg)) break; if (time_before(jiffies, tg->disptime)) From patchwork Thu Dec 2 13:04:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 12652567 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A5BCC4332F for ; Thu, 2 Dec 2021 12:52:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347029AbhLBM4L (ORCPT ); Thu, 2 Dec 2021 07:56:11 -0500 Received: from szxga08-in.huawei.com ([45.249.212.255]:29083 "EHLO szxga08-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358146AbhLBM4J (ORCPT ); Thu, 2 Dec 2021 07:56:09 -0500 Received: from kwepemi100002.china.huawei.com (unknown [172.30.72.56]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4J4bQK6Q7Wz1DJpp; Thu, 2 Dec 2021 20:50:01 +0800 (CST) Received: from kwepemm600009.china.huawei.com (7.193.23.164) by kwepemi100002.china.huawei.com (7.221.188.188) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Thu, 2 Dec 2021 20:52:44 +0800 Received: from huawei.com (10.175.127.227) by kwepemm600009.china.huawei.com (7.193.23.164) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Thu, 2 Dec 2021 20:52:43 +0800 From: Yu Kuai To: , , CC: , , , , Subject: [PATCH v4 2/2] block: cancel all throttled bios in del_gendisk() Date: Thu, 2 Dec 2021 21:04:40 +0800 Message-ID: <20211202130440.1943847-3-yukuai3@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211202130440.1943847-1-yukuai3@huawei.com> References: <20211202130440.1943847-1-yukuai3@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemm600009.china.huawei.com (7.193.23.164) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Throttled bios can't be issued after del_gendisk() is done, thus it's better to cancel them immediately rather than waiting for throttle is done. For example, if user thread is throttled with low bps while it's issuing large io, and the device is deleted. The user thread will wait for a long time for io to return. Noted this patch is mainly from revertion of commit 32e3374304c7 ("blk-throttle: remove tg_drain_bios") and commit b77412372b68 ("blk-throttle: remove blk_throtl_drain"). Signed-off-by: Yu Kuai --- block/blk-throttle.c | 69 ++++++++++++++++++++++++++++++++++++++++++++ block/blk-throttle.h | 2 ++ block/genhd.c | 2 ++ 3 files changed, 73 insertions(+) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index fdd57878e862..e60f690e01ad 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -2256,6 +2256,75 @@ void blk_throtl_bio_endio(struct bio *bio) } #endif +/* + * Dispatch all bios from all children tg's queued on @parent_sq. On + * return, @parent_sq is guaranteed to not have any active children tg's + * and all bios from previously active tg's are on @parent_sq->bio_lists[]. + */ +static void tg_drain_bios(struct throtl_service_queue *parent_sq) +{ + struct throtl_grp *tg; + + while ((tg = throtl_rb_first(parent_sq))) { + struct throtl_service_queue *sq = &tg->service_queue; + struct bio *bio; + + throtl_dequeue_tg(tg); + + while ((bio = throtl_peek_queued(&sq->queued[READ]))) + tg_dispatch_one_bio(tg, bio_data_dir(bio)); + while ((bio = throtl_peek_queued(&sq->queued[WRITE]))) + tg_dispatch_one_bio(tg, bio_data_dir(bio)); + } +} + +/** + * blk_throtl_cancel_bios - cancel throttled bios + * @q: request_queue to cancel throttled bios for + * + * This function is called to error all currently throttled bios on @q. + */ +void blk_throtl_cancel_bios(struct request_queue *q) +{ + struct throtl_data *td = q->td; + struct bio_list bio_list_on_stack; + struct blkcg_gq *blkg; + struct cgroup_subsys_state *pos_css; + struct bio *bio; + int rw; + + bio_list_init(&bio_list_on_stack); + + /* + * hold queue_lock to prevent concurrent with dispatching + * throttled bios by timer. + */ + spin_lock_irq(&q->queue_lock); + + /* + * Drain each tg while doing post-order walk on the blkg tree, so + * that all bios are propagated to td->service_queue. It'd be + * better to walk service_queue tree directly but blkg walk is + * easier. + */ + blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) + tg_drain_bios(&blkg_to_tg(blkg)->service_queue); + + /* finally, transfer bios from top-level tg's into the td */ + tg_drain_bios(&td->service_queue); + + /* all bios now should be in td->service_queue, cancel them */ + for (rw = READ; rw <= WRITE; rw++) + while ((bio = throtl_pop_queued(&td->service_queue.queued[rw], + NULL))) + bio_list_add(&bio_list_on_stack, bio); + + spin_unlock_irq(&q->queue_lock); + if (!bio_list_empty(&bio_list_on_stack)) + while ((bio = bio_list_pop(&bio_list_on_stack))) + bio_io_error(bio); +} + int blk_throtl_init(struct request_queue *q) { struct throtl_data *td; diff --git a/block/blk-throttle.h b/block/blk-throttle.h index 175f03abd9e4..9d67d5139954 100644 --- a/block/blk-throttle.h +++ b/block/blk-throttle.h @@ -160,12 +160,14 @@ static inline void blk_throtl_exit(struct request_queue *q) { } static inline void blk_throtl_register_queue(struct request_queue *q) { } static inline void blk_throtl_charge_bio_split(struct bio *bio) { } static inline bool blk_throtl_bio(struct bio *bio) { return false; } +#define blk_throtl_cancel_bios(q) do { } while (0) #else /* CONFIG_BLK_DEV_THROTTLING */ int blk_throtl_init(struct request_queue *q); void blk_throtl_exit(struct request_queue *q); void blk_throtl_register_queue(struct request_queue *q); void blk_throtl_charge_bio_split(struct bio *bio); bool __blk_throtl_bio(struct bio *bio); +void blk_throtl_cancel_bios(struct request_queue *q); static inline bool blk_throtl_bio(struct bio *bio) { struct throtl_grp *tg = blkg_to_tg(bio->bi_blkg); diff --git a/block/genhd.c b/block/genhd.c index 8e9cbf23c510..24fa3356d164 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -28,6 +28,7 @@ #include "blk.h" #include "blk-rq-qos.h" +#include "blk-throttle.h" static struct kobject *block_depr; @@ -619,6 +620,7 @@ void del_gendisk(struct gendisk *disk) blk_mq_freeze_queue_wait(q); + blk_throtl_cancel_bios(q); rq_qos_exit(q); blk_sync_queue(q); blk_flush_integrity();