From nobody Wed Sep 17 17:47:02 2025 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 411F9C4332F for ; Sat, 17 Dec 2022 02:45:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230157AbiLQCpO (ORCPT ); Fri, 16 Dec 2022 21:45:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230009AbiLQCou (ORCPT ); Fri, 16 Dec 2022 21:44:50 -0500 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 230C570218; Fri, 16 Dec 2022 18:44:50 -0800 (PST) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4NYr0X56mRz4f3rDH; Sat, 17 Dec 2022 10:44:44 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.127.227]) by APP4 (Coremail) with SMTP id gCh0CgBni9gcLZ1j2O96CQ--.47195S8; Sat, 17 Dec 2022 10:44:47 +0800 (CST) From: Yu Kuai To: tj@kernel.org, hch@infradead.org, josef@toxicpanda.com, axboe@kernel.dk Cc: cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yukuai1@huaweicloud.com, yi.zhang@huawei.com Subject: [PATCH -next 4/4] blk-iocost: guarantee the exit order of iocg Date: Sat, 17 Dec 2022 11:05:27 +0800 Message-Id: <20221217030527.1250083-5-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20221217030527.1250083-1-yukuai1@huaweicloud.com> References: <20221217030527.1250083-1-yukuai1@huaweicloud.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: gCh0CgBni9gcLZ1j2O96CQ--.47195S8 X-Coremail-Antispam: 1UD129KBjvJXoW7KF1UKFWxArWDZF15JF1DJrb_yoW8ZFy7pF 13WasIka18XFn7Wan8J3ZrX34Sva1vgw40kw4fu3ZYyF1UAw1xKrs7AryfCFWrtr93uFZ3 ZF10qFW8Aw4UX37anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPY14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JF0E3s1l82xGYI kIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2 z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F 4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq 3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7 IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4U M4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwACI402YVCY1x02628vn2 kIc2xKxwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E 14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIx kGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAF wI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r 4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUQSdkU UUUU= X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Yu Kuai pd_offline_fn() is ensured to be called in order(parent after child), while pd_free_fn() is not. Furthermore, rq_qos_exit() can also be called before pd_free_fn(). For conclusion, doing cleanups in ioc_pd_free() is not safe, which can cause many problems. By the way, iocost is the only policy to do cleanups in pd_free_fn(). Since previous patches guarantee that ioc_pd_offline() will dispatch throttled bio and prevent new io to be throttled. It's safe to move cleanup operations for iocg from ioc_pd_free() to ioc_pd_offline(). Signed-off-by: Yu Kuai --- block/blk-iocost.c | 26 ++++++++++---------------- 1 file changed, 10 insertions(+), 16 deletions(-) diff --git a/block/blk-iocost.c b/block/blk-iocost.c index b63ecfdd815c..d634ea73f991 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -3011,21 +3011,6 @@ static void ioc_pd_offline(struct blkg_policy_data *= pd) =20 iocg_lock(iocg, true, &flags); iocg->online =3D false; - iocg_unlock(iocg, true, &flags); - - hrtimer_cancel(&iocg->waitq_timer); - __wake_up(&iocg->waitq, TASK_NORMAL, 0, &ctx); - } -} - -static void ioc_pd_free(struct blkg_policy_data *pd) -{ - struct ioc_gq *iocg =3D pd_to_iocg(pd); - struct ioc *ioc =3D iocg->ioc; - unsigned long flags; - - if (ioc) { - spin_lock_irqsave(&ioc->lock, flags); =20 if (!list_empty(&iocg->active_list)) { struct ioc_now now; @@ -3038,8 +3023,17 @@ static void ioc_pd_free(struct blkg_policy_data *pd) WARN_ON_ONCE(!list_empty(&iocg->walk_list)); WARN_ON_ONCE(!list_empty(&iocg->surplus_list)); =20 - spin_unlock_irqrestore(&ioc->lock, flags); + iocg_unlock(iocg, true, &flags); + + hrtimer_cancel(&iocg->waitq_timer); + __wake_up(&iocg->waitq, TASK_NORMAL, 0, &ctx); } +} + +static void ioc_pd_free(struct blkg_policy_data *pd) +{ + struct ioc_gq *iocg =3D pd_to_iocg(pd); + free_percpu(iocg->pcpu_stat); kfree(iocg); } --=20 2.31.1