From nobody Sat Nov 30 16:35:27 2024 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 628C31B9B44; Mon, 9 Sep 2024 13:43:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725889432; cv=none; b=gYvrMh24hhX78a4cPptNC386SLNMX6lQc14tDXEpy31tTZctVnSlAtFhSUrC09tgDsxlMpwvRLonFqkQ5YuZKMv4Lkq6cABdJMNbZK3vAR02wWUPDR8FdR9JCm37tizHvLM1qUTqlWSLe0vQoQwjzx0vcob9SZpmlQpHj7noAuU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725889432; c=relaxed/simple; bh=OlmvVjbRTnVs6v8zFJ6qGOxVvIxdoEvfh0SoOG93bxU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=WJ2QEyoI9su1od7ndcuqJSJQfUOfwlzX8nE80FbPYls3SHZEilhalEq4RtkF/OnwwknegQEEUd26XNL/Hpl05MZSnwAH+sBuWYOMM21maFl1CXhIbdvD2qTPa6vXrxYRYlIiUFH9AcoWGtZKva3LGPOIyi4t/v4VjxoqLjKSMw4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.93.142]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4X2Shy70z4z4f3lDJ; Mon, 9 Sep 2024 21:43:30 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id 1FEAC1A07B6; Mon, 9 Sep 2024 21:43:47 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP4 (Coremail) with SMTP id gCh0CgCn28eQ+95mhC1hAw--.55605S6; Mon, 09 Sep 2024 21:43:46 +0800 (CST) From: Yu Kuai To: jack@suse.cz, tj@kernel.org, josef@toxicpanda.com, axboe@kernel.dk, yukuai3@huawei.com Cc: cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai1@huaweicloud.com, yi.zhang@huawei.com, yangerkun@huawei.com Subject: [PATCH for-6.12 2/7] block, bfq: fix procress reference leakage for bfqq in merge chain Date: Mon, 9 Sep 2024 21:41:49 +0800 Message-Id: <20240909134154.954924-3-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240909134154.954924-1-yukuai1@huaweicloud.com> References: <20240909134154.954924-1-yukuai1@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: gCh0CgCn28eQ+95mhC1hAw--.55605S6 X-Coremail-Antispam: 1UD129KBjvJXoWxZw4xtr1rur48Xw13GF13CFg_yoWrZr17pa 13ta13Ar1xXr45Gry7Jr4jv3WFkr1fCrZrtF92q34kJr1DAr17tF1qyw18ZFyxXrZ5uwsx Xr10qr97Jr17JFDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUm014x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jryl82xGYIkIc2 x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJw A2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS 0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2 IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0 Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwACI402YVCY1x02628vn2kIc2 xKxwCY1x0262kKe7AKxVWUtVW8ZwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWU JVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67 kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY 6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0x vEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVj vjDU0xZFpf9x0JUQXo7UUUUU= X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ From: Yu Kuai Original state: Process 1 Process 2 Process 3 Process 4 (BIC1) (BIC2) (BIC3) (BIC4) =CE=9B | | | \--------------\ \-------------\ \-------------\| V V V bfqq1--------->bfqq2---------->bfqq3----------->bfqq4 ref 0 1 2 4 After commit 0e456dba86c7 ("block, bfq: choose the last bfqq from merge chain in bfq_setup_cooperator()"), if P1 issues a new IO: Without the patch: Process 1 Process 2 Process 3 Process 4 (BIC1) (BIC2) (BIC3) (BIC4) =CE=9B | | | \------------------------------\ \-------------\| V V bfqq1--------->bfqq2---------->bfqq3----------->bfqq4 ref 0 0 2 4 bfqq3 will be used to handle IO from P1, this is not expected, IO should be redirected to bfqq4; With the patch: ------------------------------------------- | | Process 1 Process 2 Process 3 | Process 4 (BIC1) (BIC2) (BIC3) | (BIC4) | | | | \-------------\ \-------------\| V V bfqq1--------->bfqq2---------->bfqq3----------->bfqq4 ref 0 0 2 4 IO is redirected to bfqq4, however, procress reference of bfqq3 is still 2, while there is only P2 using it. Fix the problem by calling bfq_merge_bfqqs() for each bfqq in the merge chain. Also change bfqq_merge_bfqqs() to return new_bfqq to simplify code. Fixes: 0e456dba86c7 ("block, bfq: choose the last bfqq from merge chain in = bfq_setup_cooperator()") Signed-off-by: Yu Kuai --- block/bfq-iosched.c | 37 +++++++++++++++++-------------------- 1 file changed, 17 insertions(+), 20 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index d5d39974c674..f4192d5411d2 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -3129,10 +3129,12 @@ void bfq_release_process_ref(struct bfq_data *bfqd,= struct bfq_queue *bfqq) bfq_put_queue(bfqq); } =20 -static void -bfq_merge_bfqqs(struct bfq_data *bfqd, struct bfq_io_cq *bic, - struct bfq_queue *bfqq, struct bfq_queue *new_bfqq) +static struct bfq_queue *bfq_merge_bfqqs(struct bfq_data *bfqd, + struct bfq_io_cq *bic, + struct bfq_queue *bfqq) { + struct bfq_queue *new_bfqq =3D bfqq->new_bfqq; + bfq_log_bfqq(bfqd, bfqq, "merging with queue %lu", (unsigned long)new_bfqq->pid); /* Save weight raising and idle window of the merged queues */ @@ -3226,6 +3228,8 @@ bfq_merge_bfqqs(struct bfq_data *bfqd, struct bfq_io_= cq *bic, bfq_reassign_last_bfqq(bfqq, new_bfqq); =20 bfq_release_process_ref(bfqd, bfqq); + + return new_bfqq; } =20 static bool bfq_allow_bio_merge(struct request_queue *q, struct request *r= q, @@ -3261,14 +3265,8 @@ static bool bfq_allow_bio_merge(struct request_queue= *q, struct request *rq, * fulfilled, i.e., bic can be redirected to new_bfqq * and bfqq can be put. */ - bfq_merge_bfqqs(bfqd, bfqd->bio_bic, bfqq, - new_bfqq); - /* - * If we get here, bio will be queued into new_queue, - * so use new_bfqq to decide whether bio and rq can be - * merged. - */ - bfqq =3D new_bfqq; + while (bfqq !=3D new_bfqq) + bfqq =3D bfq_merge_bfqqs(bfqd, bfqd->bio_bic, bfqq); =20 /* * Change also bqfd->bio_bfqq, as @@ -5705,9 +5703,7 @@ bfq_do_early_stable_merge(struct bfq_data *bfqd, stru= ct bfq_queue *bfqq, * state before killing it. */ bfqq->bic =3D bic; - bfq_merge_bfqqs(bfqd, bic, bfqq, new_bfqq); - - return new_bfqq; + return bfq_merge_bfqqs(bfqd, bic, bfqq); } =20 /* @@ -6162,6 +6158,7 @@ static bool __bfq_insert_request(struct bfq_data *bfq= d, struct request *rq) bool waiting, idle_timer_disabled =3D false; =20 if (new_bfqq) { + struct bfq_queue *old_bfqq =3D bfqq; /* * Release the request's reference to the old bfqq * and make sure one is taken to the shared queue. @@ -6178,18 +6175,18 @@ static bool __bfq_insert_request(struct bfq_data *b= fqd, struct request *rq) * new_bfqq. */ if (bic_to_bfqq(RQ_BIC(rq), true, - bfq_actuator_index(bfqd, rq->bio)) =3D=3D bfqq) - bfq_merge_bfqqs(bfqd, RQ_BIC(rq), - bfqq, new_bfqq); + bfq_actuator_index(bfqd, rq->bio)) =3D=3D bfqq) { + while (bfqq !=3D new_bfqq) + bfqq =3D bfq_merge_bfqqs(bfqd, RQ_BIC(rq), bfqq); + } =20 - bfq_clear_bfqq_just_created(bfqq); + bfq_clear_bfqq_just_created(old_bfqq); /* * rq is about to be enqueued into new_bfqq, * release rq reference on bfqq */ - bfq_put_queue(bfqq); + bfq_put_queue(old_bfqq); rq->elv.priv[1] =3D new_bfqq; - bfqq =3D new_bfqq; } =20 bfq_update_io_thinktime(bfqd, bfqq); --=20 2.39.2