From patchwork Tue Jun 22 06:49:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yunsheng Lin X-Patchwork-Id: 465590 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F439C48BDF for ; Tue, 22 Jun 2021 06:50:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 68DC66128C for ; Tue, 22 Jun 2021 06:50:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230422AbhFVGws (ORCPT ); Tue, 22 Jun 2021 02:52:48 -0400 Received: from szxga08-in.huawei.com ([45.249.212.255]:8291 "EHLO szxga08-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229828AbhFVGwm (ORCPT ); Tue, 22 Jun 2021 02:52:42 -0400 Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.56]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4G8H2h1Qddz1BQRW; Tue, 22 Jun 2021 14:45:16 +0800 (CST) Received: from dggpemm500005.china.huawei.com (7.185.36.74) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Tue, 22 Jun 2021 14:50:24 +0800 Received: from localhost.localdomain (10.69.192.56) by dggpemm500005.china.huawei.com (7.185.36.74) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Tue, 22 Jun 2021 14:50:23 +0800 From: Yunsheng Lin To: , CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH net-next v3 3/3] net: sched: remove qdisc->empty for lockless qdisc Date: Tue, 22 Jun 2021 14:49:57 +0800 Message-ID: <1624344597-11806-4-git-send-email-linyunsheng@huawei.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1624344597-11806-1-git-send-email-linyunsheng@huawei.com> References: <1624344597-11806-1-git-send-email-linyunsheng@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.69.192.56] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500005.china.huawei.com (7.185.36.74) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org As MISSED and DRAINING state are used to indicate a non-empty qdisc, qdisc->empty is not longer needed, so remove it. Acked-by: Jakub Kicinski Tested-by: Vladimir Oltean # flexcan Signed-off-by: Yunsheng Lin --- include/net/sch_generic.h | 13 +++---------- net/sched/sch_generic.c | 3 --- 2 files changed, 3 insertions(+), 13 deletions(-) diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index 177f240..c99ffe9 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -117,8 +117,6 @@ struct Qdisc { spinlock_t busylock ____cacheline_aligned_in_smp; spinlock_t seqlock; - /* for NOLOCK qdisc, true if there are no enqueued skbs */ - bool empty; struct rcu_head rcu; /* private data */ @@ -165,7 +163,7 @@ static inline bool qdisc_is_percpu_stats(const struct Qdisc *q) static inline bool qdisc_is_empty(const struct Qdisc *qdisc) { if (qdisc_is_percpu_stats(qdisc)) - return READ_ONCE(qdisc->empty); + return nolock_qdisc_is_empty(qdisc); return !READ_ONCE(qdisc->q.qlen); } @@ -173,7 +171,7 @@ static inline bool qdisc_run_begin(struct Qdisc *qdisc) { if (qdisc->flags & TCQ_F_NOLOCK) { if (spin_trylock(&qdisc->seqlock)) - goto nolock_empty; + return true; /* If the MISSED flag is set, it means other thread has * set the MISSED flag before second spin_trylock(), so @@ -195,12 +193,7 @@ static inline bool qdisc_run_begin(struct Qdisc *qdisc) /* Retry again in case other CPU may not see the new flag * after it releases the lock at the end of qdisc_run_end(). */ - if (!spin_trylock(&qdisc->seqlock)) - return false; - -nolock_empty: - WRITE_ONCE(qdisc->empty, false); - return true; + return spin_trylock(&qdisc->seqlock); } else if (qdisc_is_running(qdisc)) { return false; } diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 9984ccc..d9ac60f 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -725,8 +725,6 @@ static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc) need_retry = false; goto retry; - } else { - WRITE_ONCE(qdisc->empty, true); } return skb; @@ -927,7 +925,6 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue, sch->enqueue = ops->enqueue; sch->dequeue = ops->dequeue; sch->dev_queue = dev_queue; - sch->empty = true; dev_hold(dev); refcount_set(&sch->refcnt, 1);