From: Yunsheng Lin <linyunsheng@huawei.com>
To: <davem@davemloft.net>, <kuba@kernel.org>
Cc: <olteanv@gmail.com>, <ast@kernel.org>, <daniel@iogearbox.net>,
<andriin@fb.com>, <edumazet@google.com>, <weiwan@google.com>,
<cong.wang@bytedance.com>, <ap420073@gmail.com>,
<netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linuxarm@openeuler.org>, <mkl@pengutronix.de>,
<linux-can@vger.kernel.org>, <jhs@mojatatu.com>,
<xiyou.wangcong@gmail.com>, <jiri@resnulli.us>,
<andrii@kernel.org>, <kafai@fb.com>, <songliubraving@fb.com>,
<yhs@fb.com>, <john.fastabend@gmail.com>, <kpsingh@kernel.org>,
<bpf@vger.kernel.org>, <jonas.bonn@netrounds.com>,
<pabeni@redhat.com>, <mzhivich@akamai.com>, <johunt@akamai.com>,
<albcamus@gmail.com>, <kehuan.feng@gmail.com>,
<a.fatoum@pengutronix.de>, <atenart@kernel.org>,
<alexander.duyck@gmail.com>, <hdanton@sina.com>,
<jgross@suse.com>, <JKosina@suse.com>, <mkubecek@suse.cz>,
<bjorn@kernel.org>, <alobakin@pm.me>
Subject: [PATCH net-next v2 3/3] net: sched: remove qdisc->empty for lockless qdisc
Date: Thu, 3 Jun 2021 09:48:00 +0800 [thread overview]
Message-ID: <1622684880-39895-4-git-send-email-linyunsheng@huawei.com> (raw)
In-Reply-To: <1622684880-39895-1-git-send-email-linyunsheng@huawei.com>
As MISSED and DRAINING state are used to indicate a non-empty
qdisc, qdisc->empty is not longer needed, so remove it.
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
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 83d7f5f..1abd9c7 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -707,8 +707,6 @@ static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
need_retry = false;
goto retry;
- } else {
- WRITE_ONCE(qdisc->empty, true);
}
return skb;
@@ -909,7 +907,6 @@ 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);
--
2.7.4
next prev parent reply other threads:[~2021-06-03 1:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-03 1:47 [PATCH net-next v2 0/3] Some optimization for lockless qdisc Yunsheng Lin
2021-06-03 1:47 ` [PATCH net-next v2 1/3] net: sched: avoid unnecessary seqcount operation " Yunsheng Lin
2021-06-03 1:47 ` [PATCH net-next v2 2/3] net: sched: implement TCQ_F_CAN_BYPASS " Yunsheng Lin
2021-06-03 1:48 ` Yunsheng Lin [this message]
2021-06-03 18:35 ` [PATCH net-next v2 0/3] Some optimization " Jakub Kicinski
2021-06-08 12:53 ` Vladimir Oltean
2021-06-09 1:31 ` Yunsheng Lin
2021-06-09 16:20 ` Jakub Kicinski
2021-06-15 23:29 ` Vladimir Oltean
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