From patchwork Sat Mar 9 09:05:12 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 13587555 X-Patchwork-Delegate: kuba@kernel.org Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 D7CD1374C4 for ; Sat, 9 Mar 2024 09:09:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709975352; cv=none; b=bDP69+HPQfHu281l7hJXGscTVv0aTdnogpcI+43oxYuMDJLUelBvBahHEmt2etLTkQLISzUSVpBtySmJNfJBVLcDpKMfP8yjqsq2Dy8uFfao/D4KEQlZlFXrZFRhaXXbJkyH9inaUcjQ1aK+0XOSw8Q1fKE3C99LP/SIXPXbPMo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709975352; c=relaxed/simple; bh=jmCAG5Wo/mrTlCqOTPTtd1rkZuoIvOg5q2z5d2L6Xnk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=m5B1Km865jrA5wBZKKKXrJ05XEtLqoHCKg9Ou/zp8dDK87mVAba8PnVY9nSFplBXfyEEYq5qYvrAj5WYlcxB+BDS5IPa/DdLLzN/niHRBZhAUF3wJgELs/1vBVTQ4XcSXAo6MnSkKefKHCwfpKUX7cI3KV9Nf05k3g28iTQgi+8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=M8KWoRCR; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=PQA6sat3; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="M8KWoRCR"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="PQA6sat3" From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1709975343; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8EaUqi9WuUxvFTdBsaKXXa/5kwjNARrRcl/IVOBk56k=; b=M8KWoRCRDpfyXbzCegIIH8QwvapVf5J7Yt0VY1Sv3ev3UtVPpuq7+WNZfKEkquTU+H70NM BAhmoRL+KM7fKzjrmB2/hHrSjuYFaL/irko9wiyTUNIzjAndf0GRr3Prks2JJXEawW4KMa 4xsQ6nB38yS6xdGZfC4d/JWStYk9Qltxi9un5XsSo2Ug993b4bbmmX6WDQ8qAi7PNt79gM 8LxgY+7IAsupI/wf/SGcRnE2E+Mmy0FZJPEiwYWjZXaALmziZX14SDTWxwXYiCXdELjFAl Ll5cTuZaqGg1LvZS02lPJQ6AIQhcS7arzHp3Yw484LU+DNCIlPvpPaePmlvMGg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1709975343; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8EaUqi9WuUxvFTdBsaKXXa/5kwjNARrRcl/IVOBk56k=; b=PQA6sat3ws/umSLd1sTAnf0IamPceAj2YC4NIcOJr28LWXbaa9Kky8JX/EKjfPRHLPLEyn WjPFMiDMyuBXFSCQ== To: netdev@vger.kernel.org Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Jesper Dangaard Brouer , Paolo Abeni , Thomas Gleixner , Wander Lairson Costa , Yan Zhai , Sebastian Andrzej Siewior Subject: [PATCH v5 net-next 4/4] net: Rename rps_lock to backlog_lock. Date: Sat, 9 Mar 2024 10:05:12 +0100 Message-ID: <20240309090824.2956805-5-bigeasy@linutronix.de> In-Reply-To: <20240309090824.2956805-1-bigeasy@linutronix.de> References: <20240309090824.2956805-1-bigeasy@linutronix.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org The rps_lock.*() functions use the inner lock of a sk_buff_head for locking. This lock is used if RPS is enabled, otherwise the list is accessed lockless and disabling interrupts is enough for the synchronisation because it is only accessed CPU local. Not only the list is protected but also the NAPI state protected. With the addition of backlog threads, the lock is also needed because of the cross CPU access even without RPS. The clean up of the defer_list list is also done via backlog threads (if enabled). It has been suggested to rename the locking function since it is no longer just RPS. Rename the rps_lock*() functions to backlog_lock*(). Suggested-by: Jakub Kicinski Acked-by: Jakub Kicinski Signed-off-by: Sebastian Andrzej Siewior --- net/core/dev.c | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index d13cb3b9bfc3e..c1ca686310aad 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -223,8 +223,8 @@ static bool use_backlog_threads(void) #endif -static inline void rps_lock_irqsave(struct softnet_data *sd, - unsigned long *flags) +static inline void backlog_lock_irq_save(struct softnet_data *sd, + unsigned long *flags) { if (IS_ENABLED(CONFIG_RPS) || use_backlog_threads()) spin_lock_irqsave(&sd->input_pkt_queue.lock, *flags); @@ -232,7 +232,7 @@ static inline void rps_lock_irqsave(struct softnet_data *sd, local_irq_save(*flags); } -static inline void rps_lock_irq_disable(struct softnet_data *sd) +static inline void backlog_lock_irq_disable(struct softnet_data *sd) { if (IS_ENABLED(CONFIG_RPS) || use_backlog_threads()) spin_lock_irq(&sd->input_pkt_queue.lock); @@ -240,8 +240,8 @@ static inline void rps_lock_irq_disable(struct softnet_data *sd) local_irq_disable(); } -static inline void rps_unlock_irq_restore(struct softnet_data *sd, - unsigned long *flags) +static inline void backlog_unlock_irq_restore(struct softnet_data *sd, + unsigned long *flags) { if (IS_ENABLED(CONFIG_RPS) || use_backlog_threads()) spin_unlock_irqrestore(&sd->input_pkt_queue.lock, *flags); @@ -249,7 +249,7 @@ static inline void rps_unlock_irq_restore(struct softnet_data *sd, local_irq_restore(*flags); } -static inline void rps_unlock_irq_enable(struct softnet_data *sd) +static inline void backlog_unlock_irq_enable(struct softnet_data *sd) { if (IS_ENABLED(CONFIG_RPS) || use_backlog_threads()) spin_unlock_irq(&sd->input_pkt_queue.lock); @@ -4727,12 +4727,12 @@ void kick_defer_list_purge(struct softnet_data *sd, unsigned int cpu) unsigned long flags; if (use_backlog_threads()) { - rps_lock_irqsave(sd, &flags); + backlog_lock_irq_save(sd, &flags); if (!__test_and_set_bit(NAPI_STATE_SCHED, &sd->backlog.state)) __napi_schedule_irqoff(&sd->backlog); - rps_unlock_irq_restore(sd, &flags); + backlog_unlock_irq_restore(sd, &flags); } else if (!cmpxchg(&sd->defer_ipi_scheduled, 0, 1)) { smp_call_function_single_async(cpu, &sd->defer_csd); @@ -4794,7 +4794,7 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu, reason = SKB_DROP_REASON_NOT_SPECIFIED; sd = &per_cpu(softnet_data, cpu); - rps_lock_irqsave(sd, &flags); + backlog_lock_irq_save(sd, &flags); if (!netif_running(skb->dev)) goto drop; qlen = skb_queue_len(&sd->input_pkt_queue); @@ -4804,7 +4804,7 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu, enqueue: __skb_queue_tail(&sd->input_pkt_queue, skb); input_queue_tail_incr_save(sd, qtail); - rps_unlock_irq_restore(sd, &flags); + backlog_unlock_irq_restore(sd, &flags); return NET_RX_SUCCESS; } @@ -4819,7 +4819,7 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu, drop: sd->dropped++; - rps_unlock_irq_restore(sd, &flags); + backlog_unlock_irq_restore(sd, &flags); dev_core_stats_rx_dropped_inc(skb->dev); kfree_skb_reason(skb, reason); @@ -5885,7 +5885,7 @@ static void flush_backlog(struct work_struct *work) local_bh_disable(); sd = this_cpu_ptr(&softnet_data); - rps_lock_irq_disable(sd); + backlog_lock_irq_disable(sd); skb_queue_walk_safe(&sd->input_pkt_queue, skb, tmp) { if (skb->dev->reg_state == NETREG_UNREGISTERING) { __skb_unlink(skb, &sd->input_pkt_queue); @@ -5893,7 +5893,7 @@ static void flush_backlog(struct work_struct *work) input_queue_head_incr(sd); } } - rps_unlock_irq_enable(sd); + backlog_unlock_irq_enable(sd); skb_queue_walk_safe(&sd->process_queue, skb, tmp) { if (skb->dev->reg_state == NETREG_UNREGISTERING) { @@ -5911,14 +5911,14 @@ static bool flush_required(int cpu) struct softnet_data *sd = &per_cpu(softnet_data, cpu); bool do_flush; - rps_lock_irq_disable(sd); + backlog_lock_irq_disable(sd); /* as insertion into process_queue happens with the rps lock held, * process_queue access may race only with dequeue */ do_flush = !skb_queue_empty(&sd->input_pkt_queue) || !skb_queue_empty_lockless(&sd->process_queue); - rps_unlock_irq_enable(sd); + backlog_unlock_irq_enable(sd); return do_flush; #endif @@ -6033,7 +6033,7 @@ static int process_backlog(struct napi_struct *napi, int quota) } - rps_lock_irq_disable(sd); + backlog_lock_irq_disable(sd); if (skb_queue_empty(&sd->input_pkt_queue)) { /* * Inline a custom version of __napi_complete(). @@ -6049,7 +6049,7 @@ static int process_backlog(struct napi_struct *napi, int quota) skb_queue_splice_tail_init(&sd->input_pkt_queue, &sd->process_queue); } - rps_unlock_irq_enable(sd); + backlog_unlock_irq_enable(sd); } return work;