From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 88F6E1A3159; Tue, 27 May 2025 17:38:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748367489; cv=none; b=tErVqDSKGzKRpHSaiYMTdcpkl/KR6q9VdIl3QkJDqkkGbRkR4JJomDQ8NryS+JwbvRkeapui8V5bxBbeW+rOLKmTs6Pyn+I3KCw8I9RG0zv32daIh5rp6gq5yJclEuIbsB/wJLGnvigSUwnbPNBJi5hyEC93udcHjy75TtTDopo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748367489; c=relaxed/simple; bh=PyI3PQ4nY4ruNenz+J0OnFKGXJ3vQrrjDgvJGHbLpKE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GJ6/YCV0iCRe6gL14hQZBwJE/QUsQmzx8m9km6uPpryhH6e4hd3/d1BAPL/auH/VktP2KqYzQrOPwYXC/PDAF7BD6c4vpER42M2ClG3wiW1ndEOSfhJDUtpa5w3mm1S2kH0GuxDtn4XMFAD++vzX6gIlIXfEq8sShnwS5RwM+wQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=jcZ5Rf2b; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="jcZ5Rf2b" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3839C4CEE9; Tue, 27 May 2025 17:38:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1748367489; bh=PyI3PQ4nY4ruNenz+J0OnFKGXJ3vQrrjDgvJGHbLpKE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jcZ5Rf2bKiPfIKv4lon+0n59yHVgTmtj2UEBUppFZRNYd7jy4rHH2KgD99/lCc1Vv egI1mb+Kpk/R03I81gHcH9fEhbqTXeq5IHViktfUiOgEVGJjPBmxfRfhes95IubQgI NMPycsKlCU9Vvn1ek+GG61BOkBsrHMCONiJZdGLY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jakub Kicinski , Breno Leitao , Sasha Levin Subject: [PATCH 6.14 404/783] netdevsim: call napi_schedule from a timer context Date: Tue, 27 May 2025 18:23:21 +0200 Message-ID: <20250527162529.550781200@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250527162513.035720581@linuxfoundation.org> References: <20250527162513.035720581@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Breno Leitao [ Upstream commit bf3624cf1c3708284c53ed99a1c43f2e104dc2dd ] The netdevsim driver was experiencing NOHZ tick-stop errors during packet transmission due to pending softirq work when calling napi_schedule(). This issue was observed when running the netconsole selftest, which triggered the following error message: NOHZ tick-stop error: local softirq work is pending, handler #08!!! To fix this issue, introduce a timer that schedules napi_schedule() from a timer context instead of calling it directly from the TX path. Create an hrtimer for each queue and kick it from the TX path, which then schedules napi_schedule() from the timer context. Suggested-by: Jakub Kicinski Signed-off-by: Breno Leitao Link: https://patch.msgid.link/20250219-netdevsim-v3-1-811e2b8abc4c@debian.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/netdevsim/netdev.c | 21 ++++++++++++++++++++- drivers/net/netdevsim/netdevsim.h | 1 + 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c index 42f247cbdceec..e4c0d77849b82 100644 --- a/drivers/net/netdevsim/netdev.c +++ b/drivers/net/netdevsim/netdev.c @@ -87,7 +87,8 @@ static netdev_tx_t nsim_start_xmit(struct sk_buff *skb, struct net_device *dev) if (unlikely(nsim_forward_skb(peer_dev, skb, rq) == NET_RX_DROP)) goto out_drop_cnt; - napi_schedule(&rq->napi); + if (!hrtimer_active(&rq->napi_timer)) + hrtimer_start(&rq->napi_timer, us_to_ktime(5), HRTIMER_MODE_REL); rcu_read_unlock(); u64_stats_update_begin(&ns->syncp); @@ -426,6 +427,22 @@ static int nsim_init_napi(struct netdevsim *ns) return err; } +static enum hrtimer_restart nsim_napi_schedule(struct hrtimer *timer) +{ + struct nsim_rq *rq; + + rq = container_of(timer, struct nsim_rq, napi_timer); + napi_schedule(&rq->napi); + + return HRTIMER_NORESTART; +} + +static void nsim_rq_timer_init(struct nsim_rq *rq) +{ + hrtimer_init(&rq->napi_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + rq->napi_timer.function = nsim_napi_schedule; +} + static void nsim_enable_napi(struct netdevsim *ns) { struct net_device *dev = ns->netdev; @@ -615,11 +632,13 @@ static struct nsim_rq *nsim_queue_alloc(void) return NULL; skb_queue_head_init(&rq->skb_queue); + nsim_rq_timer_init(rq); return rq; } static void nsim_queue_free(struct nsim_rq *rq) { + hrtimer_cancel(&rq->napi_timer); skb_queue_purge_reason(&rq->skb_queue, SKB_DROP_REASON_QUEUE_PURGE); kfree(rq); } diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h index 96d54c08043d3..e757f85ed8617 100644 --- a/drivers/net/netdevsim/netdevsim.h +++ b/drivers/net/netdevsim/netdevsim.h @@ -97,6 +97,7 @@ struct nsim_rq { struct napi_struct napi; struct sk_buff_head skb_queue; struct page_pool *page_pool; + struct hrtimer napi_timer; }; struct netdevsim { -- 2.39.5