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 EC1EB1B042F; Wed, 16 Apr 2025 13:38:14 +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=1744810695; cv=none; b=h+T6ePbkPiJZe+bJJ6BCBuwGtrsIWMlKUMKr5hmZsCEpkuOFD4wuxFoLqDqJ82HB1SjaFnfSKCGDZhw4bgk2EC0ZScP38WrX8M3dr/GQKP28DfxyoikyZ7yY44F91ZmLEsL/ZkcZiuI5jFt/JZVnxV0m2BkYB9UQWBpjZHGIqSQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744810695; c=relaxed/simple; bh=sdNLl1W288uG9ZDxKVKiy23P3vv4qT3wAIUV4yV8D9I=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Z3591700hzFcR7ngWob6ZiQp8eMHdbNB3nwJ2QD5ZSIfpQhmVSmKkXgnmhQGXny8Vy6Q6aGWBuX96sUY10Ul7RLDtQJ2CMcX7DBHVJ0PDAnw1t5MMlI5VFEl/+Yr6HvmwNvDO620yH005UceYML3zM/9uUkntkSxHvQM+rnK5xI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TYbIniVf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TYbIniVf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C543C4CEE2; Wed, 16 Apr 2025 13:38:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744810694; bh=sdNLl1W288uG9ZDxKVKiy23P3vv4qT3wAIUV4yV8D9I=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=TYbIniVfq32iDZScm88zQcbKRZ86XQ2Ol37pjImGDFMBZdm6xPxj7IUCknV5BNyz9 Ohz/V4EhD9WKM49WTQO4uYu1cSXEp8SDe7+mG/pPLwkpSxakZJ2hz3BR+L3J6qXJ8l pqBjaEIWx9OKMgPMLurd+oDcwzYc7hF++S8tZwMj3qGJyC2+uM+VZws0nJ4w5KhJA9 h3qTVreui67i9P/ADSZ9xJ5AerpRDvlcGB5WjDMiT0Z4cJJ3+AF33+836kDl/MAjpv v7NhY/yThNhc1d/VOZi+BnLx+GBx32OiU9EzegiiWeatP4TuTGSGSeWVn/RFDzXi3i 6Yvor/ydo3BjA== Date: Wed, 16 Apr 2025 06:38:13 -0700 From: Jakub Kicinski To: Jesper Dangaard Brouer Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, tom@herbertland.com, Eric Dumazet , "David S. Miller" , Paolo Abeni , Toke =?UTF-8?B?SMO4aWxhbmQtSsO4cmdlbnNl?= =?UTF-8?B?bg==?= , dsahern@kernel.org, makita.toshiaki@lab.ntt.co.jp, kernel-team@cloudflare.com, phil@nwl.cc Subject: Re: [PATCH net-next V4 2/2] veth: apply qdisc backpressure on full ptr_ring to reduce TX drops Message-ID: <20250416063813.75fb83dc@kernel.org> In-Reply-To: <174472470529.274639.17026526070544068280.stgit@firesoul> References: <174472463778.274639.12670590457453196991.stgit@firesoul> <174472470529.274639.17026526070544068280.stgit@firesoul> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 15 Apr 2025 15:45:05 +0200 Jesper Dangaard Brouer wrote: > In production, we're seeing TX drops on veth devices when the ptr_ring > fills up. This can occur when NAPI mode is enabled, though it's > relatively rare. However, with threaded NAPI - which we use in > production - the drops become significantly more frequent. It splats: [ 5319.025772][ C1] dump_stack_lvl (lib/dump_stack.c:123) [ 5319.025786][ C1] lockdep_rcu_suspicious (kernel/locking/lockdep.c:6866) [ 5319.025797][ C1] veth_xdp_rcv (drivers/net/veth.c:907 (discriminator 9)) [ 5319.025850][ C1] veth_poll (drivers/net/veth.c:977) -- pw-bot: cr