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 2C14D8F5D; Sat, 22 Jun 2024 02:06:00 +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=1719021961; cv=none; b=exuFRewh0TVNOLxlrFK+ZsNmXMQVwRBAk5+lu1neBHQDDOHF8I8rEyNkPE/wP7pNPYQWdSqMtSDgh6bm/FLcvHekGq+A3Rb2+NnHpFlKrdWBSnBrZBaZ/SvDu2ZfVhkrLvxtb3A7IpGpTyaO3T/DYFcyhuCj2cEUo7WIgz9Jh7k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719021961; c=relaxed/simple; bh=zTg822l4VjJCDrdBAaQFPxBmNa6vqsABfh8rmtt+b2w=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=eLs0RvEaI3rrIv9voxdMbOoFaCvdB9mfGYzpXrlIIAGrcGCbbiswhC3mQEHKue1g4Ei5GflUxCn71b5ytZsJtfiTc5kKziTTPgaNlEZhXGljCO0Z/puOtgUQawvLien63n+lqWrf7ZqyQ2gpNjWNSPhQt0FuifY1eCtEO31a5i8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=E+EfYuK8; 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="E+EfYuK8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9440AC2BBFC; Sat, 22 Jun 2024 02:05:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719021960; bh=zTg822l4VjJCDrdBAaQFPxBmNa6vqsABfh8rmtt+b2w=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=E+EfYuK8WxK66OXHiMfQtIlBGiEX4lQ1FEYunTYDmYkwoF9bmegzYMXnxoDVjTEZA FrlmnM4ZvT3bz0O3YQNDgDdv7dBAJnt+we2/gmUT9tphyuedBOm9o25tH1wFkVFshQ iBVUws0vgDt4QRoHMcEyPvVj/wsGsZ1Crr1FvWnl7KCiEVfpBfCSypfQl6OVD5+U3B Uda0xqcIm5wdg59X2uy8fWoKtWx/ycd1BFM0ebCtS6iGKZhKOuTPcf5ENj2CRdFB46 Z+qBd9Sg5yH3CfhF6THlwXUz9o5ha/QwEEP2/FJIvcn5yP7DFZm1xihdO7AeqOqC+N rGh0dEs8FoRIw== Date: Fri, 21 Jun 2024 19:05:58 -0700 From: Jakub Kicinski To: Sebastian Andrzej Siewior Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, "David S. Miller" , Daniel Bristot de Oliveira , Boqun Feng , Daniel Borkmann , Eric Dumazet , Frederic Weisbecker , Ingo Molnar , Paolo Abeni , Peter Zijlstra , Thomas Gleixner , Waiman Long , Will Deacon , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Alexei Starovoitov , Andrii Nakryiko , Eduard Zingerman , Hao Luo , Jesper Dangaard Brouer , Jiri Olsa , John Fastabend , Jonathan Lemon , KP Singh , Maciej Fijalkowski , Magnus Karlsson , Martin KaFai Lau , Song Liu , Stanislav Fomichev , Toke =?UTF-8?B?SMO4aWxhbmQtSsO4cmdlbnNlbg==?= , Yonghong Song , bpf@vger.kernel.org Subject: Re: [PATCH v9 net-next 15/15] net: Move per-CPU flush-lists to bpf_net_context on PREEMPT_RT. Message-ID: <20240621190558.409d778c@kernel.org> In-Reply-To: <20240620132727.660738-16-bigeasy@linutronix.de> References: <20240620132727.660738-1-bigeasy@linutronix.de> <20240620132727.660738-16-bigeasy@linutronix.de> 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 Thu, 20 Jun 2024 15:22:05 +0200 Sebastian Andrzej Siewior wrote: > void __cpu_map_flush(void) > { > - struct list_head *flush_list = this_cpu_ptr(&cpu_map_flush_list); > + struct list_head *flush_list = bpf_net_ctx_get_cpu_map_flush_list(); > struct xdp_bulk_queue *bq, *tmp; > > list_for_each_entry_safe(bq, tmp, flush_list, flush_node) { Most of the time we'll init the flush list just to walk its (empty) self. It feels really tempting to check the init flag inside xdp_do_flush() already. Since the various sub-flush handles may not get inlined - we could save ourselves not only the pointless init, but also the function calls. So the code would potentially be faster than before the changes? Can be a follow up, obviously.