From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.110 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792635519; b=hH+81fk2xcR3LAMNgVc1XUy9JWSza+sYg5iXVhYTQVuNHg+smbqaWuWBC3XJlxTz8XyP 8vh9Ra+R3RcgeeV10hBElKvhLIe8Uz2geRhJRsTS3orhJx0p/zXqLe2xWApM6ABv3JiY7 U1grw34u+3KDwIIc8jhfD5VfpVyk6g8vkY1PzgX2N7y4WRJ/Jt26orL1vUMrv9vKof+Cs kfN1okfjNeE5eTfUQCgI+4ZiAev8f7NKWzc8YtphKsFZXLx9y/192w1kgqF82Imc/i/zP pkmGoaL4nnidAF1URVs1yPzQOhtbMekkYMA0CzsO4omdyT4SZlF7BCMGWjdhAazxUXQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792635519; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:Message-ID:Date:MIME-Version:User-Agent: Subject:To:Cc:References:From:In-Reply-To:Content-Type: Content-Transfer-Encoding; bh=V/bK1oHMn1rt+dKdcCYOSmcwkHw/5HHuvQOfHL/lIbY=; b=x6aCG3S57sdKhKRMAJY+c9qaSX9t3W+I2VREJvXClFM2PJj4I1bJw+GjtSJ/shQO8NT+ G/gIN9jYUDcPtLE45FSErfDK6ucb3jYQ2Kx09Kx709xUBtz0nTm7uEaQ+WIdoLup5PnbS 9DFs34zYOEgiepQ6TAzWG9nhVCIwH8KhI4PnY3cT4nW2OC7dnJhVDzWSQ8TK5BKEQyYzz KGHsErjGY2hW0+IiBrAMIo4RJyQmp3kSCpEr4wtb5nTj2PkLHuEsb5Nj/UgTD8MIDUOKE EVU5t70AZbPsIx+CnAsSokz/CEyj2pRaN3iEiUmXZGzyBXZhAxB//o0CXee0ag+n1Rg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=HgAXSlwc; arc=none smtp.remote-ip=91.218.175.110 Received: from mta0.migadu.com (out-110.mta0.migadu.com [91.218.175.110]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7AE3C606A337 for ; Thu, 22 Oct 2026 02:18:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 7AE3C606A337 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=HgAXSlwc X-Envelope-To: netdev@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=ooqyk9o6+mpPrkv3GOQDSDUiZawfX8BzqiIhm5l6pnQ=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1792635503; v=1; x=1793240303; b=HgAXSlwchmv9Y+9KUXMqqEP/X3dvSR4dnagDzZyQV+xIkneaqn9/Mevv0XToW189HH8UMw4d w5SpfGVvRFduIkWS3FUDNKxEK/i3LgWWusv1sAwtkoB6kl9DTC5Pl7hweELWfDiPGfZMuJ/WePj BurxRwlRCGPDBb0udenPRyrs= X-Envelope-To: netdev@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id e1ec92438c6690db; Thu, 22 Oct 2026 02:18:23 +0000 X-Mizu-Trace-ID: e1ec92438c6690db X-Migadu-Flow: FLOW_OUT Message-ID: Date: Thu, 22 Oct 2026 10:18:12 +0800 X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net] ppp: linearize bridged packets when required To: Eric Dumazet Cc: netdev-bot+sinfo@kernel.org, Andrew Lunn , "David S. Miller" , Jakub Kicinski , Paolo Abeni , Breno Leitao , Kees Cook , Taegu Ha , Tom Parkin , linux-ppp@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, James Chapman , Sashiko , Felix Fietkau , Pablo Neira Ayuso References: <20261021023608.55867-1-qingfang.deng@linux.dev> <179255036282.3290.8488375760281728576@kernel.org> <315a8794-db40-4d0f-9e4c-0cad66174bff@linux.dev> <51ccddcc-53b0-47cd-9526-ccd825f0f6d9@linux.dev> From: Qingfang Deng In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 2026/10/22 1:55, Eric Dumazet wrote: >> What about NETIF_F_FRAGLIST? > I do not see your point. Can you elaborate? > > There’s also nothing left to gain on fraglist packets. > > SKB_GSO_FRAGLIST packets already go through skb_segment_list(), > which just unchains the original skbs without copying, as the fraglist > test run showed. > > Frag_list skbs that aren’t fraglist GRO go through skb_segment(), > which with NETIF_F_SG already shares the pages of the chained skbs > instead of copying them. I've run selftests and confirmed that NETIF_F_FRAGLIST is unnecessary here. One extra finding: passing NETIF_F_SG conditionally can avoid an extra reallocation in skb_linearize(). segs = skb_gso_segment(skb, chan->direct_xmit ? NETIF_F_SG : 0);