From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Ricardo Leitner Subject: Re: [PATCH RFC net-next 0/2] pskb_extract() helper function. Date: Mon, 18 Apr 2016 10:28:05 -0300 Message-ID: <20160418132805.GA5674@localhost.localdomain> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: eric.dumazet@gmail.com, netdev@vger.kernel.org To: Sowmini Varadhan Return-path: Received: from mx1.redhat.com ([209.132.183.28]:55266 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751054AbcDRN2I (ORCPT ); Mon, 18 Apr 2016 09:28:08 -0400 Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Mon, Apr 18, 2016 at 06:21:07AM -0700, Sowmini Varadhan wrote: > This patchset follows up on the discussion in > https://www.mail-archive.com/netdev@vger.kernel.org/msg105090.html > > For RDS-TCP, we have to deal with the full gamut of > nonlinear sk_buffs, including all the frag_list variants. > Also, the parent skb has to remain unchanged, while the clone > is queued for Rx on the PF_RDS socket. > > Patch 1 of this patchset adds a pskb_extract() function that > does all this without the redundant memcpy's in pskb_expand_head() > and __pskb_pull_tail(). > > A further optimization is also possible by inlining pskb_trim() > itself into pskb_carve() and thus avoiding the needless copy > of trailer frags/pages that will then get trimmed away. I am > deferring that optimization for the next iteration, and would > like to get feedback on this first pass, which by itself gives > a noticeable perf boost. I like this idea. We can also make use of it in SCTP. Marcelo