From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754810AbeDYPY1 (ORCPT ); Wed, 25 Apr 2018 11:24:27 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:53730 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754320AbeDYPYX (ORCPT ); Wed, 25 Apr 2018 11:24:23 -0400 Date: Wed, 25 Apr 2018 08:24:22 -0700 From: Christoph Hellwig To: Eric Dumazet Cc: Christoph Hellwig , Eric Dumazet , "David S . Miller" , netdev , Andy Lutomirski , linux-kernel , linux-mm , Soheil Hassas Yeganeh Subject: Re: [PATCH net-next 1/2] tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive Message-ID: <20180425152422.GB27076@infradead.org> References: <20180425052722.73022-1-edumazet@google.com> <20180425052722.73022-2-edumazet@google.com> <20180425062859.GA23914@infradead.org> <5cd31eba-63b5-9160-0a2e-f441340df0d3@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5cd31eba-63b5-9160-0a2e-f441340df0d3@gmail.com> User-Agent: Mutt/1.9.2 (2017-12-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 25, 2018 at 06:01:02AM -0700, Eric Dumazet wrote: > Thanks Christoph > > Note the high cost of zap_page_range(), needed to avoid -EBUSY being returned > from vm_insert_page() the second time TCP_ZEROCOPY_RECEIVE is used on one VMA. > > Ideally a vm_replace_page() would avoid this cost ? No my area of expertise, I'll defer to the MM folks..