Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 2 Jan 2003 17:19:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 2 Jan 2003 17:19:57 -0500 Received: from bitmover.com ([192.132.92.2]:11170 "EHLO mail.bitmover.com") by vger.kernel.org with ESMTP id ; Thu, 2 Jan 2003 17:19:53 -0500 Date: Thu, 2 Jan 2003 14:28:16 -0800 From: Larry McVoy To: Thomas Ogrisegg Cc: "David S. Miller" , linux-kernel@vger.kernel.org, Larry McVoy Subject: Re: [PATCH] TCP Zero Copy for mmapped files Message-ID: <20030102222816.GF2461@work.bitmover.com> Mail-Followup-To: Larry McVoy , Thomas Ogrisegg , "David S. Miller" , linux-kernel@vger.kernel.org, Larry McVoy References: <20021230010953.GA17731@window.dhis.org> <20021230012937.GC5156@work.bitmover.com> <1041489421.3703.6.camel@rth.ninka.net> <20030102221210.GA7704@window.dhis.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030102221210.GA7704@window.dhis.org> User-Agent: Mutt/1.4i X-MailScanner: Found to be clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 886 Lines: 23 > > 1) Does not handle writes that straddle multiple VMAs > > What exactly do you mean? In my test, files larger than a > page were handled perfectly, as well. mmap(file1 at location [a,b) mmap(file2 at location [b,c) write(sock, a, (size_t)(c - a)); > However, I didn't like the VM waste either, but I believe there > is no other way. The VM cost hurts. Badly. Imagine that the network costs ZERO. Then the map/unmap/vm ops become the dominating term. That's why it is a fruitless approach, it still has a practical limit which is too low. -- --- Larry McVoy lm at bitmover.com http://www.bitmover.com/lm - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/