From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261511AbVGLPxs (ORCPT ); Tue, 12 Jul 2005 11:53:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261497AbVGLPxs (ORCPT ); Tue, 12 Jul 2005 11:53:48 -0400 Received: from ms-smtp-01.nyroc.rr.com ([24.24.2.55]:15591 "EHLO ms-smtp-01.nyroc.rr.com") by vger.kernel.org with ESMTP id S261489AbVGLPxq (ORCPT ); Tue, 12 Jul 2005 11:53:46 -0400 Subject: Re: Merging relayfs? From: Steven Rostedt To: Jason Baron Cc: richardj_moore@uk.ibm.com, varap@us.ibm.com, karim@opersys.com, linux-kernel@vger.kernel.org, akpm@osdl.org, Tom Zanussi In-Reply-To: References: <17107.6290.734560.231978@tut.ibm.com> Content-Type: text/plain Organization: Kihon Technologies Date: Tue, 12 Jul 2005 11:53:27 -0400 Message-Id: <1121183607.6917.47.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.2.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2005-07-12 at 10:58 -0400, Jason Baron wrote: > On Mon, 11 Jul 2005, Tom Zanussi wrote: > One concern I had regarding relayfs, which was raised previously, was > regarding its use of vmap, > http://marc.theaimsgroup.com/?l=linux-kernel&m=110755199913216&w=2 On x86, > the vmap space is at a premium, and this space is reserved over the entire > lifetime of a 'channel'. Is the use of vmap really critical for > performance? I believe that (Tom correct me if I'm wrong) the use of vmap was to allocate a large buffer without risking failing to allocate. Since the buffer does not need to be in continuous pages. If this is a problem, maybe Tom can use my buffer method to make a buffer :-) See http://www.kihontech.com/logdev where my logdev debugging tool that allocates separate pages and uses an accounting system instead of the more efficient vmalloc to keep the data in the pages together. I'm currently working with Tom to get this to use relayfs as the back end. But here you can take a look at how the buffering works and it doesn't waste up vmalloc. -- Steve