From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756495Ab0ANIRl (ORCPT ); Thu, 14 Jan 2010 03:17:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756403Ab0ANIRk (ORCPT ); Thu, 14 Jan 2010 03:17:40 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:36737 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755627Ab0ANIRj (ORCPT ); Thu, 14 Jan 2010 03:17:39 -0500 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Gleb Natapov Subject: Re: [PATCH v5] add MAP_UNLOCKED mmap flag Cc: kosaki.motohiro@jp.fujitsu.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, akpm@linux-foundation.org In-Reply-To: <20100114080117.GL18808@redhat.com> References: <20100114162327.673E.A69D9226@jp.fujitsu.com> <20100114080117.GL18808@redhat.com> Message-Id: <20100114170247.6747.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Thu, 14 Jan 2010 17:17:36 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > Hmm.. > > Your answer didn't match I wanted. > Then I don't get what you want. I want to know the benefit of the patch for patch reviewing. > > few additional questions. > > > > - Why don't you change your application? It seems natural way than kernel change. > There is no way to change my application and achieve what I've described > in a multithreaded app. Then, we don't recommend to use mlockall(). I don't hope to hear your conclusion, it is not objectivization. I hope to hear why you reached such conclusion. > > - Why do you want your virtual machine have mlockall? AFAIK, current majority > > virtual machine doesn't. > It is absolutely irrelevant for that patch, but just because you ask I > want to measure the cost of swapping out of a guest memory. No. if you stop to use mlockall, the issue is vanished. > > - If this feature added, average distro user can get any benefit? > > > ?! Is this some kind of new measure? There are plenty of much more > invasive features that don't bring benefits to an average distro user. > This feature can bring benefit to embedded/RT developers. I mean who get benifit? > > I mean, many application developrs want to add their specific feature > > into kernel. but if we allow it unlimitedly, major syscall become > > the trushbox of pretty toy feature soon. > > > And if application developer wants to extend kernel in a way that it > will be possible to do something that was not possible before why is > this a bad thing? I would agree with you if for my problem was userspace > solution, but there is none. The mmap interface is asymmetric in regards > to mlock currently. There is MAP_LOCKED, but no MAP_UNLOCKED. Why > MAP_LOCKED is useful then? Why? Because this is formal LKML reviewing process. I'm reviewing your patch for YOU. If there is no objective reason, I don't want to continue reviewing.