From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id 1D2856B006A for ; Mon, 18 Jan 2010 10:39:32 -0500 (EST) Date: Mon, 18 Jan 2010 15:41:49 +0000 From: Alan Cox Subject: Re: [PATCH v6] add MAP_UNLOCKED mmap flag Message-ID: <20100118154149.38fa61d4@lxorguk.ukuu.org.uk> In-Reply-To: <1263828247.4283.612.camel@laptop> References: <20100118133755.GG30698@redhat.com> <84144f021001180609r4d7fbbd0p972d5bc0e227d09a@mail.gmail.com> <20100118141938.GI30698@redhat.com> <20100118143232.0a0c4b4d@lxorguk.ukuu.org.uk> <1263826198.4283.600.camel@laptop> <20100118150159.GB14345@redhat.com> <1263827194.4283.609.camel@laptop> <4B547A31.4090106@redhat.com> <1263827683.4283.610.camel@laptop> <4B547C09.8010906@redhat.com> <1263828247.4283.612.camel@laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Peter Zijlstra Cc: Avi Kivity , Gleb Natapov , Pekka Enberg , linux-mm@kvack.org, kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, akpm@linux-foundation.org, andrew.c.morrow@gmail.com, "Paul E. McKenney" List-ID: On Mon, 18 Jan 2010 16:24:07 +0100 Peter Zijlstra wrote: > On Mon, 2010-01-18 at 17:19 +0200, Avi Kivity wrote: > > > I would not advice that, just mlock() the text and data you need for the > > > real-time thread. mlockall() is a really blunt instrument. > > > > > > > May not be feasible due to libraries. > > Esp for the real-time case I could advise not to use those libraries > then, since they're clearly not designed for that use case. In "hard" real time cases an awful lot of libraries have things like memory allocations in them and don't care about stack growth which can cause faults and sleeps. The memory allocator if you are running threaded was not real time priority aware either last time I checked so the standard libraries are not going to give the behaviour you want unless you have a proper RT environment, and even then it may be a bit iffy here and there. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org