Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755983AbZKBQsv (ORCPT ); Mon, 2 Nov 2009 11:48:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755837AbZKBQsv (ORCPT ); Mon, 2 Nov 2009 11:48:51 -0500 Received: from smtp2.ultrahosting.com ([74.213.174.253]:50493 "EHLO smtp.ultrahosting.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755637AbZKBQsu (ORCPT ); Mon, 2 Nov 2009 11:48:50 -0500 Date: Mon, 2 Nov 2009 11:42:36 -0500 (EST) From: Christoph Lameter X-X-Sender: cl@V090114053VZO-1 To: Rik van Riel cc: Pavel Machek , David Rientjes , Andrew Morton , Mel Gorman , stable@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Frans Pop , Jiri Kosina , Sven Geggus , Karol Lewandowski , Tobias Oetiker , KOSAKI Motohiro , Pekka Enberg , Stephan von Krawczynski , kernel-testers@vger.kernel.org Subject: Re: [PATCH 2/3] page allocator: Do not allow interrupts to use ALLOC_HARDER In-Reply-To: <4AECCF6A.4020206@redhat.com> Message-ID: References: <1256650833-15516-1-git-send-email-mel@csn.ul.ie> <1256650833-15516-3-git-send-email-mel@csn.ul.ie> <20091027130924.fa903f5a.akpm@linux-foundation.org> <20091031184054.GB1475@ucw.cz> <20091031201158.GB29536@elf.ucw.cz> <4AECCF6A.4020206@redhat.com> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1060 Lines: 29 On Sat, 31 Oct 2009, Rik van Riel wrote: > On 10/31/2009 04:11 PM, Pavel Machek wrote: > > > But we can't guarantee that enough memory will be ready in the > > reserves. So if realtime task relies on it, it is broken, and will > > fail to meet its deadlines from time to time. > > Any realtime task that does networking (which may be the > majority of realtime tasks) relies on the kernel memory > allocator. What is realtime in this scenario? There are no guarantees that reclaim wont have to occur. There are no guarantees anymore and therefore you cannot really call this realtime. Is realtime anything more than: "I want to have my patches merged"? Give some criteria as to what realtime is please. I am all for decreasing kernel latencies. But some of this work is adding bloat and increasing overhead. -- 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/