Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932454AbZKBUx4 (ORCPT ); Mon, 2 Nov 2009 15:53:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932378AbZKBUxz (ORCPT ); Mon, 2 Nov 2009 15:53:55 -0500 Received: from smtp-out.google.com ([216.239.45.13]:35689 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932193AbZKBUxy (ORCPT ); Mon, 2 Nov 2009 15:53:54 -0500 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=date:from:x-x-sender:to:cc:subject:in-reply-to:message-id: references:user-agent:mime-version:content-type:x-system-of-record; b=S4ofM/E+dpcUUKcfOUIO/yqfwNX2avlJZ+X8VdDPZFj3sHLrheNg5nNu+gTz31xX0 12jrpcka3Pmmybk4cYDlg== Date: Mon, 2 Nov 2009 12:53:46 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Christoph Lameter cc: Rik van Riel , Pavel Machek , 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: 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 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1141 Lines: 28 On Mon, 2 Nov 2009, Christoph Lameter wrote: > 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. > Realtime in this scenario is anything with a priority of MAX_RT_PRIO or lower. > Is realtime anything more than: "I want to have my patches merged"? > These allocations are not using ~__GFP_WAIT for a reason, they can block on direct reclaim. But we're convoluting this issue _way_ more than it needs to be. We have used ALLOC_HARDER for these tasks as a convenience for over four years. The fix here is to address an omittion in the page allocator refactoring code that went into 2.6.31 that dropped the check for !in_interrupt(). If you'd like to raise the concern about the rt exemption being given ALLOC_HARDER, then it is seperate from this fix. -- 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/