From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 021696B009F for ; Mon, 2 Nov 2009 15:54:01 -0500 (EST) Received: from spaceape12.eur.corp.google.com (spaceape12.eur.corp.google.com [172.28.16.146]) by smtp-out.google.com with ESMTP id nA2Krr1Z007128 for ; Mon, 2 Nov 2009 12:53:54 -0800 Received: from pwi12 (pwi12.prod.google.com [10.241.219.12]) by spaceape12.eur.corp.google.com with ESMTP id nA2KroAs022549 for ; Mon, 2 Nov 2009 12:53:51 -0800 Received: by pwi12 with SMTP id 12so2291462pwi.5 for ; Mon, 02 Nov 2009 12:53:50 -0800 (PST) Date: Mon, 2 Nov 2009 12:53:46 -0800 (PST) From: David Rientjes 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> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org 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 List-ID: 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, 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