Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757650Ab1F2UM0 (ORCPT ); Wed, 29 Jun 2011 16:12:26 -0400 Received: from mga09.intel.com ([134.134.136.24]:1979 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754734Ab1F2UMZ (ORCPT ); Wed, 29 Jun 2011 16:12:25 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.65,445,1304319600"; d="scan'208";a="19829011" From: Andi Kleen To: Dave Hansen Cc: Ankita Garg , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org, svaidy@linux.vnet.ibm.com, thomas.abraham@linaro.org, "Paul E. McKenney" , KAMEZAWA Hiroyuki , Matthew Garrett , Arjan van de Ven Subject: Re: [PATCH 00/10] mm: Linux VM Infrastructure to support Memory Power Management References: <1306499498-14263-1-git-send-email-ankita@in.ibm.com> <20110629130038.GA7909@in.ibm.com> <1309367184.11430.594.camel@nimitz> <20110629174220.GA9152@in.ibm.com> <1309370342.11430.604.camel@nimitz> Date: Wed, 29 Jun 2011 13:11:00 -0700 In-Reply-To: <1309370342.11430.604.camel@nimitz> (Dave Hansen's message of "Wed, 29 Jun 2011 10:59:02 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) 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: 864 Lines: 25 Dave Hansen writes: > > It's also going to be a pain to track kernel references. On x86, our Even if you tracked them what would you do with them? It's quite hard to stop using arbitary kernel memory (see all the dancing memory-failure does) You need to track the direct accesses to user data which happens to be accessed through the direct mapping. Also it will be always unreliable because this all won't track DMA. For that you would also need to track in the dma_* infrastructure, which will likely get seriously expensive. -Andi -- ak@linux.intel.com -- Speaking for myself only -- 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/