Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932144Ab2HFPsB (ORCPT ); Mon, 6 Aug 2012 11:48:01 -0400 Received: from rcsinet15.oracle.com ([148.87.113.117]:37530 "EHLO rcsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756409Ab2HFPr6 convert rfc822-to-8bit (ORCPT ); Mon, 6 Aug 2012 11:47:58 -0400 MIME-Version: 1.0 Message-ID: Date: Mon, 6 Aug 2012 08:46:18 -0700 (PDT) From: Dan Magenheimer To: Minchan Kim , John Stultz Cc: LKML , Andrew Morton , Android Kernel Team , Robert Love , Mel Gorman , Hugh Dickins , Dave Hansen , Rik van Riel , Dmitry Adamushko , Dave Chinner , Neil Brown , Andrea Righi , "Aneesh Kumar K.V" , Mike Hommey , Jan Kara , KOSAKI Motohiro , Michel Lespinasse , linux-mm@kvack.org Subject: RE: [PATCH 4/5] [RFC][HACK] Add LRU_VOLATILE support to the VM References: <1343447832-7182-1-git-send-email-john.stultz@linaro.org> <1343447832-7182-5-git-send-email-john.stultz@linaro.org> <20120806030451.GA11468@bbox> In-Reply-To: <20120806030451.GA11468@bbox> X-Priority: 3 X-Mailer: Oracle Beehive Extensions for Outlook 2.0.1.7 (607090) [OL 12.0.6661.5003 (x86)] Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1614 Lines: 43 > From: Minchan Kim [mailto:minchan@kernel.org] > To: John Stultz > Subject: Re: [PATCH 4/5] [RFC][HACK] Add LRU_VOLATILE support to the VM Hi Minchan -- Thanks for cc'ing me on this! > Targets for the LRU list could be following as in future > > 1. volatile pages in this patchset. > 2. ephemeral pages of tmem > 3. madivse(DONTNEED) > 4. fadvise(NOREUSE) > 5. PG_reclaimed pages > 6. clean pages if we write CFLRU(clean first LRU) > > So if any guys have objection, please raise your hands > before further progress. I agree that the existing shrinker mechanism is too primitive and the kernel needs to take into account more factors in deciding how to quickly reclaim pages from a broader set of sources. However, I think it is important to ensure that both the "demand" side and the "supply" side are studied. There has to be some kind of prioritization policy among all the RAM consumers so that a lower-priority alloc_page doesn't cause a higher-priority "volatile" page to be consumed. I suspect this policy will be VERY hard to define and maintain. Related, ephemeral pages in tmem are not truly volatile as there is always at least one tmem data structure pointing to it. I haven't followed this thread previously so my apologies if it already has this, but the LRU_VOLATILE list might need to support a per-page "garbage collection" callback. Dan -- 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/