Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161221Ab2JXVNH (ORCPT ); Wed, 24 Oct 2012 17:13:07 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:41935 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161186Ab2JXVNE (ORCPT ); Wed, 24 Oct 2012 17:13:04 -0400 Date: Wed, 24 Oct 2012 14:13:03 -0700 From: Andrew Morton To: Borislav Petkov Cc: Dave Hansen , Michal Hocko , linux-mm@kvack.org, KAMEZAWA Hiroyuki , KOSAKI Motohiro , LKML , "Rafael J. Wysocki" Subject: Re: [PATCH] add some drop_caches documentation and info messsge Message-Id: <20121024141303.0797d6a1.akpm@linux-foundation.org> In-Reply-To: <20121024210600.GA17037@liondog.tnic> References: <20121012125708.GJ10110@dhcp22.suse.cz> <20121023164546.747e90f6.akpm@linux-foundation.org> <20121024062938.GA6119@dhcp22.suse.cz> <20121024125439.c17a510e.akpm@linux-foundation.org> <50884F63.8030606@linux.vnet.ibm.com> <20121024134836.a28d223a.akpm@linux-foundation.org> <20121024210600.GA17037@liondog.tnic> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1245 Lines: 29 On Wed, 24 Oct 2012 23:06:00 +0200 Borislav Petkov wrote: > On Wed, Oct 24, 2012 at 01:48:36PM -0700, Andrew Morton wrote: > > Well who knows. Could be that people's vm *does* suck. Or they have > > some particularly peculiar worklosd or requirement[*]. Or their VM > > *used* to suck, and the drop_caches is not really needed any more but > > it's there in vendor-provided code and they can't practically prevent > > it. > > I have drop_caches in my suspend-to-disk script so that the hibernation > image is kept at minimum and suspend times are as small as possible. hm, that sounds smart. > Would that be a valid use-case? I'd say so, unless we change the kernel to do that internally. We do have the hibernation-specific shrink_all_memory() in the vmscan code. We didn't see fit to document _why_ that exists, but IIRC it's there to create enough free memory for hibernation to be able to successfully complete, but no more. Who owns hibernaton nowadays? Rafael, I guess? -- 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/