Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1945992Ab3FUUIa (ORCPT ); Fri, 21 Jun 2013 16:08:30 -0400 Received: from terminus.zytor.com ([198.137.202.10]:59224 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423580Ab3FUUI3 (ORCPT ); Fri, 21 Jun 2013 16:08:29 -0400 User-Agent: K-9 Mail for Android In-Reply-To: <51C4B20B.20201@sgi.com> References: <1371831934-156971-1-git-send-email-nzimmer@sgi.com> <20130621165142.GA32125@kroah.com> <51C48745.9030304@zytor.com> <51C48ADD.207@sgi.com> <51C48D5A.4010602@zytor.com> <51C4B20B.20201@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: Re: [RFC 0/2] Delay initializing of large sections of memory From: "H. Peter Anvin" Date: Fri, 21 Jun 2013 13:08:06 -0700 To: Nathan Zimmer CC: Greg KH , holt@sgi.com, travis@sgi.com, rob@landley.net, tglx@linutronix.de, mingo@redhat.com, yinghai@kernel.org, akpm@linux-foundation.org, x86@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <4b9c45ed-15bd-49a9-b562-de01240d1649@email.android.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1783 Lines: 49 Is this init code? 32K of unconditional runtime addition isn't completely trivial. Nathan Zimmer wrote: >On 06/21/2013 12:28 PM, H. Peter Anvin wrote: >> On 06/21/2013 10:18 AM, Nathan Zimmer wrote: >>>> Since you made it a compile time option, it would be good to know >how >>>> much code it adds, but otherwise I agree with Greg here... this >really >>>> shouldn't need to be an option. It *especially* shouldn't need to >be a >>>> hand-set runtime option (which looks quite complex, to boot.) >>> The patchset as a whole is just over 400 lines so it doesn't add >alot. >>> If I were to pull the .config option it would probably remove 30 >lines. >> I'm more concerned about bytes of code. >Oh, The difference is just under 32k. >371843425 Jun 21 14:08 vmlinux.o /* DELAY_MEM_INIT is not set */ >371875600 Jun 21 14:36 vmlinux.o /* DELAY_MEM_INIT=y */ > >> >>> The command line option is too complex but some of the data I >haven't >>> found a way to get at runtime yet. >> I think that is probably key. >> >>>> I suspect the cutoff for this should be a lot lower than 8 TB even, >more >>>> like 128 GB or so. The only concern is to not set the cutoff so >low >>>> that we can end up running out of memory or with suboptimal NUMA >>>> placement just because of this. >>> Even at lower amounts of ram there is an positive impact.I it knocks >>> time off >>> boot even at as small as a 1TB of ram. >> I am not surprised. >> >> -hpa >> -- Sent from my mobile phone. Please excuse brevity and lack of formatting. -- 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/