From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423488Ab2KNVdq (ORCPT ); Wed, 14 Nov 2012 16:33:46 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:38062 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423452Ab2KNVdo (ORCPT ); Wed, 14 Nov 2012 16:33:44 -0500 Date: Wed, 14 Nov 2012 13:33:42 -0800 From: Andrew Morton To: "Kirill A. Shutemov" Cc: Andrea Arcangeli , linux-mm@kvack.org, Andi Kleen , "H. Peter Anvin" , linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: Re: [PATCH v5 00/11] Introduce huge zero page Message-Id: <20121114133342.cc7bcd6e.akpm@linux-foundation.org> In-Reply-To: <1352300463-12627-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1352300463-12627-1-git-send-email-kirill.shutemov@linux.intel.com> 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 On Wed, 7 Nov 2012 17:00:52 +0200 "Kirill A. Shutemov" wrote: > Andrew, here's updated huge zero page patchset. There is still a distinct lack of reviewed-by's and acked-by's on this patchset. On 13 Sep, Andrea did indicate that he "reviewed the whole patchset and it looks fine to me". But that information failed to make it into the changelogs, which is bad. I grabbed the patchset. I might hold it over until 3.9 depending on additional review/test feedback and upon whether Andrea can be persuaded to take another look at it all. I'm still a bit concerned over the possibility that some workloads will cause a high-frequency free/alloc/memset cycle on that huge zero page. We'll see how it goes... For this reason and for general ease-of-testing: can and should we add a knob which will enable users to disable the feature at runtime? That way if it causes problems or if we suspect it's causing problems, we can easily verify the theory and offer users a temporary fix. Such a knob could be a boot-time option, but a post-boot /proc thing would be much nicer. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx170.postini.com [74.125.245.170]) by kanga.kvack.org (Postfix) with SMTP id 355A66B00A6 for ; Wed, 14 Nov 2012 16:33:44 -0500 (EST) Date: Wed, 14 Nov 2012 13:33:42 -0800 From: Andrew Morton Subject: Re: [PATCH v5 00/11] Introduce huge zero page Message-Id: <20121114133342.cc7bcd6e.akpm@linux-foundation.org> In-Reply-To: <1352300463-12627-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1352300463-12627-1-git-send-email-kirill.shutemov@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Andrea Arcangeli , linux-mm@kvack.org, Andi Kleen , "H. Peter Anvin" , linux-kernel@vger.kernel.org, "Kirill A. Shutemov" On Wed, 7 Nov 2012 17:00:52 +0200 "Kirill A. Shutemov" wrote: > Andrew, here's updated huge zero page patchset. There is still a distinct lack of reviewed-by's and acked-by's on this patchset. On 13 Sep, Andrea did indicate that he "reviewed the whole patchset and it looks fine to me". But that information failed to make it into the changelogs, which is bad. I grabbed the patchset. I might hold it over until 3.9 depending on additional review/test feedback and upon whether Andrea can be persuaded to take another look at it all. I'm still a bit concerned over the possibility that some workloads will cause a high-frequency free/alloc/memset cycle on that huge zero page. We'll see how it goes... For this reason and for general ease-of-testing: can and should we add a knob which will enable users to disable the feature at runtime? That way if it causes problems or if we suspect it's causing problems, we can easily verify the theory and offer users a temporary fix. Such a knob could be a boot-time option, but a post-boot /proc thing would be much nicer. -- 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