Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757378Ab1CAXlX (ORCPT ); Tue, 1 Mar 2011 18:41:23 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:53865 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756799Ab1CAXlV (ORCPT ); Tue, 1 Mar 2011 18:41:21 -0500 Date: Tue, 1 Mar 2011 15:41:00 -0800 From: Andrew Morton To: nai.xia@gmail.com Cc: Izik Eidus , Hugh Dickins , Andrea Arcangeli , Chris Wright , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH] ksm: add vm_stat and meminfo entry to reflect pte mapping to ksm pages Message-Id: <20110301154100.212c4ff9.akpm@linux-foundation.org> In-Reply-To: <201102262256.31565.nai.xia@gmail.com> References: <201102262256.31565.nai.xia@gmail.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 Content-Length: 1671 Lines: 43 On Sat, 26 Feb 2011 22:56:31 +0800 Nai Xia wrote: > ksm_pages_sharing is updated by ksmd periodically. In some cases, it cannot > reflect the actual savings and makes the benchmarks on volatile VMAs very > inaccurate. > > This patch add a vm_stat entry and let the /proc/meminfo show information > about how much virutal address pte is being mapped to ksm pages. With default > ksm paramters (pages_to_scan==100 && sleep_millisecs==20), this can result in > 50% more accurate averaged savings result for the following test program. > Bigger sleep_millisecs values will increase this deviation. So I think you're saying that the existing ksm_pages_sharing sysfs file is no good. You added a new entry to /proc/meminfo and left ksm_pages_sharing as-is. Why not leave /proc/meminfo alone, and fix up the existing ksm_pages_sharing? Also, the patch accumulates the NR_KSM_PAGES_SHARING counts on a per-zone basis as well as on a global basis, but only provides the global count to userspace. The per-zone counts are potentially interesting? If not, maintaining the per-zone counters is wasted overhead. > > --- test.c----- > The "^---" token conventionally means "end of changelog". Please avoid inserting it into the middle of the changelog. > +++ b/mm/ksm.c > @@ -897,6 +897,7 @@ static int try_to_merge_one_page(struct vm_area_struct > *vma, Your email client wordwraps the patches. -- 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/