From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx202.postini.com [74.125.245.202]) by kanga.kvack.org (Postfix) with SMTP id 910A16B005D for ; Wed, 15 Aug 2012 05:05:35 -0400 (EDT) Received: from relay2.suse.de (unknown [195.135.220.254]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx2.suse.de (Postfix) with ESMTP id AB653A3B06 for ; Wed, 15 Aug 2012 11:05:33 +0200 (CEST) From: Petr Tesarik Subject: Strange VM stats in /proc/zoneinfo Date: Wed, 15 Aug 2012 11:05:27 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Message-Id: <201208151105.27411.ptesarik@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Hi folks, while looking at my /proc/zoneinfo, I noticed that the counters are a bit strange: Node 0, zone DMA pages free 3945 min 7 low 8 high 10 scanned 0 spanned 4080 present 3905 nr_free_pages 3945 OK, you'll probably argue that the rest is hidden in PCP differentials... BUT: 1. this machine has only 2 CPUs 2. stat_threshold = 4 3. vm_stat_diff[NR_FREE_PAGES] = 0 on both CPUs Is this only me? Or do I misrepresent what these number actually tell? TIA, Petr Tesarik -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx190.postini.com [74.125.245.190]) by kanga.kvack.org (Postfix) with SMTP id 52A456B005D for ; Wed, 15 Aug 2012 07:37:25 -0400 (EDT) Received: from relay1.suse.de (unknown [195.135.220.254]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx2.suse.de (Postfix) with ESMTP id 7E367A3BA5 for ; Wed, 15 Aug 2012 13:37:23 +0200 (CEST) From: Petr Tesarik Subject: Re: Strange VM stats in /proc/zoneinfo Date: Wed, 15 Aug 2012 13:37:19 +0200 References: <201208151105.27411.ptesarik@suse.cz> In-Reply-To: <201208151105.27411.ptesarik@suse.cz> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201208151337.19919.ptesarik@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Dne St 15. srpna 2012 11:05:27 Petr Tesarik napsal(a): > Hi folks, > > while looking at my /proc/zoneinfo, I noticed that the counters are a bit > strange: > > Node 0, zone DMA > pages free 3945 > min 7 > low 8 > high 10 > scanned 0 > spanned 4080 > present 3905 > nr_free_pages 3945 > > OK, you'll probably argue that the rest is hidden in PCP differentials... > BUT: > > 1. this machine has only 2 CPUs > 2. stat_threshold = 4 > 3. vm_stat_diff[NR_FREE_PAGES] = 0 on both CPUs > > Is this only me? Or do I misrepresent what these number actually tell? I verified the free lists, and this part seems sane, so the "present" count must be wrong. FYI I can see this on various x86_64 kernels between 2.6.32 and 3.5.0. Petr Tesarik -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx181.postini.com [74.125.245.181]) by kanga.kvack.org (Postfix) with SMTP id 46BF86B005D for ; Wed, 15 Aug 2012 15:03:01 -0400 (EDT) Message-ID: <502BF1F2.2020406@redhat.com> Date: Wed, 15 Aug 2012 15:01:06 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: Strange VM stats in /proc/zoneinfo References: <201208151105.27411.ptesarik@suse.cz> In-Reply-To: <201208151105.27411.ptesarik@suse.cz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Petr Tesarik Cc: linux-mm@kvack.org On 08/15/2012 05:05 AM, Petr Tesarik wrote: > Hi folks, > > while looking at my /proc/zoneinfo, I noticed that the counters are a bit > strange: > > Node 0, zone DMA > pages free 3945 > min 7 > low 8 > high 10 > scanned 0 > spanned 4080 > present 3905 > nr_free_pages 3945 > > OK, you'll probably argue that the rest is hidden in PCP differentials... BUT: > > 1. this machine has only 2 CPUs > 2. stat_threshold = 4 > 3. vm_stat_diff[NR_FREE_PAGES] = 0 on both CPUs > > Is this only me? Or do I misrepresent what these number actually tell? Present should always be equal to or smaller than spanned, as well as equal to or larger than free. Something looks odd... I wonder if the statistic ends up going off at bootmem free time? -- 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