From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754557AbaIZI5i (ORCPT ); Fri, 26 Sep 2014 04:57:38 -0400 Received: from bay004-omc2s26.hotmail.com ([65.54.190.101]:58523 "EHLO BAY004-OMC2S26.hotmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752170AbaIZI5e convert rfc822-to-8bit (ORCPT ); Fri, 26 Sep 2014 04:57:34 -0400 X-Greylist: delayed 306 seconds by postgrey-1.27 at vger.kernel.org; Fri, 26 Sep 2014 04:57:34 EDT X-TMN: [9eSrM1AnY5MnjnnEE8wGjo6Fhm4xdqm9Vxsm8kidpSI=] X-Originating-Email: [pintu.k@outlook.com] Message-ID: From: Pintu Kumar To: "mgorman@suse.de" , "linaro-mm-sig@lists.linaro.org" , "linux-arm-kernel@lists.infradead.org" , "linux-mm@kvack.org" , PINTU KUMAR , "pintu.k@samsung.com" , "linux-kernel@vger.kernel.org" Subject: Changing PAGE_ALLOC_COSTLY_ORDER from 3 to 2 Date: Fri, 26 Sep 2014 14:22:27 +0530 Importance: Normal Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-OriginalArrivalTime: 26 Sep 2014 08:52:28.0276 (UTC) FILETIME=[334FCB40:01CFD967] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I wanted to know about the impact of changing PAGE_ALLOC_COSTLY_ORDER value from 3 to 2. This macro is defined in include/linux/mmzone.h #define PAGE_ALLOC_COSTLY_ORDER   3 As I know this value should never be changed irrespective of the type of the system. Is it good to change this value for RAM size: 512MB, 256MB or 128MB? If anybody have changed this value and experience any kind of problem or benefits please let us know. We noticed that for one of the Android product with 512MB RAM, the PAGE_ALLOC_COSTLY_ORDER was set to 2. We could not figure out why this value was decreased from 3 to 2. As per my analysis, I observed that kmalloc fails little early, if we change this value to 2. This is also visible from the _slowpath_ in page_alloc.c Apart from this we could not find any other impact. If anybody is aware of any other impact, please let us know. Thank you! Regards, Pintu Kumar From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f180.google.com (mail-pd0-f180.google.com [209.85.192.180]) by kanga.kvack.org (Postfix) with ESMTP id 8651B6B0038 for ; Fri, 26 Sep 2014 04:52:29 -0400 (EDT) Received: by mail-pd0-f180.google.com with SMTP id r10so12587204pdi.39 for ; Fri, 26 Sep 2014 01:52:29 -0700 (PDT) Received: from BAY004-OMC2S26.hotmail.com (bay004-omc2s26.hotmail.com. [65.54.190.101]) by mx.google.com with ESMTPS id kn10si1977067pbd.49.2014.09.26.01.52.28 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 26 Sep 2014 01:52:28 -0700 (PDT) Message-ID: From: Pintu Kumar Subject: Changing PAGE_ALLOC_COSTLY_ORDER from 3 to 2 Date: Fri, 26 Sep 2014 14:22:27 +0530 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: "mgorman@suse.de" , "linaro-mm-sig@lists.linaro.org" , "linux-arm-kernel@lists.infradead.org" , "linux-mm@kvack.org" , PINTU KUMAR , "pintu.k@samsung.com" , "linux-kernel@vger.kernel.org" Hi=2C=0A= =0A= I wanted to know about the impact of changing PAGE_ALLOC_COSTLY_ORDER value= from 3 to 2.=0A= This macro is defined in include/linux/mmzone.h=0A= #define PAGE_ALLOC_COSTLY_ORDER=A0=A0 3=0A= =0A= As I know this value should never be changed irrespective of the type of th= e system.=0A= Is it good to change this value for RAM size: 512MB=2C 256MB or 128MB?=0A= If anybody have changed this value and experience any kind of problem or be= nefits please let us know.=0A= =0A= We noticed that for one of the Android product with 512MB RAM=2C the PAGE_A= LLOC_COSTLY_ORDER was set to 2.=0A= We could not figure out why this value was decreased from 3 to 2.=0A= =0A= As per my analysis=2C I observed that kmalloc fails little early=2C if we c= hange this value to 2.=0A= This is also visible from the _slowpath_ in page_alloc.c=0A= =0A= Apart from this we could not find any other impact.=0A= If anybody is aware of any other impact=2C please let us know.=0A= =0A= =0A= =0A= Thank you!=0A= Regards=2C=0A= Pintu Kumar=0A= =0A= = -- 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 From: pintu.k@outlook.com (Pintu Kumar) Date: Fri, 26 Sep 2014 14:22:27 +0530 Subject: Changing PAGE_ALLOC_COSTLY_ORDER from 3 to 2 Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, I wanted to know about the impact of changing PAGE_ALLOC_COSTLY_ORDER value from 3 to 2. This macro is defined in include/linux/mmzone.h #define PAGE_ALLOC_COSTLY_ORDER?? 3 As I know this value should never be changed irrespective of the type of the system. Is it good to change this value for RAM size: 512MB, 256MB or 128MB? If anybody have changed this value and experience any kind of problem or benefits please let us know. We noticed that for one of the Android product with 512MB RAM, the PAGE_ALLOC_COSTLY_ORDER was set to 2. We could not figure out why this value was decreased from 3 to 2. As per my analysis, I observed that kmalloc fails little early, if we change this value to 2. This is also visible from the _slowpath_ in page_alloc.c Apart from this we could not find any other impact. If anybody is aware of any other impact, please let us know. Thank you! Regards, Pintu Kumar