From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934886AbcHEITL (ORCPT ); Fri, 5 Aug 2016 04:19:11 -0400 Received: from LGEAMRELO11.lge.com ([156.147.23.51]:50219 "EHLO lgeamrelo11.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756024AbcHEITH (ORCPT ); Fri, 5 Aug 2016 04:19:07 -0400 X-Original-SENDERIP: 156.147.1.126 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 165.244.98.76 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 10.177.223.161 X-Original-MAILFROM: minchan@kernel.org Date: Fri, 5 Aug 2016 17:20:15 +0900 From: Minchan Kim To: PINTU KUMAR CC: , , , , Subject: Re: [linux-mm] Drastic increase in application memory usage with Kernel version upgrade Message-ID: <20160805082015.GA28235@bbox> References: <01a001d1eed5$c50726c0$4f157440$@samsung.com> MIME-Version: 1.0 In-Reply-To: <01a001d1eed5$c50726c0$4f157440$@samsung.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-MIMETrack: Itemize by SMTP Server on LGEKRMHUB07/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2016/08/05 17:19:02, Serialize by Router on LGEKRMHUB07/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2016/08/05 17:19:02, Serialize complete at 2016/08/05 17:19:02 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 05, 2016 at 10:26:37AM +0530, PINTU KUMAR wrote: > Hi All, > > For one of our ARM embedded product, we recently updated the Kernel version from > 3.4 to 3.18 and we noticed that the same application memory usage (PSS value) > gone up by ~10% and for some cases it even crossed ~50%. > There is no change in platform part. All platform component was built with ARM > 32-bit toolchain. > However, the Kernel is changed from 32-bit to 64-bit. > > Is upgrading Kernel version and moving from 32-bit to 64-bit is such a risk ? > After the upgrade, what can we do further to reduce the application memory usage > ? > Is there any other factor that will help us to improve without major > modifications in platform ? > > As a proof, we did a small experiment on our Ubuntu-32 bit machine. > We upgraded Ubuntu Kernel version from 3.13 to 4.01 and we observed the > following: > -------------------------------------------------------------------------------- > ------------- > |UBUNTU-32 bit |Kernel 3.13 |Kernel 4.03 |DIFF | > |CALCULATOR PSS |6057 KB |6466 KB |409 KB | > -------------------------------------------------------------------------------- > ------------- > So, just by upgrading the Kernel version: PSS value for calculator is increased > by 409KB. > > If anybody knows any in-sight about it please point out more details about the > root cause. One of culprit is [8c6e50b0290c, mm: introduce vm_ops->map_pages()].