From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 19F296B025F for ; Fri, 5 Aug 2016 11:21:27 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id h186so522612441pfg.2 for ; Fri, 05 Aug 2016 08:14:43 -0700 (PDT) Received: from mailout4.samsung.com (mailout4.samsung.com. [203.254.224.34]) by mx.google.com with ESMTPS id q11si20826185pfd.42.2016.08.05.07.48.05 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 05 Aug 2016 07:48:06 -0700 (PDT) Received: from epcas2p3.samsung.com (unknown [182.195.41.55]) by mailout4.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0OBF02KA9YG49M10@mailout4.samsung.com> for linux-mm@kvack.org; Fri, 05 Aug 2016 23:48:04 +0900 (KST) From: PINTU KUMAR In-reply-to: <20160805082015.GA28235@bbox> Subject: RE: [linux-mm] Drastic increase in application memory usage with Kernel version upgrade Date: Fri, 05 Aug 2016 20:17:36 +0530 Message-id: <01c101d1ef28$50706ad0$f1514070$@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7bit Content-language: en-us References: <01a001d1eed5$c50726c0$4f157440$@samsung.com> <20160805082015.GA28235@bbox> Sender: owner-linux-mm@kvack.org List-ID: To: 'Minchan Kim' Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, jaejoon.seo@samsung.com, jy0.jeon@samsung.com, vishnu.ps@samsung.com Hi, > -----Original Message----- > From: Minchan Kim [mailto:minchan@kernel.org] > Sent: Friday, August 05, 2016 1:50 PM > To: PINTU KUMAR > Cc: linux-kernel@vger.kernel.org; linux-mm@kvack.org; > jaejoon.seo@samsung.com; jy0.jeon@samsung.com; vishnu.ps@samsung.com > Subject: Re: [linux-mm] Drastic increase in application memory usage with Kernel > version upgrade > > 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()]. Ok. Thank you for your reply. So, if I revert this patch, will the memory usage be decreased for the processes with Kernel 3.18 ? -- 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