Hi, > -----Original Message----- > From: Minchan Kim [mailto:minchan@xxxxxxxxxx] > Sent: Friday, August 05, 2016 1:50 PM > To: PINTU KUMAR > Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; > jaejoon.seo@xxxxxxxxxxx; jy0.jeon@xxxxxxxxxxx; vishnu.ps@xxxxxxxxxxx > 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@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>