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()]. -- 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>