On Tue, Sep 26, 2017 at 03:21:29PM +0200, Michal Hocko wrote: > On Thu 21-09-17 09:33:10, Huang, Ying wrote: > > From: Huang Ying <ying.huang@xxxxxxxxx> > > > > This patch adds a new Kconfig option VMA_SWAP_READAHEAD and wraps VMA > > based swap readahead code inside #ifdef CONFIG_VMA_SWAP_READAHEAD/#endif. > > This is more friendly for tiny kernels. > > How (much)? > > > And as pointed to by Minchan > > Kim, give people who want to disable the swap readahead an opportunity > > to notice the changes to the swap readahead algorithm and the > > corresponding knobs. > > Why would anyone want that? > > Please note that adding new config options make the already complicated > config space even more problematic so there should be a good reason to > add one. Please make sure your justification is clear on why this is > worth the future maintenance and configurability burden. The problem is users have disabled swap readahead by echo 0 > /proc/sys/ vm/page-cluster are regressed by this new interface /sys/kernel/mm/swap/ vma_ra_max_order. Because for disabling readahead completely, they should disable vma_ra_max_order as well as page-cluster from now on. So, goal of new config to notice new feature to admins so they can be aware of new konb vma_ra_max_order as well as page-cluster. I canont think other better idea to preventing such regression. http://lkml.kernel.org/r/%3C20170913014019.GB29422@bbox%3E -- 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>
