On 01/27/2016 01:41 PM, Vlastimil Babka wrote: > On 01/27/2016 01:59 AM, Joonsoo Kim wrote: >> On Tue, Jan 26, 2016 at 04:36:11PM -0800, David Rientjes wrote: >>> >>> If we can convert existing users that only check for >>> CONFIG_DEBUG_PAGEALLOC to rather check for debug_pagealloc_enabled() and >>> agree that it is only enabled for debug_pagealloc=on, then this would seem >>> fine. However, I think we should at least consult with those users before >>> removing an artifact from the kernel log that could be useful in debugging >>> why a particular BUG() happened. >> >> Yes, at least, non-architecture dependent code (vmalloc, SLAB, SLUB) should >> be changed first. If Christian doesn't mind, I will try to fix above 3 >> things. > > I think it might be worth also to convert debug_pagealloc_enabled() to be based > on static key, like I did for page_owner [1]. That should help make it possible > to have virtually no overhead when compiling kernel with CONFIG_DEBUG_PAGEALLOC > without enabling it boot-time. I assume it's one of the goals here? We could do something like that but dump_stack and setup of the initial identity mapping of the kernel as well as the initial page protection are not hot path as far as I can tell. Any other places? > > [1] http://www.spinics.net/lists/linux-mm/msg100795.html -- 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>