On Mon, 2020-02-03 at 16:14 +0100, Christophe Leroy wrote: > > Le 02/02/2020 à 12:26, Qian Cai a écrit : > > > > > > > On Jan 30, 2020, at 9:13 AM, Christophe Leroy <christophe.leroy@xxxxxx> wrote: > > > > > > config DEBUG_VM_PGTABLE > > > bool "Debug arch page table for semantics compliance" if ARCH_HAS_DEBUG_VM_PGTABLE || EXPERT > > > depends on MMU > > > default 'n' if !ARCH_HAS_DEBUG_VM_PGTABLE > > > default 'y' if DEBUG_VM > > > > Does it really necessary to potentially force all bots to run this? Syzbot, kernel test robot etc? Does it ever pay off for all their machine times there? > > > > Machine time ? > > On a 32 bits powerpc running at 132 MHz, the tests takes less than 10ms. > Is it worth taking the risk of not detecting faults by not selecting it > by default ? The risk is quite low as Catalin mentioned this thing is not to detect regressions but rather for arch/mm maintainers. I do appreciate the efforts to get everyone as possible to run this thing, so it get more notices once it is broken. However, DEBUG_VM seems like such a generic Kconfig those days that have even been enabled by default for Fedora Linux, so I would rather see a more sensitive default been taken even though the test runtime is fairly quickly on a small machine for now. > > [ 5.656916] debug_vm_pgtable: debug_vm_pgtable: Validating > architecture page table helpers > [ 5.665661] debug_vm_pgtable: debug_vm_pgtable: Validated > architecture page table helpers
