On Tue, Jul 10, 2018 at 03:25:14PM +0200, Arnd Bergmann wrote: > On Tue, Jul 10, 2018 at 3:06 PM, Will Deacon <will.dea...@arm.com> wrote: > > On Tue, Jul 10, 2018 at 02:55:41PM +0200, Arnd Bergmann wrote: > >> On Fri, Jul 6, 2018 at 7:47 PM, Nikunj Kela <nk...@cisco.com> wrote: > >> > Flatmem is useful in reducing kernel memory usage. > >> > One usecase is in kdump kernel. We are able to save > >> > ~14M by moving to flatmem scheme. > >> > > >> > Cc: xe-ker...@external.cisco.com > >> > Cc: Nikunj Kela <nk...@cisco.com> > >> > Signed-off-by: Nikunj Kela <nk...@cisco.com> > >> > --- > >> > arch/arm64/Kconfig | 3 +++ > >> > 1 file changed, 3 insertions(+) > >> > > >> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > >> > index 42c090c..f5b4c49 100644 > >> > --- a/arch/arm64/Kconfig > >> > +++ b/arch/arm64/Kconfig > >> > @@ -775,6 +775,9 @@ config ARCH_SPARSEMEM_DEFAULT > >> > config ARCH_SELECT_MEMORY_MODEL > >> > def_bool ARCH_SPARSEMEM_ENABLE > >> > > >> > +config ARCH_FLATMEM_ENABLE > >> > + def_bool y > >> > + > >> > config HAVE_ARCH_PFN_VALID > >> > def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM > >> > > >> > >> I'm getting hundreds of errors in randconfig builds with this: > > > > Damn, I was worried something like this might happen. Sorry! > > > > Does randconfig also fuzz CONFIG_EXPERT? We only added ARCH_FLATMEM_ENABLE > > so that people can hand-configure crashkernels to make them small; there > > will > > be plenty of situations where it's just going to cause more problems than it > > solves, so I'd be happy hiding it behind EXPERT if it helps. > > Yes, randconfig also tests EXPERT and COMPILE_TEST configurations, though I > don't test the !COMPILE_TEST ones myself, so you can also hide options from > me by making them 'depends on !COMPILE_TEST'. > > > Otherwise we can probably through a 'def_bool !NUMA' at it. > > Yes, I was going to send a patch with that next after testing it some more. > So far it's holding up. This is also what some other architectures have, so > it's probably safe.
Ok, let's go with that then. If I don't see a patch from you in a day or two, I'll write one myself :) Will
