On 03/16/23 11:15, Mike Kravetz wrote: > On 03/15/23 14:31, Kirill A. Shutemov wrote: > > MAX_ORDER currently defined as number of orders page allocator supports: > > user can ask buddy allocator for page order between 0 and MAX_ORDER-1. > > > > This definition is counter-intuitive and lead to number of bugs all over > > the kernel. > > > > Change the definition of MAX_ORDER to be inclusive: the range of orders > > user can ask from buddy allocator is 0..MAX_ORDER now. > > > > --- a/arch/arc/Kconfig > > +++ b/arch/arc/Kconfig > > @@ -556,7 +556,7 @@ endmenu # "ARC Architecture Configuration" > > > > config ARCH_FORCE_MAX_ORDER > > int "Maximum zone order" > > - default "12" if ARC_HUGEPAGE_16M > > - default "11" > > + default "11" if ARC_HUGEPAGE_16M > > + default "10" > > Is this Kconfig file wrong (off by 1) today? It seems like it wants MAX_ORDER > to be sufficiently large to allocate 16M if ARC_HUGEPAGE_16M. So, seems like > it should be 13 today? Nevermind, PAGE_SIZE seems to be 8K by default although it appears to be configurable. Not exactly sure how the hard coded values above work if PAGE_SIZE is configurable. Too confusing for me to make an intelligent comment. Sorry for the noise. -- Mike Kravetz
