Messages in this thread | | | Date | Thu, 28 Sep 2017 10:10:34 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCHv7 02/19] mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS |
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* Kirill A. Shutemov <kirill.shutemov@linux.intel.com> wrote:
> With boot-time switching between paging mode we will have variable > MAX_PHYSMEM_BITS. > > Let's use the maximum variable possible for CONFIG_X86_5LEVEL=y > configuration to define zsmalloc data structures. > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > Cc: Minchan Kim <minchan@kernel.org> > Cc: Nitin Gupta <ngupta@vflare.org> > Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> > --- > mm/zsmalloc.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index 7c38e850a8fc..fe22661f2fe5 100644 > --- a/mm/zsmalloc.c > +++ b/mm/zsmalloc.c > @@ -93,7 +93,13 @@ > #define MAX_PHYSMEM_BITS BITS_PER_LONG > #endif > #endif > + > +#ifdef CONFIG_X86_5LEVEL > +/* MAX_PHYSMEM_BITS is variable, use maximum value here */ > +#define _PFN_BITS (52 - PAGE_SHIFT) > +#else > #define _PFN_BITS (MAX_PHYSMEM_BITS - PAGE_SHIFT) > +#endif
This is a totally ugly hack, polluting generic MM code with an x86-ism and an arbitrary hard-coded constant that would silently lose validity when x86 paging gets extended again ...
Thanks,
Ingo
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