"Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com> writes:
> Michal Suchánek <msucha...@suse.de> writes: > >> Hello, >> >> On Sun, 19 Feb 2017 15:37:15 +0530 >> "Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com> wrote: >> >>> We update the hash linux page table layout such that we can support >>> 512TB. But we limit the TASK_SIZE to 128TB. We can switch to 128TB by >>> default without conditional because that is the max virtual address >>> supported by other architectures. We will later add a mechanism to >>> on-demand increase the application's effective address range to 512TB. >>> >>> Having the page table layout changed to accommodate 512TB makes >>> testing large memory configuration easier with less code changes to >>> kernel >>> >>> Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com> > > .... > >> index b64daf124fee..c7ca70dc3ba5 100644 >>> --- a/arch/powerpc/kernel/paca.c >>> +++ b/arch/powerpc/kernel/paca.c >>> @@ -253,8 +253,15 @@ void copy_mm_to_paca(struct mm_struct *mm) >>> get_paca()->mm_ctx_id = context->id; >>> #ifdef CONFIG_PPC_MM_SLICES >>> get_paca()->mm_ctx_low_slices_psize = >>> context->low_slices_psize; >>> + /* >>> + * We support upto 128TB for now. Hence copy only 128/2 >>> bytes. >>> + * Later when we support tasks with different max effective >>> + * address, we can optimize this based on mm->task_size. >>> + */ >>> + BUILD_BUG_ON(TASK_SIZE_USER64 != TASK_SIZE_128TB); >> >> Can this be handled by KConfig? >> Above I see > > I am reworking the series so that we depend on mm->task_size. Will send > a new version soon. > > > >>> +#ifdef CONFIG_PPC_BOOK3S_64 >>> +#define TASK_SIZE_USER64 TASK_SIZE_128TB >>> +#else >>> +#define TASK_SIZE_USER64 TASK_SIZE_64TB >>> +#endif >> and >>> #ifdef CONFIG_PPC_MM_SLICES >>> ILD_BUG_ON(TASK_SIZE_USER64 != TASK_SIZE_128TB) >> >> which boils down to >> #ifndef CONFIG_PPC_BOOK3S_64 >> #ifdef CONFIG_PPC_MM_SLICES >> #error TASK_SIZE_USER64 != TASK_SIZE_128TB >> >> >>> memcpy(&get_paca()->mm_ctx_high_slices_psize, >>> - &context->high_slices_psize, SLICE_ARRAY_SIZE); >>> + &context->high_slices_psize, TASK_SIZE_128TB >> 41); >> >> Can we avoid magic numbers, please? >> > > Since array is 4 bytes per each TB which is documented else where. 4 bits per teach TB. -aneesh