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. Considering we are just converting max range there, do we need that as a macro ? -aneesh
