On Wed, Mar 06, 2013 at 11:40:11AM +0530, Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com>
>
> We look at both the segment base page size and actual page size and store
> the pte-lp-encodings in an array per base page size.
>
> We also update all relevant functions to take actual page size argument
> so that we can use the correct PTE LP encoding in HPTE. This should also
> get the basic Multiple Page Size per Segment (MPSS) support. This is needed
> to enable THP on ppc64.
[snip]
> --- a/arch/powerpc/include/asm/mmu-hash64.h
> +++ b/arch/powerpc/include/asm/mmu-hash64.h
> @@ -154,7 +154,7 @@ extern unsigned long htab_hash_mask;
> struct mmu_psize_def
> {
> unsigned int shift; /* number of bits */
> - unsigned int penc; /* HPTE encoding */
> + unsigned int penc[MMU_PAGE_COUNT]; /* HPTE encoding */
Since we are using -1 as an invalid flag, it would be better to change
penc[] to be an array of int (or signed int) rather than unsigned
int. That would eliminate a few (signed int) casts in your subsequent
patches.
> +static inline int hpte_actual_psize(struct hash_pte *hptep, int psize)
> +{
> + int i, shift;
> + unsigned int mask;
> + /* Look at the 8 bit LP value */
> + unsigned int lp = (hptep->r >> LP_SHIFT) & ((1 << LP_BITS) - 1);
> +
> + /* First check if it is large page */
> + if (!(hptep->v & HPTE_V_LARGE))
> + return MMU_PAGE_4K;
> +
> + /* start from 1 ignoring MMU_PAGE_4K */
> + for (i = 1; i < MMU_PAGE_COUNT; i++) {
> + /* valid entries have a shift value */
> + if (!mmu_psize_defs[i].shift)
> + continue;
> + /*
> + * encoding bits per actual page size
> + * PTE LP actual page size
> + * rrrr rrrz ≥8KB
> + * rrrr rrzz ≥16KB
> + * rrrr rzzz ≥32KB
> + * rrrr zzzz ≥64KB
> + * .......
> + */
> + shift = mmu_psize_defs[i].shift -
> + mmu_psize_defs[MMU_PAGE_4K].shift;
The memory reference for mmu_psize_defs[MMU_PAGE_4K].shift seems
unnecessary here. Just use LP_SHIFT, same as when you calculated lp.
Paul.
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
