On Wed, Jun 21, 2017 at 12:24:34PM +0530, Aneesh Kumar K.V wrote: > Ram Pai <linux...@us.ibm.com> writes: > > .... > > > diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c > > b/arch/powerpc/mm/hugetlbpage-hash64.c > > index a84bb44..239ca86 100644 > > --- a/arch/powerpc/mm/hugetlbpage-hash64.c > > +++ b/arch/powerpc/mm/hugetlbpage-hash64.c > > @@ -22,6 +22,7 @@ int __hash_page_huge(unsigned long ea, unsigned long > > access, unsigned long vsid, > > pte_t *ptep, unsigned long trap, unsigned long flags, > > int ssize, unsigned int shift, unsigned int mmu_psize) > > { > > + real_pte_t rpte; > > unsigned long vpn; > > unsigned long old_pte, new_pte; > > unsigned long rflags, pa, sz; > > @@ -61,6 +62,7 @@ int __hash_page_huge(unsigned long ea, unsigned long > > access, unsigned long vsid, > > } while(!pte_xchg(ptep, __pte(old_pte), __pte(new_pte))); > > > > rflags = htab_convert_pte_flags(new_pte); > > + rpte = __real_pte(__pte(old_pte), ptep); > > > > sz = ((1UL) << shift); > > if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) > > @@ -71,15 +73,10 @@ int __hash_page_huge(unsigned long ea, unsigned long > > access, unsigned long vsid, > > /* Check if pte already has an hpte (case 2) */ > > if (unlikely(old_pte & H_PAGE_HASHPTE)) { > > /* There MIGHT be an HPTE for this pte */ > > - unsigned long hash, slot; > > + unsigned long gslot; > > > > - hash = hpt_hash(vpn, shift, ssize); > > - if (old_pte & H_PAGE_F_SECOND) > > - hash = ~hash; > > - slot = (hash & htab_hash_mask) * HPTES_PER_GROUP; > > - slot += (old_pte & H_PAGE_F_GIX) >> H_PAGE_F_GIX_SHIFT; > > - > > - if (mmu_hash_ops.hpte_updatepp(slot, rflags, vpn, mmu_psize, > > + gslot = get_hidx_gslot(vpn, shift, ssize, rpte, 0); > > + if (mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn, mmu_psize, > > mmu_psize, ssize, flags) == -1) > > old_pte &= ~_PAGE_HPTEFLAGS; > > } > > @@ -106,8 +103,7 @@ int __hash_page_huge(unsigned long ea, unsigned long > > access, unsigned long vsid, > > return -1; > > } > > > > - new_pte |= (slot << H_PAGE_F_GIX_SHIFT) & > > - (H_PAGE_F_SECOND | H_PAGE_F_GIX); > > + new_pte |= set_hidx_slot(ptep, rpte, 0, slot); > > We don't really need rpte here. We are just need to track one entry > here. May be it becomes simpler if use different helpers for 4k hpte and > others ?
actually we need rpte here. the hidx for these 64K-hpte backed PTEs are now stored in the second half of the pte. I have abstracted the helpers, so that the caller need not know the location of the hidx. It comes in really handy. RP