From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751798AbdFUUOg (ORCPT ); Wed, 21 Jun 2017 16:14:36 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:45360 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751143AbdFUUOf (ORCPT ); Wed, 21 Jun 2017 16:14:35 -0400 Date: Wed, 21 Jun 2017 13:14:25 -0700 From: Ram Pai To: "Aneesh Kumar K.V" Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, khandual@linux.vnet.ibm.com, bsingharora@gmail.com, dave.hansen@intel.com, hbabu@us.ibm.com Subject: Re: [RFC v2 02/12] powerpc: Free up four 64K PTE bits in 64K backed hpte pages. Reply-To: Ram Pai References: <1497671564-20030-1-git-send-email-linuxram@us.ibm.com> <1497671564-20030-3-git-send-email-linuxram@us.ibm.com> <87wp85al05.fsf@skywalker.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87wp85al05.fsf@skywalker.in.ibm.com> User-Agent: Mutt/1.5.20 (2009-12-10) X-TM-AS-GCONF: 00 x-cbid: 17062120-2213-0000-0000-000001E42BA0 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007267; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000214; SDB=6.00877952; UDB=6.00437410; IPR=6.00658092; BA=6.00005434; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00015912; XFM=3.00000015; UTC=2017-06-21 20:14:31 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17062120-2214-0000-0000-00005697ECC7 Message-Id: <20170621201425.GM5845@ram.oc3035372033.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-06-21_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1706210338 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 21, 2017 at 12:24:34PM +0530, Aneesh Kumar K.V wrote: > Ram Pai 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