From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f197.google.com (mail-qt0-f197.google.com [209.85.216.197]) by kanga.kvack.org (Postfix) with ESMTP id E1D6D83292 for ; Tue, 23 May 2017 06:40:50 -0400 (EDT) Received: by mail-qt0-f197.google.com with SMTP id k11so58155139qtk.4 for ; Tue, 23 May 2017 03:40:50 -0700 (PDT) Received: from mail-qk0-x244.google.com (mail-qk0-x244.google.com. [2607:f8b0:400d:c09::244]) by mx.google.com with ESMTPS id h12si21220613qte.190.2017.05.23.03.40.49 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 23 May 2017 03:40:50 -0700 (PDT) Received: by mail-qk0-x244.google.com with SMTP id k74so22339004qke.2 for ; Tue, 23 May 2017 03:40:49 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20170523040524.13717-4-oohall@gmail.com> References: <20170523040524.13717-1-oohall@gmail.com> <20170523040524.13717-4-oohall@gmail.com> From: Balbir Singh Date: Tue, 23 May 2017 20:40:48 +1000 Message-ID: Subject: Re: [PATCH 4/6] powerpc/mm: Add devmap support for ppc64 Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Oliver O'Halloran Cc: "open list:LINUX FOR POWERPC (32-BIT AND 64-BIT)" , linux-mm , "Aneesh Kumar K . V" On Tue, May 23, 2017 at 2:05 PM, Oliver O'Halloran wrote: > Add support for the devmap bit on PTEs and PMDs for PPC64 Book3S. This > is used to differentiate device backed memory from transparent huge > pages since they are handled in more or less the same manner by the core > mm code. > > Cc: Aneesh Kumar K.V > Signed-off-by: Oliver O'Halloran > --- > v1 -> v2: Properly differentiate THP and PMD Devmap entries. The > mm core assumes that pmd_trans_huge() and pmd_devmap() are mutually > exclusive and v1 had pmd_trans_huge() being true on a devmap pmd. > > Aneesh, this has been fleshed out substantially since v1. Can you > re-review it? Also no explicit gup support is required in this patch > since devmap support was added generic GUP as a part of making x86 use > the generic version. > --- > arch/powerpc/include/asm/book3s/64/hash-64k.h | 2 +- > arch/powerpc/include/asm/book3s/64/pgtable.h | 37 ++++++++++++++++++++++++++- > arch/powerpc/include/asm/book3s/64/radix.h | 2 +- > arch/powerpc/mm/hugetlbpage.c | 2 +- > arch/powerpc/mm/pgtable-book3s64.c | 4 +-- > arch/powerpc/mm/pgtable-hash64.c | 4 ++- > arch/powerpc/mm/pgtable-radix.c | 3 ++- > arch/powerpc/mm/pgtable_64.c | 2 +- > 8 files changed, 47 insertions(+), 9 deletions(-) > > diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h > index 9732837aaae8..eaaf613c5347 100644 > --- a/arch/powerpc/include/asm/book3s/64/hash-64k.h > +++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h > @@ -180,7 +180,7 @@ static inline void mark_hpte_slot_valid(unsigned char *hpte_slot_array, > */ > static inline int hash__pmd_trans_huge(pmd_t pmd) > { > - return !!((pmd_val(pmd) & (_PAGE_PTE | H_PAGE_THP_HUGE)) == > + return !!((pmd_val(pmd) & (_PAGE_PTE | H_PAGE_THP_HUGE | _PAGE_DEVMAP)) == > (_PAGE_PTE | H_PAGE_THP_HUGE)); > } Like Aneesh suggested, I think we can probably skip this check here > > diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h > index 85bc9875c3be..24634e92dd0b 100644 > --- a/arch/powerpc/include/asm/book3s/64/pgtable.h > +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h > @@ -79,6 +79,9 @@ > > #define _PAGE_SOFT_DIRTY _RPAGE_SW3 /* software: software dirty tracking */ > #define _PAGE_SPECIAL _RPAGE_SW2 /* software: special page */ > +#define _PAGE_DEVMAP _RPAGE_SW1 > +#define __HAVE_ARCH_PTE_DEVMAP > + > /* > * Drivers request for cache inhibited pte mapping using _PAGE_NO_CACHE > * Instead of fixing all of them, add an alternate define which > @@ -599,6 +602,16 @@ static inline pte_t pte_mkhuge(pte_t pte) > return pte; > } > > +static inline pte_t pte_mkdevmap(pte_t pte) > +{ > + return __pte(pte_val(pte) | _PAGE_SPECIAL|_PAGE_DEVMAP); > +} > + > +static inline int pte_devmap(pte_t pte) > +{ > + return !!(pte_raw(pte) & cpu_to_be64(_PAGE_DEVMAP)); > +} > + > static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) > { > /* FIXME!! check whether this need to be a conditional */ > @@ -963,6 +976,9 @@ static inline pte_t *pmdp_ptep(pmd_t *pmd) > #define pmd_mk_savedwrite(pmd) pte_pmd(pte_mk_savedwrite(pmd_pte(pmd))) > #define pmd_clear_savedwrite(pmd) pte_pmd(pte_clear_savedwrite(pmd_pte(pmd))) > > +#define pud_pfn(...) (0) > +#define pgd_pfn(...) (0) > + Don't get these bits.. why are they zero? > #ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY > #define pmd_soft_dirty(pmd) pte_soft_dirty(pmd_pte(pmd)) > #define pmd_mksoft_dirty(pmd) pte_pmd(pte_mksoft_dirty(pmd_pte(pmd))) > @@ -1137,7 +1153,6 @@ static inline int pmd_move_must_withdraw(struct spinlock *new_pmd_ptl, > return true; > } > > - > #define arch_needs_pgtable_deposit arch_needs_pgtable_deposit > static inline bool arch_needs_pgtable_deposit(void) > { > @@ -1146,6 +1161,26 @@ static inline bool arch_needs_pgtable_deposit(void) > return true; > } > > +static inline pmd_t pmd_mkdevmap(pmd_t pmd) > +{ > + return pte_pmd(pte_mkdevmap(pmd_pte(pmd))); > +} > + > +static inline int pmd_devmap(pmd_t pmd) > +{ > + return pte_devmap(pmd_pte(pmd)); > +} This should be defined only if #ifdef __HAVE_ARCH_PTE_DEVMAP The rest looks OK Balbir Singh. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org