From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f197.google.com (mail-qk0-f197.google.com [209.85.220.197]) by kanga.kvack.org (Postfix) with ESMTP id 0354B6B02B4 for ; Tue, 23 May 2017 22:17:58 -0400 (EDT) Received: by mail-qk0-f197.google.com with SMTP id i81so68993063qke.6 for ; Tue, 23 May 2017 19:17:57 -0700 (PDT) Received: from mail-qt0-x242.google.com (mail-qt0-x242.google.com. [2607:f8b0:400d:c0d::242]) by mx.google.com with ESMTPS id b52si23610334qta.156.2017.05.23.19.17.56 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 23 May 2017 19:17:56 -0700 (PDT) Received: by mail-qt0-x242.google.com with SMTP id a46so24670729qte.0 for ; Tue, 23 May 2017 19:17:56 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20170523040524.13717-1-oohall@gmail.com> <20170523040524.13717-4-oohall@gmail.com> From: "Oliver O'Halloran" Date: Wed, 24 May 2017 12:17:55 +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: Balbir Singh Cc: "open list:LINUX FOR POWERPC (32-BIT AND 64-BIT)" , linux-mm , "Aneesh Kumar K . V" On Tue, May 23, 2017 at 8:40 PM, Balbir Singh wrote: > 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? I think that was just hacking stuff until it worked. pud_pfn() needs to exist for the kernel to build when __HAVE_ARCH_PTE_DEVMAP is set, but we don't need it to do anything (yet) since pud_pfn() is only used for handing devmap PUD faults. We currently support those so we will never hit that code path. pgd_pfn() can die though. >> #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 ok > > 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