From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp07.in.ibm.com (e28smtp07.in.ibm.com [122.248.162.7]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 5196C1A0024 for ; Tue, 5 May 2015 03:29:33 +1000 (AEST) Received: from /spool/local by e28smtp07.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 4 May 2015 22:59:30 +0530 Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id 3CEDEE0056 for ; Mon, 4 May 2015 23:02:19 +0530 (IST) Received: from d28av01.in.ibm.com (d28av01.in.ibm.com [9.184.220.63]) by d28relay01.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t44HTRH862586972 for ; Mon, 4 May 2015 22:59:27 +0530 Received: from d28av01.in.ibm.com (localhost [127.0.0.1]) by d28av01.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t44HTQAL022252 for ; Mon, 4 May 2015 22:59:26 +0530 From: "Aneesh Kumar K.V" To: akpm@linux-foundation.org, mpe@ellerman.id.au, paulus@samba.org, benh@kernel.crashing.org, kirill.shutemov@linux.intel.com, aarcange@redhat.com Subject: [RFC PATCH] mm/thp: Use new function to clear pmd before THP splitting Date: Mon, 4 May 2015 22:59:16 +0530 Message-Id: <1430760556-28137-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, "Aneesh Kumar K.V" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Archs like ppc64 require pte_t * to remain stable in some code path. They use local_irq_disable to prevent a parallel split. Generic code clear pmd instead of marking it _PAGE_SPLITTING in code path where we can afford to mark pmd none before splitting. Use a variant of pmdp_splitting_clear_notify that arch can override. Signed-off-by: Aneesh Kumar K.V --- arch/powerpc/include/asm/pgtable-ppc64.h | 4 ++++ arch/powerpc/mm/pgtable_64.c | 11 +++++++++++ include/asm-generic/pgtable.h | 4 ++++ mm/huge_memory.c | 4 ++-- 4 files changed, 21 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h index 43e6ad424c7f..307e705cbead 100644 --- a/arch/powerpc/include/asm/pgtable-ppc64.h +++ b/arch/powerpc/include/asm/pgtable-ppc64.h @@ -576,6 +576,10 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm, unsigned long addr, extern void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp); +#define __HAVE_ARCH_PMDP_SPLITTING_CLEAR_NOTIFY +extern void pmdp_splitting_clear_notify(struct vm_area_struct *vma, + unsigned long address, pmd_t *pmdp); + #define __HAVE_ARCH_PGTABLE_DEPOSIT extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, pgtable_t pgtable); diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c index 59daa5eeec25..c30b15894edf 100644 --- a/arch/powerpc/mm/pgtable_64.c +++ b/arch/powerpc/mm/pgtable_64.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include @@ -598,6 +599,16 @@ pmd_t pmdp_clear_flush(struct vm_area_struct *vma, unsigned long address, return pmd; } +void pmdp_splitting_clear_notify(struct vm_area_struct *vma, + unsigned long address, pmd_t *pmdp) +{ + pmdp_clear_flush_notify(vma, address, pmdp); + /* + * Serialize against find_linux_pte_or_hugepte + */ + kick_all_cpus_sync(); +} + int pmdp_test_and_clear_young(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp) { diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index 39f1d6a2b04d..83ed56c8594a 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -189,6 +189,10 @@ extern void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp); #endif +#ifndef __HAVE_ARCH_PMDP_SPLITTING_CLEAR_NOTIFY +#define pmdp_splitting_clear_notify pmdp_clear_flush_notify +#endif + #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, pgtable_t pgtable); diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 078832cf3636..f596312980f9 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1031,7 +1031,7 @@ static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, goto out_free_pages; VM_BUG_ON_PAGE(!PageHead(page), page); - pmdp_clear_flush_notify(vma, haddr, pmd); + pmdp_splitting_clear_notify(vma, haddr, pmd); /* leave pmd empty until pte is filled */ pgtable = pgtable_trans_huge_withdraw(mm, pmd); @@ -2865,7 +2865,7 @@ static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, pmd_t _pmd; int i; - pmdp_clear_flush_notify(vma, haddr, pmd); + pmdp_splitting_clear_notify(vma, haddr, pmd); /* leave pmd empty until pte is filled */ pgtable = pgtable_trans_huge_withdraw(mm, pmd); -- 2.1.4