Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423550Ab2KNXWG (ORCPT ); Wed, 14 Nov 2012 18:22:06 -0500 Received: from mail-pb0-f46.google.com ([209.85.160.46]:61356 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932216Ab2KNXWF (ORCPT ); Wed, 14 Nov 2012 18:22:05 -0500 Date: Wed, 14 Nov 2012 15:22:03 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: "Kirill A. Shutemov" cc: Andrew Morton , Andrea Arcangeli , linux-mm@kvack.org, Andi Kleen , "H. Peter Anvin" , linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: Re: [PATCH v5 06/11] thp: change split_huge_page_pmd() interface In-Reply-To: <1352300463-12627-7-git-send-email-kirill.shutemov@linux.intel.com> Message-ID: References: <1352300463-12627-1-git-send-email-kirill.shutemov@linux.intel.com> <1352300463-12627-7-git-send-email-kirill.shutemov@linux.intel.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5417 Lines: 146 On Wed, 7 Nov 2012, Kirill A. Shutemov wrote: > diff --git a/Documentation/vm/transhuge.txt b/Documentation/vm/transhuge.txt > index f734bb2..677a599 100644 > --- a/Documentation/vm/transhuge.txt > +++ b/Documentation/vm/transhuge.txt > @@ -276,7 +276,7 @@ unaffected. libhugetlbfs will also work fine as usual. > == Graceful fallback == > > Code walking pagetables but unware about huge pmds can simply call > -split_huge_page_pmd(mm, pmd) where the pmd is the one returned by > +split_huge_page_pmd(vma, pmd, addr) where the pmd is the one returned by > pmd_offset. It's trivial to make the code transparent hugepage aware > by just grepping for "pmd_offset" and adding split_huge_page_pmd where > missing after pmd_offset returns the pmd. Thanks to the graceful > @@ -299,7 +299,7 @@ diff --git a/mm/mremap.c b/mm/mremap.c > return NULL; > > pmd = pmd_offset(pud, addr); > -+ split_huge_page_pmd(mm, pmd); > ++ split_huge_page_pmd(vma, pmd, addr); > if (pmd_none_or_clear_bad(pmd)) > return NULL; > > diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c > index 5c9687b..1dfe69c 100644 > --- a/arch/x86/kernel/vm86_32.c > +++ b/arch/x86/kernel/vm86_32.c > @@ -182,7 +182,7 @@ static void mark_screen_rdonly(struct mm_struct *mm) > if (pud_none_or_clear_bad(pud)) > goto out; > pmd = pmd_offset(pud, 0xA0000); > - split_huge_page_pmd(mm, pmd); > + split_huge_page_pmd_mm(mm, 0xA0000, pmd); > if (pmd_none_or_clear_bad(pmd)) > goto out; > pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl); Why not be consistent and make this split_huge_page_pmd_mm(mm, pmd, addr)? > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index 90c63f9..291a0d1 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -643,7 +643,7 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr, > spinlock_t *ptl; > struct page *page; > > - split_huge_page_pmd(walk->mm, pmd); > + split_huge_page_pmd(vma, addr, pmd); Ah, it's because the change to the documentation is wrong: the format is actually split_huge_page_pmd(vma, addr, pmd). > if (pmd_trans_unstable(pmd)) > return 0; > > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h > index b31cb7d..856f080 100644 > --- a/include/linux/huge_mm.h > +++ b/include/linux/huge_mm.h > @@ -91,12 +91,14 @@ extern int handle_pte_fault(struct mm_struct *mm, > struct vm_area_struct *vma, unsigned long address, > pte_t *pte, pmd_t *pmd, unsigned int flags); > extern int split_huge_page(struct page *page); > -extern void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd); > -#define split_huge_page_pmd(__mm, __pmd) \ > +extern void __split_huge_page_pmd(struct vm_area_struct *vma, > + unsigned long address, pmd_t *pmd); > +#define split_huge_page_pmd(__vma, __address, __pmd) \ > do { \ > pmd_t *____pmd = (__pmd); \ > if (unlikely(pmd_trans_huge(*____pmd))) \ > - __split_huge_page_pmd(__mm, ____pmd); \ > + __split_huge_page_pmd(__vma, __address, \ > + ____pmd); \ > } while (0) > #define wait_split_huge_page(__anon_vma, __pmd) \ > do { \ > @@ -106,6 +108,8 @@ extern void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd); > BUG_ON(pmd_trans_splitting(*____pmd) || \ > pmd_trans_huge(*____pmd)); \ > } while (0) > +extern void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address, > + pmd_t *pmd); > #if HPAGE_PMD_ORDER > MAX_ORDER > #error "hugepages can't be allocated by the buddy allocator" > #endif > @@ -173,10 +177,12 @@ static inline int split_huge_page(struct page *page) > { > return 0; > } > -#define split_huge_page_pmd(__mm, __pmd) \ > +#define split_huge_page_pmd(__vma, __address, __pmd) \ > do { } while (0) > #define wait_split_huge_page(__anon_vma, __pmd) \ > do { } while (0) > +#define split_huge_page_pmd_mm(__mm, __address, __pmd) \ > + do { } while (0) > #define compound_trans_head(page) compound_head(page) > static inline int hugepage_madvise(struct vm_area_struct *vma, > unsigned long *vm_flags, int advice) > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 05490b3..90e651c 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -2509,19 +2509,23 @@ static int khugepaged(void *none) > return 0; > } > > -void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd) > +void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address, > + pmd_t *pmd) > { > struct page *page; > + unsigned long haddr = address & HPAGE_PMD_MASK; > Just do struct mm_struct *mm = vma->vm_mm; here and it makes everything else simpler. > - spin_lock(&mm->page_table_lock); > + BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE); > + > + spin_lock(&vma->vm_mm->page_table_lock); > if (unlikely(!pmd_trans_huge(*pmd))) { > - spin_unlock(&mm->page_table_lock); > + spin_unlock(&vma->vm_mm->page_table_lock); > return; > } > page = pmd_page(*pmd); > VM_BUG_ON(!page_count(page)); > get_page(page); > - spin_unlock(&mm->page_table_lock); > + spin_unlock(&vma->vm_mm->page_table_lock); > > split_huge_page(page); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/