Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2993222Ab2KOIvR (ORCPT ); Thu, 15 Nov 2012 03:51:17 -0500 Received: from mga14.intel.com ([143.182.124.37]:22014 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2993193Ab2KOIvO (ORCPT ); Thu, 15 Nov 2012 03:51:14 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.83,255,1352102400"; d="asc'?scan'208";a="218101351" Date: Thu, 15 Nov 2012 10:52:00 +0200 From: "Kirill A. Shutemov" To: David Rientjes 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 Message-ID: <20121115085200.GD9676@otc-wbsnb-06> References: <1352300463-12627-1-git-send-email-kirill.shutemov@linux.intel.com> <1352300463-12627-7-git-send-email-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="fXStkuK2IQBfcDe+" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7001 Lines: 193 --fXStkuK2IQBfcDe+ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Nov 14, 2012 at 03:22:03PM -0800, David Rientjes wrote: > On Wed, 7 Nov 2012, Kirill A. Shutemov wrote: >=20 > > diff --git a/Documentation/vm/transhuge.txt b/Documentation/vm/transhug= e.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 usu= al. > > =3D=3D Graceful fallback =3D=3D > > =20 > > 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; > > =20 > > pmd =3D 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; > > =20 > > 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 =3D 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 =3D pte_offset_map_lock(mm, pmd, 0xA0000, &ptl); >=20 > Why not be consistent and make this split_huge_page_pmd_mm(mm, pmd, addr)? >=20 > > 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, unsigne= d long addr, > > spinlock_t *ptl; > > struct page *page; > > =20 > > - split_huge_page_pmd(walk->mm, pmd); > > + split_huge_page_pmd(vma, addr, pmd); >=20 > Ah, it's because the change to the documentation is wrong: the format is= =20 > actually split_huge_page_pmd(vma, addr, pmd). Thanks, will fix. > > if (pmd_trans_unstable(pmd)) > > return 0; > > =20 > > 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 =3D (__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 *pa= ge) > > { > > 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; > > } > > =20 > > -void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd) > > +void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long a= ddress, > > + pmd_t *pmd) > > { > > struct page *page; > > + unsigned long haddr =3D address & HPAGE_PMD_MASK; > >=20 >=20 > Just do >=20 > struct mm_struct *mm =3D vma->vm_mm; >=20 > here and it makes everything else simpler. Okay. > > - 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 =3D 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); > > =20 > > split_huge_page(page); > > =20 --=20 Kirill A. 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