From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f70.google.com (mail-pg0-f70.google.com [74.125.83.70]) by kanga.kvack.org (Postfix) with ESMTP id 816106B0261 for ; Wed, 13 Dec 2017 05:58:16 -0500 (EST) Received: by mail-pg0-f70.google.com with SMTP id v190so1388869pgv.11 for ; Wed, 13 Dec 2017 02:58:16 -0800 (PST) Received: from mga18.intel.com (mga18.intel.com. [134.134.136.126]) by mx.google.com with ESMTPS id p26si1225030pfh.220.2017.12.13.02.58.15 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 13 Dec 2017 02:58:15 -0800 (PST) From: "Kirill A. Shutemov" Subject: [PATCHv4 11/12] mm: Use updated pmdp_invalidate() interface to track dirty/accessed bits Date: Wed, 13 Dec 2017 13:57:55 +0300 Message-Id: <20171213105756.69879-12-kirill.shutemov@linux.intel.com> In-Reply-To: <20171213105756.69879-1-kirill.shutemov@linux.intel.com> References: <20171213105756.69879-1-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Vlastimil Babka , Andrea Arcangeli , Michal Hocko , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" This patch uses modifed pmdp_invalidate(), that return previous value of pmd, to transfer dirty and accessed bits. Signed-off-by: Kirill A. Shutemov --- fs/proc/task_mmu.c | 8 ++++---- mm/huge_memory.c | 29 ++++++++++++----------------- 2 files changed, 16 insertions(+), 21 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 339e4c1c044d..b4408c642fec 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -977,14 +977,14 @@ static inline void clear_soft_dirty(struct vm_area_struct *vma, static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmdp) { - pmd_t pmd = *pmdp; + pmd_t old, pmd = *pmdp; if (pmd_present(pmd)) { /* See comment in change_huge_pmd() */ - pmdp_invalidate(vma, addr, pmdp); - if (pmd_dirty(*pmdp)) + old = pmdp_invalidate(vma, addr, pmdp); + if (pmd_dirty(old)) pmd = pmd_mkdirty(pmd); - if (pmd_young(*pmdp)) + if (pmd_young(old)) pmd = pmd_mkyoung(pmd); pmd = pmd_wrprotect(pmd); diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 2f2f5e774902..10278d03d60f 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1910,17 +1910,7 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, * pmdp_invalidate() is required to make sure we don't miss * dirty/young flags set by hardware. */ - entry = *pmd; - pmdp_invalidate(vma, addr, pmd); - - /* - * Recover dirty/young flags. It relies on pmdp_invalidate to not - * corrupt them. - */ - if (pmd_dirty(*pmd)) - entry = pmd_mkdirty(entry); - if (pmd_young(*pmd)) - entry = pmd_mkyoung(entry); + entry = pmdp_invalidate(vma, addr, pmd); entry = pmd_modify(entry, newprot); if (preserve_write) @@ -2073,8 +2063,8 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, struct mm_struct *mm = vma->vm_mm; struct page *page; pgtable_t pgtable; - pmd_t _pmd; - bool young, write, dirty, soft_dirty, pmd_migration = false; + pmd_t old, _pmd; + bool young, write, soft_dirty, pmd_migration = false; unsigned long addr; int i; @@ -2130,7 +2120,6 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, page_ref_add(page, HPAGE_PMD_NR - 1); write = pmd_write(*pmd); young = pmd_young(*pmd); - dirty = pmd_dirty(*pmd); soft_dirty = pmd_soft_dirty(*pmd); pmdp_huge_split_prepare(vma, haddr, pmd); @@ -2160,8 +2149,6 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, if (soft_dirty) entry = pte_mksoft_dirty(entry); } - if (dirty) - SetPageDirty(page + i); pte = pte_offset_map(&_pmd, addr); BUG_ON(!pte_none(*pte)); set_pte_at(mm, addr, pte, entry); @@ -2210,7 +2197,15 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, * and finally we write the non-huge version of the pmd entry with * pmd_populate. */ - pmdp_invalidate(vma, haddr, pmd); + old = pmdp_invalidate(vma, haddr, pmd); + + /* + * Transfer dirty bit using value returned by pmd_invalidate() to be + * sure we don't race with CPU that can set the bit under us. + */ + if (pmd_dirty(old)) + SetPageDirty(page); + pmd_populate(mm, pmd, pgtable); if (freeze) { -- 2.15.0 -- 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