From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f46.google.com (mail-qg0-f46.google.com [209.85.192.46]) by kanga.kvack.org (Postfix) with ESMTP id F3687900002 for ; Fri, 1 Aug 2014 15:21:27 -0400 (EDT) Received: by mail-qg0-f46.google.com with SMTP id z60so6293054qgd.19 for ; Fri, 01 Aug 2014 12:21:27 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id j107si2132823qge.8.2014.08.01.12.21.27 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 01 Aug 2014 12:21:27 -0700 (PDT) From: Naoya Horiguchi Subject: [PATCH -mm v6 12/13] mm: /proc/pid/clear_refs: avoid split_huge_page() Date: Fri, 1 Aug 2014 15:20:48 -0400 Message-Id: <1406920849-25908-13-git-send-email-n-horiguchi@ah.jp.nec.com> In-Reply-To: <1406920849-25908-1-git-send-email-n-horiguchi@ah.jp.nec.com> References: <1406920849-25908-1-git-send-email-n-horiguchi@ah.jp.nec.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Dave Hansen , Hugh Dickins , "Kirill A. Shutemov" , Jerome Marchand , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Naoya Horiguchi , "Kirill A. Shutemov" , Pavel Emelyanov , Andrea Arcangeli From: "Kirill A. Shutemov" Currently pagewalker splits all THP pages on any clear_refs request. It's not necessary. We can handle this on PMD level. One side effect is that soft dirty will potentially see more dirty memory, since we will mark whole THP page dirty at once. Sanity checked with CRIU test suite. More testing is required. ChangeLog: - move code for thp to clear_refs_pte_range() Signed-off-by: Kirill A. Shutemov Cc: Pavel Emelyanov Cc: Andrea Arcangeli Cc: Dave Hansen Signed-off-by: Naoya Horiguchi Reviewed-by: Cyrill Gorcunov --- fs/proc/task_mmu.c | 47 ++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 44 insertions(+), 3 deletions(-) diff --git mmotm-2014-07-30-15-57.orig/fs/proc/task_mmu.c mmotm-2014-07-30-15-57/fs/proc/task_mmu.c index 084d750f6177..5b71471b9647 100644 --- mmotm-2014-07-30-15-57.orig/fs/proc/task_mmu.c +++ mmotm-2014-07-30-15-57/fs/proc/task_mmu.c @@ -712,10 +712,10 @@ struct clear_refs_private { enum clear_refs_types type; }; +#ifdef CONFIG_MEM_SOFT_DIRTY static inline void clear_soft_dirty(struct vm_area_struct *vma, unsigned long addr, pte_t *pte) { -#ifdef CONFIG_MEM_SOFT_DIRTY /* * The soft-dirty tracker uses #PF-s to catch writes * to pages, so write-protect the pte as well. See the @@ -734,9 +734,35 @@ static inline void clear_soft_dirty(struct vm_area_struct *vma, } set_pte_at(vma->vm_mm, addr, pte, ptent); -#endif } +static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma, + unsigned long addr, pmd_t *pmdp) +{ + pmd_t pmd = *pmdp; + + pmd = pmd_wrprotect(pmd); + pmd = pmd_clear_flags(pmd, _PAGE_SOFT_DIRTY); + + if (vma->vm_flags & VM_SOFTDIRTY) + vma->vm_flags &= ~VM_SOFTDIRTY; + + set_pmd_at(vma->vm_mm, addr, pmdp, pmd); +} + +#else + +static inline void clear_soft_dirty(struct vm_area_struct *vma, + unsigned long addr, pte_t *pte) +{ +} + +static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma, + unsigned long addr, pmd_t *pmdp) +{ +} +#endif + static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, struct mm_walk *walk) { @@ -746,7 +772,22 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr, spinlock_t *ptl; struct page *page; - split_huge_page_pmd(vma, addr, pmd); + if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { + if (cp->type == CLEAR_REFS_SOFT_DIRTY) { + clear_soft_dirty_pmd(vma, addr, pmd); + goto out; + } + + page = pmd_page(*pmd); + + /* Clear accessed and referenced bits. */ + pmdp_test_and_clear_young(vma, addr, pmd); + ClearPageReferenced(page); +out: + spin_unlock(ptl); + return 0; + } + if (pmd_trans_unstable(pmd)) return 0; -- 1.9.3 -- 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