From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f54.google.com (mail-pa0-f54.google.com [209.85.220.54]) by kanga.kvack.org (Postfix) with ESMTP id 13E406B0255 for ; Tue, 6 Oct 2015 11:24:22 -0400 (EDT) Received: by pablk4 with SMTP id lk4so212476749pab.3 for ; Tue, 06 Oct 2015 08:24:21 -0700 (PDT) Received: from mga09.intel.com (mga09.intel.com. [134.134.136.24]) by mx.google.com with ESMTP id k13si49616091pbq.238.2015.10.06.08.24.19 for ; Tue, 06 Oct 2015 08:24:19 -0700 (PDT) From: "Kirill A. Shutemov" Subject: [PATCHv12 05/37] mm: adjust FOLL_SPLIT for new refcounting Date: Tue, 6 Oct 2015 18:23:32 +0300 Message-Id: <1444145044-72349-6-git-send-email-kirill.shutemov@linux.intel.com> In-Reply-To: <1444145044-72349-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1444145044-72349-1-git-send-email-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Andrea Arcangeli , Hugh Dickins Cc: Dave Hansen , Mel Gorman , Rik van Riel , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Steve Capper , "Aneesh Kumar K.V" , Johannes Weiner , Michal Hocko , Jerome Marchand , Sasha Levin , linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Kirill A. Shutemov" We need to prepare kernel to allow transhuge pages to be mapped with ptes too. We need to handle FOLL_SPLIT in follow_page_pte(). Also we use split_huge_page() directly instead of split_huge_page_pmd(). split_huge_page_pmd() will gone. Signed-off-by: Kirill A. Shutemov Tested-by: Sasha Levin Tested-by: Aneesh Kumar K.V Acked-by: Vlastimil Babka Acked-by: Jerome Marchand --- mm/gup.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 49 insertions(+), 18 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index deafa2c91b36..745a50f2d57d 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -116,6 +116,19 @@ retry: } } + if (flags & FOLL_SPLIT && PageTransCompound(page)) { + int ret; + get_page(page); + pte_unmap_unlock(ptep, ptl); + lock_page(page); + ret = split_huge_page(page); + unlock_page(page); + put_page(page); + if (ret) + return ERR_PTR(ret); + goto retry; + } + if (flags & FOLL_GET) get_page_foll(page); if (flags & FOLL_TOUCH) { @@ -220,27 +233,45 @@ struct page *follow_page_mask(struct vm_area_struct *vma, } if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) return no_page_table(vma, flags); - if (pmd_trans_huge(*pmd)) { - if (flags & FOLL_SPLIT) { + if (likely(!pmd_trans_huge(*pmd))) + return follow_page_pte(vma, address, pmd, flags); + + ptl = pmd_lock(mm, pmd); + if (unlikely(!pmd_trans_huge(*pmd))) { + spin_unlock(ptl); + return follow_page_pte(vma, address, pmd, flags); + } + + if (unlikely(pmd_trans_splitting(*pmd))) { + spin_unlock(ptl); + wait_split_huge_page(vma->anon_vma, pmd); + return follow_page_pte(vma, address, pmd, flags); + } + + if (flags & FOLL_SPLIT) { + int ret; + page = pmd_page(*pmd); + if (is_huge_zero_page(page)) { + spin_unlock(ptl); + ret = 0; split_huge_page_pmd(vma, address, pmd); - return follow_page_pte(vma, address, pmd, flags); - } - ptl = pmd_lock(mm, pmd); - if (likely(pmd_trans_huge(*pmd))) { - if (unlikely(pmd_trans_splitting(*pmd))) { - spin_unlock(ptl); - wait_split_huge_page(vma->anon_vma, pmd); - } else { - page = follow_trans_huge_pmd(vma, address, - pmd, flags); - spin_unlock(ptl); - *page_mask = HPAGE_PMD_NR - 1; - return page; - } - } else + } else { + get_page(page); spin_unlock(ptl); + lock_page(page); + ret = split_huge_page(page); + unlock_page(page); + put_page(page); + } + + return ret ? ERR_PTR(ret) : + follow_page_pte(vma, address, pmd, flags); } - return follow_page_pte(vma, address, pmd, flags); + + page = follow_trans_huge_pmd(vma, address, pmd, flags); + spin_unlock(ptl); + *page_mask = HPAGE_PMD_NR - 1; + return page; } static int get_gate_page(struct mm_struct *mm, unsigned long address, -- 2.5.3 -- 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