From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933472AbbGJRsa (ORCPT ); Fri, 10 Jul 2015 13:48:30 -0400 Received: from mga09.intel.com ([134.134.136.24]:16500 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933061AbbGJRmy (ORCPT ); Fri, 10 Jul 2015 13:42:54 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,448,1432623600"; d="scan'208";a="762076745" From: "Kirill A. Shutemov" 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" Subject: [PATCH 05/36] mm: adjust FOLL_SPLIT for new refcounting Date: Fri, 10 Jul 2015 20:41:39 +0300 Message-Id: <1436550130-112636-6-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1436550130-112636-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1436550130-112636-1-git-send-email-kirill.shutemov@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Acked-by: Vlastimil Babka --- mm/gup.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 49 insertions(+), 18 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 6297f6bccfb1..2dd6706ea29f 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -79,6 +79,19 @@ retry: page = pte_page(pte); } + 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) { @@ -186,27 +199,45 @@ 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, -- 2.1.4