Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934650Ab3CNRuj (ORCPT ); Thu, 14 Mar 2013 13:50:39 -0400 Received: from mga02.intel.com ([134.134.136.20]:52060 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934615Ab3CNRt0 (ORCPT ); Thu, 14 Mar 2013 13:49:26 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,845,1355126400"; d="scan'208";a="279559823" From: "Kirill A. Shutemov" To: Andrea Arcangeli , Andrew Morton , Al Viro , Hugh Dickins Cc: Wu Fengguang , Jan Kara , Mel Gorman , linux-mm@kvack.org, Andi Kleen , Matthew Wilcox , "Kirill A. Shutemov" , Hillf Danton , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCHv2, RFC 28/30] thp: handle write-protect exception to file-backed huge pages Date: Thu, 14 Mar 2013 19:50:33 +0200 Message-Id: <1363283435-7666-29-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1363283435-7666-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1363283435-7666-1-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 Content-Length: 3766 Lines: 120 From: "Kirill A. Shutemov" Signed-off-by: Kirill A. Shutemov --- mm/huge_memory.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 67 insertions(+), 2 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index d1adaea..a416a77 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1339,7 +1339,6 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long mmun_start; /* For mmu_notifiers */ unsigned long mmun_end; /* For mmu_notifiers */ - VM_BUG_ON(!vma->anon_vma); haddr = address & HPAGE_PMD_MASK; if (is_huge_zero_pmd(orig_pmd)) goto alloc; @@ -1349,7 +1348,7 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, page = pmd_page(orig_pmd); VM_BUG_ON(!PageCompound(page) || !PageHead(page)); - if (page_mapcount(page) == 1) { + if (PageAnon(page) && page_mapcount(page) == 1) { pmd_t entry; entry = pmd_mkyoung(orig_pmd); entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); @@ -1357,10 +1356,72 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, update_mmu_cache_pmd(vma, address, pmd); ret |= VM_FAULT_WRITE; goto out_unlock; + } else if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == + (VM_WRITE|VM_SHARED)) { + struct vm_fault vmf; + pmd_t entry; + struct address_space *mapping; + + /* not yet impemented */ + VM_BUG_ON(!vma->vm_ops || !vma->vm_ops->page_mkwrite); + + vmf.virtual_address = (void __user *)haddr; + vmf.pgoff = page->index; + vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; + vmf.page = page; + + page_cache_get(page); + spin_unlock(&mm->page_table_lock); + + ret = vma->vm_ops->page_mkwrite(vma, &vmf); + if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { + page_cache_release(page); + goto out; + } + if (unlikely(!(ret & VM_FAULT_LOCKED))) { + lock_page(page); + if (!page->mapping) { + ret = 0; /* retry */ + unlock_page(page); + page_cache_release(page); + goto out; + } + } else + VM_BUG_ON(!PageLocked(page)); + spin_lock(&mm->page_table_lock); + if (unlikely(!pmd_same(*pmd, orig_pmd))) { + unlock_page(page); + page_cache_release(page); + goto out_unlock; + } + + flush_cache_page(vma, address, pmd_pfn(orig_pmd)); + entry = pmd_mkyoung(orig_pmd); + entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); + if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) + update_mmu_cache_pmd(vma, address, pmd); + ret = VM_FAULT_WRITE; + spin_unlock(&mm->page_table_lock); + + mapping = page->mapping; + set_page_dirty(page); + unlock_page(page); + page_cache_release(page); + if (mapping) { + /* + * Some device drivers do not set page.mapping + * but still dirty their pages + */ + balance_dirty_pages_ratelimited(mapping); + } + return ret; } get_page(page); spin_unlock(&mm->page_table_lock); alloc: + if (unlikely(anon_vma_prepare(vma))) + return VM_FAULT_OOM; + if (transparent_hugepage_enabled(vma) && !transparent_hugepage_debug_cow()) new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), @@ -1424,6 +1485,10 @@ alloc: add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); put_huge_zero_page(); } else { + if (!PageAnon(page)) { + add_mm_counter(mm, MM_FILEPAGES, -HPAGE_PMD_NR); + add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); + } VM_BUG_ON(!PageHead(page)); page_remove_rmap(page); put_page(page); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/