From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id 653E72808D6 for ; Thu, 9 Mar 2017 09:24:38 -0500 (EST) Received: by mail-pf0-f197.google.com with SMTP id x63so113906169pfx.7 for ; Thu, 09 Mar 2017 06:24:38 -0800 (PST) Received: from mga09.intel.com (mga09.intel.com. [134.134.136.24]) by mx.google.com with ESMTPS id j187si6595298pge.96.2017.03.09.06.24.37 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 09 Mar 2017 06:24:37 -0800 (PST) From: "Kirill A. Shutemov" Subject: [PATCHv2 7/7] mm: introduce __p4d_alloc() Date: Thu, 9 Mar 2017 17:24:08 +0300 Message-Id: <20170309142408.2868-8-kirill.shutemov@linux.intel.com> In-Reply-To: <20170309142408.2868-1-kirill.shutemov@linux.intel.com> References: <20170309142408.2868-1-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Linus Torvalds , Andrew Morton , x86@kernel.org, Thomas Gleixner , Ingo Molnar , Arnd Bergmann , "H. Peter Anvin" Cc: Andi Kleen , Dave Hansen , Andy Lutomirski , Michal Hocko , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" For full 5-level paging we need a helper to allocate p4d page table. Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko --- mm/memory.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/mm/memory.c b/mm/memory.c index 7f1c2163b3ce..235ba51b2fbf 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3906,6 +3906,29 @@ int handle_mm_fault(struct vm_area_struct *vma, unsigned long address, } EXPORT_SYMBOL_GPL(handle_mm_fault); +#ifndef __PAGETABLE_P4D_FOLDED +/* + * Allocate p4d page table. + * We've already handled the fast-path in-line. + */ +int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) +{ + p4d_t *new = p4d_alloc_one(mm, address); + if (!new) + return -ENOMEM; + + smp_wmb(); /* See comment in __pte_alloc */ + + spin_lock(&mm->page_table_lock); + if (pgd_present(*pgd)) /* Another has populated it */ + p4d_free(mm, new); + else + pgd_populate(mm, pgd, new); + spin_unlock(&mm->page_table_lock); + return 0; +} +#endif /* __PAGETABLE_P4D_FOLDED */ + #ifndef __PAGETABLE_PUD_FOLDED /* * Allocate page upper directory. -- 2.11.0 -- 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