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Date: Fri, 17 Feb 2017 17:13:02 +0300 From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com> To: Linus Torvalds <torvalds@...ux-foundation.org>, Andrew Morton <akpm@...ux-foundation.org>, x86@...nel.org, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Arnd Bergmann <arnd@...db.de>, "H. Peter Anvin" <hpa@...or.com> Cc: Andi Kleen <ak@...ux.intel.com>, Dave Hansen <dave.hansen@...el.com>, Andy Lutomirski <luto@...capital.net>, linux-arch@...r.kernel.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org, "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com> Subject: [PATCHv3 07/33] mm: introduce __p4d_alloc() For full 5-level paging we need a helper to allocate p4d page table. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com> --- mm/memory.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/mm/memory.c b/mm/memory.c index e4a37c340a56..c1e3706dc597 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3844,6 +3844,29 @@ 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
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