From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751953AbZINFSv (ORCPT ); Mon, 14 Sep 2009 01:18:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751511AbZINFSv (ORCPT ); Mon, 14 Sep 2009 01:18:51 -0400 Received: from mail-yx0-f191.google.com ([209.85.210.191]:63208 "EHLO mail-yx0-f191.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751382AbZINFSu (ORCPT ); Mon, 14 Sep 2009 01:18:50 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:cc:content-type; b=lP9Ccr7EchrjUse6z3lBv1QiBoATtPkf25S6BxjZNJ3EVaBgaA9HTrQeigtxxHgAMA hQgoF99gb1ro/TWs39unlhsu8L1WtB+SMauWZ1XbLPZgdPrkh7ZEETtlqvMzrN0Oi1rD vEDJ4wL/UOONiAPynfKH+eYdPAQosi3xbrcgk= MIME-Version: 1.0 Date: Mon, 14 Sep 2009 17:18:53 +1200 Message-ID: <202cde0e0909132218k70c31a5u922636914e603ad4@mail.gmail.com> Subject: [PATCH 2/3] Helper which returns the huge page at a given address (Take 3) From: Alexey Korolev To: Mel Gorman , Eric Munson , Alexey Korolev Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch provides helper function which returns the huge page at a given address for population before the page has been faulted. It is possible to call hugetlb_get_user_page function in file mmap procedure to get pages before they have been requested by user level. include/linux/hugetlb.h | 3 +++ mm/hugetlb.c | 23 +++++++++++++++++++++++ 2 files changed, 26 insertions(+) --- Signed-off-by: Alexey Korolev diff -aurp clean/include/linux/hugetlb.h patched/include/linux/hugetlb.h --- clean/include/linux/hugetlb.h 2009-09-11 15:33:48.000000000 +1200 +++ patched/include/linux/hugetlb.h 2009-09-11 20:09:02.000000000 +1200 @@ -39,6 +39,8 @@ int hugetlb_reserve_pages(struct inode * struct vm_area_struct *vma, int acctflags); void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed); +struct page *hugetlb_get_user_page(struct vm_area_struct *vma, + unsigned long address); extern unsigned long hugepages_treat_as_movable; extern const unsigned long hugetlb_zero, hugetlb_infinity; @@ -100,6 +102,7 @@ static inline void hugetlb_report_meminf #define is_hugepage_only_range(mm, addr, len) 0 #define hugetlb_free_pgd_range(tlb, addr, end, floor, ceiling) ({BUG(); 0; }) #define hugetlb_fault(mm, vma, addr, flags) ({ BUG(); 0; }) +#define hugetlb_get_user_page(vma, address) ERR_PTR(-EINVAL) #define hugetlb_change_protection(vma, address, end, newprot) diff -aurp clean/mm/hugetlb.c patched/mm/hugetlb.c --- clean/mm/hugetlb.c 2009-09-06 11:38:12.000000000 +1200 +++ patched/mm/hugetlb.c 2009-09-11 08:34:00.000000000 +1200 @@ -2187,6 +2187,29 @@ static int huge_zeropage_ok(pte_t *ptep, return huge_pte_none(huge_ptep_get(ptep)); } +/* + * hugetlb_get_user_page returns the page at a given address for population + * before the page has been faulted. + */ +struct page *hugetlb_get_user_page(struct vm_area_struct *vma, + unsigned long address) +{ + int ret; + int cnt = 1; + struct page *pg; + struct hstate *h = hstate_vma(vma); + + address = address & huge_page_mask(h); + ret = follow_hugetlb_page(vma->vm_mm, vma, &pg, + NULL, &address, &cnt, 0, 0); + if (ret < 0) + return ERR_PTR(ret); + put_page(pg); + + return pg; +} +EXPORT_SYMBOL_GPL(hugetlb_get_user_page); + int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, struct page **pages, struct vm_area_struct **vmas, unsigned long *position, int *length, int i,