From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753167AbcFFRrN (ORCPT ); Mon, 6 Jun 2016 13:47:13 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:17055 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752122AbcFFRrJ (ORCPT ); Mon, 6 Jun 2016 13:47:09 -0400 From: Mike Kravetz To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Andrea Arcangeli , Hugh Dickins , Dave Hansen , "Kirill A. Shutemov" , Naoya Horiguchi , Hillf Danton , Michal Hocko , Andrew Morton , Mike Kravetz Subject: [RFC PATCH 4/6] mm/hugetlb: add userfaultfd hugetlb hook Date: Mon, 6 Jun 2016 10:45:29 -0700 Message-Id: <1465235131-6112-5-git-send-email-mike.kravetz@oracle.com> X-Mailer: git-send-email 2.4.11 In-Reply-To: <1465235131-6112-1-git-send-email-mike.kravetz@oracle.com> References: <1465235131-6112-1-git-send-email-mike.kravetz@oracle.com> X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When processing a hugetlb fault for no page present, check the vma to determine if faults are to be handled via userfaultfd. If so, drop the hugetlb_fault_mutex and call handle_userfault(). Signed-off-by: Mike Kravetz --- mm/hugetlb.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 4943d8b..a2814e7 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -32,6 +32,7 @@ #include #include #include +#include #include "internal.h" int hugepages_treat_as_movable; @@ -3569,6 +3570,27 @@ retry: size = i_size_read(mapping->host) >> huge_page_shift(h); if (idx >= size) goto out; + + /* + * Check for page in userfault range + */ + if (userfaultfd_missing(vma)) { + u32 hash; + + /* + * hugetlb_fault_mutex must be dropped before + * handling userfault. Reacquire after handling + * fault to make calling code simpler. + */ + hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping, + idx, address); + mutex_unlock(&hugetlb_fault_mutex_table[hash]); + ret = handle_userfault(vma, address, flags, + VM_UFFD_MISSING); + mutex_lock(&hugetlb_fault_mutex_table[hash]); + goto out; + } + page = alloc_huge_page(vma, address, 0); if (IS_ERR(page)) { ret = PTR_ERR(page); -- 2.4.11