From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f70.google.com (mail-oi0-f70.google.com [209.85.218.70]) by kanga.kvack.org (Postfix) with ESMTP id C74076B007E for ; Mon, 6 Jun 2016 13:50:04 -0400 (EDT) Received: by mail-oi0-f70.google.com with SMTP id s139so160552617oie.0 for ; Mon, 06 Jun 2016 10:50:04 -0700 (PDT) Received: from aserp1040.oracle.com (aserp1040.oracle.com. [141.146.126.69]) by mx.google.com with ESMTPS id e138si13617355ite.59.2016.06.06.10.50.03 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 06 Jun 2016 10:50:03 -0700 (PDT) From: 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> In-Reply-To: <1465235131-6112-1-git-send-email-mike.kravetz@oracle.com> References: <1465235131-6112-1-git-send-email-mike.kravetz@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: 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 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 -- 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