From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f198.google.com (mail-qk0-f198.google.com [209.85.220.198]) by kanga.kvack.org (Postfix) with ESMTP id 46C856B02AD for ; Wed, 2 Nov 2016 15:34:12 -0400 (EDT) Received: by mail-qk0-f198.google.com with SMTP id o68so24650223qkf.3 for ; Wed, 02 Nov 2016 12:34:12 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id o64si1924840qki.173.2016.11.02.12.34.11 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 Nov 2016 12:34:11 -0700 (PDT) From: Andrea Arcangeli Subject: [PATCH 16/33] userfaultfd: hugetlbfs: add userfaultfd hugetlb hook Date: Wed, 2 Nov 2016 20:33:48 +0100 Message-Id: <1478115245-32090-17-git-send-email-aarcange@redhat.com> In-Reply-To: <1478115245-32090-1-git-send-email-aarcange@redhat.com> References: <1478115245-32090-1-git-send-email-aarcange@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm@kvack.org, Michael Rapoport , "Dr. David Alan Gilbert"@v2.random, " , Mike Kravetz , Shaohua Li , Pavel Emelyanov "@v2.random From: 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 Signed-off-by: Andrea Arcangeli --- mm/hugetlb.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index baf7fd4..7247f8c 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; @@ -3589,6 +3590,38 @@ static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 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; + struct fault_env fe = { + .vma = vma, + .address = address, + .flags = flags, + /* + * Hard to debug if it ends up being + * used by a callee that assumes + * something about the other + * uninitialized fields... same as in + * memory.c + */ + }; + + /* + * 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(&fe, 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); -- 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