From: Mike Kravetz <mike.kravetz@oracle.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Hugh Dickins <hughd@google.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Hillf Danton <hillf.zj@alibaba-inc.com>,
Michal Hocko <mhocko@suse.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Kravetz <mike.kravetz@oracle.com>
Subject: [RFC PATCH 4/6] mm/hugetlb: add userfaultfd hugetlb hook
Date: Mon, 6 Jun 2016 10:45:29 -0700 [thread overview]
Message-ID: <1465235131-6112-5-git-send-email-mike.kravetz@oracle.com> (raw)
In-Reply-To: <1465235131-6112-1-git-send-email-mike.kravetz@oracle.com>
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 <mike.kravetz@oracle.com>
---
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 <linux/hugetlb.h>
#include <linux/hugetlb_cgroup.h>
#include <linux/node.h>
+#include <linux/userfaultfd_k.h>
#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
--
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next prev parent reply other threads:[~2016-06-06 17:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-06 17:45 [RFC PATCH 0/6] hugetlb support for userfaultfd Mike Kravetz
2016-06-06 17:45 ` [RFC PATCH 1/6] mm/memory: add copy_huge_page_from_user for hugetlb userfaultfd support Mike Kravetz
2016-06-06 17:45 ` [RFC PATCH 2/6] mm/hugetlb: add hugetlb_mcopy_atomic_pte for " Mike Kravetz
2016-06-06 17:45 ` [RFC PATCH 3/6] mm/userfaultfd: add __mcopy_atomic_hugetlb for huge page UFFDIO_COPY Mike Kravetz
2016-06-07 6:27 ` Hillf Danton
2016-06-07 16:35 ` Mike Kravetz
2016-06-06 17:45 ` Mike Kravetz [this message]
2016-06-06 17:45 ` [RFC PATCH 5/6] fs/userfaultfd: allow registration of ranges containing huge pages Mike Kravetz
2016-06-06 17:45 ` [RFC PATCH 6/6] selftests/userfaultfd: add userfaultfd_hugetlb test Mike Kravetz
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