From: Peter Xu <peterx@redhat.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: David Hildenbrand <david@redhat.com>,
Hugh Dickins <hughd@google.com>, Maya Gokhale <gokhale2@llnl.gov>,
Jerome Glisse <jglisse@redhat.com>,
Pavel Emelyanov <xemul@virtuozzo.com>,
Johannes Weiner <hannes@cmpxchg.org>,
peterx@redhat.com, Martin Cracauer <cracauer@cons.org>,
Shaohua Li <shli@fb.com>, Andrea Arcangeli <aarcange@redhat.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Denis Plotnikov <dplotnikov@virtuozzo.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Marty McFadden <mcfadden8@llnl.gov>, Mel Gorman <mgorman@suse.de>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>
Subject: [PATCH v3 05/28] mm: gup: allow VM_FAULT_RETRY for multiple times
Date: Wed, 20 Mar 2019 10:06:19 +0800 [thread overview]
Message-ID: <20190320020642.4000-6-peterx@redhat.com> (raw)
In-Reply-To: <20190320020642.4000-1-peterx@redhat.com>
This is the gup counterpart of the change that allows the VM_FAULT_RETRY
to happen for more than once.
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
mm/gup.c | 17 +++++++++++++----
mm/hugetlb.c | 6 ++++--
2 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index 9bb3bed68ee3..f56dee055f26 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -528,7 +528,10 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma,
if (*flags & FOLL_NOWAIT)
fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT;
if (*flags & FOLL_TRIED) {
- VM_WARN_ON_ONCE(fault_flags & FAULT_FLAG_ALLOW_RETRY);
+ /*
+ * Note: FAULT_FLAG_ALLOW_RETRY and FAULT_FLAG_TRIED
+ * can co-exist
+ */
fault_flags |= FAULT_FLAG_TRIED;
}
@@ -943,17 +946,23 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
/* VM_FAULT_RETRY triggered, so seek to the faulting offset */
pages += ret;
start += ret << PAGE_SHIFT;
+ lock_dropped = true;
+retry:
/*
* Repeat on the address that fired VM_FAULT_RETRY
- * without FAULT_FLAG_ALLOW_RETRY but with
+ * with both FAULT_FLAG_ALLOW_RETRY and
* FAULT_FLAG_TRIED.
*/
*locked = 1;
- lock_dropped = true;
down_read(&mm->mmap_sem);
ret = __get_user_pages(tsk, mm, start, 1, flags | FOLL_TRIED,
- pages, NULL, NULL);
+ pages, NULL, locked);
+ if (!*locked) {
+ /* Continue to retry until we succeeded */
+ BUG_ON(ret != 0);
+ goto retry;
+ }
if (ret != 1) {
BUG_ON(ret > 1);
if (!pages_done)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 52296ce4025a..040779a7b906 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4267,8 +4267,10 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
fault_flags |= FAULT_FLAG_ALLOW_RETRY |
FAULT_FLAG_RETRY_NOWAIT;
if (flags & FOLL_TRIED) {
- VM_WARN_ON_ONCE(fault_flags &
- FAULT_FLAG_ALLOW_RETRY);
+ /*
+ * Note: FAULT_FLAG_ALLOW_RETRY and
+ * FAULT_FLAG_TRIED can co-exist
+ */
fault_flags |= FAULT_FLAG_TRIED;
}
ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
--
2.17.1
next prev parent reply other threads:[~2019-03-20 2:07 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-20 2:06 [PATCH v3 00/28] userfaultfd: write protection support Peter Xu
2019-03-20 2:06 ` [PATCH v3 01/28] mm: gup: rename "nonblocking" to "locked" where proper Peter Xu
2019-03-20 2:06 ` [PATCH v3 02/28] mm: userfault: return VM_FAULT_RETRY on signals Peter Xu
2019-03-20 2:06 ` [PATCH v3 03/28] userfaultfd: don't retake mmap_sem to emulate NOPAGE Peter Xu
2019-03-20 2:06 ` [PATCH v3 04/28] mm: allow VM_FAULT_RETRY for multiple times Peter Xu
2019-04-18 20:11 ` Jerome Glisse
2019-04-19 6:00 ` Peter Xu
2019-03-20 2:06 ` Peter Xu [this message]
2019-03-20 2:06 ` [PATCH v3 06/28] userfaultfd: wp: add helper for writeprotect check Peter Xu
2019-03-20 2:06 ` [PATCH v3 07/28] userfaultfd: wp: hook userfault handler to write protection fault Peter Xu
2019-04-18 20:03 ` Jerome Glisse
2019-03-20 2:06 ` [PATCH v3 08/28] userfaultfd: wp: add WP pagetable tracking to x86 Peter Xu
2019-03-20 2:06 ` [PATCH v3 09/28] userfaultfd: wp: userfaultfd_pte/huge_pmd_wp() helpers Peter Xu
2019-03-20 2:06 ` [PATCH v3 10/28] userfaultfd: wp: add UFFDIO_COPY_MODE_WP Peter Xu
2019-03-20 2:06 ` [PATCH v3 11/28] mm: merge parameters for change_protection() Peter Xu
2019-03-20 2:06 ` [PATCH v3 12/28] userfaultfd: wp: apply _PAGE_UFFD_WP bit Peter Xu
2019-03-20 2:06 ` [PATCH v3 13/28] mm: export wp_page_copy() Peter Xu
2019-03-20 2:06 ` [PATCH v3 14/28] userfaultfd: wp: handle COW properly for uffd-wp Peter Xu
2019-04-18 20:51 ` Jerome Glisse
2019-04-19 6:26 ` Peter Xu
2019-04-19 15:02 ` Jerome Glisse
2019-04-22 12:20 ` Peter Xu
2019-04-22 14:54 ` Jerome Glisse
2019-04-23 3:00 ` Peter Xu
2019-04-23 15:34 ` Jerome Glisse
2019-04-24 8:38 ` Peter Xu
2019-03-20 2:06 ` [PATCH v3 15/28] userfaultfd: wp: drop _PAGE_UFFD_WP properly when fork Peter Xu
2019-03-20 2:06 ` [PATCH v3 16/28] userfaultfd: wp: add pmd_swp_*uffd_wp() helpers Peter Xu
2019-03-20 2:06 ` [PATCH v3 17/28] userfaultfd: wp: support swap and page migration Peter Xu
2019-04-18 20:59 ` Jerome Glisse
2019-04-19 7:42 ` Peter Xu
2019-04-19 15:08 ` Jerome Glisse
2019-04-22 12:23 ` Peter Xu
2019-03-20 2:06 ` [PATCH v3 18/28] khugepaged: skip collapse if uffd-wp detected Peter Xu
2019-03-20 2:06 ` [PATCH v3 19/28] userfaultfd: introduce helper vma_find_uffd Peter Xu
2019-03-20 2:06 ` [PATCH v3 20/28] userfaultfd: wp: support write protection for userfault vma range Peter Xu
2019-03-20 2:06 ` [PATCH v3 21/28] userfaultfd: wp: add the writeprotect API to userfaultfd ioctl Peter Xu
2019-03-20 2:06 ` [PATCH v3 22/28] userfaultfd: wp: enabled write protection in userfaultfd API Peter Xu
2019-03-22 21:37 ` Mike Rapoport
2019-03-20 2:06 ` [PATCH v3 23/28] userfaultfd: wp: don't wake up when doing write protect Peter Xu
2019-03-20 2:06 ` [PATCH v3 24/28] userfaultfd: wp: UFFDIO_REGISTER_MODE_WP documentation update Peter Xu
2019-03-22 21:46 ` Mike Rapoport
2019-03-20 2:06 ` [PATCH v3 25/28] userfaultfd: wp: fixup swap entries in change_pte_range Peter Xu
2019-04-18 21:01 ` Jerome Glisse
2019-03-20 2:06 ` [PATCH v3 26/28] userfaultfd: wp: declare _UFFDIO_WRITEPROTECT conditionally Peter Xu
2019-03-22 21:43 ` Mike Rapoport
2019-03-20 2:06 ` [PATCH v3 27/28] userfaultfd: selftests: refactor statistics Peter Xu
2019-03-20 2:06 ` [PATCH v3 28/28] userfaultfd: selftests: add write-protect test Peter Xu
2019-04-09 6:08 ` [PATCH v3 00/28] userfaultfd: write protection support Peter Xu
2019-04-18 21:07 ` Jerome Glisse
2019-04-19 7:53 ` Peter Xu
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