From: Mike Rapoport <rppt@kernel.org>
To: linux-mm@kvack.org
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
David Hildenbrand <david@redhat.com>,
Hugh Dickins <hughd@google.com>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Michal Hocko <mhocko@suse.com>, Mike Rapoport <rppt@kernel.org>,
Nikita Kalyazin <kalyazin@amazon.com>,
Paolo Bonzini <pbonzini@redhat.com>, Peter Xu <peterx@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Shuah Khan <shuah@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-kselftest@vger.kernel.org
Subject: [RFC PATCH 1/4] userfaultfd: move vma_can_userfault out of line
Date: Mon, 17 Nov 2025 13:46:28 +0200 [thread overview]
Message-ID: <20251117114631.2029447-2-rppt@kernel.org> (raw)
In-Reply-To: <20251117114631.2029447-1-rppt@kernel.org>
From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
vma_can_userfault() has grown pretty big and it's not called on
performance critical path.
Move it out of line.
No functional changes.
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
include/linux/userfaultfd_k.h | 36 ++---------------------------------
mm/userfaultfd.c | 34 +++++++++++++++++++++++++++++++++
2 files changed, 36 insertions(+), 34 deletions(-)
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index c0e716aec26a..e4f43e7b063f 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -208,40 +208,8 @@ static inline bool userfaultfd_armed(struct vm_area_struct *vma)
return vma->vm_flags & __VM_UFFD_FLAGS;
}
-static inline bool vma_can_userfault(struct vm_area_struct *vma,
- vm_flags_t vm_flags,
- bool wp_async)
-{
- vm_flags &= __VM_UFFD_FLAGS;
-
- if (vma->vm_flags & VM_DROPPABLE)
- return false;
-
- if ((vm_flags & VM_UFFD_MINOR) &&
- (!is_vm_hugetlb_page(vma) && !vma_is_shmem(vma)))
- return false;
-
- /*
- * If wp async enabled, and WP is the only mode enabled, allow any
- * memory type.
- */
- if (wp_async && (vm_flags == VM_UFFD_WP))
- return true;
-
-#ifndef CONFIG_PTE_MARKER_UFFD_WP
- /*
- * If user requested uffd-wp but not enabled pte markers for
- * uffd-wp, then shmem & hugetlbfs are not supported but only
- * anonymous.
- */
- if ((vm_flags & VM_UFFD_WP) && !vma_is_anonymous(vma))
- return false;
-#endif
-
- /* By default, allow any of anon|shmem|hugetlb */
- return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) ||
- vma_is_shmem(vma);
-}
+bool vma_can_userfault(struct vm_area_struct *vma, vm_flags_t vm_flags,
+ bool wp_async);
static inline bool vma_has_uffd_without_event_remap(struct vm_area_struct *vma)
{
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index af61b95c89e4..8dc964389b0d 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -1977,6 +1977,40 @@ ssize_t move_pages(struct userfaultfd_ctx *ctx, unsigned long dst_start,
return moved ? moved : err;
}
+bool vma_can_userfault(struct vm_area_struct *vma, vm_flags_t vm_flags,
+ bool wp_async)
+{
+ vm_flags &= __VM_UFFD_FLAGS;
+
+ if (vma->vm_flags & VM_DROPPABLE)
+ return false;
+
+ if ((vm_flags & VM_UFFD_MINOR) &&
+ (!is_vm_hugetlb_page(vma) && !vma_is_shmem(vma)))
+ return false;
+
+ /*
+ * If wp async enabled, and WP is the only mode enabled, allow any
+ * memory type.
+ */
+ if (wp_async && (vm_flags == VM_UFFD_WP))
+ return true;
+
+#ifndef CONFIG_PTE_MARKER_UFFD_WP
+ /*
+ * If user requested uffd-wp but not enabled pte markers for
+ * uffd-wp, then shmem & hugetlbfs are not supported but only
+ * anonymous.
+ */
+ if ((vm_flags & VM_UFFD_WP) && !vma_is_anonymous(vma))
+ return false;
+#endif
+
+ /* By default, allow any of anon|shmem|hugetlb */
+ return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) ||
+ vma_is_shmem(vma);
+}
+
static void userfaultfd_set_vm_flags(struct vm_area_struct *vma,
vm_flags_t vm_flags)
{
--
2.50.1
next prev parent reply other threads:[~2025-11-17 11:46 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-17 11:46 [RFC PATCH 0/4] mm, kvm: add guest_memfd support for uffd minor faults Mike Rapoport
2025-11-17 11:46 ` Mike Rapoport [this message]
2025-11-17 17:00 ` [RFC PATCH 1/4] userfaultfd: move vma_can_userfault out of line David Hildenbrand (Red Hat)
2025-11-17 11:46 ` [RFC PATCH 2/4] userfaultfd, shmem: use a VMA callback to handle UFFDIO_CONTINUE Mike Rapoport
2025-11-17 17:08 ` David Hildenbrand (Red Hat)
2025-11-21 11:52 ` Mike Rapoport
2025-11-17 11:46 ` [RFC PATCH 3/4] userfaultfd, guest_memfd: support userfault minor mode in guest_memfd Mike Rapoport
2025-11-18 16:41 ` David Hildenbrand (Red Hat)
2025-11-21 11:59 ` Mike Rapoport
2025-11-17 11:46 ` [RFC PATCH 4/4] KVM: selftests: test userfaultfd minor for guest_memfd Mike Rapoport
2025-11-17 17:55 ` [RFC PATCH 0/4] mm, kvm: add guest_memfd support for uffd minor faults Nikita Kalyazin
2025-11-17 19:39 ` Peter Xu
2025-11-19 17:35 ` Nikita Kalyazin
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