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authorDavid Hildenbrand <david@redhat.com>2022-11-16 11:26:46 +0100
committerAndrew Morton <akpm@linux-foundation.org>2022-11-30 15:58:58 -0800
commitaea06577a9005ca81c35196d6171cac346d3b251 (patch)
tree4b85baac7d202c287e6d66da5b2b8f45761ec79f /mm/memory.c
parentb9086fde6d44e8a95dc95b822bd87386129b832d (diff)
mm: don't call vm_ops->huge_fault() in wp_huge_pmd()/wp_huge_pud() for private mappings
If we already have a PMD/PUD mapped write-protected in a private mapping and we want to break COW either due to FAULT_FLAG_WRITE or FAULT_FLAG_UNSHARE, there is no need to inform the file system just like on the PTE path. Let's just split (->zap) + fallback in that case. This is a preparation for more generic FAULT_FLAG_UNSHARE support in COW mappings. Link: https://lkml.kernel.org/r/20221116102659.70287-8-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c24
1 files changed, 15 insertions, 9 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 5d4b42f1a8d6..6cec0adab37f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4802,6 +4802,7 @@ static inline vm_fault_t create_huge_pmd(struct vm_fault *vmf)
static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf)
{
const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE;
+ vm_fault_t ret;
if (vma_is_anonymous(vmf->vma)) {
if (likely(!unshare) &&
@@ -4809,11 +4810,13 @@ static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf)
return handle_userfault(vmf, VM_UFFD_WP);
return do_huge_pmd_wp_page(vmf);
}
- if (vmf->vma->vm_ops->huge_fault) {
- vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD);
- if (!(ret & VM_FAULT_FALLBACK))
- return ret;
+ if (vmf->vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) {
+ if (vmf->vma->vm_ops->huge_fault) {
+ ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD);
+ if (!(ret & VM_FAULT_FALLBACK))
+ return ret;
+ }
}
/* COW or write-notify handled on pte level: split pmd. */
@@ -4839,14 +4842,17 @@ static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud)
{
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
+ vm_fault_t ret;
+
/* No support for anonymous transparent PUD pages yet */
if (vma_is_anonymous(vmf->vma))
goto split;
- if (vmf->vma->vm_ops->huge_fault) {
- vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD);
-
- if (!(ret & VM_FAULT_FALLBACK))
- return ret;
+ if (vmf->vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) {
+ if (vmf->vma->vm_ops->huge_fault) {
+ ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD);
+ if (!(ret & VM_FAULT_FALLBACK))
+ return ret;
+ }
}
split:
/* COW or write-notify not handled on PUD level: split pud.*/