unsigned long addr = vma->vm_start;
unsigned long end = vma->vm_end;
+ /*
+ * Don't copy ptes where a page fault will fill them correctly.
+ * Fork becomes much lighter when there are big shared or private
+ * readonly mappings. The tradeoff is that copy_page_range is more
+ * efficient than faulting.
+ */
+ if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_RESERVED))) {
+ if (!vma->anon_vma)
+ return 0;
+ }
+
if (is_vm_hugetlb_page(vma))
return copy_hugetlb_page_range(dst_mm, src_mm, vma);
page->index > details->last_index))
continue;
}
- ptent = ptep_get_and_clear(tlb->mm, addr, pte);
+ ptent = ptep_get_and_clear_full(tlb->mm, addr, pte,
+ tlb->fullmm);
tlb_remove_tlb_entry(tlb, pte, addr);
if (unlikely(!page))
continue;
continue;
if (!pte_file(ptent))
free_swap_and_cache(pte_to_swp_entry(ptent));
- pte_clear(tlb->mm, addr, pte);
+ pte_clear_full(tlb->mm, addr, pte, tlb->fullmm);
} while (pte++, addr += PAGE_SIZE, addr != end);
pte_unmap(pte - 1);
}
cond_resched_lock(&mm->page_table_lock);
while (!(page = follow_page(mm, start, write_access))) {
+ int ret;
+
/*
* Shortcut for anonymous pages. We don't want
* to force the creation of pages tables for
break;
}
spin_unlock(&mm->page_table_lock);
- switch (__handle_mm_fault(mm, vma, start,
- write_access)) {
- case VM_FAULT_WRITE:
- /*
- * do_wp_page has broken COW when
- * necessary, even if maybe_mkwrite
- * decided not to set pte_write
- */
+ ret = __handle_mm_fault(mm, vma, start, write_access);
+
+ /*
+ * The VM_FAULT_WRITE bit tells us that do_wp_page has
+ * broken COW when necessary, even if maybe_mkwrite
+ * decided not to set pte_write. We can thus safely do
+ * subsequent page lookups as if they were reads.
+ */
+ if (ret & VM_FAULT_WRITE)
write_access = 0;
- /* FALLTHRU */
+
+ switch (ret & ~VM_FAULT_WRITE) {
case VM_FAULT_MINOR:
tsk->min_flt++;
break;
* Fall back to the linear mapping if the fs does not support
* ->populate:
*/
- if (!vma->vm_ops || !vma->vm_ops->populate ||
+ if (!vma->vm_ops->populate ||
(write_access && !(vma->vm_flags & VM_SHARED))) {
pte_clear(mm, address, pte);
return do_no_page(mm, vma, address, write_access, pte, pmd);
#if !defined(__HAVE_ARCH_GATE_AREA)
#if defined(AT_SYSINFO_EHDR)
-struct vm_area_struct gate_vma;
+static struct vm_area_struct gate_vma;
static int __init gate_vma_init(void)
{