}
/*
+ * Some rmap walk that needs to find all ptes/hugepmds without false
+ * negatives (like migrate and split_huge_page) running concurrent
+ * with operations that copy or move pagetables (like mremap() and
+ * fork()) to be safe. They depend on the anon_vma "same_anon_vma"
+ * list to be in a certain order: the dst_vma must be placed after the
+ * src_vma in the list. This is always guaranteed by fork() but
+ * mremap() needs to call this function to enforce it in case the
+ * dst_vma isn't newly allocated and chained with the anon_vma_clone()
+ * function but just an extension of a pre-existing vma through
+ * vma_merge.
+ *
+ * NOTE: the same_anon_vma list can still be changed by other
+ * processes while mremap runs because mremap doesn't hold the
+ * anon_vma mutex to prevent modifications to the list while it
+ * runs. All we need to enforce is that the relative order of this
+ * process vmas isn't changing (we don't care about other vmas
+ * order). Each vma corresponds to an anon_vma_chain structure so
+ * there's no risk that other processes calling anon_vma_moveto_tail()
+ * and changing the same_anon_vma list under mremap() will screw with
+ * the relative order of this process vmas in the list, because we
+ * they can't alter the order of any vma that belongs to this
+ * process. And there can't be another anon_vma_moveto_tail() running
+ * concurrently with mremap() coming from this process because we hold
+ * the mmap_sem for the whole mremap(). fork() ordering dependency
+ * also shouldn't be affected because fork() only cares that the
+ * parent vmas are placed in the list before the child vmas and
+ * anon_vma_moveto_tail() won't reorder vmas from either the fork()
+ * parent or child.
+ */
+void anon_vma_moveto_tail(struct vm_area_struct *dst)
+{
+ struct anon_vma_chain *pavc;
+ struct anon_vma *root = NULL;
+
+ list_for_each_entry_reverse(pavc, &dst->anon_vma_chain, same_vma) {
+ struct anon_vma *anon_vma = pavc->anon_vma;
+ VM_BUG_ON(pavc->vma != dst);
+ root = lock_anon_vma_root(root, anon_vma);
+ list_del(&pavc->same_anon_vma);
+ list_add_tail(&pavc->same_anon_vma, &anon_vma->head);
+ }
+ unlock_anon_vma_root(root);
+}
+
+/*
* Attach vma to its own anon_vma, as well as to the anon_vmas that
* the corresponding VMA in the parent process is attached to.
* Returns 0 on success, non-zero on failure.
}
static int page_referenced_anon(struct page *page,
- struct mem_cgroup *mem_cont,
+ struct mem_cgroup *memcg,
unsigned long *vm_flags)
{
unsigned int mapcount;
* counting on behalf of references from different
* cgroups
*/
- if (mem_cont && !mm_match_cgroup(vma->vm_mm, mem_cont))
+ if (memcg && !mm_match_cgroup(vma->vm_mm, memcg))
continue;
referenced += page_referenced_one(page, vma, address,
&mapcount, vm_flags);
/**
* page_referenced_file - referenced check for object-based rmap
* @page: the page we're checking references on.
- * @mem_cont: target memory controller
+ * @memcg: target memory control group
* @vm_flags: collect encountered vma->vm_flags who actually referenced the page
*
* For an object-based mapped page, find all the places it is mapped and
* This function is only called from page_referenced for object-based pages.
*/
static int page_referenced_file(struct page *page,
- struct mem_cgroup *mem_cont,
+ struct mem_cgroup *memcg,
unsigned long *vm_flags)
{
unsigned int mapcount;
* counting on behalf of references from different
* cgroups
*/
- if (mem_cont && !mm_match_cgroup(vma->vm_mm, mem_cont))
+ if (memcg && !mm_match_cgroup(vma->vm_mm, memcg))
continue;
referenced += page_referenced_one(page, vma, address,
&mapcount, vm_flags);
* page_referenced - test if the page was referenced
* @page: the page to test
* @is_locked: caller holds lock on the page
- * @mem_cont: target memory controller
+ * @memcg: target memory cgroup
* @vm_flags: collect encountered vma->vm_flags who actually referenced the page
*
* Quick test_and_clear_referenced for all mappings to a page,
*/
int page_referenced(struct page *page,
int is_locked,
- struct mem_cgroup *mem_cont,
+ struct mem_cgroup *memcg,
unsigned long *vm_flags)
{
int referenced = 0;
}
}
if (unlikely(PageKsm(page)))
- referenced += page_referenced_ksm(page, mem_cont,
+ referenced += page_referenced_ksm(page, memcg,
vm_flags);
else if (PageAnon(page))
- referenced += page_referenced_anon(page, mem_cont,
+ referenced += page_referenced_anon(page, memcg,
vm_flags);
else if (page->mapping)
- referenced += page_referenced_file(page, mem_cont,
+ referenced += page_referenced_file(page, memcg,
vm_flags);
if (we_locked)
unlock_page(page);
projects / platform / adaptation / renesas_rcar / renesas_kernel.git / blobdiff