ksm: prepare to new THP semantics

[karo-tx-linux.git] / mm / ksm.c

diff --git a/mm/ksm.c b/mm/ksm.c
index b5cd647daa524935f73ae99f6e42743771768eaa..80c29b1b2b8af3b631dfb30954794560394f1af0 100644 (file)
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -441,20 +441,6 @@ static void break_cow(struct rmap_item *rmap_item)
        up_read(&mm->mmap_sem);
 }
 
-static struct page *page_trans_compound_anon(struct page *page)
-{
-       if (PageTransCompound(page)) {
-               struct page *head = compound_head(page);
-               /*
-                * head may actually be splitted and freed from under
-                * us but it's ok here.
-                */
-               if (PageAnon(head))
-                       return head;
-       }
-       return NULL;
-}
-
 static struct page *get_mergeable_page(struct rmap_item *rmap_item)
 {
        struct mm_struct *mm = rmap_item->mm;
@@ -470,7 +456,7 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
        page = follow_page(vma, addr, FOLL_GET);
        if (IS_ERR_OR_NULL(page))
                goto out;
-       if (PageAnon(page) || page_trans_compound_anon(page)) {
+       if (PageAnon(page)) {
                flush_anon_page(vma, page, addr);
                flush_dcache_page(page);
        } else {
@@ -740,8 +726,7 @@ static int remove_stable_node(struct stable_node *stable_node)
 
 static int remove_all_stable_nodes(void)
 {
-       struct stable_node *stable_node;
-       struct list_head *this, *next;
+       struct stable_node *stable_node, *next;
        int nid;
        int err = 0;
 
@@ -756,8 +741,7 @@ static int remove_all_stable_nodes(void)
                        cond_resched();
                }
        }
-       list_for_each_safe(this, next, &migrate_nodes) {
-               stable_node = list_entry(this, struct stable_node, list);
+       list_for_each_entry_safe(stable_node, next, &migrate_nodes, list) {
                if (remove_stable_node(stable_node))
                        err = -EBUSY;
                cond_resched();
@@ -958,13 +942,13 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
        }
 
        get_page(kpage);
-       page_add_anon_rmap(kpage, vma, addr);
+       page_add_anon_rmap(kpage, vma, addr, false);
 
        flush_cache_page(vma, addr, pte_pfn(*ptep));
        ptep_clear_flush_notify(vma, addr, ptep);
        set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot));
 
-       page_remove_rmap(page);
+       page_remove_rmap(page, false);
        if (!page_mapped(page))
                try_to_free_swap(page);
        put_page(page);
@@ -977,33 +961,6 @@ out:
        return err;
 }
 
-static int page_trans_compound_anon_split(struct page *page)
-{
-       int ret = 0;
-       struct page *transhuge_head = page_trans_compound_anon(page);
-       if (transhuge_head) {
-               /* Get the reference on the head to split it. */
-               if (get_page_unless_zero(transhuge_head)) {
-                       /*
-                        * Recheck we got the reference while the head
-                        * was still anonymous.
-                        */
-                       if (PageAnon(transhuge_head))
-                               ret = split_huge_page(transhuge_head);
-                       else
-                               /*
-                                * Retry later if split_huge_page run
-                                * from under us.
-                                */
-                               ret = 1;
-                       put_page(transhuge_head);
-               } else
-                       /* Retry later if split_huge_page run from under us. */
-                       ret = 1;
-       }
-       return ret;
-}
-
 /*
  * try_to_merge_one_page - take two pages and merge them into one
  * @vma: the vma that holds the pte pointing to page
@@ -1022,9 +979,6 @@ static int try_to_merge_one_page(struct vm_area_struct *vma,
        if (page == kpage)                      /* ksm page forked */
                return 0;
 
-       if (PageTransCompound(page) && page_trans_compound_anon_split(page))
-               goto out;
-       BUG_ON(PageTransCompound(page));
        if (!PageAnon(page))
                goto out;
 
@@ -1037,6 +991,13 @@ static int try_to_merge_one_page(struct vm_area_struct *vma,
         */
        if (!trylock_page(page))
                goto out;
+
+       if (PageTransCompound(page)) {
+               err = split_huge_page(page);
+               if (err)
+                       goto out_unlock;
+       }
+
        /*
         * If this anonymous page is mapped only here, its pte may need
         * to be write-protected.  If it's mapped elsewhere, all of its
@@ -1067,6 +1028,7 @@ static int try_to_merge_one_page(struct vm_area_struct *vma,
                }
        }
 
+out_unlock:
        unlock_page(page);
 out:
        return err;
@@ -1583,13 +1545,11 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
                 * so prune them once before each full scan.
                 */
                if (!ksm_merge_across_nodes) {
-                       struct stable_node *stable_node;
-                       struct list_head *this, *next;
+                       struct stable_node *stable_node, *next;
                        struct page *page;
 
-                       list_for_each_safe(this, next, &migrate_nodes) {
-                               stable_node = list_entry(this,
-                                               struct stable_node, list);
+                       list_for_each_entry_safe(stable_node, next,
+                                                &migrate_nodes, list) {
                                page = get_ksm_page(stable_node, false);
                                if (page)
                                        put_page(page);
@@ -1639,8 +1599,7 @@ next_mm:
                                cond_resched();
                                continue;
                        }
-                       if (PageAnon(*page) ||
-                           page_trans_compound_anon(*page)) {
+                       if (PageAnon(*page)) {
                                flush_anon_page(vma, *page, ksm_scan.address);
                                flush_dcache_page(*page);
                                rmap_item = get_next_rmap_item(slot,
@@ -1903,7 +1862,7 @@ struct page *ksm_might_need_to_copy(struct page *page,
 
                SetPageDirty(new_page);
                __SetPageUptodate(new_page);
-               __set_page_locked(new_page);
+               __SetPageLocked(new_page);
        }
 
        return new_page;
@@ -2012,8 +1971,7 @@ static void wait_while_offlining(void)
 static void ksm_check_stable_tree(unsigned long start_pfn,
                                  unsigned long end_pfn)
 {
-       struct stable_node *stable_node;
-       struct list_head *this, *next;
+       struct stable_node *stable_node, *next;
        struct rb_node *node;
        int nid;
 
@@ -2034,8 +1992,7 @@ static void ksm_check_stable_tree(unsigned long start_pfn,
                        cond_resched();
                }
        }
-       list_for_each_safe(this, next, &migrate_nodes) {
-               stable_node = list_entry(this, struct stable_node, list);
+       list_for_each_entry_safe(stable_node, next, &migrate_nodes, list) {
                if (stable_node->kpfn >= start_pfn &&
                    stable_node->kpfn < end_pfn)
                        remove_node_from_stable_tree(stable_node);