thp: clean up __collapse_huge_page_isolate
Bob Liu [Wed, 12 Dec 2012 00:00:34 +0000 (16:00 -0800)]
There are duplicated places using release_pte_pages().
And release_all_pte_pages() can be removed.

Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Ni zhan Chen <nizhan.chen@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/huge_memory.c

index 40f17c3..6f022f5 100644 (file)
@@ -1701,64 +1701,49 @@ static void release_pte_pages(pte_t *pte, pte_t *_pte)
        }
 }
 
-static void release_all_pte_pages(pte_t *pte)
-{
-       release_pte_pages(pte, pte + HPAGE_PMD_NR);
-}
-
 static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
                                        unsigned long address,
                                        pte_t *pte)
 {
        struct page *page;
        pte_t *_pte;
-       int referenced = 0, isolated = 0, none = 0;
+       int referenced = 0, none = 0;
        for (_pte = pte; _pte < pte+HPAGE_PMD_NR;
             _pte++, address += PAGE_SIZE) {
                pte_t pteval = *_pte;
                if (pte_none(pteval)) {
                        if (++none <= khugepaged_max_ptes_none)
                                continue;
-                       else {
-                               release_pte_pages(pte, _pte);
+                       else
                                goto out;
-                       }
                }
-               if (!pte_present(pteval) || !pte_write(pteval)) {
-                       release_pte_pages(pte, _pte);
+               if (!pte_present(pteval) || !pte_write(pteval))
                        goto out;
-               }
                page = vm_normal_page(vma, address, pteval);
-               if (unlikely(!page)) {
-                       release_pte_pages(pte, _pte);
+               if (unlikely(!page))
                        goto out;
-               }
+
                VM_BUG_ON(PageCompound(page));
                BUG_ON(!PageAnon(page));
                VM_BUG_ON(!PageSwapBacked(page));
 
                /* cannot use mapcount: can't collapse if there's a gup pin */
-               if (page_count(page) != 1) {
-                       release_pte_pages(pte, _pte);
+               if (page_count(page) != 1)
                        goto out;
-               }
                /*
                 * We can do it before isolate_lru_page because the
                 * page can't be freed from under us. NOTE: PG_lock
                 * is needed to serialize against split_huge_page
                 * when invoked from the VM.
                 */
-               if (!trylock_page(page)) {
-                       release_pte_pages(pte, _pte);
+               if (!trylock_page(page))
                        goto out;
-               }
                /*
                 * Isolate the page to avoid collapsing an hugepage
                 * currently in use by the VM.
                 */
                if (isolate_lru_page(page)) {
                        unlock_page(page);
-                       release_pte_pages(pte, _pte);
                        goto out;
                }
                /* 0 stands for page_is_file_cache(page) == false */
@@ -1771,12 +1756,11 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
                    mmu_notifier_test_young(vma->vm_mm, address))
                        referenced = 1;
        }
-       if (unlikely(!referenced))
-               release_all_pte_pages(pte);
-       else
-               isolated = 1;
+       if (likely(referenced))
+               return 1;
 out:
-       return isolated;
+       release_pte_pages(pte, _pte);
+       return 0;
 }
 
 static void __collapse_huge_page_copy(pte_t *pte, struct page *page,