mm: remove unevictable's show_page_path

Hugh Dickins reported show_page_path() is buggy and unsafe because

 - lack dput() against d_find_alias()
 - don't concern vma->vm_mm->owner == NULL
 - lack lock_page()

it was only for debugging, so rather than trying to fix it, just remove
it now.

Reported-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
CC: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 3b58602..c141b3e 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2368,39 +2368,6 @@ int page_evictable(struct page *page, struct vm_area_struct *vma)
        return 1;
 }
 
-static void show_page_path(struct page *page)
-{
-       char buf[256];
-       if (page_is_file_cache(page)) {
-               struct address_space *mapping = page->mapping;
-               struct dentry *dentry;
-               pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
-
-               spin_lock(&mapping->i_mmap_lock);
-               dentry = d_find_alias(mapping->host);
-               printk(KERN_INFO "rescued: %s %lu\n",
-                      dentry_path(dentry, buf, 256), pgoff);
-               spin_unlock(&mapping->i_mmap_lock);
-       } else {
-#if defined(CONFIG_MM_OWNER) && defined(CONFIG_MMU)
-               struct anon_vma *anon_vma;
-               struct vm_area_struct *vma;
-
-               anon_vma = page_lock_anon_vma(page);
-               if (!anon_vma)
-                       return;
-
-               list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {
-                       printk(KERN_INFO "rescued: anon %s\n",
-                              vma->vm_mm->owner->comm);
-                       break;
-               }
-               page_unlock_anon_vma(anon_vma);
-#endif
-       }
-}
-
-
 /**
  * check_move_unevictable_page - check page for evictability and move to appropriate zone lru list
  * @page: page to check evictability and move to appropriate lru list
@@ -2421,8 +2388,6 @@ retry:
        if (page_evictable(page, NULL)) {
                enum lru_list l = LRU_INACTIVE_ANON + page_is_file_cache(page);
 
-               show_page_path(page);
-
                __dec_zone_state(zone, NR_UNEVICTABLE);
                list_move(&page->lru, &zone->lru[l].list);
                __inc_zone_state(zone, NR_INACTIVE_ANON + l);