hugepage: convert huge zero page shrinker to new shrinker API

It consists of:

* returning long instead of int
* separating count from scan
* returning the number of freed entities in scan

Signed-off-by: Glauber Costa <[email protected]>
Reviewed-by: Greg Thelen <[email protected]>
Acked-by: Kirill A. Shutemov <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: "Theodore Ts'o" <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Artem Bityutskiy <[email protected]>
Cc: Arve Hjønnevåg <[email protected]>
Cc: Carlos Maiolino <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Chuck Lever <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Gleb Natapov <[email protected]>
Cc: Greg Thelen <[email protected]>
Cc: J. Bruce Fields <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Jerome Glisse <[email protected]>
Cc: John Stultz <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Marcelo Tosatti <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Steven Whitehouse <[email protected]>
Cc: Thomas Hellstrom <[email protected]>
Cc: Trond Myklebust <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Al Viro <[email protected]>

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index a92012a71702e7156baba919e636bcfcce8971f2..d94f7dee3997cd7d5bcad601a339be9f58507852 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -211,24 +211,29 @@ static void put_huge_zero_page(void)
        BUG_ON(atomic_dec_and_test(&huge_zero_refcount));
 }
 
-static int shrink_huge_zero_page(struct shrinker *shrink,
-               struct shrink_control *sc)
+static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink,
+                                       struct shrink_control *sc)
 {
-       if (!sc->nr_to_scan)
-               /* we can free zero page only if last reference remains */
-               return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0;
+       /* we can free zero page only if last reference remains */
+       return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0;
+}
 
+static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink,
+                                      struct shrink_control *sc)
+{
        if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) {
                struct page *zero_page = xchg(&huge_zero_page, NULL);
                BUG_ON(zero_page == NULL);
                __free_page(zero_page);
+               return HPAGE_PMD_NR;
        }
 
        return 0;
 }
 
 static struct shrinker huge_zero_page_shrinker = {
-       .shrink = shrink_huge_zero_page,
+       .count_objects = shrink_huge_zero_page_count,
+       .scan_objects = shrink_huge_zero_page_scan,
        .seeks = DEFAULT_SEEKS,
 };