zsmalloc: cosmetic compaction code adjustments

Change zs_object_copy() argument order to be (DST, SRC) rather than
(SRC, DST).  copy/move functions usually have (to, from) arguments
order.

Rename alloc_target_page() to isolate_target_page().  This function
doesn't allocate anything, it isolates target page, pretty much like
isolate_source_page().

Tweak __zs_compact() comment.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 4b39e5e..2a1f952 100644 (file)
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1471,7 +1471,7 @@ void zs_free(struct zs_pool *pool, unsigned long handle)
 }
 EXPORT_SYMBOL_GPL(zs_free);
 
-static void zs_object_copy(unsigned long src, unsigned long dst,
+static void zs_object_copy(unsigned long dst, unsigned long src,
                                struct size_class *class)
 {
        struct page *s_page, *d_page;
@@ -1612,7 +1612,7 @@ static int migrate_zspage(struct zs_pool *pool, struct size_class *class,
 
                used_obj = handle_to_obj(handle);
                free_obj = obj_malloc(d_page, class, handle);
-               zs_object_copy(used_obj, free_obj, class);
+               zs_object_copy(free_obj, used_obj, class);
                index++;
                record_obj(handle, free_obj);
                unpin_tag(handle);
@@ -1628,7 +1628,7 @@ static int migrate_zspage(struct zs_pool *pool, struct size_class *class,
        return ret;
 }
 
-static struct page *alloc_target_page(struct size_class *class)
+static struct page *isolate_target_page(struct size_class *class)
 {
        int i;
        struct page *page;
@@ -1718,11 +1718,11 @@ static unsigned long __zs_compact(struct zs_pool *pool,
                cc.index = 0;
                cc.s_page = src_page;
 
-               while ((dst_page = alloc_target_page(class))) {
+               while ((dst_page = isolate_target_page(class))) {
                        cc.d_page = dst_page;
                        /*
-                        * If there is no more space in dst_page, try to
-                        * allocate another zspage.
+                        * If there is no more space in dst_page, resched
+                        * and see if anyone had allocated another zspage.
                         */
                        if (!migrate_zspage(pool, class, &cc))
                                break;