mm/zsmalloc: do not pass __GFP_MOVABLE if CONFIG_COMPACTION=n

Commit 48b4800 ("zsmalloc: page migration support") added support for
migrating zsmalloc pages using the movable_operations migration framework.
However, the commit did not take into account that zsmalloc supports
migration only when CONFIG_COMPACTION is enabled.  Tracing shows that
zsmalloc was still passing the __GFP_MOVABLE flag even when compaction is
not supported.

This can result in unmovable pages being allocated from movable page
blocks (even without stealing page blocks), ZONE_MOVABLE and CMA area.

Possible user visible effects:
- Some ZONE_MOVABLE memory can be not actually movable
- CMA allocation can fail because of this
- Increased memory fragmentation due to ignoring the page mobility
  grouping feature  
I'm not really sure who uses kernels without compaction support, though :(


To fix this, clear the __GFP_MOVABLE flag when
!IS_ENABLED(CONFIG_COMPACTION).

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 48b4800 ("zsmalloc: page migration support")
Signed-off-by: Harry Yoo <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Reviewed-by: Sergey Senozhatsky <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: hygoni

mm/zsmalloc.c

@@ -1043,6 +1043,9 @@ static struct zspage *alloc_zspage(struct zs_pool *pool,
 	if (!zspage)
 		return NULL;
 
+	if (!IS_ENABLED(CONFIG_COMPACTION))
+		gfp &= ~__GFP_MOVABLE;
+
 	zspage->magic = ZSPAGE_MAGIC;
 	zspage->pool = pool;
 	zspage->class = class->index;