Commit 48b4800a1c ("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/20250704103053.6913-1-harry.yoo@oracle.com
Fixes: 48b4800a1c ("zsmalloc: page migration support")
Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
694d6b9992