FAILED: patch "[PATCH] mm/zsmalloc: do not pass __GFP_MOVABLE if CONFIG_COMPACTION=n" failed to apply to 5.4-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 694d6b99923eb05a8fd188be44e26077d19f0e21
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025072811-ethanol-arbitrary-a664@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 694d6b99923eb05a8fd188be44e26077d19f0e21 Mon Sep 17 00:00:00 2001
From: Harry Yoo <harry.yoo@oracle.com>
Date: Fri, 4 Jul 2025 19:30:53 +0900
Subject: [PATCH] mm/zsmalloc: do not pass __GFP_MOVABLE if CONFIG_COMPACTION=n

Commit 48b4800a1c6a ("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: 48b4800a1c6a ("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>

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 999b513c7fdf..f3e2215f95eb 100644
--- a/mm/zsmalloc.c
+++ b/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;