From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3B975293C4B; Wed, 30 Jul 2025 09:54:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753869269; cv=none; b=lOOw5RBy8niUy9o2OUHKEnOUKyElLg/UFNXcdzO3LglFSfjkWS4JXl1cKNnWpIICl2vRcfRbkXdoLl4MCrP+ymaFK18Ox32WeyLISAoGmF5DitN1vXLnR2LFXX9hVmR8DjI/ISGjMyF3RkcIKi4eNaSbyrEqn9ldI5vsUVL6kGU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753869269; c=relaxed/simple; bh=+oznMkJv7HfzA60uyCd3JCf0vK/mdL+8agN7IkiE2gA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=az4L2mcKXOemGPkMd7EJvg8dot70XgR3jMdDZkQy60SYZOpz27CCe6Y2yG6PNPQCqwBkkCTWRx5LpgwZqEpI2q7s2KfXVIwKMP8N7bUAaieY4QhKhCG7+JREbw/NtyYoYirFaPNeifsgd7JbG8rOmHHJ3Zr+KjqycGQP4cvaZHo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EgOThebd; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="EgOThebd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2513AC4CEFA; Wed, 30 Jul 2025 09:54:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1753869269; bh=+oznMkJv7HfzA60uyCd3JCf0vK/mdL+8agN7IkiE2gA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EgOThebd4yug9hIpTz/2QTy3qtOLkGq53VXSqhTWDw+l1NDxl+vnPKCxEYp3mxvNx vO27Z7G820VQGOaRs5dWGqTOmvySAN0tOrOrASEokRLmHNfK+B+KOy+vqE8GC88XR1 gQcR26dveSiRzgcouPNzaJFtUV/bMQc6W/DB1UqM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Harry Yoo , David Hildenbrand , Sergey Senozhatsky , Minchan Kim , Andrew Morton Subject: [PATCH 6.15 79/92] mm/zsmalloc: do not pass __GFP_MOVABLE if CONFIG_COMPACTION=n Date: Wed, 30 Jul 2025 11:36:27 +0200 Message-ID: <20250730093233.811136065@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250730093230.629234025@linuxfoundation.org> References: <20250730093230.629234025@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Harry Yoo commit 694d6b99923eb05a8fd188be44e26077d19f0e21 upstream. 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 Acked-by: David Hildenbrand Reviewed-by: Sergey Senozhatsky Cc: Minchan Kim Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/zsmalloc.c | 3 +++ 1 file changed, 3 insertions(+) --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1053,6 +1053,9 @@ static struct zspage *alloc_zspage(struc if (!zspage) return NULL; + if (!IS_ENABLED(CONFIG_COMPACTION)) + gfp &= ~__GFP_MOVABLE; + zspage->magic = ZSPAGE_MAGIC; zspage->pool = pool; zspage->class = class->index;