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 2323135FC1E; Tue, 26 Aug 2025 14:42:06 +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=1756219326; cv=none; b=u9sojrIC54X8vDNJj5yYrJmZ3htQBgHyA9PhotmFrZIT16SMy5ScAMT9EDw33zcbCVPVGRsHMxSMiib1W9ddH9o/bkO5wZ9SwRA3QGZYGwtAg2LcG+6cWic3Uvc8Q08wNrdJ02C4PC5ML3e4jHdYk7gSrG91D867qjrNWBG0K5I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756219326; c=relaxed/simple; bh=qvcDY7wh/80rY+4v29+tVIDjQ0cvjumB4vbUWyP1xD0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=P5V6HZ16GFdb46bF+23lcG/eto1jfa/xUS51DAOiZpStDl4tmJjT+B4EbCBo978CyOgJjPmGZO6rC88JSZxQe6m7rXCfltaDSgzvV3ewWwdvmCnQxxkD92cn4BK4+4I/U8kwoASuWiMFCBev65J+lJSW5OxDMZxPuxT8hWiC/SM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lAXKydHl; 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="lAXKydHl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A3427C116D0; Tue, 26 Aug 2025 14:42:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756219326; bh=qvcDY7wh/80rY+4v29+tVIDjQ0cvjumB4vbUWyP1xD0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lAXKydHlvQu9j/Fm09Bv9WZubRjKjSMk3VnYhdVk0xpxnxrvLg29vB0c28FSukIit 1L5kz2PbsP3w6XH2mPPeaKZ6OhfTUECRkkgE/syQ3MgiR7co0IHZRv4rYf34aNVTge h07+r2u16E9paPQdfyuwkBL5msTUT/I+BSCk7H30= 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 , Sasha Levin Subject: [PATCH 5.4 338/403] mm/zsmalloc: do not pass __GFP_MOVABLE if CONFIG_COMPACTION=n Date: Tue, 26 Aug 2025 13:11:04 +0200 Message-ID: <20250826110916.189137255@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110905.607690791@linuxfoundation.org> References: <20250826110905.607690791@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 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Harry Yoo [ Upstream commit 694d6b99923eb05a8fd188be44e26077d19f0e21 ] 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: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- mm/zsmalloc.c | 3 +++ 1 file changed, 3 insertions(+) --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1067,6 +1067,9 @@ static struct zspage *alloc_zspage(struc if (!zspage) return NULL; + if (!IS_ENABLED(CONFIG_COMPACTION)) + gfp &= ~__GFP_MOVABLE; + zspage->magic = ZSPAGE_MAGIC; migrate_lock_init(zspage);