From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 21688C433F5 for ; Mon, 18 Apr 2022 15:13:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229831AbiDRPQM (ORCPT ); Mon, 18 Apr 2022 11:16:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54522 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244207AbiDRPPo (ORCPT ); Mon, 18 Apr 2022 11:15:44 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A17D3B91A1 for ; Mon, 18 Apr 2022 07:12:34 -0700 (PDT) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4KhpmC3PH9zhXXX; Mon, 18 Apr 2022 22:12:27 +0800 (CST) Received: from huawei.com (10.175.124.27) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 18 Apr 2022 22:12:32 +0800 From: Miaohe Lin To: CC: , , , , , Subject: [PATCH 12/12] mm: compaction: make sure highest is above the min_pfn Date: Mon, 18 Apr 2022 22:12:53 +0800 Message-ID: <20220418141253.24298-13-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20220418141253.24298-1-linmiaohe@huawei.com> References: <20220418141253.24298-1-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It's not guaranteed that highest will be above the min_pfn. If highest is below the min_pfn, migrate_pfn and free_pfn can meet prematurely and lead to some useless work. Make sure highest is above min_pfn to avoid making a futile effort. Signed-off-by: Miaohe Lin --- mm/compaction.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/compaction.c b/mm/compaction.c index 609a76d7e051..65970107b789 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1532,7 +1532,7 @@ fast_isolate_freepages(struct compact_control *cc) * not found, be pessimistic for direct compaction * and use the min mark. */ - if (highest) { + if (highest >= min_pfn) { page = pfn_to_page(highest); cc->free_pfn = highest; } else { -- 2.23.0