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 AD8D2C43334 for ; Tue, 28 Jun 2022 13:31:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345675AbiF1NbD (ORCPT ); Tue, 28 Jun 2022 09:31:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346422AbiF1N35 (ORCPT ); Tue, 28 Jun 2022 09:29:57 -0400 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D7012AC78 for ; Tue, 28 Jun 2022 06:28:45 -0700 (PDT) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.56]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4LXQNN1VVjz1L8Vy; Tue, 28 Jun 2022 21:26:28 +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; Tue, 28 Jun 2022 21:28:42 +0800 From: Miaohe Lin To: CC: , , , , , , Subject: [PATCH v2 10/16] mm/huge_memory: check pmd_present first in is_huge_zero_pmd Date: Tue, 28 Jun 2022 21:28:29 +0800 Message-ID: <20220628132835.8925-11-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20220628132835.8925-1-linmiaohe@huawei.com> References: <20220628132835.8925-1-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: dggems701-chm.china.huawei.com (10.3.19.178) 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 When pmd is non-present, pmd_pfn returns an insane value. So we should check pmd_present first to avoid acquiring such insane value and also avoid touching possible cold huge_zero_pfn cache line when pmd isn't present. Signed-off-by: Miaohe Lin Reviewed-by: Muchun Song --- include/linux/huge_mm.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index ae3d8e2fd9e2..12b297f9951d 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -273,7 +273,7 @@ static inline bool is_huge_zero_page(struct page *page) static inline bool is_huge_zero_pmd(pmd_t pmd) { - return READ_ONCE(huge_zero_pfn) == pmd_pfn(pmd) && pmd_present(pmd); + return pmd_present(pmd) && READ_ONCE(huge_zero_pfn) == pmd_pfn(pmd); } static inline bool is_huge_zero_pud(pud_t pud) -- 2.23.0