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 ADD58ECAAD3 for ; Tue, 6 Sep 2022 02:44:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232447AbiIFCow (ORCPT ); Mon, 5 Sep 2022 22:44:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57832 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232503AbiIFCot (ORCPT ); Mon, 5 Sep 2022 22:44:49 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC51215FDE for ; Mon, 5 Sep 2022 19:44:47 -0700 (PDT) Received: from dggpemm500023.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MM8kS72WNzZcNm; Tue, 6 Sep 2022 10:40:16 +0800 (CST) Received: from dggpemm500002.china.huawei.com (7.185.36.229) by dggpemm500023.china.huawei.com (7.185.36.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 6 Sep 2022 10:44:45 +0800 Received: from localhost.localdomain (10.175.112.125) by dggpemm500002.china.huawei.com (7.185.36.229) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 6 Sep 2022 10:44:45 +0800 From: Chen Wandun To: , , CC: , Subject: [PATCH] mm: avoid unnecessary page table walk for __get_user_pages Date: Tue, 6 Sep 2022 10:44:01 +0800 Message-ID: <20220906024401.133336-1-chenwandun@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpemm500002.china.huawei.com (7.185.36.229) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It is no need to walk page table and find pages if faultin_page success and __get_user_pages does't care pages at all, so directly handle next page. Signed-off-by: Chen Wandun --- mm/gup.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/gup.c b/mm/gup.c index 983e24fd4b70..c8de33cc37af 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1198,7 +1198,10 @@ static long __get_user_pages(struct mm_struct *mm, PTR_ERR(page) == -EMLINK, locked); switch (ret) { case 0: - goto retry; + if (pages) + goto retry; + else + goto next_page; case -EBUSY: case -EAGAIN: ret = 0; -- 2.25.1