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 X-Spam-Level: X-Spam-Status: No, score=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AC99CC433E7 for ; Fri, 9 Oct 2020 13:31:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 67DA2222BA for ; Fri, 9 Oct 2020 13:31:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388635AbgJINbV (ORCPT ); Fri, 9 Oct 2020 09:31:21 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:15200 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1733281AbgJINbR (ORCPT ); Fri, 9 Oct 2020 09:31:17 -0400 Received: from DGGEMS407-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id E9E41D92F087A57A3BDC; Fri, 9 Oct 2020 21:31:13 +0800 (CST) Received: from huawei.com (10.175.104.175) by DGGEMS407-HUB.china.huawei.com (10.3.19.207) with Microsoft SMTP Server id 14.3.487.0; Fri, 9 Oct 2020 21:31:07 +0800 From: Miaohe Lin To: CC: , , Subject: [PATCH] mm/swap_state: Skip meaningless swap cache readahead when ra_info.win == 0 Date: Fri, 9 Oct 2020 09:30:59 -0400 Message-ID: <20201009133059.58407-1-linmiaohe@huawei.com> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.104.175] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org swap_ra_info() may leave ra_info untouched in non_swap_entry() case as page table lock is not held. In this case, we have ra_info.nr_pte == 0 and it is meaningless to continue with swap cache readahead. Skip such ops by init ra_info.win = 1. Signed-off-by: Miaohe Lin --- mm/swap_state.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/swap_state.c b/mm/swap_state.c index ee465827420e..b9013c3f94c9 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -839,7 +839,7 @@ static struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask, swp_entry_t entry; unsigned int i; bool page_allocated; - struct vma_swap_readahead ra_info = {0,}; + struct vma_swap_readahead ra_info = {1,}; swap_ra_info(vmf, &ra_info); if (ra_info.win == 1) -- 2.19.1