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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 3E366C433E0 for ; Mon, 4 Jan 2021 02:41:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0264D207FB for ; Mon, 4 Jan 2021 02:41:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727939AbhADCli (ORCPT ); Sun, 3 Jan 2021 21:41:38 -0500 Received: from mail.cn.fujitsu.com ([183.91.158.132]:16931 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727922AbhADCli (ORCPT ); Sun, 3 Jan 2021 21:41:38 -0500 X-IronPort-AV: E=Sophos;i="5.78,472,1599494400"; d="scan'208";a="103151571" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 04 Jan 2021 10:40:46 +0800 Received: from G08CNEXMBPEKD06.g08.fujitsu.local (unknown [10.167.33.206]) by cn.fujitsu.com (Postfix) with ESMTP id 81C544CE546D; Mon, 4 Jan 2021 10:40:42 +0800 (CST) Received: from G08CNEXCHPEKD06.g08.fujitsu.local (10.167.33.205) by G08CNEXMBPEKD06.g08.fujitsu.local (10.167.33.206) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 4 Jan 2021 10:40:43 +0800 Received: from localhost.localdomain (10.167.225.206) by G08CNEXCHPEKD06.g08.fujitsu.local (10.167.33.209) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Mon, 4 Jan 2021 10:40:42 +0800 From: Hao Li To: CC: , , , , , , , , Subject: [PATCH] Documentation/dax: Update description of DAX policy changing Date: Mon, 4 Jan 2021 10:40:40 +0800 Message-ID: <20210104024040.5381-1-lihao2018.fnst@cn.fujitsu.com> X-Mailer: git-send-email 2.28.0 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-yoursite-MailScanner-ID: 81C544CE546D.AB630 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: lihao2018.fnst@cn.fujitsu.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org After commit 77573fa310d9 ("fs: Kill DCACHE_DONTCACHE dentry even if DCACHE_REFERENCED is set"), changes to DAX policy will take effect as soon as all references to this file are gone. Update the documentation accordingly. Signed-off-by: Hao Li --- Documentation/filesystems/dax.txt | 15 ++------------- 1 file changed, 2 insertions(+), 13 deletions(-) diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.txt index 8fdb78f3c6c9..a5af22831087 100644 --- a/Documentation/filesystems/dax.txt +++ b/Documentation/filesystems/dax.txt @@ -84,19 +84,8 @@ Summary described in 6) below. 6. When changing the S_DAX policy via toggling the persistent FS_XFLAG_DAX flag, - the change in behaviour for existing regular files may not occur - immediately. If the change must take effect immediately, the administrator - needs to: - - a) stop the application so there are no active references to the data set - the policy change will affect - - b) evict the data set from kernel caches so it will be re-instantiated when - the application is restarted. This can be achieved by: - - i. drop-caches - ii. a filesystem unmount and mount cycle - iii. a system reboot + the change to existing regular file won't take effect until the file is closed + by all processes or all processes referencing the file are stopped. Details -- 2.29.2