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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 D0A09C2BB85 for ; Thu, 9 Apr 2020 20:49:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A73F22082D for ; Thu, 9 Apr 2020 20:49:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727349AbgDIUtz (ORCPT ); Thu, 9 Apr 2020 16:49:55 -0400 Received: from mga17.intel.com ([192.55.52.151]:43445 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726964AbgDIUtz (ORCPT ); Thu, 9 Apr 2020 16:49:55 -0400 IronPort-SDR: uXuWMNIRaWcJ3HWZL8ZTsRL/q4urg2weWeN1PdqnxNbjT8SlR3aEoGHjDucOfUB8ItnLhqSjB5 C44WU4ixg5TA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Apr 2020 13:49:54 -0700 IronPort-SDR: uGT2DQfawKjjxTzrrboYSQ2lFlqOecSpTc00bpqC/04zZXNNxhOiDe9kG3EkErDx95QHN0t0w6 ULbqkaHAeq0g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,364,1580803200"; d="scan'208";a="452138957" Received: from iweiny-desk2.sc.intel.com ([10.3.52.147]) by fmsmga005.fm.intel.com with ESMTP; 09 Apr 2020 13:49:53 -0700 Date: Thu, 9 Apr 2020 13:49:53 -0700 From: Ira Weiny To: Christoph Hellwig Cc: Dave Chinner , Jan Kara , Dan Williams , Linux Kernel Mailing List , "Darrick J. Wong" , "Theodore Y. Ts'o" , Jeff Moyer , linux-ext4 , linux-xfs , linux-fsdevel Subject: Re: [PATCH V6 6/8] fs/xfs: Combine xfs_diflags_to_linux() and xfs_diflags_to_iflags() Message-ID: <20200409204952.GB801897@iweiny-DESK2.sc.intel.com> References: <20200407182958.568475-1-ira.weiny@intel.com> <20200407182958.568475-7-ira.weiny@intel.com> <20200408020827.GI24067@dread.disaster.area> <20200408170923.GC569068@iweiny-DESK2.sc.intel.com> <20200408210236.GK24067@dread.disaster.area> <20200408235836.GQ24067@dread.disaster.area> <20200409002203.GE664132@iweiny-DESK2.sc.intel.com> <20200409124127.GB18171@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200409124127.GB18171@lst.de> User-Agent: Mutt/1.11.1 (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 09, 2020 at 02:41:27PM +0200, Christoph Hellwig wrote: > On Wed, Apr 08, 2020 at 05:22:03PM -0700, Ira Weiny wrote: > > > You mean something like XFS_IDONTCACHE? > > > > > > i.e. the functionality already exists in XFS to selectively evict an > > > inode from cache when the last reference to it is dropped rather > > > than let it go to the LRUs and hang around in memory. > > > > > > That flag can be set when changing the on disk DAX flag, and we can > > > tweak how it works so new cache hits don't clear it (as happens > > > now). Hence the only thing that can prevent eviction are active > > > references. > > > > > > That means we'll still need to stop the application and drop_caches, > > > because we need to close all the files and purge the dentries that > > > hold references to the inode before it can be evicted. > > > > That sounds like a great idea... > > > > Jan? Christoph? > > Sounds ok. Note that we could also pretty trivially lift > XFS_IDONTCACHE to the VFS if we need to apply the same scheme to > ext4. Yes I have been slowing working on ext4 in the background. So lifting XXX_IDONTCACHE to VFS will be part of that series. Thanks, Ira