From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ipmail06.adl6.internode.on.net ([150.101.137.145]:36908 "EHLO ipmail06.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725811AbfBVXLp (ORCPT ); Fri, 22 Feb 2019 18:11:45 -0500 Date: Sat, 23 Feb 2019 10:11:36 +1100 From: Dave Chinner Subject: Re: [RFC PATCH] pmem: advertise page alignment for pmem devices supporting fsdax Message-ID: <20190222231136.GC23020@dastard> References: <20190222182008.GT6503@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190222182008.GT6503@magnolia> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: "Darrick J. Wong" Cc: dan.j.williams@intel.com, linux-nvdimm@lists.01.org, zwisler@kernel.org, vishal.l.verma@intel.com, xfs , linux-fsdevel On Fri, Feb 22, 2019 at 10:20:08AM -0800, Darrick J. Wong wrote: > Hi all! > > Uh, we have an internal customer who's been trying out MAP_SYNC > on pmem, and they've observed that one has to do a fair amount of > legwork (in the form of mkfs.xfs parameters) to get the kernel to set up > 2M PMD mappings. They (of course) want to mmap hundreds of GB of pmem, > so the PMD mappings are much more efficient. > > I started poking around w.r.t. what mkfs.xfs was doing and realized that > if the fsdax pmem device advertised iomin/ioopt of 2MB, then mkfs will > set up all the parameters automatically. Below is my ham-handed attempt > to teach the kernel to do this. What's the before and after mkfs output? (need to see the context that this "fixes" before I comment) Cheers, Dave. -- Dave Chinner david@fromorbit.com