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From: Dan Williams <dan.j.williams@intel.com>
To: "Du, Fan" <fan.du@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
	"dave@sr71.net" <dave@sr71.net>,
	"thomas.lendacky@amd.com" <thomas.lendacky@amd.com>,
	"mhocko@suse.com" <mhocko@suse.com>,
	"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
	"tiwai@suse.de" <tiwai@suse.de>,
	"zwisler@kernel.org" <zwisler@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"Wu, Fengguang" <fengguang.wu@intel.com>,
	"baiyaowei@cmss.chinamobile.com" <baiyaowei@cmss.chinamobile.com>,
	"Huang, Ying" <ying.huang@intel.com>,
	"bhelgaas@google.com" <bhelgaas@google.com>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"bp@suse.de" <bp@suse.de>
Subject: Re: [PATCH 4/4] dax: "Hotplug" persistent memory for use like normal RAM
Date: Thu, 17 Jan 2019 08:56:08 -0800	[thread overview]
Message-ID: <CAPcyv4heNGQf4NHYrMzUdBRw2n3tE08bMaVKzgYrPYVaVDWE9Q@mail.gmail.com> (raw)
In-Reply-To: <5A90DA2E42F8AE43BC4A093BF06788482571FCB1@SHSMSX103.ccr.corp.intel.com>

On Wed, Jan 16, 2019 at 9:21 PM Du, Fan <fan.du@intel.com> wrote:
[..]
> >From: Dave Hansen <dave.hansen@linux.intel.com>
> >
> >Currently, a persistent memory region is "owned" by a device driver,
> >either the "Direct DAX" or "Filesystem DAX" drivers.  These drivers
> >allow applications to explicitly use persistent memory, generally
> >by being modified to use special, new libraries.
> >
> >However, this limits persistent memory use to applications which
> >*have* been modified.  To make it more broadly usable, this driver
> >"hotplugs" memory into the kernel, to be managed ad used just like
> >normal RAM would be.
> >
> >To make this work, management software must remove the device from
> >being controlled by the "Device DAX" infrastructure:
> >
> >       echo -n dax0.0 > /sys/bus/dax/drivers/device_dax/remove_id
> >       echo -n dax0.0 > /sys/bus/dax/drivers/device_dax/unbind
> >
> >and then bind it to this new driver:
> >
> >       echo -n dax0.0 > /sys/bus/dax/drivers/kmem/new_id
> >       echo -n dax0.0 > /sys/bus/dax/drivers/kmem/bind
>
> Is there any plan to introduce additional mode, e.g. "kmem" in the userspace
> ndctl tool to do the configuration?
>

Yes, but not to ndctl. The daxctl tool will grow a helper for this.
The policy of what device-dax instances should be hotplugged at system
init will be managed by a persistent configuration file and udev
rules.

  reply	other threads:[~2019-01-17 16:56 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-16 18:18 [PATCH 0/4] Allow persistent memory to be used like normal RAM Dave Hansen
2019-01-16 18:19 ` [PATCH 1/4] mm/resource: return real error codes from walk failures Dave Hansen
2019-01-16 20:38   ` Bjorn Helgaas
2019-01-16 18:19 ` [PATCH 2/4] mm/memory-hotplug: allow memory resources to be children Dave Hansen
2019-01-16 19:16   ` Jerome Glisse
2019-01-16 23:01     ` Dave Hansen
2019-01-16 23:38       ` Jerome Glisse
2019-01-23 20:03         ` Dave Hansen
2019-01-23 20:15           ` Jerome Glisse
2019-01-18 19:58     ` Dave Hansen
2019-01-18 20:26       ` Jerome Glisse
2019-01-23 17:05   ` Michal Hocko
2019-01-16 18:19 ` [PATCH 3/4] dax/kmem: let walk_system_ram_range() search child resources Dave Hansen
2019-01-16 18:19 ` [PATCH 4/4] dax: "Hotplug" persistent memory for use like normal RAM Dave Hansen
2019-01-16 21:16   ` Bjorn Helgaas
2019-01-16 21:40     ` Dave Hansen
2019-01-16 21:44       ` Bjorn Helgaas
2019-01-16 22:06       ` Dan Williams
2019-01-16 21:53     ` Dave Hansen
2019-01-16 21:59       ` Bjorn Helgaas
2019-01-16 21:31   ` Dan Williams
2019-01-17  5:21   ` Du, Fan
2019-01-17 16:56     ` Dan Williams [this message]
2019-01-17  8:19   ` Yanmin Zhang
2019-01-17 15:17     ` Dave Hansen
2019-01-18  7:47       ` Yanmin Zhang
2019-01-18 15:20         ` Dave Hansen
2019-01-17 16:29 ` [PATCH 0/4] Allow persistent memory to be used " Jeff Moyer
2019-01-17 16:47   ` Keith Busch
2019-01-17 17:20     ` Jeff Moyer
2019-01-17 19:34       ` Keith Busch
2019-01-17 21:57         ` Jeff Moyer
2019-01-18 11:48       ` Fengguang Wu
2019-01-17 16:50   ` Dan Williams
2019-01-17 22:43   ` Dave Hansen

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