From: "Verma, Vishal L" <vishal.l.verma@intel.com>
To: "lizhijian@fujitsu.com" <lizhijian@fujitsu.com>,
"Jiang, Dave" <dave.jiang@intel.com>
Cc: "david@redhat.com" <david@redhat.com>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
"Huang, Ying" <ying.huang@intel.com>,
"Jonathan.Cameron@huawei.com" <Jonathan.Cameron@huawei.com>,
"linux-cxl@vger.kernel.org" <linux-cxl@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Williams, Dan J" <dan.j.williams@intel.com>,
"nvdimm@lists.linux.dev" <nvdimm@lists.linux.dev>
Subject: Re: [PATCH v2 2/2] dax: add a sysfs knob to control memmap_on_memory behavior
Date: Fri, 8 Dec 2023 21:24:24 +0000 [thread overview]
Message-ID: <ee14082752fd634d7b619b7dd438170fdc0bbe1a.camel@intel.com> (raw)
In-Reply-To: <ad95e550-cdb3-448f-beb1-fc4899053639@fujitsu.com>
On Fri, 2023-12-08 at 09:20 +0000, Zhijian Li (Fujitsu) wrote:
>
>
> On 08/12/2023 03:25, Verma, Vishal L wrote:
> > On Thu, 2023-12-07 at 08:29 +0000, Zhijian Li (Fujitsu) wrote:
> > > Hi Vishal,
> > >
> > >
> > > On 07/12/2023 12:36, Vishal Verma wrote:
> > > > +
> > > > +What: /sys/bus/dax/devices/daxX.Y/memmap_on_memory
> > > > +Date: October, 2023
> > > > +KernelVersion: v6.8
> > > > +Contact: nvdimm@lists.linux.dev
> > > > +Description:
> > > > + (RW) Control the memmap_on_memory setting if the dax device
> > > > + were to be hotplugged as system memory. This determines whether
> > > > + the 'altmap' for the hotplugged memory will be placed on the
> > > > + device being hotplugged (memmap_on+memory=1) or if it will be
> > >
> > > s/memmap_on+memory=1/memmap_on_memory=1
> >
> > Thanks, will fix.
> > >
> > >
> > > I have a question here
> > >
> > > What relationship about memmap_on_memory and 'ndctl-create-namespace
> > > -M' option which
> > > specifies where is the vmemmap backed memory.
> > > I'm confused that memmap_on_memory=1 and '-M dev' are the same for
> > > nvdimm devdax mode ?
> > >
> > The main difference is that memory that comes from non-nvdimm sources,
> > such as hmem, or cxl, doesn't have a chance to set up the altmaps as
> > pmem can with '-M dev'. For these, memmap_on_memory does this as part
> > of the memory hotplug.
>
> Thanks for your explanation.
> (I wrongly thought nvdimm.kmem was also controlled by '-M dev' before)
>
> feel free add:
> Tested-by: Li Zhijian <lizhijian@fujitsu.com>
Thank you Zhijian!
next prev parent reply other threads:[~2023-12-08 21:27 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-07 4:36 [PATCH v2 0/2] Add DAX ABI for memmap_on_memory Vishal Verma
2023-12-07 4:36 ` [PATCH v2 1/2] Documentatiion/ABI: Add ABI documentation for sys-bus-dax Vishal Verma
2023-12-07 4:36 ` [PATCH v2 2/2] dax: add a sysfs knob to control memmap_on_memory behavior Vishal Verma
2023-12-07 8:29 ` Zhijian Li (Fujitsu)
2023-12-07 19:25 ` Verma, Vishal L
2023-12-08 9:20 ` Zhijian Li (Fujitsu)
2023-12-08 21:24 ` Verma, Vishal L [this message]
2023-12-08 3:13 ` Huang, Ying
2023-12-08 21:25 ` Verma, Vishal L
2023-12-08 11:36 ` David Hildenbrand
2023-12-08 21:26 ` Verma, Vishal L
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