From: Heinrich Schuchardt <xypron.glpk@gmx.de>
To: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>,
"H . Peter Anvin" <hpa@zytor.com>,
Alistair Popple <apopple@au1.ibm.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Bharata B Rao <bharata@linux.vnet.ibm.com>,
Frank Rowand <frowand.list@gmail.com>,
Ingo Molnar <mingo@redhat.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Nathan Fontenot <nfont@linux.vnet.ibm.com>,
Paul Mackerras <paulus@samba.org>,
Rob Herring <robh+dt@kernel.org>,
Stewart Smith <stewart@linux.vnet.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, Heinrich Schuchardt <xypron.glpk@gmx.de>
Subject: Re: [PATCH v6 4/4] of/fdt: mark hotpluggable memory
Date: Sun, 25 Dec 2016 10:02:22 +0100 [thread overview]
Message-ID: <20161225090222.3703-1-xypron.glpk@gmx.de> (raw)
In-Reply-To: <1478562276-25539-5-git-send-email-arbab@linux.vnet.ibm.com>
The patch adds a new property "linux,hotpluggable" to memory nodes of the
device tree.
memory@0 {
reg = <0x0 0x01000000 0x0 0x7f000000>;
linux,hotpluggable;
}
Memory areas marked by this property can later be disabled using the hotplugging
API. Especially for virtual machines this is a very useful capability.
Unfortunately the notation chosen does not fit well with the concept of
devicetree overlays which allow to change the devicetree during runtime.
I suggest to use the following notation
memory@0 {
compatible = "linux,hotpluggable-memory";
reg = <0x0 0x01000000 0x0 0x7f000000>;
status = "disabled";
}
This will allow us to write a device driver that can react to changes of the
devicetree made via devicetree overlays.
This driver could react to the change of the status between "okay" and
"disabled" and update the memory status accordingly.
Further we could use devicetree overlays to provide additional hotpluggable
memory.
The referenced patch has already been pulled for 4.10. But I hope it is not
too late for this design change.
Best regards
Heinrich Schuchardt
next prev parent reply other threads:[~2016-12-25 9:04 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-07 23:44 [PATCH v6 0/4] enable movable nodes on non-x86 configs Reza Arbab
2016-11-07 23:44 ` [PATCH v6 1/4] powerpc/mm: allow memory hotplug into a memoryless node Reza Arbab
2016-11-10 1:37 ` Michael Ellerman
2016-11-07 23:44 ` [PATCH v6 2/4] mm: remove x86-only restriction of movable_node Reza Arbab
2016-11-07 23:44 ` [PATCH v6 3/4] mm: enable CONFIG_MOVABLE_NODE on non-x86 arches Reza Arbab
2016-11-07 23:44 ` [PATCH v6 4/4] of/fdt: mark hotpluggable memory Reza Arbab
2016-11-08 1:59 ` kbuild test robot
2016-11-08 19:59 ` Reza Arbab
2016-11-09 18:12 ` Rob Herring
2016-11-09 20:15 ` Reza Arbab
2016-11-10 0:56 ` Balbir Singh
2016-11-10 20:52 ` Reza Arbab
2016-11-11 1:17 ` Balbir Singh
2016-11-14 11:59 ` Michael Ellerman
2016-11-14 19:34 ` Reza Arbab
2016-12-25 9:02 ` Heinrich Schuchardt [this message]
2016-12-27 0:09 ` Frank Rowand
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