On Fri, Apr 11, 2014 at 04:00:20AM -0700, David Rientjes wrote:
> On Thu, 10 Apr 2014, Naoya Horiguchi wrote:
>
> > Yes, that's right, but it seems to me that just node_start_pfn and node_end_pfn
> > is not enough because there can be holes (without any page struct backed) inside
> > [node_start_pfn, node_end_pfn), and it's not aware of memory hotplug.
> >
>
> So? Who cares if there are non-addressable holes in part of the span?
> Ulrich, correct me if I'm wrong, but it seems you're looking for just a
> address-to-nodeid mapping (or pfn-to-nodeid mapping) and aren't actually
> expecting that there are no holes in a node for things like acpi or I/O or
> reserved memory.
>
> The node spans a contiguous length of memory, there's no consideration for
> addresses that aren't actually backed by physical memory. We are just
> representing proximity domains that have a base address and length in the
> acpi world.
>
> Memory hotplug is already taken care of because onlining and offlining
> nodes already add these node classes and {start,end}_phys_addr would
> show up automatically. If you use node_start_pfn(nid) and
> node_end_pfn(nid) as suggested, there's no futher consideration needed for
> hotplug.
>
> I think trying to represent holes and handling different memory models and
> hotplug in special ways is complete overkill.
OK, I agree to your idea.
Your patch looks good to me.
Thanks,
Naoya Horiguchi
> Ulrich, can I have your ack?
> ---
> Documentation/ABI/stable/sysfs-devices-node | 12 ++++++++++++
> drivers/base/node.c | 18 ++++++++++++++++++
> 2 files changed, 30 insertions(+)
>
> diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node
> --- a/Documentation/ABI/stable/sysfs-devices-node
> +++ b/Documentation/ABI/stable/sysfs-devices-node
> @@ -63,6 +63,18 @@ Description:
> The node's hit/miss statistics, in units of pages.
> See Documentation/numastat.txt
>
> +What: /sys/devices/system/node/nodeX/start_phys_addr
> +Date: April 2014
> +Contact: David Rientjes <rientjes@xxxxxxxxxx>
> +Description:
> + The physical base address of this node.
> +
> +What: /sys/devices/system/node/nodeX/end_phys_addr
> +Date: April 2014
> +Contact: David Rientjes <rientjes@xxxxxxxxxx>
> +Description:
> + The physical base + length address of this node.
> +
> What: /sys/devices/system/node/nodeX/distance
> Date: October 2002
> Contact: Linux Memory Management list <linux-mm@xxxxxxxxx>
> diff --git a/drivers/base/node.c b/drivers/base/node.c
> --- a/drivers/base/node.c
> +++ b/drivers/base/node.c
> @@ -170,6 +170,20 @@ static ssize_t node_read_numastat(struct device *dev,
> }
> static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
>
> +static ssize_t node_read_start_phys_addr(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + return sprintf(buf, "0x%lx\n", node_start_pfn(dev->id) << PAGE_SHIFT);
> +}
> +static DEVICE_ATTR(start_phys_addr, S_IRUGO, node_read_start_phys_addr, NULL);
> +
> +static ssize_t node_read_end_phys_addr(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + return sprintf(buf, "0x%lx\n", node_end_pfn(dev->id) << PAGE_SHIFT);
> +}
> +static DEVICE_ATTR(end_phys_addr, S_IRUGO, node_read_end_phys_addr, NULL);
> +
> static ssize_t node_read_vmstat(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> @@ -286,6 +300,8 @@ static int register_node(struct node *node, int num, struct node *parent)
> device_create_file(&node->dev, &dev_attr_cpulist);
> device_create_file(&node->dev, &dev_attr_meminfo);
> device_create_file(&node->dev, &dev_attr_numastat);
> + device_create_file(&node->dev, &dev_attr_start_phys_addr);
> + device_create_file(&node->dev, &dev_attr_end_phys_addr);
> device_create_file(&node->dev, &dev_attr_distance);
> device_create_file(&node->dev, &dev_attr_vmstat);
>
> @@ -311,6 +327,8 @@ void unregister_node(struct node *node)
> device_remove_file(&node->dev, &dev_attr_cpulist);
> device_remove_file(&node->dev, &dev_attr_meminfo);
> device_remove_file(&node->dev, &dev_attr_numastat);
> + device_remove_file(&node->dev, &dev_attr_start_phys_addr);
> + device_remove_file(&node->dev, &dev_attr_end_phys_addr);
> device_remove_file(&node->dev, &dev_attr_distance);
> device_remove_file(&node->dev, &dev_attr_vmstat);
>
>
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