Re: [PATCH 3/3] cxl/mem: Add partition information to sysfs

[Ira Weiny <ira.weiny@intel.com>]

On Fri, Jun 11, 2021 at 10:26:15AM -0700, Widawsky, Ben wrote:
> On 21-06-10 17:22:24, ira.weiny@intel.com wrote:
> > From: Ira Weiny <ira.weiny@intel.com>
> > 
> > Partitionable space is added to the ram and pmem size sysfs attributes
> > but this does not show the entire story.
> > 
> > Add full partition information about the device under <sysfs>/partition.
> 
> Please add these to:
> Documentation/ABI/testing/sysfs-bus-cxl

Good point...  Thanks!

> 
> It might be time to break that file up... maybe a syfs-bus-cxl-memdev?
> 
> I'll also pose the original question here, what's the justification for exposing
> this via sysfs versus having userspace executing the mailbox command itself? Are
> you planning to have these attributes be writable at some point to do the
> partition programming?

Well...  if we have ram/size and pmem/size this is nice to have to know how it
is configured...

For me I like not having to have to execute mailbox commands for everything but
I understand having sysfs 'explosion'...  not really sure were to draw the
line.  For now this helps me to see what the emulators are returning.

Ira

> > 
> > Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> > ---
> >  drivers/cxl/pci.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 49 insertions(+)
> > 
> > diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> > index bcc2829e4475..7e4e9605e4ed 100644
> > --- a/drivers/cxl/pci.c
> > +++ b/drivers/cxl/pci.c
> > @@ -1226,6 +1226,42 @@ static ssize_t pmem_size_show(struct device *dev, struct device_attribute *attr,
> >  static struct device_attribute dev_attr_pmem_size =
> >  	__ATTR(size, 0444, pmem_size_show, NULL);
> >  
> > +static ssize_t part_vo_show(struct device *dev, struct device_attribute *attr,
> > +			     char *buf)
> > +{
> > +	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> > +	struct cxl_mem *cxlm = cxlmd->cxlm;
> > +
> > +	return sysfs_emit(buf, "%#llx\n", cxlm->volatile_cap_bytes);
> > +}
> > +
> > +static struct device_attribute dev_attr_part_vo =
> > +	__ATTR(volatile_only, 0444, part_vo_show, NULL);
> > +
> > +static ssize_t part_po_show(struct device *dev, struct device_attribute *attr,
> > +			     char *buf)
> > +{
> > +	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> > +	struct cxl_mem *cxlm = cxlmd->cxlm;
> > +
> > +	return sysfs_emit(buf, "%#llx\n", cxlm->persistent_cap_bytes);
> > +}
> > +
> > +static struct device_attribute dev_attr_part_po =
> > +	__ATTR(persistent_only, 0444, part_po_show, NULL);
> > +
> > +static ssize_t part_total_show(struct device *dev, struct device_attribute *attr,
> > +			     char *buf)
> > +{
> > +	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> > +	struct cxl_mem *cxlm = cxlmd->cxlm;
> > +
> > +	return sysfs_emit(buf, "%#llx\n", cxlm->total_cap_bytes);
> > +}
> > +
> > +static struct device_attribute dev_attr_part_total =
> > +	__ATTR(total, 0444, part_total_show, NULL);
> > +
> >  static struct attribute *cxl_memdev_attributes[] = {
> >  	&dev_attr_firmware_version.attr,
> >  	&dev_attr_payload_max.attr,
> > @@ -1243,6 +1279,13 @@ static struct attribute *cxl_memdev_ram_attributes[] = {
> >  	NULL,
> >  };
> >  
> > +static struct attribute *cxl_memdev_part_attributes[] = {
> > +	&dev_attr_part_vo.attr,
> > +	&dev_attr_part_po.attr,
> > +	&dev_attr_part_total.attr,
> > +	NULL,
> > +};
> > +
> >  static struct attribute_group cxl_memdev_attribute_group = {
> >  	.attrs = cxl_memdev_attributes,
> >  };
> > @@ -1257,10 +1300,16 @@ static struct attribute_group cxl_memdev_pmem_attribute_group = {
> >  	.attrs = cxl_memdev_pmem_attributes,
> >  };
> >  
> > +static struct attribute_group cxl_memdev_part_attribute_group = {
> > +	.name = "partition",
> > +	.attrs = cxl_memdev_part_attributes,
> > +};
> > +
> >  static const struct attribute_group *cxl_memdev_attribute_groups[] = {
> >  	&cxl_memdev_attribute_group,
> >  	&cxl_memdev_ram_attribute_group,
> >  	&cxl_memdev_pmem_attribute_group,
> > +	&cxl_memdev_part_attribute_group,
> >  	NULL,
> >  };
> >  
> > -- 
> > 2.28.0.rc0.12.gb6a658bd00c9
> >