linux-nvdimm.lists.01.org archive mirror
 help / color / mirror / Atom feed
* [PATCH v2] powerpc/papr_scm: Make 'perf_stats' invisible if perf-stats unavailable
@ 2021-05-07 11:39 Vaibhav Jain
  2021-05-12 19:48 ` Dan Williams
  0 siblings, 1 reply; 3+ messages in thread
From: Vaibhav Jain @ 2021-05-07 11:39 UTC (permalink / raw)
  To: linuxppc-dev, linux-nvdimm
  Cc: Vaibhav Jain, Aneesh Kumar K . V, Michael Ellerman

In case performance stats for an nvdimm are not available, reading the
'perf_stats' sysfs file returns an -ENOENT error. A better approach is
to make the 'perf_stats' file entirely invisible to indicate that
performance stats for an nvdimm are unavailable.

So this patch updates 'papr_nd_attribute_group' to add a 'is_visible'
callback implemented as newly introduced 'papr_nd_attribute_visible()'
that returns an appropriate mode in case performance stats aren't
supported in a given nvdimm.

Also the initialization of 'papr_scm_priv.stat_buffer_len' is moved
from papr_scm_nvdimm_init() to papr_scm_probe() so that it value is
available when 'papr_nd_attribute_visible()' is called during nvdimm
initialization.

Fixes: 2d02bf835e57('powerpc/papr_scm: Fetch nvdimm performance stats from PHYP')
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
---
Changelog:

v2:
* Removed a redundant dev_info() from pap_scm_nvdimm_init() [ Aneesh ]
* Marked papr_nd_attribute_visible() as static which also fixed the
  build warning reported by kernel build robot
---
 arch/powerpc/platforms/pseries/papr_scm.c | 35 ++++++++++++++++-------
 1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index e2b69cc3beaf..11e7b90a3360 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -907,6 +907,20 @@ static ssize_t flags_show(struct device *dev,
 }
 DEVICE_ATTR_RO(flags);
 
+static umode_t papr_nd_attribute_visible(struct kobject *kobj,
+					 struct attribute *attr, int n)
+{
+	struct device *dev = container_of(kobj, typeof(*dev), kobj);
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+	struct papr_scm_priv *p = nvdimm_provider_data(nvdimm);
+
+	/* For if perf-stats not available remove perf_stats sysfs */
+	if (attr == &dev_attr_perf_stats.attr && p->stat_buffer_len == 0)
+		return 0;
+
+	return attr->mode;
+}
+
 /* papr_scm specific dimm attributes */
 static struct attribute *papr_nd_attributes[] = {
 	&dev_attr_flags.attr,
@@ -916,6 +930,7 @@ static struct attribute *papr_nd_attributes[] = {
 
 static struct attribute_group papr_nd_attribute_group = {
 	.name = "papr",
+	.is_visible = papr_nd_attribute_visible,
 	.attrs = papr_nd_attributes,
 };
 
@@ -931,7 +946,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 	struct nd_region_desc ndr_desc;
 	unsigned long dimm_flags;
 	int target_nid, online_nid;
-	ssize_t stat_size;
 
 	p->bus_desc.ndctl = papr_scm_ndctl;
 	p->bus_desc.module = THIS_MODULE;
@@ -1016,16 +1030,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 	list_add_tail(&p->region_list, &papr_nd_regions);
 	mutex_unlock(&papr_ndr_lock);
 
-	/* Try retriving the stat buffer and see if its supported */
-	stat_size = drc_pmem_query_stats(p, NULL, 0);
-	if (stat_size > 0) {
-		p->stat_buffer_len = stat_size;
-		dev_dbg(&p->pdev->dev, "Max perf-stat size %lu-bytes\n",
-			p->stat_buffer_len);
-	} else {
-		dev_info(&p->pdev->dev, "Dimm performance stats unavailable\n");
-	}
-
 	return 0;
 
 err:	nvdimm_bus_unregister(p->bus);
@@ -1102,6 +1106,7 @@ static int papr_scm_probe(struct platform_device *pdev)
 	u64 blocks, block_size;
 	struct papr_scm_priv *p;
 	const char *uuid_str;
+	ssize_t stat_size;
 	u64 uuid[2];
 	int rc;
 
@@ -1179,6 +1184,14 @@ static int papr_scm_probe(struct platform_device *pdev)
 	p->res.name  = pdev->name;
 	p->res.flags = IORESOURCE_MEM;
 
+	/* Try retriving the stat buffer and see if its supported */
+	stat_size = drc_pmem_query_stats(p, NULL, 0);
+	if (stat_size > 0) {
+		p->stat_buffer_len = stat_size;
+		dev_dbg(&p->pdev->dev, "Max perf-stat size %lu-bytes\n",
+			p->stat_buffer_len);
+	}
+
 	rc = papr_scm_nvdimm_init(p);
 	if (rc)
 		goto err2;
-- 
2.31.1
_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
To unsubscribe send an email to linux-nvdimm-leave@lists.01.org

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] powerpc/papr_scm: Make 'perf_stats' invisible if perf-stats unavailable
  2021-05-07 11:39 [PATCH v2] powerpc/papr_scm: Make 'perf_stats' invisible if perf-stats unavailable Vaibhav Jain
@ 2021-05-12 19:48 ` Dan Williams
  2021-05-13  9:26   ` Vaibhav Jain
  0 siblings, 1 reply; 3+ messages in thread
From: Dan Williams @ 2021-05-12 19:48 UTC (permalink / raw)
  To: Vaibhav Jain
  Cc: linuxppc-dev, linux-nvdimm, Aneesh Kumar K . V, Michael Ellerman

On Fri, May 7, 2021 at 4:40 AM Vaibhav Jain <vaibhav@linux.ibm.com> wrote:
>
> In case performance stats for an nvdimm are not available, reading the
> 'perf_stats' sysfs file returns an -ENOENT error. A better approach is
> to make the 'perf_stats' file entirely invisible to indicate that
> performance stats for an nvdimm are unavailable.
>
> So this patch updates 'papr_nd_attribute_group' to add a 'is_visible'
> callback implemented as newly introduced 'papr_nd_attribute_visible()'
> that returns an appropriate mode in case performance stats aren't
> supported in a given nvdimm.
>
> Also the initialization of 'papr_scm_priv.stat_buffer_len' is moved
> from papr_scm_nvdimm_init() to papr_scm_probe() so that it value is
> available when 'papr_nd_attribute_visible()' is called during nvdimm
> initialization.
>
> Fixes: 2d02bf835e57('powerpc/papr_scm: Fetch nvdimm performance stats from PHYP')

Since this has been the exposed ABI since v5.9 perhaps a note /
analysis is needed here that the disappearance of this file will not
break any existing scripts/tools.

> Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
> ---
> Changelog:
>
> v2:
> * Removed a redundant dev_info() from pap_scm_nvdimm_init() [ Aneesh ]
> * Marked papr_nd_attribute_visible() as static which also fixed the
>   build warning reported by kernel build robot
> ---
>  arch/powerpc/platforms/pseries/papr_scm.c | 35 ++++++++++++++++-------
>  1 file changed, 24 insertions(+), 11 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
> index e2b69cc3beaf..11e7b90a3360 100644
> --- a/arch/powerpc/platforms/pseries/papr_scm.c
> +++ b/arch/powerpc/platforms/pseries/papr_scm.c
> @@ -907,6 +907,20 @@ static ssize_t flags_show(struct device *dev,
>  }
>  DEVICE_ATTR_RO(flags);
>
> +static umode_t papr_nd_attribute_visible(struct kobject *kobj,
> +                                        struct attribute *attr, int n)
> +{
> +       struct device *dev = container_of(kobj, typeof(*dev), kobj);

This can use the kobj_to_dev() helper.

> +       struct nvdimm *nvdimm = to_nvdimm(dev);
> +       struct papr_scm_priv *p = nvdimm_provider_data(nvdimm);
> +
> +       /* For if perf-stats not available remove perf_stats sysfs */
> +       if (attr == &dev_attr_perf_stats.attr && p->stat_buffer_len == 0)
> +               return 0;
> +
> +       return attr->mode;
> +}
> +
>  /* papr_scm specific dimm attributes */
>  static struct attribute *papr_nd_attributes[] = {
>         &dev_attr_flags.attr,
> @@ -916,6 +930,7 @@ static struct attribute *papr_nd_attributes[] = {
>
>  static struct attribute_group papr_nd_attribute_group = {
>         .name = "papr",
> +       .is_visible = papr_nd_attribute_visible,
>         .attrs = papr_nd_attributes,
>  };
>
> @@ -931,7 +946,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
>         struct nd_region_desc ndr_desc;
>         unsigned long dimm_flags;
>         int target_nid, online_nid;
> -       ssize_t stat_size;
>
>         p->bus_desc.ndctl = papr_scm_ndctl;
>         p->bus_desc.module = THIS_MODULE;
> @@ -1016,16 +1030,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
>         list_add_tail(&p->region_list, &papr_nd_regions);
>         mutex_unlock(&papr_ndr_lock);
>
> -       /* Try retriving the stat buffer and see if its supported */
> -       stat_size = drc_pmem_query_stats(p, NULL, 0);
> -       if (stat_size > 0) {
> -               p->stat_buffer_len = stat_size;
> -               dev_dbg(&p->pdev->dev, "Max perf-stat size %lu-bytes\n",
> -                       p->stat_buffer_len);
> -       } else {
> -               dev_info(&p->pdev->dev, "Dimm performance stats unavailable\n");
> -       }
> -
>         return 0;
>
>  err:   nvdimm_bus_unregister(p->bus);
> @@ -1102,6 +1106,7 @@ static int papr_scm_probe(struct platform_device *pdev)
>         u64 blocks, block_size;
>         struct papr_scm_priv *p;
>         const char *uuid_str;
> +       ssize_t stat_size;
>         u64 uuid[2];
>         int rc;
>
> @@ -1179,6 +1184,14 @@ static int papr_scm_probe(struct platform_device *pdev)
>         p->res.name  = pdev->name;
>         p->res.flags = IORESOURCE_MEM;
>
> +       /* Try retriving the stat buffer and see if its supported */

s/retriving/retrieving/

> +       stat_size = drc_pmem_query_stats(p, NULL, 0);
> +       if (stat_size > 0) {
> +               p->stat_buffer_len = stat_size;
> +               dev_dbg(&p->pdev->dev, "Max perf-stat size %lu-bytes\n",
> +                       p->stat_buffer_len);
> +       }
> +
>         rc = papr_scm_nvdimm_init(p);
>         if (rc)
>                 goto err2;
> --
> 2.31.1
>

After the minor fixups above you can add:

Reviewed-by: Dan Williams <dan.j.williams@intel.com>

...I assume this will go through the PPC tree.
_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
To unsubscribe send an email to linux-nvdimm-leave@lists.01.org

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] powerpc/papr_scm: Make 'perf_stats' invisible if perf-stats unavailable
  2021-05-12 19:48 ` Dan Williams
@ 2021-05-13  9:26   ` Vaibhav Jain
  0 siblings, 0 replies; 3+ messages in thread
From: Vaibhav Jain @ 2021-05-13  9:26 UTC (permalink / raw)
  To: Dan Williams
  Cc: linuxppc-dev, linux-nvdimm, Aneesh Kumar K . V, Michael Ellerman

Thanks for looking into this patch Dan,

Dan Williams <dan.j.williams@intel.com> writes:

> On Fri, May 7, 2021 at 4:40 AM Vaibhav Jain <vaibhav@linux.ibm.com> wrote:
>>
>> In case performance stats for an nvdimm are not available, reading the
>> 'perf_stats' sysfs file returns an -ENOENT error. A better approach is
>> to make the 'perf_stats' file entirely invisible to indicate that
>> performance stats for an nvdimm are unavailable.
>>
>> So this patch updates 'papr_nd_attribute_group' to add a 'is_visible'
>> callback implemented as newly introduced 'papr_nd_attribute_visible()'
>> that returns an appropriate mode in case performance stats aren't
>> supported in a given nvdimm.
>>
>> Also the initialization of 'papr_scm_priv.stat_buffer_len' is moved
>> from papr_scm_nvdimm_init() to papr_scm_probe() so that it value is
>> available when 'papr_nd_attribute_visible()' is called during nvdimm
>> initialization.
>>
>> Fixes: 2d02bf835e57('powerpc/papr_scm: Fetch nvdimm performance stats from PHYP')
>
> Since this has been the exposed ABI since v5.9 perhaps a note /
> analysis is needed here that the disappearance of this file will not
> break any existing scripts/tools.
>
Yes, I have added a note in patch description and also updated
Documentation/ABI/testing/sysfs-bus-papr-pmem with a note on when this
sysfs attr would be available. Thanks for this suggestion.

>> Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
>> ---
>> Changelog:
>>
>> v2:
>> * Removed a redundant dev_info() from pap_scm_nvdimm_init() [ Aneesh ]
>> * Marked papr_nd_attribute_visible() as static which also fixed the
>>   build warning reported by kernel build robot
>> ---
>>  arch/powerpc/platforms/pseries/papr_scm.c | 35 ++++++++++++++++-------
>>  1 file changed, 24 insertions(+), 11 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
>> index e2b69cc3beaf..11e7b90a3360 100644
>> --- a/arch/powerpc/platforms/pseries/papr_scm.c
>> +++ b/arch/powerpc/platforms/pseries/papr_scm.c
>> @@ -907,6 +907,20 @@ static ssize_t flags_show(struct device *dev,
>>  }
>>  DEVICE_ATTR_RO(flags);
>>
>> +static umode_t papr_nd_attribute_visible(struct kobject *kobj,
>> +                                        struct attribute *attr, int n)
>> +{
>> +       struct device *dev = container_of(kobj, typeof(*dev), kobj);
>
> This can use the kobj_to_dev() helper.
>
Fixed in v3
>> +       struct nvdimm *nvdimm = to_nvdimm(dev);
>> +       struct papr_scm_priv *p = nvdimm_provider_data(nvdimm);
>> +
>> +       /* For if perf-stats not available remove perf_stats sysfs */
>> +       if (attr == &dev_attr_perf_stats.attr && p->stat_buffer_len == 0)
>> +               return 0;
>> +
>> +       return attr->mode;
>> +}
>> +
>>  /* papr_scm specific dimm attributes */
>>  static struct attribute *papr_nd_attributes[] = {
>>         &dev_attr_flags.attr,
>> @@ -916,6 +930,7 @@ static struct attribute *papr_nd_attributes[] = {
>>
>>  static struct attribute_group papr_nd_attribute_group = {
>>         .name = "papr",
>> +       .is_visible = papr_nd_attribute_visible,
>>         .attrs = papr_nd_attributes,
>>  };
>>
>> @@ -931,7 +946,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
>>         struct nd_region_desc ndr_desc;
>>         unsigned long dimm_flags;
>>         int target_nid, online_nid;
>> -       ssize_t stat_size;
>>
>>         p->bus_desc.ndctl = papr_scm_ndctl;
>>         p->bus_desc.module = THIS_MODULE;
>> @@ -1016,16 +1030,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
>>         list_add_tail(&p->region_list, &papr_nd_regions);
>>         mutex_unlock(&papr_ndr_lock);
>>
>> -       /* Try retriving the stat buffer and see if its supported */
>> -       stat_size = drc_pmem_query_stats(p, NULL, 0);
>> -       if (stat_size > 0) {
>> -               p->stat_buffer_len = stat_size;
>> -               dev_dbg(&p->pdev->dev, "Max perf-stat size %lu-bytes\n",
>> -                       p->stat_buffer_len);
>> -       } else {
>> -               dev_info(&p->pdev->dev, "Dimm performance stats unavailable\n");
>> -       }
>> -
>>         return 0;
>>
>>  err:   nvdimm_bus_unregister(p->bus);
>> @@ -1102,6 +1106,7 @@ static int papr_scm_probe(struct platform_device *pdev)
>>         u64 blocks, block_size;
>>         struct papr_scm_priv *p;
>>         const char *uuid_str;
>> +       ssize_t stat_size;
>>         u64 uuid[2];
>>         int rc;
>>
>> @@ -1179,6 +1184,14 @@ static int papr_scm_probe(struct platform_device *pdev)
>>         p->res.name  = pdev->name;
>>         p->res.flags = IORESOURCE_MEM;
>>
>> +       /* Try retriving the stat buffer and see if its supported */
>
> s/retriving/retrieving/
>
Fixed in v3.
>> +       stat_size = drc_pmem_query_stats(p, NULL, 0);
>> +       if (stat_size > 0) {
>> +               p->stat_buffer_len = stat_size;
>> +               dev_dbg(&p->pdev->dev, "Max perf-stat size %lu-bytes\n",
>> +                       p->stat_buffer_len);
>> +       }
>> +
>>         rc = papr_scm_nvdimm_init(p);
>>         if (rc)
>>                 goto err2;
>> --
>> 2.31.1
>>
>
> After the minor fixups above you can add:
>
> Reviewed-by: Dan Williams <dan.j.williams@intel.com>

Thanks

>
> ...I assume this will go through the PPC tree.
Yes

-- 
Cheers
~ Vaibhav
_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
To unsubscribe send an email to linux-nvdimm-leave@lists.01.org

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-05-13  9:26 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-05-07 11:39 [PATCH v2] powerpc/papr_scm: Make 'perf_stats' invisible if perf-stats unavailable Vaibhav Jain
2021-05-12 19:48 ` Dan Williams
2021-05-13  9:26   ` Vaibhav Jain

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).