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| author | Vaibhav Jain <vaibhav@linux.ibm.com> | 2021-05-13 14:53:49 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-06-25 14:47:18 +1000 |
| commit | ed78f56e1271f108e8af61baeba383dcd77adbec (patch) | |
| tree | 24025b13edabaa71a1b86d240e9c394df4705d60 /Documentation/ABI | |
| parent | 511eea5e2ccdfdbf3d626bde0314e551f247dd18 (diff) | |
| download | lwn-ed78f56e1271f108e8af61baeba383dcd77adbec.tar.gz lwn-ed78f56e1271f108e8af61baeba383dcd77adbec.zip | |
powerpc/papr_scm: Make 'perf_stats' invisible if perf-stats unavailable
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.
Even though 'perf_stats' attribute is available since v5.9, there are
no known user-space tools/scripts that are dependent on presence of its
sysfs file. Hence I dont expect any user-space breakage with this
patch.
Fixes: 2d02bf835e57 ("powerpc/papr_scm: Fetch nvdimm performance stats from PHYP")
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210513092349.285021-1-vaibhav@linux.ibm.com
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-papr-pmem | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-papr-pmem b/Documentation/ABI/testing/sysfs-bus-papr-pmem index 92e2db0e2d3d..95254cec92bf 100644 --- a/Documentation/ABI/testing/sysfs-bus-papr-pmem +++ b/Documentation/ABI/testing/sysfs-bus-papr-pmem @@ -39,9 +39,11 @@ KernelVersion: v5.9 Contact: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>, nvdimm@lists.linux.dev, Description: (RO) Report various performance stats related to papr-scm NVDIMM - device. Each stat is reported on a new line with each line - composed of a stat-identifier followed by it value. Below are - currently known dimm performance stats which are reported: + device. This attribute is only available for NVDIMM devices + that support reporting NVDIMM performance stats. Each stat is + reported on a new line with each line composed of a + stat-identifier followed by it value. Below are currently known + dimm performance stats which are reported: * "CtlResCt" : Controller Reset Count * "CtlResTm" : Controller Reset Elapsed Time |