From: Vaibhav Jain <vaibhav@linux.ibm.com>
To: nvdimm@lists.linux.dev, linuxppc-dev@lists.ozlabs.org
Cc: Vaibhav Jain <vaibhav@linux.ibm.com>,
Dan Williams <dan.j.williams@intel.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Santosh Sivaraj <santosh@fossix.org>,
Ira Weiny <ira.weiny@intel.com>
Subject: [PATCH v2] powerpc/papr_scm: Add support for reporting dirty-shutdown-count
Date: Thu, 27 May 2021 16:46:48 +0530 [thread overview]
Message-ID: <20210527111648.764690-1-vaibhav@linux.ibm.com> (raw)
Persistent memory devices like NVDIMMs can loose cached writes in case
something prevents flush on power-fail. Such situations are termed as
dirty shutdown and are exposed to applications as
last-shutdown-state (LSS) flag and a dirty-shutdown-counter(DSC) as
described at [1]. The latter being useful in conditions where multiple
applications want to detect a dirty shutdown event without racing with
one another.
PAPR-NVDIMMs have so far only exposed LSS style flags to indicate a
dirty-shutdown-state. This patch further adds support for DSC via the
"ibm,persistence-failed-count" device tree property of an NVDIMM. This
property is a monotonic increasing 64-bit counter thats an indication
of number of times an NVDIMM has encountered a dirty-shutdown event
causing persistence loss.
Since this value is not expected to change after system-boot hence
papr_scm reads & caches its value during NVDIMM probe and exposes it
as a PAPR sysfs attributed named 'dirty_shutdown' to match the name of
similarly named NFIT sysfs attribute. Also this value is available to
libnvdimm via PAPR_PDSM_HEALTH payload. 'struct nd_papr_pdsm_health'
has been extended to add a new member called 'dimm_dsc' presence of
which is indicated by the newly introduced PDSM_DIMM_DSC_VALID flag.
References:
[1] https://pmem.io/documents/Dirty_Shutdown_Handling-V1.0.pdf
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
---
Changelog:
v2:
* Rebased the patch on latest ppc-next tree
* s/psdm/psdm/g [ Santosh ]
---
arch/powerpc/include/uapi/asm/papr_pdsm.h | 6 +++++
arch/powerpc/platforms/pseries/papr_scm.c | 30 +++++++++++++++++++++++
2 files changed, 36 insertions(+)
diff --git a/arch/powerpc/include/uapi/asm/papr_pdsm.h b/arch/powerpc/include/uapi/asm/papr_pdsm.h
index 50ef95e2f5b1..82488b1e7276 100644
--- a/arch/powerpc/include/uapi/asm/papr_pdsm.h
+++ b/arch/powerpc/include/uapi/asm/papr_pdsm.h
@@ -77,6 +77,9 @@
/* Indicate that the 'dimm_fuel_gauge' field is valid */
#define PDSM_DIMM_HEALTH_RUN_GAUGE_VALID 1
+/* Indicate that the 'dimm_dsc' field is valid */
+#define PDSM_DIMM_DSC_VALID 2
+
/*
* Struct exchanged between kernel & ndctl in for PAPR_PDSM_HEALTH
* Various flags indicate the health status of the dimm.
@@ -105,6 +108,9 @@ struct nd_papr_pdsm_health {
/* Extension flag PDSM_DIMM_HEALTH_RUN_GAUGE_VALID */
__u16 dimm_fuel_gauge;
+
+ /* Extension flag PDSM_DIMM_DSC_VALID */
+ __u64 dimm_dsc;
};
__u8 buf[ND_PDSM_PAYLOAD_MAX_SIZE];
};
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index 11e7b90a3360..eb8be0eb6119 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -114,6 +114,9 @@ struct papr_scm_priv {
/* Health information for the dimm */
u64 health_bitmap;
+ /* Holds the last known dirty shutdown counter value */
+ u64 dirty_shutdown_counter;
+
/* length of the stat buffer as expected by phyp */
size_t stat_buffer_len;
};
@@ -603,6 +606,16 @@ static int papr_pdsm_fuel_gauge(struct papr_scm_priv *p,
return rc;
}
+/* Add the dirty-shutdown-counter value to the pdsm */
+static int papr_pdsm_dsc(struct papr_scm_priv *p,
+ union nd_pdsm_payload *payload)
+{
+ payload->health.extension_flags |= PDSM_DIMM_DSC_VALID;
+ payload->health.dimm_dsc = p->dirty_shutdown_counter;
+
+ return sizeof(struct nd_papr_pdsm_health);
+}
+
/* Fetch the DIMM health info and populate it in provided package. */
static int papr_pdsm_health(struct papr_scm_priv *p,
union nd_pdsm_payload *payload)
@@ -646,6 +659,8 @@ static int papr_pdsm_health(struct papr_scm_priv *p,
/* Populate the fuel gauge meter in the payload */
papr_pdsm_fuel_gauge(p, payload);
+ /* Populate the dirty-shutdown-counter field */
+ papr_pdsm_dsc(p, payload);
rc = sizeof(struct nd_papr_pdsm_health);
@@ -907,6 +922,16 @@ static ssize_t flags_show(struct device *dev,
}
DEVICE_ATTR_RO(flags);
+static ssize_t dirty_shutdown_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct nvdimm *dimm = to_nvdimm(dev);
+ struct papr_scm_priv *p = nvdimm_provider_data(dimm);
+
+ return sysfs_emit(buf, "%llu\n", p->dirty_shutdown_counter);
+}
+DEVICE_ATTR_RO(dirty_shutdown);
+
static umode_t papr_nd_attribute_visible(struct kobject *kobj,
struct attribute *attr, int n)
{
@@ -925,6 +950,7 @@ static umode_t papr_nd_attribute_visible(struct kobject *kobj,
static struct attribute *papr_nd_attributes[] = {
&dev_attr_flags.attr,
&dev_attr_perf_stats.attr,
+ &dev_attr_dirty_shutdown.attr,
NULL,
};
@@ -1149,6 +1175,10 @@ static int papr_scm_probe(struct platform_device *pdev)
p->is_volatile = !of_property_read_bool(dn, "ibm,cache-flush-required");
p->hcall_flush_required = of_property_read_bool(dn, "ibm,hcall-flush-required");
+ if (of_property_read_u64(dn, "ibm,persistence-failed-count",
+ &p->dirty_shutdown_counter))
+ p->dirty_shutdown_counter = 0;
+
/* We just need to ensure that set cookies are unique across */
uuid_parse(uuid_str, (uuid_t *) uuid);
/*
--
2.31.1
next reply other threads:[~2021-05-27 11:17 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-27 11:16 Vaibhav Jain [this message]
2021-06-04 8:53 ` [PATCH v2] powerpc/papr_scm: Add support for reporting dirty-shutdown-count Aneesh Kumar K.V
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