From: Dan Williams <dan.j.williams@intel.com>
To: linux-nvdimm@lists.01.org
Cc: Erwin Tsaur <erwin.tsaur@oracle.com>,
vishal.l.verma@intel.com, linux-kernel@vger.kernel.org
Subject: [PATCH 3/6] nfit/ars: Allow root to busy-poll the ARS state machine
Date: Thu, 14 Feb 2019 12:10:21 -0800 [thread overview]
Message-ID: <155017502147.944049.2893295352368862579.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <155017500427.944049.2254497897075714747.stgit@dwillia2-desk3.amr.corp.intel.com>
The ARS implementation implements exponential back-off on the poll
interval to prevent high-frequency access to the DIMM / platform
interface. Depending on when the ARS completes the poll interval may
exceed the completion event by minutes. Allow root to reset the timeout
each time it probes the status. A one-second timeout is still enforced,
but root can otherwise can control the poll interval.
Reported-by: Erwin Tsaur <erwin.tsaur@oracle.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/acpi/nfit/core.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 934be96dc149..5ec0e19760ea 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -1328,6 +1328,12 @@ static ssize_t scrub_show(struct device *dev,
rc = sprintf(buf, "%d%s", acpi_desc->scrub_count,
acpi_desc->scrub_busy
&& !acpi_desc->cancel ? "+\n" : "\n");
+ /* Allow an admin to poll the busy state at a higher rate */
+ if (acpi_desc->scrub_busy && !acpi_desc->cancel
+ && capable(CAP_SYS_RAWIO)) {
+ acpi_desc->scrub_tmo = 1;
+ queue_delayed_work(nfit_wq, &acpi_desc->dwork, HZ);
+ }
mutex_unlock(&acpi_desc->init_mutex);
}
device_unlock(dev);
next prev parent reply other threads:[~2019-02-14 20:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-14 20:10 [PATCH 0/6] nfit/ars: Improve polling and short-ARS execution Dan Williams
2019-02-14 20:10 ` [PATCH 1/6] nfit/ars: Attempt a short-ARS whenever the ARS state is idle at boot Dan Williams
2019-02-14 20:10 ` [PATCH 2/6] nfit/ars: Attempt short-ARS even in the no_init_ars case Dan Williams
2019-02-14 20:10 ` Dan Williams [this message]
2019-02-14 20:19 ` [PATCH v2] nfit/ars: Allow root to busy-poll the ARS state machine Dan Williams
2019-02-15 16:43 ` Dan Williams
2019-02-14 20:27 ` [PATCH 3/6] " Dan Williams
2019-02-14 20:10 ` [PATCH 4/6] nfit/ars: Remove ars_start_flags Dan Williams
2019-02-14 20:10 ` [PATCH 5/6] nfit/ars: Introduce scrub_flags Dan Williams
2019-02-14 20:10 ` [PATCH 6/6] nfit/ars: Avoid stale ARS results Dan Williams
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