Messages in this thread Patch in this message | | | Subject | [PATCH v2] nfit/ars: Allow root to busy-poll the ARS state machine | From | Dan Williams <> | Date | Thu, 14 Feb 2019 12:19:26 -0800 |
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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> --- Change since v1: Use mod_delayed_work() instead of queue_delayed_work() to modify the timeout for existing work.
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..b1ab593a808a 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; + mod_delayed_work(nfit_wq, &acpi_desc->dwork, HZ); + } mutex_unlock(&acpi_desc->init_mutex); } device_unlock(dev);
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