From: Dan Williams <dan.j.williams@intel.com>
To: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Linux ACPI <linux-acpi@vger.kernel.org>,
linux-nvdimm <linux-nvdimm@lists.01.org>
Subject: Re: [PATCH 0/3] acpi, nfit: Add dirty shutdown count to sysfs
Date: Thu, 27 Sep 2018 08:33:30 -0700 [thread overview]
Message-ID: <CAPcyv4jHbT=C0FAzHN57rQKcO+A3nXbpmb6fzc26sGFpD8y_fQ@mail.gmail.com> (raw)
In-Reply-To: <20180927071135.GB6959@linux-x5ow.site>
On Thu, Sep 27, 2018 at 12:12 AM Johannes Thumshirn <jthumshirn@suse.de> wrote:
>
> On Wed, Sep 26, 2018 at 09:24:20PM -0700, Dan Williams wrote:
> > The Intel NVDIMM command specification publishes a dirty-shutdown-count
> > in addition to the dirty-shutdown / flush-failed indication that comes
> > from the ACPI NFIT. This is expected to be a common property of NVDIMMs
> > and is a static hardware health detail to be cached / exported via
> > sysfs.
> >
> > Add plumbing for retrieving this data at driver load time, publish the
> > count, and use the dynamically retrieved dirty-shutdown indicator to
> > augment the existing 'flush_failed' flag.
>
> Is this the same thing as the LSS Latch stuff that went into ndctl?
It's a replacement. The latch mechanism is awkward especially when all
that it needed is a rolling count of dirty-shutdown events. The
expectation going forward is that the platform firmware will handle
the latch, if it is present, and the OS need only consume the
dirty-shutdown count. The ndctl implementation called libndctl apis
from the udev queue which we discovered injects unnecessary udev queue
drains / stalls into the boot path. Lastly, the userspace caching
scheme for non-root users to consume the dirty-shutdown-count just
isn't as efficient as teaching the kernel to cache this value and
export it as a standard sysfs attribute.
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prev parent reply other threads:[~2018-09-27 15:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-27 4:24 [PATCH 0/3] acpi, nfit: Add dirty shutdown count to sysfs Dan Williams
2018-09-27 4:24 ` [PATCH 1/3] acpi, nfit: Introduce nfit_mem flags Dan Williams
2018-09-27 19:37 ` Keith Busch
2018-09-27 4:24 ` [PATCH 2/3] acpi, nfit: Collect shutdown status Dan Williams
2018-09-27 19:37 ` Keith Busch
2018-09-27 4:24 ` [PATCH 3/3] tools/testing/nvdimm: Populate dirty shutdown data Dan Williams
2018-09-27 19:37 ` Keith Busch
2018-09-27 7:11 ` [PATCH 0/3] acpi, nfit: Add dirty shutdown count to sysfs Johannes Thumshirn
2018-09-27 15:21 ` Keith Busch
2018-09-27 15:33 ` Dan Williams [this message]
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