Messages in this thread | | | From | John Stultz <> | Date | Fri, 6 Jan 2017 20:02:20 -0800 | Subject | Re: [PATCH v3 1/3] timekeeping: Add a fast and NMI safe boot clock |
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On Fri, Jan 6, 2017 at 6:39 PM, Joel Fernandes <joelaf@google.com> wrote: > Hi John, > > On Fri, Jan 6, 2017 at 4:48 PM, John Stultz <john.stultz@linaro.org> wrote: >> On Thu, Nov 24, 2016 at 12:20 PM, Joel Fernandes <joelaf@google.com> wrote: >>> This boot clock can be used as a tracing clock and will account for >>> suspend time. >>> >>> To keep it NMI safe since we're accessing from tracing, we're not using a >>> separate timekeeper with updates to monotonic clock and boot offset >>> protected with seqlocks. This has the following minor side effects: >>> >>> (1) Its possible that a timestamp be taken after the boot offset is updated >>> but before the timekeeper is updated. If this happens, the new boot offset >>> is added to the old timekeeping making the clock appear to update slightly >>> earlier: >>> CPU 0 CPU 1 >>> timekeeping_inject_sleeptime64() >>> __timekeeping_inject_sleeptime(tk, delta); >>> timestamp(); >>> timekeeping_update(tk, TK_CLEAR_NTP...); >>> >>> (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be >>> partially updated. Since the tk->offs_boot update is a rare event, this >>> should be a rare occurrence which postprocessing should be able to handle. >>> >>> Cc: Steven Rostedt <rostedt@goodmis.org> >>> Cc: Thomas Gleixner <tglx@linutronix.de> >>> Cc: John Stultz <john.stultz@linaro.org> >>> Cc: Ingo Molnar <mingo@redhat.com> >>> Signed-off-by: Joel Fernandes <joelaf@google.com> >> >> Hey Joel, >> Hope you had a good new years! I was queuing this up for testing, > > Thanks, yes I had a great new years, hope you did too. > >> and the patch set no longer applies (to v4.10-rc2). Can you respin it >> and resend it? > > Actually these patches are already in 4.10-rc2.
Ha! Well, apologies for missing that over the holidays.
Sorry for the noise. -john
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