Re: [PATCH v2 04/28] kernel: Add masks support for Raw and NTP time
From: Thomas Gleixner <hidden>
Date: 2018-11-29 22:41:26
Also in:
linux-arm-kernel
On Thu, 29 Nov 2018, Vincenzo Frascino wrote:
quoted hunk ↗ jump to hunk
Depending on the clocksource selected there can be supported a different resolution hence we require a mask to be applied to the time calculation. This patch exposes the mask in the datapage for Raw and NTP adjusted clock. Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> --- include/vdso/datapage.h | 2 ++ 1 file changed, 2 insertions(+)diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h index d50a108afaed..0a7bdccf5773 100644 --- a/include/vdso/datapage.h +++ b/include/vdso/datapage.h@@ -34,6 +34,8 @@ struct vdso_data { __u64 wtm_clock_nsec; __u64 btm_nsec; /* Monotonic to boot time */ __u64 tai_sec; /* International Atomic Time */ + __u64 cs_mono_mask; /* NTP-adjusted clocksource mask */ + __u64 cs_raw_mask; /* Raw clocksource mask */
And why would they be different? The core timekeeper has them duplicated purely for access pattern optimization and simplicity. Thanks, tglx