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Release 4.12 include/linux/timekeeper_internal.h

Directory: include/linux
 * You SHOULD NOT be including this unless you're vsyscall
 * handling code or timekeeping internal code!



#include <linux/clocksource.h>
#include <linux/jiffies.h>
#include <linux/time.h>

 * struct tk_read_base - base structure for timekeeping readout
 * @clock:      Current clocksource used for timekeeping.
 * @read:       Read function of @clock
 * @mask:       Bitmask for two's complement subtraction of non 64bit clocks
 * @cycle_last: @clock cycle value at last update
 * @mult:       (NTP adjusted) multiplier for scaled math conversion
 * @shift:      Shift value for scaled math conversion
 * @xtime_nsec: Shifted (fractional) nano seconds offset for readout
 * @base:       ktime_t (nanoseconds) base time for readout
 * This struct has size 56 byte on 64 bit. Together with a seqcount it
 * occupies a single 64byte cache line.
 * The struct is separate from struct timekeeper as it is also used
 * for a fast NMI safe accessors.

struct tk_read_base {
struct clocksource	*clock;
u64			mask;
u64			cycle_last;
u32			mult;
u32			shift;
u64			xtime_nsec;
ktime_t			base;

 * struct timekeeper - Structure holding internal timekeeping values.
 * @tkr_mono:           The readout base structure for CLOCK_MONOTONIC
 * @tkr_raw:            The readout base structure for CLOCK_MONOTONIC_RAW
 * @xtime_sec:          Current CLOCK_REALTIME time in seconds
 * @ktime_sec:          Current CLOCK_MONOTONIC time in seconds
 * @wall_to_monotonic:  CLOCK_REALTIME to CLOCK_MONOTONIC offset
 * @offs_real:          Offset clock monotonic -> clock realtime
 * @offs_boot:          Offset clock monotonic -> clock boottime
 * @offs_tai:           Offset clock monotonic -> clock tai
 * @tai_offset:         The current UTC to TAI offset in seconds
 * @clock_was_set_seq:  The sequence number of clock was set events
 * @cs_was_changed_seq: The sequence number of clocksource change events
 * @next_leap_ktime:    CLOCK_MONOTONIC time value of a pending leap-second
 * @raw_time:           Monotonic raw base time in timespec64 format
 * @cycle_interval:     Number of clock cycles in one NTP interval
 * @xtime_interval:     Number of clock shifted nano seconds in one NTP
 *                      interval.
 * @xtime_remainder:    Shifted nano seconds left over when rounding
 *                      @cycle_interval
 * @raw_interval:       Shifted raw nano seconds accumulated per NTP interval.
 * @ntp_error:          Difference between accumulated time and NTP time in ntp
 *                      shifted nano seconds.
 * @ntp_error_shift:    Shift conversion between clock shifted nano seconds and
 *                      ntp shifted nano seconds.
 * @last_warning:       Warning ratelimiter (DEBUG_TIMEKEEPING)
 * @underflow_seen:     Underflow warning flag (DEBUG_TIMEKEEPING)
 * @overflow_seen:      Overflow warning flag (DEBUG_TIMEKEEPING)
 * Note: For timespec(64) based interfaces wall_to_monotonic is what
 * we need to add to xtime (or xtime corrected for sub jiffie times)
 * to get to monotonic time.  Monotonic is pegged at zero at system
 * boot time, so wall_to_monotonic will be negative, however, we will
 * ALWAYS keep the tv_nsec part positive so we can use the usual
 * normalization.
 * wall_to_monotonic is moved after resume from suspend for the
 * monotonic time not to jump. We need to add total_sleep_time to
 * wall_to_monotonic to get the real boot based time offset.
 * wall_to_monotonic is no longer the boot time, getboottime must be
 * used instead.

struct timekeeper {
struct tk_read_base	tkr_mono;
struct tk_read_base	tkr_raw;
u64			xtime_sec;
unsigned long		ktime_sec;
struct timespec64	wall_to_monotonic;
ktime_t			offs_real;
ktime_t			offs_boot;
ktime_t			offs_tai;
s32			tai_offset;
unsigned int		clock_was_set_seq;
u8			cs_was_changed_seq;
ktime_t			next_leap_ktime;
struct timespec64	raw_time;

	/* The following members are for timekeeping internal use */
u64			cycle_interval;
u64			xtime_interval;
s64			xtime_remainder;
u64			raw_interval;
	/* The ntp_tick_length() value currently being used.
         * This cached copy ensures we consistently apply the tick
         * length for an entire tick, as ntp_tick_length may change
         * mid-tick, and we don't want to apply that new value to
         * the tick in progress.
u64			ntp_tick;
	/* Difference between accumulated time and NTP time in ntp
         * shifted nano seconds. */
s64			ntp_error;
u32			ntp_error_shift;
u32			ntp_err_mult;
long			last_warning;
         * These simple flag variables are managed
         * without locks, which is racy, but they are
         * ok since we don't really care about being
         * super precise about how many events were
         * seen, just that a problem was observed.
int			underflow_seen;
int			overflow_seen;


extern void update_vsyscall(struct timekeeper *tk);
extern void update_vsyscall_tz(void);


extern void update_vsyscall_old(struct timespec *ts, struct timespec *wtm,
				struct clocksource *c, u32 mult,
				u64 cycle_last);
extern void update_vsyscall_tz(void);


static inline void update_vsyscall(struct timekeeper *tk) { }


John Stultz11100.00%2100.00%

static inline void update_vsyscall_tz(void) { }


John Stultz8100.00%1100.00%

#endif #endif /* _LINUX_TIMEKEEPER_INTERNAL_H */

Overall Contributors

John Stultz15770.40%945.00%
Thomas Gleixner5223.32%735.00%
Peter Zijlstra73.14%210.00%
Heena Sirwani41.79%15.00%
Christopher S. Hall31.35%15.00%
Directory: include/linux
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