#include <linux/version.h>
#include <asm/local.h>
#include "../lttng-kernel-version.h"
+#include "../lttng-clock.h"
+#include "percpu-defs.h"
#include "random.h"
-#if LTTNG_KERNEL_RANGE(3,10,0, 3,10,14) || LTTNG_KERNEL_RANGE(3,11,0, 3,11,3)
+#if ((LTTNG_KERNEL_RANGE(3,10,0, 3,10,14) && !LTTNG_RHEL_KERNEL_RANGE(3,10,0,7,0, 3,10,14,0,0)) \
+ || LTTNG_KERNEL_RANGE(3,11,0, 3,11,3))
#error "Linux kernels 3.10 and 3.11 introduce a deadlock in the timekeeping subsystem. Fixed by commit 7bd36014460f793c19e7d6c94dab67b0afcfcb7f \"timekeeping: Fix HRTICK related deadlock from ntp lock changes\" in Linux."
#endif
+extern struct lttng_trace_clock *lttng_trace_clock;
+
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0))
DECLARE_PER_CPU(local_t, lttng_last_tsc);
#endif /* #else #if (BITS_PER_LONG == 32) */
/*
- * Always called with preemption disabled. Can be interrupted.
+ * Sometimes called with preemption enabled. Can be interrupted.
*/
static inline u64 trace_clock_monotonic_wrapper(void)
{
local_t *last_tsc;
/* Use fast nmi-safe monotonic clock provided by the Linux kernel. */
- last_tsc = &__get_cpu_var(lttng_last_tsc);
+ preempt_disable();
+ last_tsc = lttng_this_cpu_ptr(<tng_last_tsc);
last = local_read(last_tsc);
/*
* Read "last" before "now". It is not strictly required, but it ensures
if (((long) now - (long) last) < 0)
now = trace_clock_fixup(now, last);
result = local_cmpxchg(last_tsc, last, (unsigned long) now);
+ preempt_enable();
if (result == last) {
/* Update done. */
return now;
}
#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0)) */
-static inline u32 trace_clock_read32(void)
-{
- return (u32) trace_clock_monotonic_wrapper();
-}
-
-static inline u64 trace_clock_read64(void)
+static inline u64 trace_clock_read64_monotonic(void)
{
return (u64) trace_clock_monotonic_wrapper();
}
-static inline u64 trace_clock_freq(void)
+static inline u64 trace_clock_freq_monotonic(void)
{
return (u64) NSEC_PER_SEC;
}
-static inline int trace_clock_uuid(char *uuid)
+static inline int trace_clock_uuid_monotonic(char *uuid)
{
return wrapper_get_bootid(uuid);
}
+static inline const char *trace_clock_name_monotonic(void)
+{
+ return "monotonic";
+}
+
+static inline const char *trace_clock_description_monotonic(void)
+{
+ return "Monotonic Clock";
+}
+
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0))
static inline int get_trace_clock(void)
{
{
}
+static inline u64 trace_clock_read64(void)
+{
+ struct lttng_trace_clock *ltc = ACCESS_ONCE(lttng_trace_clock);
+
+ if (likely(!ltc)) {
+ return trace_clock_read64_monotonic();
+ } else {
+ read_barrier_depends(); /* load ltc before content */
+ return ltc->read64();
+ }
+}
+
+static inline u64 trace_clock_freq(void)
+{
+ struct lttng_trace_clock *ltc = ACCESS_ONCE(lttng_trace_clock);
+
+ if (!ltc) {
+ return trace_clock_freq_monotonic();
+ } else {
+ read_barrier_depends(); /* load ltc before content */
+ return ltc->freq();
+ }
+}
+
+static inline int trace_clock_uuid(char *uuid)
+{
+ struct lttng_trace_clock *ltc = ACCESS_ONCE(lttng_trace_clock);
+
+ read_barrier_depends(); /* load ltc before content */
+ /* Use default UUID cb when NULL */
+ if (!ltc || !ltc->uuid) {
+ return trace_clock_uuid_monotonic(uuid);
+ } else {
+ return ltc->uuid(uuid);
+ }
+}
+
+static inline const char *trace_clock_name(void)
+{
+ struct lttng_trace_clock *ltc = ACCESS_ONCE(lttng_trace_clock);
+
+ if (!ltc) {
+ return trace_clock_name_monotonic();
+ } else {
+ read_barrier_depends(); /* load ltc before content */
+ return ltc->name();
+ }
+}
+
+static inline const char *trace_clock_description(void)
+{
+ struct lttng_trace_clock *ltc = ACCESS_ONCE(lttng_trace_clock);
+
+ if (!ltc) {
+ return trace_clock_description_monotonic();
+ } else {
+ read_barrier_depends(); /* load ltc before content */
+ return ltc->description();
+ }
+}
+
#endif /* CONFIG_HAVE_TRACE_CLOCK */
#endif /* _LTTNG_TRACE_CLOCK_H */