X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=wrapper%2Ftrace-clock.h;h=9f4e366afbcbeecc89302a2cb205b41b3e9012e5;hb=HEAD;hp=7f17ccd4f82fd9bcb51446bfda45e6c778c10079;hpb=60e1cd0751eec323c62c923629da4abe345e123f;p=lttng-modules.git diff --git a/wrapper/trace-clock.h b/wrapper/trace-clock.h deleted file mode 100644 index 7f17ccd4..00000000 --- a/wrapper/trace-clock.h +++ /dev/null @@ -1,240 +0,0 @@ -#ifndef _LTTNG_TRACE_CLOCK_H -#define _LTTNG_TRACE_CLOCK_H - -/* - * wrapper/trace-clock.h - * - * Contains LTTng trace clock mapping to LTTng trace clock or mainline monotonic - * clock. This wrapper depends on CONFIG_HIGH_RES_TIMERS=y. - * - * Copyright (C) 2011-2012 Mathieu Desnoyers - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; only - * version 2.1 of the License. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - */ - -#ifdef CONFIG_HAVE_TRACE_CLOCK -#include -#else /* CONFIG_HAVE_TRACE_CLOCK */ - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#if ((LTTNG_KERNEL_RANGE(3,10,0, 3,10,14) && !LTTNG_RHEL_KERNEL_RANGE(3,10,0,123,0,0, 3,10,14,0,0,0)) \ - || 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; - -/* - * Upstream Linux commit 27727df240c7 ("Avoid taking lock in NMI path with - * CONFIG_DEBUG_TIMEKEEPING") introduces a buggy ktime_get_mono_fast_ns(). - * This is fixed by patch "timekeeping: Fix __ktime_get_fast_ns() regression". - */ -#if (LTTNG_KERNEL_RANGE(4,8,0, 4,8,2) \ - || LTTNG_KERNEL_RANGE(4,7,4, 4,7,8) \ - || LTTNG_KERNEL_RANGE(4,4,20, 4,4,25) \ - || LTTNG_KERNEL_RANGE(4,1,32, 4,1,35)) -#define LTTNG_CLOCK_NMI_SAFE_BROKEN -#endif - -/* - * We need clock values to be monotonically increasing per-cpu, which is - * not strictly guaranteed by ktime_get_mono_fast_ns(). It is - * straightforward to do on architectures with a 64-bit cmpxchg(), but - * not so on architectures without 64-bit cmpxchg. For now, only enable - * this feature on 64-bit architectures. - */ - -#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0) \ - && BITS_PER_LONG == 64 \ - && !defined(LTTNG_CLOCK_NMI_SAFE_BROKEN)) -#define LTTNG_USE_NMI_SAFE_CLOCK -#endif - -#ifdef LTTNG_USE_NMI_SAFE_CLOCK - -DECLARE_PER_CPU(u64, lttng_last_tsc); - -/* - * Sometimes called with preemption enabled. Can be interrupted. - */ -static inline u64 trace_clock_monotonic_wrapper(void) -{ - u64 now, last, result; - u64 *last_tsc_ptr; - - /* Use fast nmi-safe monotonic clock provided by the Linux kernel. */ - preempt_disable(); - last_tsc_ptr = lttng_this_cpu_ptr(<tng_last_tsc); - last = *last_tsc_ptr; - /* - * Read "last" before "now". It is not strictly required, but it ensures - * that an interrupt coming in won't artificially trigger a case where - * "now" < "last". This kind of situation should only happen if the - * mono_fast time source goes slightly backwards. - */ - barrier(); - now = ktime_get_mono_fast_ns(); - if (U64_MAX / 2 < now - last) - now = last; - result = cmpxchg64_local(last_tsc_ptr, last, now); - preempt_enable(); - if (result == last) { - /* Update done. */ - return now; - } else { - /* - * Update not done, due to concurrent update. We can use - * "result", since it has been sampled concurrently with our - * time read, so it should not be far from "now". - */ - return result; - } -} - -#else /* #ifdef LTTNG_USE_NMI_SAFE_CLOCK */ -static inline u64 trace_clock_monotonic_wrapper(void) -{ - ktime_t ktime; - - /* - * Refuse to trace from NMIs with this wrapper, because an NMI could - * nest over the xtime write seqlock and deadlock. - */ - if (in_nmi()) - return (u64) -EIO; - - ktime = ktime_get(); - return ktime_to_ns(ktime); -} -#endif /* #else #ifdef LTTNG_USE_NMI_SAFE_CLOCK */ - -static inline u64 trace_clock_read64_monotonic(void) -{ - return (u64) trace_clock_monotonic_wrapper(); -} - -static inline u64 trace_clock_freq_monotonic(void) -{ - return (u64) NSEC_PER_SEC; -} - -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"; -} - -#ifdef LTTNG_USE_NMI_SAFE_CLOCK -static inline int get_trace_clock(void) -{ - printk_once(KERN_WARNING "LTTng: Using mainline kernel monotonic fast clock, which is NMI-safe.\n"); - return 0; -} -#else /* #ifdef LTTNG_USE_NMI_SAFE_CLOCK */ -static inline int get_trace_clock(void) -{ - printk_once(KERN_WARNING "LTTng: Using mainline kernel monotonic clock. NMIs will not be traced.\n"); - return 0; -} -#endif /* #else #ifdef LTTNG_USE_NMI_SAFE_CLOCK */ - -static inline void put_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 */