/* * tracing clocks * * Copyright (C) 2009 Red Hat, Inc., Ingo Molnar * * Implements 3 trace clock variants, with differing scalability/precision * tradeoffs: * * - local: CPU-local trace clock * - medium: scalable global clock with some jitter * - global: globally monotonic, serialized clock * * Tracer plugins will chose a default from these clocks. */ #include #include #include #include #include #include #include #include /* * trace_clock_local(): the simplest and least coherent tracing clock. * * Useful for tracing that does not cross to other CPUs nor * does it go through idle events. */ u64 notrace trace_clock_local(void) { u64 clock; /* * sched_clock() is an architecture implemented, fast, scalable, * lockless clock. It is not guaranteed to be coherent across * CPUs, nor across CPU idle events. */ preempt_disable_notrace(); clock = sched_clock(); preempt_enable_notrace(); return clock; } EXPORT_SYMBOL_GPL(trace_clock_local); /* * trace_clock(): 'between' trace clock. Not completely serialized, * but not completely incorrect when crossing CPUs either. * * This is based on cpu_clock(), which will allow at most ~1 jiffy of * jitter between CPUs. So it's a pretty scalable clock, but there * can be offsets in the trace data. */ u64 notrace trace_clock(void) { return local_clock(); } EXPORT_SYMBOL_GPL(trace_clock); /* * trace_jiffy_clock(): Simply use jiffies as a clock counter. * Note that this use of jiffies_64 is not completely safe on * 32-bit systems. But the window is tiny, and the effect if * we are affected is that we will have an obviously bogus * timestamp on a trace event - i.e. not life threatening. */ u64 notrace trace_clock_jiffies(void) { return jiffies_64_to_clock_t(jiffies_64 - INITIAL_JIFFIES); } EXPORT_SYMBOL_GPL(trace_clock_jiffies); /* * trace_clock_global(): special globally coherent trace clock * * It has higher overhead than the other trace clocks but is still * an order of magnitude faster than GTOD derived hardware clocks. * * Used by plugins that need globally coherent timestamps. */ /* keep prev_time and lock in the same cacheline. */ static struct { u64 prev_time; arch_spinlock_t lock; } trace_clock_struct ____cacheline_aligned_in_smp = { .lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED, }; u64 notrace trace_clock_global(void) { unsigned long flags; int this_cpu; u64 now; local_irq_save(flags); this_cpu = raw_smp_processor_id(); now = sched_clock_cpu(this_cpu); /* * If in an NMI context then dont risk lockups and return the * cpu_clock() time: */ if (unlikely(in_nmi())) goto out; arch_spin_lock(&trace_clock_struct.lock); /* * TODO: if this happens often then maybe we should reset * my_scd->clock to prev_time+1, to make sure * we start ticking with the local clock from now on? */ if ((s64)(now - trace_clock_struct.prev_time) < 0) now = trace_clock_struct.prev_time + 1; trace_clock_struct.prev_time = now; arch_spin_unlock(&trace_clock_struct.lock); out: local_irq_restore(flags); return now; } EXPORT_SYMBOL_GPL(trace_clock_global); static atomic64_t trace_counter; /* * trace_clock_counter(): simply an atomic counter. * Use the trace_counter "counter" for cases where you do not care * about timings, but are interested in strict ordering. */ u64 notrace trace_clock_counter(void) { return atomic64_add_return(1, &trace_counter); } alue='3' selected='selected'>3space:mode:
authorDavid S. Miller <davem@davemloft.net>2017-01-30 14:28:22 -0800
committerDavid S. Miller <davem@davemloft.net>2017-01-30 14:28:22 -0800
commit54791b276b4000b307339f269d3bf7db877d536f (patch)
tree1c2616bd373ce5ea28aac2a53e32f5b5834901ce /include/net/irda/irda.h
parent5d0e7705774dd412a465896d08d59a81a345c1e4 (diff)
parent047487241ff59374fded8c477f21453681f5995c (diff)
Merge branch 'sparc64-non-resumable-user-error-recovery'
Liam R. Howlett says: ==================== sparc64: Recover from userspace non-resumable PIO & MEM errors A non-resumable error from userspace is able to cause a kernel panic or trap loop due to the setup and handling of the queued traps once in the kernel. This patch series addresses both of these issues. The queues are fixed by simply zeroing the memory before use. PIO errors from userspace will result in a SIGBUS being sent to the user process. The MEM errors form userspace will result in a SIGKILL and also cause the offending pages to be claimed so they are no longer used in future tasks. SIGKILL is used to ensure that the process does not try to coredump and result in an attempt to read the memory again from within kernel space. Although there is a HV call to scrub the memory (mem_scrub), there is no easy way to guarantee that the real memory address(es) are not used by other tasks. Clearing the error with mem_scrub would zero the memory and cause the other processes to proceed with bad data. The handling of other non-resumable errors remain unchanged and will cause a panic. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/irda/irda.h')