ping...................
Shan Wei said, at 2012/11/3 12:38:
> From: Shan Wei <davids...@tencent.com>
>
> When doing per-cpu helper optimizing work, find that this code is so puzzled.
> 1. It's mark as comment text, maybe a sample function for guidelines
> or a todo work.
> 2. But, this sample code is odd where struct perf_trace_buf is nonexistent.
> commit ce71b9 delete struct perf_trace_buf definition.
>
> Author: Frederic Weisbecker <fweis...@gmail.com>
> Date: Sun Nov 22 05:26:55 2009 +0100
>
> tracing: Use the perf recursion protection from trace event
>
> Is it necessary to keep there?
> just compile test.
>
>
>
> Signed-off-by: Shan Wei <davids...@tencent.com>
> ---
> include/trace/ftrace.h | 73
> ------------------------------------------------
> 1 files changed, 0 insertions(+), 73 deletions(-)
>
> diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
> index a763888..4f993c2 100644
> --- a/include/trace/ftrace.h
> +++ b/include/trace/ftrace.h
> @@ -620,79 +620,6 @@ __attribute__((section("_ftrace_events")))
> *__event_##call = &event_##call
>
> #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
>
> -/*
> - * Define the insertion callback to perf events
> - *
> - * The job is very similar to ftrace_raw_event_<call> except that we don't
> - * insert in the ring buffer but in a perf counter.
> - *
> - * static void ftrace_perf_<call>(proto)
> - * {
> - * struct ftrace_data_offsets_<call> __maybe_unused __data_offsets;
> - * struct ftrace_event_call *event_call = &event_<call>;
> - * extern void perf_tp_event(int, u64, u64, void *, int);
> - * struct ftrace_raw_##call *entry;
> - * struct perf_trace_buf *trace_buf;
> - * u64 __addr = 0, __count = 1;
> - * unsigned long irq_flags;
> - * struct trace_entry *ent;
> - * int __entry_size;
> - * int __data_size;
> - * int __cpu
> - * int pc;
> - *
> - * pc = preempt_count();
> - *
> - * __data_size = ftrace_get_offsets_<call>(&__data_offsets, args);
> - *
> - * // Below we want to get the aligned size by taking into account
> - * // the u32 field that will later store the buffer size
> - * __entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32),
> - * sizeof(u64));
> - * __entry_size -= sizeof(u32);
> - *
> - * // Protect the non nmi buffer
> - * // This also protects the rcu read side
> - * local_irq_save(irq_flags);
> - * __cpu = smp_processor_id();
> - *
> - * if (in_nmi())
> - * trace_buf = rcu_dereference_sched(perf_trace_buf_nmi);
> - * else
> - * trace_buf = rcu_dereference_sched(perf_trace_buf);
> - *
> - * if (!trace_buf)
> - * goto end;
> - *
> - * trace_buf = per_cpu_ptr(trace_buf, __cpu);
> - *
> - * // Avoid recursion from perf that could mess up the buffer
> - * if (trace_buf->recursion++)
> - * goto end_recursion;
> - *
> - * raw_data = trace_buf->buf;
> - *
> - * // Make recursion update visible before entering perf_tp_event
> - * // so that we protect from perf recursions.
> - *
> - * barrier();
> - *
> - * //zero dead bytes from alignment to avoid stack leak to userspace:
> - * *(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL;
> - * entry = (struct ftrace_raw_<call> *)raw_data;
> - * ent = &entry->ent;
> - * tracing_generic_entry_update(ent, irq_flags, pc);
> - * ent->type = event_call->id;
> - *
> - * <tstruct> <- do some jobs with dynamic arrays
> - *
> - * <assign> <- affect our values
> - *
> - * perf_tp_event(event_call->id, __addr, __count, entry,
> - * __entry_size); <- submit them to perf counter
> - *
> - * }
> - */
>
> #ifdef CONFIG_PERF_EVENTS
>
>
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