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author | Steven Rostedt <srostedt@redhat.com> | 2011-06-15 03:02:29 +0400 |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2011-07-08 06:26:27 +0400 |
commit | e4a3f541f0b67fdad98b326c851dfe7f4b6b6dad (patch) | |
tree | e93b858ab3313374d23c4ebadc5077816f1894f2 /kernel/trace/trace.h | |
parent | e08fbb78f03fe2c4f88824faf6f51ce6af185e11 (diff) | |
download | linux-e4a3f541f0b67fdad98b326c851dfe7f4b6b6dad.tar.xz |
tracing: Still trace filtered irq functions when irq trace is disabled
If a function is set to be traced by the set_graph_function, but the
option funcgraph-irqs is zero, and the traced function happens to be
called from a interrupt, it will not be traced.
The point of funcgraph-irqs is to not trace interrupts when we are
preempted by an irq, not to not trace functions we want to trace that
happen to be *in* a irq.
Luckily the current->trace_recursion element is perfect to add a flag
to help us be able to trace functions within an interrupt even when
we are not tracing interrupts that preempt the trace.
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace.h')
-rw-r--r-- | kernel/trace/trace.h | 50 |
1 files changed, 34 insertions, 16 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index a3e2db708072..651f35be372a 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -278,6 +278,29 @@ struct tracer { }; +/* Only current can touch trace_recursion */ +#define trace_recursion_inc() do { (current)->trace_recursion++; } while (0) +#define trace_recursion_dec() do { (current)->trace_recursion--; } while (0) + +/* Ring buffer has the 10 LSB bits to count */ +#define trace_recursion_buffer() ((current)->trace_recursion & 0x3ff) + +/* for function tracing recursion */ +#define TRACE_INTERNAL_BIT (1<<11) +#define TRACE_GLOBAL_BIT (1<<12) +/* + * Abuse of the trace_recursion. + * As we need a way to maintain state if we are tracing the function + * graph in irq because we want to trace a particular function that + * was called in irq context but we have irq tracing off. Since this + * can only be modified by current, we can reuse trace_recursion. + */ +#define TRACE_IRQ_BIT (1<<13) + +#define trace_recursion_set(bit) do { (current)->trace_recursion |= (bit); } while (0) +#define trace_recursion_clear(bit) do { (current)->trace_recursion &= ~(bit); } while (0) +#define trace_recursion_test(bit) ((current)->trace_recursion & (bit)) + #define TRACE_PIPE_ALL_CPU -1 int tracer_init(struct tracer *t, struct trace_array *tr); @@ -516,8 +539,18 @@ static inline int ftrace_graph_addr(unsigned long addr) return 1; for (i = 0; i < ftrace_graph_count; i++) { - if (addr == ftrace_graph_funcs[i]) + if (addr == ftrace_graph_funcs[i]) { + /* + * If no irqs are to be traced, but a set_graph_function + * is set, and called by an interrupt handler, we still + * want to trace it. + */ + if (in_irq()) + trace_recursion_set(TRACE_IRQ_BIT); + else + trace_recursion_clear(TRACE_IRQ_BIT); return 1; + } } return 0; @@ -794,19 +827,4 @@ extern const char *__stop___trace_bprintk_fmt[]; FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print)) #include "trace_entries.h" -/* Only current can touch trace_recursion */ -#define trace_recursion_inc() do { (current)->trace_recursion++; } while (0) -#define trace_recursion_dec() do { (current)->trace_recursion--; } while (0) - -/* Ring buffer has the 10 LSB bits to count */ -#define trace_recursion_buffer() ((current)->trace_recursion & 0x3ff) - -/* for function tracing recursion */ -#define TRACE_INTERNAL_BIT (1<<11) -#define TRACE_GLOBAL_BIT (1<<12) - -#define trace_recursion_set(bit) do { (current)->trace_recursion |= (bit); } while (0) -#define trace_recursion_clear(bit) do { (current)->trace_recursion &= ~(bit); } while (0) -#define trace_recursion_test(bit) ((current)->trace_recursion & (bit)) - #endif /* _LINUX_KERNEL_TRACE_H */ |