Commit 214b9313 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'trace-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace 

Pull tracing updates from Steven Rostedt:
 "Lots of tweaks, small fixes, optimizations, and some helper functions
  to help out the rest of the kernel to ease their use of trace events.

  The big change for this release is the allowing of other tracers, such
  as the latency tracers, to be used in the trace instances and allow
  for function or function graph tracing to be in the top level
  simultaneously"

* tag 'trace-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits)
  tracing: Fix memory leak on instance deletion
  tracing: Fix leak of ring buffer data when new instances creation fails
  tracing/kprobes: Avoid self tests if tracing is disabled on boot up
  tracing: Return error if ftrace_trace_arrays list is empty
  tracing: Only calculate stats of tracepoint benchmarks for 2^32 times
  tracing: Convert stddev into u64 in tracepoint benchmark
  tracing: Introduce saved_cmdlines_size file
  tracing: Add __get_dynamic_array_len() macro for trace events
  tracing: Remove unused variable in trace_benchmark
  tracing: Eliminate double free on failure of allocation on boot up
  ftrace/x86: Call text_ip_addr() instead of the duplicated code
  tracing: Print max callstack on stacktrace bug
  tracing: Move locking of trace_cmdline_lock into start/stop seq calls
  tracing: Try again for saved cmdline if failed due to locking
  tracing: Have saved_cmdlines use the seq_read infrastructure
  tracing: Add tracepoint benchmark tracepoint
  tracing: Print nasty banner when trace_printk() is in use
  tracing: Add funcgraph_tail option to print function name after closing braces
  tracing: Eliminate duplicate TRACE_GRAPH_PRINT_xx defines
  tracing: Add __bitmask() macro to trace events to cpumasks and other bitmasks
  ...
parents 14208b0e a9fcaaac

Documentation/trace/ftrace.txt

+26 −0
Original line number Diff line number Diff line
@@ -2003,6 +2003,32 @@ want, depending on your needs. 
  360.774530 |   1)   0.594 us    |                                          __phys_addr();





The function name is always displayed after the closing bracket

for a function if the start of that function is not in the

trace buffer.



Display of the function name after the closing bracket may be

enabled for functions whose start is in the trace buffer,

allowing easier searching with grep for function durations.

It is default disabled.



	hide: echo nofuncgraph-tail > trace_options

	show: echo funcgraph-tail > trace_options



  Example with nofuncgraph-tail (default):

  0)               |      putname() {

  0)               |        kmem_cache_free() {

  0)   0.518 us    |          __phys_addr();

  0)   1.757 us    |        }

  0)   2.861 us    |      }



  Example with funcgraph-tail:

  0)               |      putname() {

  0)               |        kmem_cache_free() {

  0)   0.518 us    |          __phys_addr();

  0)   1.757 us    |        } /* kmem_cache_free() */

  0)   2.861 us    |      } /* putname() */



You can put some comments on specific functions by using

trace_printk() For example, if you want to put a comment inside

the __might_sleep() function, you just have to include

Documentation/trace/tracepoints.txt

+24 −0
Original line number Diff line number Diff line
@@ -115,6 +115,30 @@ If the tracepoint has to be used in kernel modules, an 
EXPORT_TRACEPOINT_SYMBOL_GPL() or EXPORT_TRACEPOINT_SYMBOL() can be

used to export the defined tracepoints.



If you need to do a bit of work for a tracepoint parameter, and

that work is only used for the tracepoint, that work can be encapsulated

within an if statement with the following:



	if (trace_foo_bar_enabled()) {

		int i;

		int tot = 0;



		for (i = 0; i < count; i++)

			tot += calculate_nuggets();



		trace_foo_bar(tot);

	}



All trace_<tracepoint>() calls have a matching trace_<tracepoint>_enabled()

function defined that returns true if the tracepoint is enabled and

false otherwise. The trace_<tracepoint>() should always be within the

block of the if (trace_<tracepoint>_enabled()) to prevent races between

the tracepoint being enabled and the check being seen.



The advantage of using the trace_<tracepoint>_enabled() is that it uses

the static_key of the tracepoint to allow the if statement to be implemented

with jump labels and avoid conditional branches.



Note: The convenience macro TRACE_EVENT provides an alternative way to

      define tracepoints. Check http://lwn.net/Articles/379903,

      http://lwn.net/Articles/381064 and http://lwn.net/Articles/383362

MAINTAINERS

+0 −1
Original line number Diff line number Diff line
@@ -9106,7 +9106,6 @@ F: drivers/char/tpm/ 


TRACING

M:	Steven Rostedt <rostedt@goodmis.org>

M:	Frederic Weisbecker <fweisbec@gmail.com>

M:	Ingo Molnar <mingo@redhat.com>

T:	git git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git perf/core

S:	Maintained

arch/x86/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ obj-$(CONFIG_IRQ_WORK) += irq_work.o 
obj-y			+= probe_roms.o

obj-$(CONFIG_X86_32)	+= i386_ksyms_32.o

obj-$(CONFIG_X86_64)	+= sys_x86_64.o x8664_ksyms_64.o

obj-$(CONFIG_X86_64)	+= mcount_64.o

obj-y			+= syscall_$(BITS).o vsyscall_gtod.o

obj-$(CONFIG_X86_64)	+= vsyscall_64.o

obj-$(CONFIG_X86_64)	+= vsyscall_emu_64.o

arch/x86/kernel/entry_64.S

+0 −204
Original line number Diff line number Diff line
@@ -53,7 +53,6 @@ 
#include <asm/page_types.h>

#include <asm/irqflags.h>

#include <asm/paravirt.h>

#include <asm/ftrace.h>

#include <asm/percpu.h>

#include <asm/asm.h>

#include <asm/context_tracking.h>
@@ -70,209 +69,6 @@ 
	.code64

	.section .entry.text, "ax"



#ifdef CONFIG_FUNCTION_TRACER



#ifdef CC_USING_FENTRY

# define function_hook	__fentry__

#else

# define function_hook	mcount

#endif



#ifdef CONFIG_DYNAMIC_FTRACE



ENTRY(function_hook)

	retq

END(function_hook)



/* skip is set if stack has been adjusted */

.macro ftrace_caller_setup skip=0

	MCOUNT_SAVE_FRAME \skip



	/* Load the ftrace_ops into the 3rd parameter */

	movq function_trace_op(%rip), %rdx



	/* Load ip into the first parameter */

	movq RIP(%rsp), %rdi

	subq $MCOUNT_INSN_SIZE, %rdi

	/* Load the parent_ip into the second parameter */

#ifdef CC_USING_FENTRY

	movq SS+16(%rsp), %rsi

#else

	movq 8(%rbp), %rsi

#endif

.endm



ENTRY(ftrace_caller)

	/* Check if tracing was disabled (quick check) */

	cmpl $0, function_trace_stop

	jne  ftrace_stub



	ftrace_caller_setup

	/* regs go into 4th parameter (but make it NULL) */

	movq $0, %rcx



GLOBAL(ftrace_call)

	call ftrace_stub



	MCOUNT_RESTORE_FRAME

ftrace_return:



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

GLOBAL(ftrace_graph_call)

	jmp ftrace_stub

#endif



GLOBAL(ftrace_stub)

	retq

END(ftrace_caller)



ENTRY(ftrace_regs_caller)

	/* Save the current flags before compare (in SS location)*/

	pushfq



	/* Check if tracing was disabled (quick check) */

	cmpl $0, function_trace_stop

	jne  ftrace_restore_flags



	/* skip=8 to skip flags saved in SS */

	ftrace_caller_setup 8



	/* Save the rest of pt_regs */

	movq %r15, R15(%rsp)

	movq %r14, R14(%rsp)

	movq %r13, R13(%rsp)

	movq %r12, R12(%rsp)

	movq %r11, R11(%rsp)

	movq %r10, R10(%rsp)

	movq %rbp, RBP(%rsp)

	movq %rbx, RBX(%rsp)

	/* Copy saved flags */

	movq SS(%rsp), %rcx

	movq %rcx, EFLAGS(%rsp)

	/* Kernel segments */

	movq $__KERNEL_DS, %rcx

	movq %rcx, SS(%rsp)

	movq $__KERNEL_CS, %rcx

	movq %rcx, CS(%rsp)

	/* Stack - skipping return address */

	leaq SS+16(%rsp), %rcx

	movq %rcx, RSP(%rsp)



	/* regs go into 4th parameter */

	leaq (%rsp), %rcx



GLOBAL(ftrace_regs_call)

	call ftrace_stub



	/* Copy flags back to SS, to restore them */

	movq EFLAGS(%rsp), %rax

	movq %rax, SS(%rsp)



	/* Handlers can change the RIP */

	movq RIP(%rsp), %rax

	movq %rax, SS+8(%rsp)



	/* restore the rest of pt_regs */

	movq R15(%rsp), %r15

	movq R14(%rsp), %r14

	movq R13(%rsp), %r13

	movq R12(%rsp), %r12

	movq R10(%rsp), %r10

	movq RBP(%rsp), %rbp

	movq RBX(%rsp), %rbx



	/* skip=8 to skip flags saved in SS */

	MCOUNT_RESTORE_FRAME 8



	/* Restore flags */

	popfq



	jmp ftrace_return

ftrace_restore_flags:

	popfq

	jmp  ftrace_stub



END(ftrace_regs_caller)





#else /* ! CONFIG_DYNAMIC_FTRACE */



ENTRY(function_hook)

	cmpl $0, function_trace_stop

	jne  ftrace_stub



	cmpq $ftrace_stub, ftrace_trace_function

	jnz trace



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

	cmpq $ftrace_stub, ftrace_graph_return

	jnz ftrace_graph_caller



	cmpq $ftrace_graph_entry_stub, ftrace_graph_entry

	jnz ftrace_graph_caller

#endif



GLOBAL(ftrace_stub)

	retq



trace:

	MCOUNT_SAVE_FRAME



	movq RIP(%rsp), %rdi

#ifdef CC_USING_FENTRY

	movq SS+16(%rsp), %rsi

#else

	movq 8(%rbp), %rsi

#endif

	subq $MCOUNT_INSN_SIZE, %rdi



	call   *ftrace_trace_function



	MCOUNT_RESTORE_FRAME



	jmp ftrace_stub

END(function_hook)

#endif /* CONFIG_DYNAMIC_FTRACE */

#endif /* CONFIG_FUNCTION_TRACER */



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

ENTRY(ftrace_graph_caller)

	MCOUNT_SAVE_FRAME



#ifdef CC_USING_FENTRY

	leaq SS+16(%rsp), %rdi

	movq $0, %rdx	/* No framepointers needed */

#else

	leaq 8(%rbp), %rdi

	movq (%rbp), %rdx

#endif

	movq RIP(%rsp), %rsi

	subq $MCOUNT_INSN_SIZE, %rsi



	call	prepare_ftrace_return



	MCOUNT_RESTORE_FRAME



	retq

END(ftrace_graph_caller)



GLOBAL(return_to_handler)

	subq  $24, %rsp



	/* Save the return values */

	movq %rax, (%rsp)

	movq %rdx, 8(%rsp)

	movq %rbp, %rdi



	call ftrace_return_to_handler



	movq %rax, %rdi

	movq 8(%rsp), %rdx

	movq (%rsp), %rax

	addq $24, %rsp

	jmp *%rdi

#endif





#ifndef CONFIG_PREEMPT

#define retint_kernel retint_restore_args

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