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Commit 7c6baa30 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull perf fixes from Ingo Molnar:
 "Misc minor fixes mostly related to tracing"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  s390: Fix a header dependencies related build error
  tracing: update documentation of snapshot utility
  tracing: Do not return EINVAL in snapshot when not allocated
  tracing: Add help of snapshot feature when snapshot is empty
  ftrace: Update the kconfig for DYNAMIC_FTRACE
parents 0cb77508 cb16b91a

Documentation/trace/ftrace.txt

+1 −1
Original line number Original line Diff line number Diff line
@@ -1873,7 +1873,7 @@ feature: 




	status\input  |     0      |     1      |    else    |

	status\input  |     0      |     1      |    else    |

	--------------+------------+------------+------------+

	--------------+------------+------------+------------+

	not allocated |(do nothing)| alloc+swap |   EINVAL   |

	not allocated |(do nothing)| alloc+swap |(do nothing)|

	--------------+------------+------------+------------+

	--------------+------------+------------+------------+

	allocated     |    free    |    swap    |   clear    |

	allocated     |    free    |    swap    |   clear    |

	--------------+------------+------------+------------+

	--------------+------------+------------+------------+

arch/s390/include/asm/cpu_mf.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -12,6 +12,7 @@ 
#ifndef _ASM_S390_CPU_MF_H

#ifndef _ASM_S390_CPU_MF_H

#define _ASM_S390_CPU_MF_H

#define _ASM_S390_CPU_MF_H





#include <linux/errno.h>

#include <asm/facility.h>

#include <asm/facility.h>





#define CPU_MF_INT_SF_IAE	(1 << 31)	/* invalid entry address */

#define CPU_MF_INT_SF_IAE	(1 << 31)	/* invalid entry address */

kernel/trace/Kconfig

+14 −10
Original line number Original line Diff line number Diff line
@@ -414,24 +414,28 @@ config PROBE_EVENTS 
	def_bool n

	def_bool n





config DYNAMIC_FTRACE

config DYNAMIC_FTRACE

	bool "enable/disable ftrace tracepoints dynamically"

	bool "enable/disable function tracing dynamically"

	depends on FUNCTION_TRACER

	depends on FUNCTION_TRACER

	depends on HAVE_DYNAMIC_FTRACE

	depends on HAVE_DYNAMIC_FTRACE

	default y

	default y

	help

	help

          This option will modify all the calls to ftrace dynamically

	  This option will modify all the calls to function tracing

	  (will patch them out of the binary image and replace them

	  dynamically (will patch them out of the binary image and

	  with a No-Op instruction) as they are called. A table is

	  replace them with a No-Op instruction) on boot up. During

	  created to dynamically enable them again.

	  compile time, a table is made of all the locations that ftrace

	  can function trace, and this table is linked into the kernel

	  image. When this is enabled, functions can be individually

	  enabled, and the functions not enabled will not affect

	  performance of the system.



	  See the files in /sys/kernel/debug/tracing:

	    available_filter_functions

	    set_ftrace_filter

	    set_ftrace_notrace





	  This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but

	  This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but

	  otherwise has native performance as long as no tracing is active.

	  otherwise has native performance as long as no tracing is active.





	  The changes to the code are done by a kernel thread that

	  wakes up once a second and checks to see if any ftrace calls

	  were made. If so, it runs stop_machine (stops all CPUS)

	  and modifies the code to jump over the call to ftrace.



config DYNAMIC_FTRACE_WITH_REGS

config DYNAMIC_FTRACE_WITH_REGS

	def_bool y

	def_bool y

	depends on DYNAMIC_FTRACE

	depends on DYNAMIC_FTRACE

kernel/trace/trace.c

+24 −3
Original line number Original line Diff line number Diff line
@@ -2400,6 +2400,27 @@ static void test_ftrace_alive(struct seq_file *m) 
	seq_printf(m, "#          MAY BE MISSING FUNCTION EVENTS\n");

	seq_printf(m, "#          MAY BE MISSING FUNCTION EVENTS\n");

}

}





#ifdef CONFIG_TRACER_MAX_TRACE

static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)

{

	if (iter->trace->allocated_snapshot)

		seq_printf(m, "#\n# * Snapshot is allocated *\n#\n");

	else

		seq_printf(m, "#\n# * Snapshot is freed *\n#\n");



	seq_printf(m, "# Snapshot commands:\n");

	seq_printf(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");

	seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");

	seq_printf(m, "#                      Takes a snapshot of the main buffer.\n");

	seq_printf(m, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n");

	seq_printf(m, "#                      (Doesn't have to be '2' works with any number that\n");

	seq_printf(m, "#                       is not a '0' or '1')\n");

}

#else

/* Should never be called */

static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }

#endif



static int s_show(struct seq_file *m, void *v)

static int s_show(struct seq_file *m, void *v)

{

{

	struct trace_iterator *iter = v;

	struct trace_iterator *iter = v;
@@ -2411,7 +2432,9 @@ static int s_show(struct seq_file *m, void *v) 
			seq_puts(m, "#\n");

			seq_puts(m, "#\n");

			test_ftrace_alive(m);

			test_ftrace_alive(m);

		}

		}

		if (iter->trace && iter->trace->print_header)

		if (iter->snapshot && trace_empty(iter))

			print_snapshot_help(m, iter);

		else if (iter->trace && iter->trace->print_header)

			iter->trace->print_header(m);

			iter->trace->print_header(m);

		else

		else

			trace_default_header(m);

			trace_default_header(m);
@@ -4144,8 +4167,6 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, 
	default:

	default:

		if (current_trace->allocated_snapshot)

		if (current_trace->allocated_snapshot)

			tracing_reset_online_cpus(&max_tr);

			tracing_reset_online_cpus(&max_tr);

		else

			ret = -EINVAL;

		break;

		break;

	}

	}