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authorLinus Torvalds <torvalds@linux-foundation.org>2013-03-11 07:54:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-03-11 07:54:29 -0700
commit7c6baa304b841673d3a55ea4fcf9a5cbf7a1674b (patch)
treea6f9970cebfb573a74a4abd06ff9caee41460e9a
parentMerge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net (diff)
parents390: Fix a header dependencies related build error (diff)
downloadlinux-dev-7c6baa304b841673d3a55ea4fcf9a5cbf7a1674b.tar.xz
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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
-rw-r--r--Documentation/trace/ftrace.txt2
-rw-r--r--arch/s390/include/asm/cpu_mf.h1
-rw-r--r--kernel/trace/Kconfig24
-rw-r--r--kernel/trace/trace.c27
4 files changed, 40 insertions, 14 deletions
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index 53d6a3c51d87..a372304aef10 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -1873,7 +1873,7 @@ feature:
status\input | 0 | 1 | else |
--------------+------------+------------+------------+
- not allocated |(do nothing)| alloc+swap | EINVAL |
+ not allocated |(do nothing)| alloc+swap |(do nothing)|
--------------+------------+------------+------------+
allocated | free | swap | clear |
--------------+------------+------------+------------+
diff --git a/arch/s390/include/asm/cpu_mf.h b/arch/s390/include/asm/cpu_mf.h
index f1eddd150dd7..c879fad404c8 100644
--- a/arch/s390/include/asm/cpu_mf.h
+++ b/arch/s390/include/asm/cpu_mf.h
@@ -12,6 +12,7 @@
#ifndef _ASM_S390_CPU_MF_H
#define _ASM_S390_CPU_MF_H
+#include <linux/errno.h>
#include <asm/facility.h>
#define CPU_MF_INT_SF_IAE (1 << 31) /* invalid entry address */
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 192473b22799..fc382d6e2765 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -414,24 +414,28 @@ config PROBE_EVENTS
def_bool n
config DYNAMIC_FTRACE
- bool "enable/disable ftrace tracepoints dynamically"
+ bool "enable/disable function tracing dynamically"
depends on FUNCTION_TRACER
depends on HAVE_DYNAMIC_FTRACE
default y
help
- This option will modify all the calls to ftrace dynamically
- (will patch them out of the binary image and replace them
- with a No-Op instruction) as they are called. A table is
- created to dynamically enable them again.
+ This option will modify all the calls to function tracing
+ dynamically (will patch them out of the binary image and
+ replace them with a No-Op instruction) on boot up. During
+ 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
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
def_bool y
depends on DYNAMIC_FTRACE
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c2e2c2310374..1f835a83cb2c 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2400,6 +2400,27 @@ static void test_ftrace_alive(struct seq_file *m)
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)
{
struct trace_iterator *iter = v;
@@ -2411,7 +2432,9 @@ static int s_show(struct seq_file *m, void *v)
seq_puts(m, "#\n");
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);
else
trace_default_header(m);
@@ -4144,8 +4167,6 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
default:
if (current_trace->allocated_snapshot)
tracing_reset_online_cpus(&max_tr);
- else
- ret = -EINVAL;
break;
}