Tracing/fastboot: Get the initcall name before it disappears
PATCH 2/2 Tracing/fastboot: Get the initcall name before it disappears
After some initcall traces, some initcall names may be inconsistent. That's because these functions will disappear from the .init section and also their name from the symbols table.
So we have to copy the name of the function in a buffer large enough during the trace appending. It is not costly for the ring_buffer because the number of initcall entries is commonly not really large.
--- include/linux/ftrace.h | 7 ++++--- init/main.c | 3 +-- kernel/trace/trace_boot.c | 14 ++++++++++---- 3 files changed, 15 insertions(+), 9 deletions(-)
include/linux/ftrace.h +4 -3
@@ -7,6 +7,7 @@#include <linux/fs.h> #include <linux/init.h> #include <linux/types.h> +#include <linux/kallsyms.h> extern int ftrace_enabled; extern int
@@ -213,7 +214,7 @@ ftrace_init_module(unsigned long *start, unsigned long *end) { }struct boot_trace {pid_t caller; -initcall_t func; +char func[KSYM_NAME_LEN ];int result;unsigned long long duration;ktime_t calltime;
@@ -221,10 +222,10 @@ struct boot_trace { };#ifdef CONFIG_BOOT_TRACER -extern void trace_boot (struct boot_trace *it); +extern void trace_boot (struct boot_trace *it,initcall_t fn);extern void start_boot_trace (void );#else -static inline void trace_boot (struct boot_trace *it) { } +static inline void trace_boot (struct boot_trace *it,initcall_t fn) { }static inline void start_boot_trace (void ) { }#endif
init/main.c +1 -2
@@ -727,7 +727,6 @@ int do_one_initcall(initcall_t fn)if (initcall_debug) { it.caller =task_pid_nr (current); - it.func = fn;printk ("calling %pF @ %i\n" , fn, it.caller); it.calltime =ktime_get (); }
@@ -740,7 +739,7 @@ int do_one_initcall(initcall_t fn) it.duration = (unsigned long long ) delta.tv64 >>20 ;printk ("initcall %pF returned %d after %Ld msecs\n" , fn, it.result, it.duration); -trace_boot (&it); +trace_boot (&it, fn); } msgbuf[0 ] =0 ;
kernel/trace/trace_boot.c +10 -4
@@ -8,6 +8,7 @@#include <linux/init.h> #include <linux/debugfs.h> #include <linux/ftrace.h> +#include <linux/kallsyms.h> #include "trace.h"
@@ -56,17 +57,19 @@ static enum print_line_t initcall_print_line(struct trace_iterator *iter)struct timespec rettime =ktime_to_timespec (it->rettime);if (entry->type ==TRACE_BOOT ) { - ret =trace_seq_printf (s,"[%5ld.%06ld] calling %pF @ %i\n" , + ret =trace_seq_printf (s,"[%5ld.%06ld] calling %s @ %i\n" , calltime.tv_sec, calltime.tv_nsec, it->func, it->caller);if (!ret)return TRACE_TYPE_PARTIAL_LINE ; - ret =trace_seq_printf (s,"[%5ld.%06ld] initcall %pF " + + ret =trace_seq_printf (s,"[%5ld.%06ld] initcall %s " "returned %d after %lld msecs\n" , rettime.tv_sec, rettime.tv_nsec, it->func, it->result, it->duration); +if (!ret)return TRACE_TYPE_PARTIAL_LINE ;return TRACE_TYPE_HANDLED ;
@@ -83,8 +86,7 @@ struct tracer boot_tracer __read_mostly = .print_line = initcall_print_line, }; - -void trace_boot (struct boot_trace *it) +void trace_boot (struct boot_trace *it,initcall_t fn) {struct ring_buffer_event *event;struct trace_boot *entry;
@@ -95,6 +97,10 @@ void trace_boot(struct boot_trace *it)if (!trace_boot_enabled)return ; +/* Get its name now since this function could +* disappear because it is in the .init section. +*/ +sprint_symbol (it->func, (unsigned long )fn);preempt_disable (); data = tr->data[smp_processor_id ()];
Quoted 8 lines · Frederic Weisbecker
After some initcall traces, some initcall names may be inconsistent. That's because these functions will disappear from the .init section and also their name from the symbols table.
So we have to copy the name of the function in a buffer large enough during the trace appending. It is not costly for thering_bufferbecause the number of initcall entries is commonly not really large.Signed-off-by Frederic Weisbecker <[email protected]>
applied to tip/tracing/fastboot, thanks Frederic,
Ingo
2008/10/2 Ingo Molnar <[email protected]>:
Quoted 10 lines · Frederic Weisbecker
Quoted 8 lines
After some initcall traces, some initcall names may be inconsistent. That's because these functions will disappear from the .init section and also their name from the symbols table.
So we have to copy the name of the function in a buffer large enough during the trace appending. It is not costly for thering_bufferbecause the number of initcall entries is commonly not really large.
Quoted 6 lines
Quoted 1 line
Signed-off-by Frederic Weisbecker <[email protected]>applied to tip/tracing/fastboot, thanks Frederic,
Ingo
BTW I forgot to cc Arjan.
Arjan if you have some time to test it, I would be interested by your feeling about it since
the boot tracer has now an output which is parsable by bootgraph.pl.
Thanks!
PATCH 1/1 tracing/fastboot: build fix
In reply to Ingo MolnarQuoted 2 lines
From
7d14307eeaa710427436c09c6f77dde1974621cfMon Sep 17 00:00:00 2001
From: Ingo Molnar <[email protected]>
Date: Thu, 2 Oct 2008 17:45:47 +0200
Subject: [PATCH] tracing/fastboot: build fix
fix:
In file included from kernel/sysctl.c:52:
include/linux/ftrace.h:217: error: 'KSYM_NAME_LEN' undeclared here (not in a function)
--- include/linux/ftrace.h | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)
include/linux/ftrace.h +2 -2
@@ -1,14 +1,14 @@#ifndef _LINUX_FTRACE_H#define _LINUX_FTRACE_H -#ifdef CONFIG_FTRACE -#include <linux/linkage.h> #include <linux/fs.h> #include <linux/init.h> #include <linux/types.h> #include <linux/kallsyms.h> +#ifdef CONFIG_FTRACE +extern int ftrace_enabled; extern int ftrace_enable_sysctl(struct ctl_table *table, int write,