diff options
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/Kconfig | 13 | ||||
| -rw-r--r-- | kernel/trace/ftrace.c | 15 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 40 | ||||
| -rw-r--r-- | kernel/trace/trace_sched_switch.c | 1 | ||||
| -rw-r--r-- | kernel/trace/trace_stack.c | 49 |
5 files changed, 85 insertions, 33 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index d8bae6f4219e..e2a4ff6fc3a6 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -244,10 +244,15 @@ config STACK_TRACER This tracer works by hooking into every function call that the kernel executes, and keeping a maximum stack depth value and - stack-trace saved. Because this logic has to execute in every - kernel function, all the time, this option can slow down the - kernel measurably and is generally intended for kernel - developers only. + stack-trace saved. If this is configured with DYNAMIC_FTRACE + then it will not have any overhead while the stack tracer + is disabled. + + To enable the stack tracer on bootup, pass in 'stacktrace' + on the kernel command line. + + The stack tracer can also be enabled or disabled via the + sysctl kernel.stack_tracer_enabled Say N if unsure. diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index a12f80efceaa..2f32969c09df 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1047,6 +1047,13 @@ ftrace_match(unsigned char *buff, int len, int enable) int type = MATCH_FULL; unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE; unsigned i, match = 0, search_len = 0; + int not = 0; + + if (buff[0] == '!') { + not = 1; + buff++; + len--; + } for (i = 0; i < len; i++) { if (buff[i] == '*') { @@ -1100,8 +1107,12 @@ ftrace_match(unsigned char *buff, int len, int enable) matched = 1; break; } - if (matched) - rec->flags |= flag; + if (matched) { + if (not) + rec->flags &= ~flag; + else + rec->flags |= flag; + } } pg = pg->next; } diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 1a3d6b329782..0eb6d48347f7 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1748,6 +1748,13 @@ lat_print_timestamp(struct trace_seq *s, u64 abs_usecs, static const char state_to_char[] = TASK_STATE_TO_CHAR_STR; +static int task_state_char(unsigned long state) +{ + int bit = state ? __ffs(state) + 1 : 0; + + return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?'; +} + /* * The message is supposed to contain an ending newline. * If the printing stops prematurely, try to add a newline of our own. @@ -1816,7 +1823,6 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) char *comm; int S, T; int i; - unsigned state; if (entry->type == TRACE_CONT) return TRACE_TYPE_HANDLED; @@ -1862,12 +1868,8 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) trace_assign_type(field, entry); - T = field->next_state < sizeof(state_to_char) ? - state_to_char[field->next_state] : 'X'; - - state = field->prev_state ? - __ffs(field->prev_state) + 1 : 0; - S = state < sizeof(state_to_char) - 1 ? state_to_char[state] : 'X'; + T = task_state_char(field->next_state); + S = task_state_char(field->prev_state); comm = trace_find_cmdline(field->next_pid); trace_seq_printf(s, " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n", field->prev_pid, @@ -2008,10 +2010,8 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter) trace_assign_type(field, entry); - S = field->prev_state < sizeof(state_to_char) ? - state_to_char[field->prev_state] : 'X'; - T = field->next_state < sizeof(state_to_char) ? - state_to_char[field->next_state] : 'X'; + T = task_state_char(field->next_state); + S = task_state_char(field->prev_state); ret = trace_seq_printf(s, " %5d:%3d:%c %s [%03d] %5d:%3d:%c\n", field->prev_pid, field->prev_prio, @@ -2141,12 +2141,9 @@ static enum print_line_t print_raw_fmt(struct trace_iterator *iter) trace_assign_type(field, entry); - S = field->prev_state < sizeof(state_to_char) ? - state_to_char[field->prev_state] : 'X'; - T = field->next_state < sizeof(state_to_char) ? - state_to_char[field->next_state] : 'X'; - if (entry->type == TRACE_WAKE) - S = '+'; + T = task_state_char(field->next_state); + S = entry->type == TRACE_WAKE ? '+' : + task_state_char(field->prev_state); ret = trace_seq_printf(s, "%d %d %c %d %d %d %c\n", field->prev_pid, field->prev_prio, @@ -2233,12 +2230,9 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter) trace_assign_type(field, entry); - S = field->prev_state < sizeof(state_to_char) ? - state_to_char[field->prev_state] : 'X'; - T = field->next_state < sizeof(state_to_char) ? - state_to_char[field->next_state] : 'X'; - if (entry->type == TRACE_WAKE) - S = '+'; + T = task_state_char(field->next_state); + S = entry->type == TRACE_WAKE ? '+' : + task_state_char(field->prev_state); SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid); SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio); SEQ_PUT_HEX_FIELD_RET(s, S); diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index 863390557b44..781d72ef873c 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -247,3 +247,4 @@ __init static int init_sched_switch_trace(void) return register_tracer(&sched_switch_trace); } device_initcall(init_sched_switch_trace); + diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 0b863f2cbc8e..d0871bc0aca5 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -10,6 +10,7 @@ #include <linux/debugfs.h> #include <linux/ftrace.h> #include <linux/module.h> +#include <linux/sysctl.h> #include <linux/init.h> #include <linux/fs.h> #include "trace.h" @@ -31,6 +32,10 @@ static raw_spinlock_t max_stack_lock = static int stack_trace_disabled __read_mostly; static DEFINE_PER_CPU(int, trace_active); +static DEFINE_MUTEX(stack_sysctl_mutex); + +int stack_tracer_enabled; +static int last_stack_tracer_enabled; static inline void check_stack(void) { @@ -174,7 +179,7 @@ stack_max_size_write(struct file *filp, const char __user *ubuf, return count; } -static struct file_operations stack_max_size_fops = { +static const struct file_operations stack_max_size_fops = { .open = tracing_open_generic, .read = stack_max_size_read, .write = stack_max_size_write, @@ -272,7 +277,7 @@ static int t_show(struct seq_file *m, void *v) return 0; } -static struct seq_operations stack_trace_seq_ops = { +static const struct seq_operations stack_trace_seq_ops = { .start = t_start, .next = t_next, .stop = t_stop, @@ -288,12 +293,47 @@ static int stack_trace_open(struct inode *inode, struct file *file) return ret; } -static struct file_operations stack_trace_fops = { +static const struct file_operations stack_trace_fops = { .open = stack_trace_open, .read = seq_read, .llseek = seq_lseek, }; +int +stack_trace_sysctl(struct ctl_table *table, int write, + struct file *file, void __user *buffer, size_t *lenp, + loff_t *ppos) +{ + int ret; + + mutex_lock(&stack_sysctl_mutex); + + ret = proc_dointvec(table, write, file, buffer, lenp, ppos); + + if (ret || !write || + (last_stack_tracer_enabled == stack_tracer_enabled)) + goto out; + + last_stack_tracer_enabled = stack_tracer_enabled; + + if (stack_tracer_enabled) + register_ftrace_function(&trace_ops); + else + unregister_ftrace_function(&trace_ops); + + out: + mutex_unlock(&stack_sysctl_mutex); + return ret; +} + +static __init int enable_stacktrace(char *str) +{ + stack_tracer_enabled = 1; + last_stack_tracer_enabled = 1; + return 1; +} +__setup("stacktrace", enable_stacktrace); + static __init int stack_trace_init(void) { struct dentry *d_tracer; @@ -311,7 +351,8 @@ static __init int stack_trace_init(void) if (!entry) pr_warning("Could not create debugfs 'stack_trace' entry\n"); - register_ftrace_function(&trace_ops); + if (stack_tracer_enabled) + register_ftrace_function(&trace_ops); return 0; } |