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aha/kernel/trace/trace.h
Steven Rostedt 38697053fa ftrace: preempt disable over interrupt disable 
With the new ring buffer infrastructure in ftrace, I'm trying to make
ftrace a little more light weight.

This patch converts a lot of the local_irq_save/restore into
preempt_disable/enable.  The original preempt count in a lot of cases
has to be sent in as a parameter so that it can be recorded correctly.
Some places were recording it incorrectly before anyway.

This is also laying the ground work to make ftrace a little bit
more reentrant, and remove all locking. The function tracers must
still protect from reentrancy.

Note: All the function tracers must be careful when using preempt_disable.
  It must do the following:

  resched = need_resched();
  preempt_disable_notrace();
  [...]
  if (resched)
	preempt_enable_no_resched_notrace();
  else
	preempt_enable_notrace();

The reason is that if this function traces schedule() itself, the
preempt_enable_notrace() will cause a schedule, which will lead
us into a recursive failure.

If we needed to reschedule before calling preempt_disable, we
should have already scheduled. Since we did not, this is most
likely that we should not and are probably inside a schedule
function.

If resched was not set, we still need to catch the need resched
flag being set when preemption was off and the if case at the
end will catch that for us.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:39:09 +02:00

420 lines
11 KiB
C
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#ifndef _LINUX_KERNEL_TRACE_H
#define _LINUX_KERNEL_TRACE_H
#include <linux/fs.h>
#include <asm/atomic.h>
#include <linux/sched.h>
#include <linux/clocksource.h>
#include <linux/ring_buffer.h>
#include <linux/mmiotrace.h>
#include <linux/ftrace.h>
enum trace_type {
__TRACE_FIRST_TYPE = 0,
TRACE_FN,
TRACE_CTX,
TRACE_WAKE,
TRACE_CONT,
TRACE_STACK,
TRACE_PRINT,
TRACE_SPECIAL,
TRACE_MMIO_RW,
TRACE_MMIO_MAP,
TRACE_BOOT,
__TRACE_LAST_TYPE
};
/*
* The trace entry - the most basic unit of tracing. This is what
* is printed in the end as a single line in the trace output, such as:
*
* bash-15816 [01] 235.197585: idle_cpu <- irq_enter
*/
struct trace_entry {
unsigned char type;
unsigned char cpu;
unsigned char flags;
unsigned char preempt_count;
int pid;
};
/*
* Function trace entry - function address and parent function addres:
*/
struct ftrace_entry {
struct trace_entry ent;
unsigned long ip;
unsigned long parent_ip;
};
extern struct tracer boot_tracer;
/*
* Context switch trace entry - which task (and prio) we switched from/to:
*/
struct ctx_switch_entry {
struct trace_entry ent;
unsigned int prev_pid;
unsigned char prev_prio;
unsigned char prev_state;
unsigned int next_pid;
unsigned char next_prio;
unsigned char next_state;
unsigned int next_cpu;
};
/*
* Special (free-form) trace entry:
*/
struct special_entry {
struct trace_entry ent;
unsigned long arg1;
unsigned long arg2;
unsigned long arg3;
};
/*
* Stack-trace entry:
*/
#define FTRACE_STACK_ENTRIES 8
struct stack_entry {
struct trace_entry ent;
unsigned long caller[FTRACE_STACK_ENTRIES];
};
/*
* ftrace_printk entry:
*/
struct print_entry {
struct trace_entry ent;
unsigned long ip;
char buf[];
};
#define TRACE_OLD_SIZE 88
struct trace_field_cont {
unsigned char type;
/* Temporary till we get rid of this completely */
char buf[TRACE_OLD_SIZE - 1];
};
struct trace_mmiotrace_rw {
struct trace_entry ent;
struct mmiotrace_rw rw;
};
struct trace_mmiotrace_map {
struct trace_entry ent;
struct mmiotrace_map map;
};
struct trace_boot {
struct trace_entry ent;
struct boot_trace initcall;
};
/*
* trace_flag_type is an enumeration that holds different
* states when a trace occurs. These are:
* IRQS_OFF - interrupts were disabled
* NEED_RESCED - reschedule is requested
* HARDIRQ - inside an interrupt handler
* SOFTIRQ - inside a softirq handler
* CONT - multiple entries hold the trace item
*/
enum trace_flag_type {
TRACE_FLAG_IRQS_OFF = 0x01,
TRACE_FLAG_NEED_RESCHED = 0x02,
TRACE_FLAG_HARDIRQ = 0x04,
TRACE_FLAG_SOFTIRQ = 0x08,
TRACE_FLAG_CONT = 0x10,
};
#define TRACE_BUF_SIZE 1024
/*
* The CPU trace array - it consists of thousands of trace entries
* plus some other descriptor data: (for example which task started
* the trace, etc.)
*/
struct trace_array_cpu {
atomic_t disabled;
/* these fields get copied into max-trace: */
unsigned long trace_idx;
unsigned long overrun;
unsigned long saved_latency;
unsigned long critical_start;
unsigned long critical_end;
unsigned long critical_sequence;
unsigned long nice;
unsigned long policy;
unsigned long rt_priority;
cycle_t preempt_timestamp;
pid_t pid;
uid_t uid;
char comm[TASK_COMM_LEN];
};
struct trace_iterator;
/*
* The trace array - an array of per-CPU trace arrays. This is the
* highest level data structure that individual tracers deal with.
* They have on/off state as well:
*/
struct trace_array {
struct ring_buffer *buffer;
unsigned long entries;
long ctrl;
int cpu;
cycle_t time_start;
struct task_struct *waiter;
struct trace_array_cpu *data[NR_CPUS];
};
#define FTRACE_CMP_TYPE(var, type) \
__builtin_types_compatible_p(typeof(var), type *)
#undef IF_ASSIGN
#define IF_ASSIGN(var, entry, etype, id) \
if (FTRACE_CMP_TYPE(var, etype)) { \
var = (typeof(var))(entry); \
WARN_ON(id && (entry)->type != id); \
break; \
}
/* Will cause compile errors if type is not found. */
extern void __ftrace_bad_type(void);
/*
* The trace_assign_type is a verifier that the entry type is
* the same as the type being assigned. To add new types simply
* add a line with the following format:
*
* IF_ASSIGN(var, ent, type, id);
*
* Where "type" is the trace type that includes the trace_entry
* as the "ent" item. And "id" is the trace identifier that is
* used in the trace_type enum.
*
* If the type can have more than one id, then use zero.
*/
#define trace_assign_type(var, ent) \
do { \
IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN); \
IF_ASSIGN(var, ent, struct ctx_switch_entry, 0); \
IF_ASSIGN(var, ent, struct trace_field_cont, TRACE_CONT); \
IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK); \
IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT); \
IF_ASSIGN(var, ent, struct special_entry, 0); \
IF_ASSIGN(var, ent, struct trace_mmiotrace_rw, \
TRACE_MMIO_RW); \
IF_ASSIGN(var, ent, struct trace_mmiotrace_map, \
TRACE_MMIO_MAP); \
IF_ASSIGN(var, ent, struct trace_boot, TRACE_BOOT); \
__ftrace_bad_type(); \
} while (0)
/* Return values for print_line callback */
enum print_line_t {
TRACE_TYPE_PARTIAL_LINE = 0, /* Retry after flushing the seq */
TRACE_TYPE_HANDLED = 1,
TRACE_TYPE_UNHANDLED = 2 /* Relay to other output functions */
};
/*
* A specific tracer, represented by methods that operate on a trace array:
*/
struct tracer {
const char *name;
void (*init)(struct trace_array *tr);
void (*reset)(struct trace_array *tr);
void (*open)(struct trace_iterator *iter);
void (*pipe_open)(struct trace_iterator *iter);
void (*close)(struct trace_iterator *iter);
void (*start)(struct trace_iterator *iter);
void (*stop)(struct trace_iterator *iter);
ssize_t (*read)(struct trace_iterator *iter,
struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos);
void (*ctrl_update)(struct trace_array *tr);
#ifdef CONFIG_FTRACE_STARTUP_TEST
int (*selftest)(struct tracer *trace,
struct trace_array *tr);
#endif
enum print_line_t (*print_line)(struct trace_iterator *iter);
struct tracer *next;
int print_max;
};
struct trace_seq {
unsigned char buffer[PAGE_SIZE];
unsigned int len;
unsigned int readpos;
};
/*
* Trace iterator - used by printout routines who present trace
* results to users and which routines might sleep, etc:
*/
struct trace_iterator {
struct trace_array *tr;
struct tracer *trace;
void *private;
struct ring_buffer_iter *buffer_iter[NR_CPUS];
/* The below is zeroed out in pipe_read */
struct trace_seq seq;
struct trace_entry *ent;
int cpu;
u64 ts;
unsigned long iter_flags;
loff_t pos;
long idx;
};
void trace_wake_up(void);
void tracing_reset(struct trace_array *tr, int cpu);
int tracing_open_generic(struct inode *inode, struct file *filp);
struct dentry *tracing_init_dentry(void);
void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
struct trace_array_cpu *data);
void tracing_generic_entry_update(struct trace_entry *entry,
unsigned long flags,
int pc);
void ftrace(struct trace_array *tr,
struct trace_array_cpu *data,
unsigned long ip,
unsigned long parent_ip,
unsigned long flags, int pc);
void tracing_sched_switch_trace(struct trace_array *tr,
struct trace_array_cpu *data,
struct task_struct *prev,
struct task_struct *next,
unsigned long flags, int pc);
void tracing_record_cmdline(struct task_struct *tsk);
void tracing_sched_wakeup_trace(struct trace_array *tr,
struct trace_array_cpu *data,
struct task_struct *wakee,
struct task_struct *cur,
unsigned long flags, int pc);
void trace_special(struct trace_array *tr,
struct trace_array_cpu *data,
unsigned long arg1,
unsigned long arg2,
unsigned long arg3, int pc);
void trace_function(struct trace_array *tr,
struct trace_array_cpu *data,
unsigned long ip,
unsigned long parent_ip,
unsigned long flags, int pc);
void tracing_start_cmdline_record(void);
void tracing_stop_cmdline_record(void);
int register_tracer(struct tracer *type);
void unregister_tracer(struct tracer *type);
extern unsigned long nsecs_to_usecs(unsigned long nsecs);
extern unsigned long tracing_max_latency;
extern unsigned long tracing_thresh;
void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
void update_max_tr_single(struct trace_array *tr,
struct task_struct *tsk, int cpu);
extern cycle_t ftrace_now(int cpu);
#ifdef CONFIG_FTRACE
void tracing_start_function_trace(void);
void tracing_stop_function_trace(void);
#else
# define tracing_start_function_trace() do { } while (0)
# define tracing_stop_function_trace() do { } while (0)
#endif
#ifdef CONFIG_CONTEXT_SWITCH_TRACER
typedef void
(*tracer_switch_func_t)(void *private,
void *__rq,
struct task_struct *prev,
struct task_struct *next);
struct tracer_switch_ops {
tracer_switch_func_t func;
void *private;
struct tracer_switch_ops *next;
};
#endif /* CONFIG_CONTEXT_SWITCH_TRACER */
#ifdef CONFIG_DYNAMIC_FTRACE
extern unsigned long ftrace_update_tot_cnt;
#define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
extern int DYN_FTRACE_TEST_NAME(void);
#endif
#ifdef CONFIG_FTRACE_STARTUP_TEST
extern int trace_selftest_startup_function(struct tracer *trace,
struct trace_array *tr);
extern int trace_selftest_startup_irqsoff(struct tracer *trace,
struct trace_array *tr);
extern int trace_selftest_startup_preemptoff(struct tracer *trace,
struct trace_array *tr);
extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
struct trace_array *tr);
extern int trace_selftest_startup_wakeup(struct tracer *trace,
struct trace_array *tr);
extern int trace_selftest_startup_nop(struct tracer *trace,
struct trace_array *tr);
extern int trace_selftest_startup_sched_switch(struct tracer *trace,
struct trace_array *tr);
extern int trace_selftest_startup_sysprof(struct tracer *trace,
struct trace_array *tr);
#endif /* CONFIG_FTRACE_STARTUP_TEST */
extern void *head_page(struct trace_array_cpu *data);
extern int trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
extern void trace_seq_print_cont(struct trace_seq *s,
struct trace_iterator *iter);
extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
size_t cnt);
extern long ns2usecs(cycle_t nsec);
extern int trace_vprintk(unsigned long ip, const char *fmt, va_list args);
extern unsigned long trace_flags;
/*
* trace_iterator_flags is an enumeration that defines bit
* positions into trace_flags that controls the output.
*
* NOTE: These bits must match the trace_options array in
* trace.c.
*/
enum trace_iterator_flags {
TRACE_ITER_PRINT_PARENT = 0x01,
TRACE_ITER_SYM_OFFSET = 0x02,
TRACE_ITER_SYM_ADDR = 0x04,
TRACE_ITER_VERBOSE = 0x08,
TRACE_ITER_RAW = 0x10,
TRACE_ITER_HEX = 0x20,
TRACE_ITER_BIN = 0x40,
TRACE_ITER_BLOCK = 0x80,
TRACE_ITER_STACKTRACE = 0x100,
TRACE_ITER_SCHED_TREE = 0x200,
TRACE_ITER_PRINTK = 0x400,
};
extern struct tracer nop_trace;
#endif /* _LINUX_KERNEL_TRACE_H */
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