![Frederic Weisbecker](/assets/img/avatar_default.png)
Currently the trace event profile buffer is allocated in the stack. But this may be too much for the stack, as the events can have large statically defined field size and can also grow with dynamic arrays. Allocate two per cpu buffer for all profiled events. The first cpu buffer is used to host every non-nmi context traces. It is protected by disabling the interrupts while writing and committing the trace. The second buffer is reserved for nmi. So that there is no race between them and the first buffer. The whole write/commit section is rcu protected because we release these buffers while deactivating the last profiling trace event. v2: Move the buffers from trace_event to be global, as pointed by Steven Rostedt. v3: Fix the syscall events to handle the profiling buffer races by disabling interrupts, now that the buffers are globals. Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Masami Hiramatsu <mhiramat@redhat.com> Cc: Ingo Molnar <mingo@elte.hu>
190 lines
5.2 KiB
C
190 lines
5.2 KiB
C
#ifndef _LINUX_FTRACE_EVENT_H
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#define _LINUX_FTRACE_EVENT_H
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#include <linux/ring_buffer.h>
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#include <linux/trace_seq.h>
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#include <linux/percpu.h>
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#include <linux/hardirq.h>
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struct trace_array;
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struct tracer;
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struct dentry;
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DECLARE_PER_CPU(struct trace_seq, ftrace_event_seq);
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struct trace_print_flags {
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unsigned long mask;
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const char *name;
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};
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const char *ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
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unsigned long flags,
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const struct trace_print_flags *flag_array);
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const char *ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
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const struct trace_print_flags *symbol_array);
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/*
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* The trace entry - the most basic unit of tracing. This is what
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* is printed in the end as a single line in the trace output, such as:
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*
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* bash-15816 [01] 235.197585: idle_cpu <- irq_enter
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*/
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struct trace_entry {
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unsigned short type;
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unsigned char flags;
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unsigned char preempt_count;
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int pid;
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int lock_depth;
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};
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#define FTRACE_MAX_EVENT \
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((1 << (sizeof(((struct trace_entry *)0)->type) * 8)) - 1)
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/*
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* Trace iterator - used by printout routines who present trace
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* results to users and which routines might sleep, etc:
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*/
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struct trace_iterator {
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struct trace_array *tr;
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struct tracer *trace;
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void *private;
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int cpu_file;
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struct mutex mutex;
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struct ring_buffer_iter *buffer_iter[NR_CPUS];
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unsigned long iter_flags;
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/* The below is zeroed out in pipe_read */
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struct trace_seq seq;
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struct trace_entry *ent;
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int cpu;
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u64 ts;
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loff_t pos;
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long idx;
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cpumask_var_t started;
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};
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typedef enum print_line_t (*trace_print_func)(struct trace_iterator *iter,
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int flags);
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struct trace_event {
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struct hlist_node node;
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struct list_head list;
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int type;
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trace_print_func trace;
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trace_print_func raw;
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trace_print_func hex;
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trace_print_func binary;
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};
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extern int register_ftrace_event(struct trace_event *event);
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extern int unregister_ftrace_event(struct trace_event *event);
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/* Return values for print_line callback */
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enum print_line_t {
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TRACE_TYPE_PARTIAL_LINE = 0, /* Retry after flushing the seq */
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TRACE_TYPE_HANDLED = 1,
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TRACE_TYPE_UNHANDLED = 2, /* Relay to other output functions */
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TRACE_TYPE_NO_CONSUME = 3 /* Handled but ask to not consume */
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};
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void tracing_generic_entry_update(struct trace_entry *entry,
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unsigned long flags,
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int pc);
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struct ring_buffer_event *
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trace_current_buffer_lock_reserve(struct ring_buffer **current_buffer,
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int type, unsigned long len,
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unsigned long flags, int pc);
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void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
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struct ring_buffer_event *event,
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unsigned long flags, int pc);
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void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer,
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struct ring_buffer_event *event,
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unsigned long flags, int pc);
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void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
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struct ring_buffer_event *event);
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void tracing_record_cmdline(struct task_struct *tsk);
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struct event_filter;
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struct ftrace_event_call {
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struct list_head list;
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char *name;
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char *system;
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struct dentry *dir;
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struct trace_event *event;
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int enabled;
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int (*regfunc)(void *);
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void (*unregfunc)(void *);
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int id;
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int (*raw_init)(void);
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int (*show_format)(struct ftrace_event_call *call,
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struct trace_seq *s);
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int (*define_fields)(struct ftrace_event_call *);
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struct list_head fields;
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int filter_active;
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struct event_filter *filter;
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void *mod;
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void *data;
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atomic_t profile_count;
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int (*profile_enable)(void);
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void (*profile_disable)(void);
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};
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#define FTRACE_MAX_PROFILE_SIZE 2048
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extern char *trace_profile_buf;
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extern char *trace_profile_buf_nmi;
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#define MAX_FILTER_PRED 32
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#define MAX_FILTER_STR_VAL 256 /* Should handle KSYM_SYMBOL_LEN */
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extern void destroy_preds(struct ftrace_event_call *call);
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extern int filter_match_preds(struct ftrace_event_call *call, void *rec);
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extern int filter_current_check_discard(struct ring_buffer *buffer,
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struct ftrace_event_call *call,
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void *rec,
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struct ring_buffer_event *event);
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enum {
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FILTER_OTHER = 0,
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FILTER_STATIC_STRING,
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FILTER_DYN_STRING,
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FILTER_PTR_STRING,
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};
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extern int trace_define_field(struct ftrace_event_call *call,
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const char *type, const char *name,
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int offset, int size, int is_signed,
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int filter_type);
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extern int trace_define_common_fields(struct ftrace_event_call *call);
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#define is_signed_type(type) (((type)(-1)) < 0)
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int trace_set_clr_event(const char *system, const char *event, int set);
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/*
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* The double __builtin_constant_p is because gcc will give us an error
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* if we try to allocate the static variable to fmt if it is not a
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* constant. Even with the outer if statement optimizing out.
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*/
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#define event_trace_printk(ip, fmt, args...) \
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do { \
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__trace_printk_check_format(fmt, ##args); \
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tracing_record_cmdline(current); \
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if (__builtin_constant_p(fmt)) { \
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static const char *trace_printk_fmt \
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__attribute__((section("__trace_printk_fmt"))) = \
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__builtin_constant_p(fmt) ? fmt : NULL; \
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\
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__trace_bprintk(ip, trace_printk_fmt, ##args); \
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} else \
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__trace_printk(ip, fmt, ##args); \
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} while (0)
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#endif /* _LINUX_FTRACE_EVENT_H */
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