ftrace: add a buffer for output (214023c3) · Commits · 戴 / test

kernel/trace/trace.c

+134 −68

Original line number	Diff line number	Diff line
		@@ -169,6 +169,66 @@ void head_page(struct trace_array_cpu data)
		return page_address(page);
		}

		static notrace int
		trace_seq_printf(struct trace_seq s, const char fmt, ...)
		{
		int len = (PAGE_SIZE - 1) - s->len;
		va_list ap;

		if (!len)
		return 0;

		va_start(ap, fmt);
		len = vsnprintf(s->buffer + s->len, len, fmt, ap);
		va_end(ap);

		s->len += len;

		return len;
		}

		static notrace int
		trace_seq_puts(struct trace_seq s, const char str)
		{
		int len = strlen(str);

		if (len > ((PAGE_SIZE - 1) - s->len))
		len = (PAGE_SIZE - 1) - s->len;

		memcpy(s->buffer + s->len, str, len);
		s->len += len;

		return len;
		}

		static notrace int
		trace_seq_putc(struct trace_seq *s, unsigned char c)
		{
		if (s->len >= (PAGE_SIZE - 1))
		return 0;

		s->buffer[s->len++] = c;

		return 1;
		}

		static notrace void
		trace_seq_reset(struct trace_seq *s)
		{
		s->len = 0;
		}

		static notrace void
		trace_print_seq(struct seq_file m, struct trace_seq s)
		{
		int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;

		s->buffer[len] = 0;
		seq_puts(m, s->buffer);

		trace_seq_reset(s);
		}

		notrace static void
		flip_trace(struct trace_array_cpu tr1, struct trace_array_cpu tr2)
		{
		@@ -756,25 +816,26 @@ static void s_stop(struct seq_file m, void p)
		}

		static void
		seq_print_sym_short(struct seq_file m, const char fmt, unsigned long address)
		seq_print_sym_short(struct trace_seq s, const char fmt, unsigned long address)
		{
		#ifdef CONFIG_KALLSYMS
		char str[KSYM_SYMBOL_LEN];

		kallsyms_lookup(address, NULL, NULL, NULL, str);

		seq_printf(m, fmt, str);
		trace_seq_printf(s, fmt, str);
		#endif
		}

		static void
		seq_print_sym_offset(struct seq_file m, const char fmt, unsigned long address)
		seq_print_sym_offset(struct trace_seq s, const char fmt,
		unsigned long address)
		{
		#ifdef CONFIG_KALLSYMS
		char str[KSYM_SYMBOL_LEN];

		sprint_symbol(str, address);
		seq_printf(m, fmt, str);
		trace_seq_printf(s, fmt, str);
		#endif
		}

		@@ -785,20 +846,20 @@ seq_print_sym_offset(struct seq_file m, const char fmt, unsigned long address)
		#endif

		static notrace void
		seq_print_ip_sym(struct seq_file *m, unsigned long ip, unsigned long sym_flags)
		seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
		{
		if (!ip) {
		seq_printf(m, "0");
		trace_seq_printf(s, "0");
		return;
		}

		if (sym_flags & TRACE_ITER_SYM_OFFSET)
		seq_print_sym_offset(m, "%s", ip);
		seq_print_sym_offset(s, "%s", ip);
		else
		seq_print_sym_short(m, "%s", ip);
		seq_print_sym_short(s, "%s", ip);

		if (sym_flags & TRACE_ITER_SYM_ADDR)
		seq_printf(m, " <" IP_FMT ">", ip);
		trace_seq_printf(s, " <" IP_FMT ">", ip);
		}

		static notrace void print_lat_help_header(struct seq_file *m)
		@@ -881,9 +942,11 @@ print_trace_header(struct seq_file m, struct trace_iterator iter)

		if (data->critical_start) {
		seq_puts(m, " => started at: ");
		seq_print_ip_sym(m, data->critical_start, sym_flags);
		seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
		trace_print_seq(m, &iter->seq);
		seq_puts(m, "\n => ended at: ");
		seq_print_ip_sym(m, data->critical_end, sym_flags);
		seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
		trace_print_seq(m, &iter->seq);
		seq_puts(m, "\n");
		}

		@@ -891,61 +954,61 @@ print_trace_header(struct seq_file m, struct trace_iterator iter)
		}

		static notrace void
		lat_print_generic(struct seq_file m, struct trace_entry entry, int cpu)
		lat_print_generic(struct trace_seq s, struct trace_entry entry, int cpu)
		{
		int hardirq, softirq;
		char *comm;

		comm = trace_find_cmdline(entry->pid);

		seq_printf(m, "%8.8s-%-5d ", comm, entry->pid);
		seq_printf(m, "%d", cpu);
		seq_printf(m, "%c%c",
		trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
		trace_seq_printf(s, "%d", cpu);
		trace_seq_printf(s, "%c%c",
		(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' : '.',
		((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));

		hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
		softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
		if (hardirq && softirq)
		seq_putc(m, 'H');
		trace_seq_putc(s, 'H');
		else {
		if (hardirq)
		seq_putc(m, 'h');
		trace_seq_putc(s, 'h');
		else {
		if (softirq)
		seq_putc(m, 's');
		trace_seq_putc(s, 's');
		else
		seq_putc(m, '.');
		trace_seq_putc(s, '.');
		}
		}

		if (entry->preempt_count)
		seq_printf(m, "%x", entry->preempt_count);
		trace_seq_printf(s, "%x", entry->preempt_count);
		else
		seq_puts(m, ".");
		trace_seq_puts(s, ".");
		}

		unsigned long preempt_mark_thresh = 100;

		static notrace void
		lat_print_timestamp(struct seq_file *m, unsigned long long abs_usecs,
		lat_print_timestamp(struct trace_seq *s, unsigned long long abs_usecs,
		unsigned long rel_usecs)
		{
		seq_printf(m, " %4lldus", abs_usecs);
		trace_seq_printf(s, " %4lldus", abs_usecs);
		if (rel_usecs > preempt_mark_thresh)
		seq_puts(m, "!: ");
		trace_seq_puts(s, "!: ");
		else if (rel_usecs > 1)
		seq_puts(m, "+: ");
		trace_seq_puts(s, "+: ");
		else
		seq_puts(m, " : ");
		trace_seq_puts(s, " : ");
		}

		static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;

		static notrace void
		print_lat_fmt(struct seq_file m, struct trace_iterator iter,
		unsigned int trace_idx, int cpu)
		print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
		{
		struct trace_seq *s = &iter->seq;
		unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
		struct trace_entry *next_entry = find_next_entry(iter, NULL);
		unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
		@@ -962,30 +1025,31 @@ print_lat_fmt(struct seq_file m, struct trace_iterator iter,

		if (verbose) {
		comm = trace_find_cmdline(entry->pid);
		seq_printf(m, "%16s %5d %d %d %08x %08x [%08lx]"
		trace_seq_printf(s, "%16s %5d %d %d %08x %08x [%08lx]"
		" %ld.%03ldms (+%ld.%03ldms): ",
		comm,
		entry->pid, cpu, entry->flags,
		entry->preempt_count, trace_idx,
		ns2usecs(entry->t),
		abs_usecs/1000,
		abs_usecs % 1000, rel_usecs/1000, rel_usecs % 1000);
		abs_usecs % 1000, rel_usecs/1000,
		rel_usecs % 1000);
		} else {
		lat_print_generic(m, entry, cpu);
		lat_print_timestamp(m, abs_usecs, rel_usecs);
		lat_print_generic(s, entry, cpu);
		lat_print_timestamp(s, abs_usecs, rel_usecs);
		}
		switch (entry->type) {
		case TRACE_FN:
		seq_print_ip_sym(m, entry->fn.ip, sym_flags);
		seq_puts(m, " (");
		seq_print_ip_sym(m, entry->fn.parent_ip, sym_flags);
		seq_puts(m, ")\n");
		seq_print_ip_sym(s, entry->fn.ip, sym_flags);
		trace_seq_puts(s, " (");
		seq_print_ip_sym(s, entry->fn.parent_ip, sym_flags);
		trace_seq_puts(s, ")\n");
		break;
		case TRACE_CTX:
		S = entry->ctx.prev_state < sizeof(state_to_char) ?
		state_to_char[entry->ctx.prev_state] : 'X';
		comm = trace_find_cmdline(entry->ctx.next_pid);
		seq_printf(m, " %d:%d:%c --> %d:%d %s\n",
		trace_seq_printf(s, " %d:%d:%c --> %d:%d %s\n",
		entry->ctx.prev_pid,
		entry->ctx.prev_prio,
		S,
		@@ -994,7 +1058,7 @@ print_lat_fmt(struct seq_file m, struct trace_iterator iter,
		comm);
		break;
		default:
		seq_printf(m, "Unknown type %d\n", entry->type);
		trace_seq_printf(s, "Unknown type %d\n", entry->type);
		}
		}

		@@ -1026,8 +1090,9 @@ static notrace void sync_time_offset(struct trace_iterator *iter)
		}

		static notrace void
		print_trace_fmt(struct seq_file m, struct trace_iterator iter)
		print_trace_fmt(struct trace_iterator *iter)
		{
		struct trace_seq *s = &iter->seq;
		unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
		struct trace_entry *entry;
		unsigned long usec_rem;
		@@ -1045,24 +1110,24 @@ print_trace_fmt(struct seq_file m, struct trace_iterator iter)
		usec_rem = do_div(t, 1000000ULL);
		secs = (unsigned long)t;

		seq_printf(m, "%16s-%-5d ", comm, entry->pid);
		seq_printf(m, "[%02d] ", iter->cpu);
		seq_printf(m, "%5lu.%06lu: ", secs, usec_rem);
		trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid);
		trace_seq_printf(s, "[%02d] ", iter->cpu);
		trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem);

		switch (entry->type) {
		case TRACE_FN:
		seq_print_ip_sym(m, entry->fn.ip, sym_flags);
		seq_print_ip_sym(s, entry->fn.ip, sym_flags);
		if ((sym_flags & TRACE_ITER_PRINT_PARENT) &&
		entry->fn.parent_ip) {
		seq_printf(m, " <-");
		seq_print_ip_sym(m, entry->fn.parent_ip, sym_flags);
		trace_seq_printf(s, " <-");
		seq_print_ip_sym(s, entry->fn.parent_ip, sym_flags);
		}
		seq_printf(m, "\n");
		trace_seq_printf(s, "\n");
		break;
		case TRACE_CTX:
		S = entry->ctx.prev_state < sizeof(state_to_char) ?
		state_to_char[entry->ctx.prev_state] : 'X';
		seq_printf(m, " %d:%d:%c ==> %d:%d\n",
		trace_seq_printf(s, " %d:%d:%c ==> %d:%d\n",
		entry->ctx.prev_pid,
		entry->ctx.prev_prio,
		S,
		@@ -1108,9 +1173,10 @@ static int s_show(struct seq_file m, void v)
		}
		} else {
		if (iter->iter_flags & TRACE_FILE_LAT_FMT)
		print_lat_fmt(m, iter, iter->idx, iter->cpu);
		print_lat_fmt(iter, iter->idx, iter->cpu);
		else
		print_trace_fmt(m, iter);
		print_trace_fmt(iter);
		trace_print_seq(m, &iter->seq);
		}

		return 0;

kernel/trace/trace.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -111,11 +111,17 @@ struct tracer {
		int print_max;
		};

		struct trace_seq {
		unsigned char buffer[PAGE_SIZE];
		unsigned int len;
		};

		/*
		* Trace iterator - used by printout routines who present trace
		* results to users and which routines might sleep, etc:
		*/
		struct trace_iterator {
		struct trace_seq seq;
		struct trace_array *tr;
		struct tracer *trace;

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