lkml.org 
[lkml]   [2008]   [Sep]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH V2 -tip 1/4] Tracing/ftrace: Change the type of the print_line callback
We need a kind of disambiguation when a print_line callback
returns 0.

_There is not enough space to print all the entry.
Please flush the seq and retry.
_I can't handle this type of entry

This patch changes the type of this callback for better information.

Also some changes have been made in this V2.

_ Only relay to default functions after the print_line callback fails.
_ This patch doesn't fix the issue with the broken pipe (see patch 2/4 for that)

Some things are still in discussion:

_ Find better names for the enum print_line_t values
_ Change the type of print_trace_line into boolean.

Patches to change that can be sent later.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
kernel/trace/trace.c | 77 ++++++++++++++++++++++++++-----------------------
kernel/trace/trace.h | 10 ++++++-
2 files changed, 50 insertions(+), 37 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 6ada059..61f33da 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1510,7 +1510,7 @@ void trace_seq_print_cont(struct trace_seq *s, struct trace_iterator *iter)
trace_seq_putc(s, '\n');
}

-static int
+static enum print_line_t
print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
{
struct trace_seq *s = &iter->seq;
@@ -1530,7 +1530,7 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
next_entry = entry;

if (entry->type == TRACE_CONT)
- return 1;
+ return TRACE_TYPE_HANDLED;

rel_usecs = ns2usecs(next_entry->field.t - entry->field.t);
abs_usecs = ns2usecs(entry->field.t - iter->tr->time_start);
@@ -1601,10 +1601,10 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
default:
trace_seq_printf(s, "Unknown type %d\n", entry->type);
}
- return 1;
+ return TRACE_TYPE_HANDLED;
}

-static int print_trace_fmt(struct trace_iterator *iter)
+static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
@@ -1621,7 +1621,7 @@ static int print_trace_fmt(struct trace_iterator *iter)
entry = iter->ent;

if (entry->type == TRACE_CONT)
- return 1;
+ return TRACE_TYPE_HANDLED;

field = &entry->field;

@@ -1633,24 +1633,24 @@ static int print_trace_fmt(struct trace_iterator *iter)

ret = trace_seq_printf(s, "%16s-%-5d ", comm, field->pid);
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;
ret = trace_seq_printf(s, "[%03d] ", iter->cpu);
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;
ret = trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem);
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;

switch (entry->type) {
case TRACE_FN:
ret = seq_print_ip_sym(s, field->fn.ip, sym_flags);
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;
if ((sym_flags & TRACE_ITER_PRINT_PARENT) &&
field->fn.parent_ip) {
ret = trace_seq_printf(s, " <-");
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;
if (kretprobed(field->fn.parent_ip))
ret = trace_seq_puts(s, KRETPROBE_MSG);
else
@@ -1658,11 +1658,11 @@ static int print_trace_fmt(struct trace_iterator *iter)
field->fn.parent_ip,
sym_flags);
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;
}
ret = trace_seq_printf(s, "\n");
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;
break;
case TRACE_CTX:
case TRACE_WAKE:
@@ -1680,7 +1680,7 @@ static int print_trace_fmt(struct trace_iterator *iter)
field->ctx.next_prio,
T);
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;
break;
case TRACE_SPECIAL:
ret = trace_seq_printf(s, "# %ld %ld %ld\n",
@@ -1688,23 +1688,23 @@ static int print_trace_fmt(struct trace_iterator *iter)
field->special.arg2,
field->special.arg3);
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;
break;
case TRACE_STACK:
for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
if (i) {
ret = trace_seq_puts(s, " <= ");
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;
}
ret = seq_print_ip_sym(s, field->stack.caller[i],
sym_flags);
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;
}
ret = trace_seq_puts(s, "\n");
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;
break;
case TRACE_PRINT:
seq_print_ip_sym(s, field->print.ip, sym_flags);
@@ -1713,10 +1713,10 @@ static int print_trace_fmt(struct trace_iterator *iter)
trace_seq_print_cont(s, iter);
break;
}
- return 1;
+ return TRACE_TYPE_HANDLED;
}

-static int print_raw_fmt(struct trace_iterator *iter)
+static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
struct trace_entry *entry;
@@ -1727,14 +1727,14 @@ static int print_raw_fmt(struct trace_iterator *iter)
entry = iter->ent;

if (entry->type == TRACE_CONT)
- return 1;
+ return TRACE_TYPE_HANDLED;

field = &entry->field;

ret = trace_seq_printf(s, "%d %d %llu ",
field->pid, iter->cpu, field->t);
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;

switch (entry->type) {
case TRACE_FN:
@@ -1742,7 +1742,7 @@ static int print_raw_fmt(struct trace_iterator *iter)
field->fn.ip,
field->fn.parent_ip);
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;
break;
case TRACE_CTX:
case TRACE_WAKE:
@@ -1761,7 +1761,7 @@ static int print_raw_fmt(struct trace_iterator *iter)
field->ctx.next_prio,
T);
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;
break;
case TRACE_SPECIAL:
case TRACE_STACK:
@@ -1770,7 +1770,7 @@ static int print_raw_fmt(struct trace_iterator *iter)
field->special.arg2,
field->special.arg3);
if (!ret)
- return 0;
+ return TRACE_TYPE_PARTIAL_LINE;
break;
case TRACE_PRINT:
trace_seq_printf(s, "# %lx %s",
@@ -1779,7 +1779,7 @@ static int print_raw_fmt(struct trace_iterator *iter)
trace_seq_print_cont(s, iter);
break;
}
- return 1;
+ return TRACE_TYPE_HANDLED;
}

#define SEQ_PUT_FIELD_RET(s, x) \
@@ -1794,7 +1794,7 @@ do { \
return 0; \
} while (0)

-static int print_hex_fmt(struct trace_iterator *iter)
+static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
unsigned char newline = '\n';
@@ -1805,7 +1805,7 @@ static int print_hex_fmt(struct trace_iterator *iter)
entry = iter->ent;

if (entry->type == TRACE_CONT)
- return 1;
+ return TRACE_TYPE_HANDLED;

field = &entry->field;

@@ -1843,10 +1843,10 @@ static int print_hex_fmt(struct trace_iterator *iter)
}
SEQ_PUT_FIELD_RET(s, newline);

- return 1;
+ return TRACE_TYPE_HANDLED;
}

-static int print_bin_fmt(struct trace_iterator *iter)
+static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
struct trace_entry *entry;
@@ -1855,7 +1855,7 @@ static int print_bin_fmt(struct trace_iterator *iter)
entry = iter->ent;

if (entry->type == TRACE_CONT)
- return 1;
+ return TRACE_TYPE_HANDLED;

field = &entry->field;

@@ -1883,7 +1883,7 @@ static int print_bin_fmt(struct trace_iterator *iter)
SEQ_PUT_FIELD_RET(s, field->special.arg3);
break;
}
- return 1;
+ return TRACE_TYPE_HANDLED;
}

static int trace_empty(struct trace_iterator *iter)
@@ -1902,10 +1902,15 @@ static int trace_empty(struct trace_iterator *iter)
return 1;
}

-static int print_trace_line(struct trace_iterator *iter)
+static enum print_line_t print_trace_line(struct trace_iterator *iter)
{
- if (iter->trace && iter->trace->print_line)
- return iter->trace->print_line(iter);
+ enum print_line_t ret;
+
+ if (iter->trace && iter->trace->print_line) {
+ ret = iter->trace->print_line(iter);
+ if (ret != TRACE_TYPE_UNHANDLED)
+ return ret;
+ }

if (trace_flags & TRACE_ITER_BIN)
return print_bin_fmt(iter);
@@ -2715,11 +2720,11 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
}

while (find_next_entry_inc(iter) != NULL) {
- int ret;
+ enum print_line_t ret;
int len = iter->seq.len;

ret = print_trace_line(iter);
- if (!ret) {
+ if (ret == TRACE_TYPE_PARTIAL_LINE) {
/* don't print partial lines */
iter->seq.len = len;
break;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index b28bf88..73cd7c5 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -180,6 +180,14 @@ struct trace_array {
struct trace_array_cpu *data[NR_CPUS];
};

+
+/* 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:
*/
@@ -200,7 +208,7 @@ struct tracer {
int (*selftest)(struct tracer *trace,
struct trace_array *tr);
#endif
- int (*print_line)(struct trace_iterator *iter);
+ enum print_line_t (*print_line)(struct trace_iterator *iter);
struct tracer *next;
int print_max;
};

\
 
 \ /
  Last update: 2008-09-29 20:21    [from the cache]
©2003-2011 Jasper Spaans