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Subject[PATCH 5/7] mmiotrace: handle TRACE_PRINT entries.
From 6a458e250857907e16cb16799392fccbfd5f0f4a Mon Sep 17 00:00:00 2001
From: Pekka Paalanen <pq@iki.fi>
Date: Sun, 17 Aug 2008 18:15:13 +0300
Subject: [PATCH] mmiotrace: handle TRACE_PRINT entries.

Also make trace_seq_print_cont() non-static, and add a newline if the
seq buffer can't hold all data.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
---
kernel/trace/trace.c | 31 +++++++++++--------------------
kernel/trace/trace.h | 19 +++++++++++++++++++
kernel/trace/trace_mmiotrace.c | 23 +++++++++++++++++++++++
3 files changed, 53 insertions(+), 20 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 406de9c..7e7154f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -200,23 +200,6 @@ unsigned long nsecs_to_usecs(unsigned long nsecs)
}

/*
- * 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,
-};
-
-/*
* TRACE_ITER_SYM_MASK masks the options in trace_flags that
* control the output of kernel symbols.
*/
@@ -1517,12 +1500,16 @@ lat_print_timestamp(struct trace_seq *s, unsigned long long abs_usecs,

static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;

-static void
-trace_seq_print_cont(struct trace_seq *s, struct trace_iterator *iter)
+/*
+ * The message is supposed to contain an ending newline.
+ * If the printing stops prematurely, try to add a newline of our own.
+ */
+void trace_seq_print_cont(struct trace_seq *s, struct trace_iterator *iter)
{
struct trace_array *tr = iter->tr;
struct trace_array_cpu *data = tr->data[iter->cpu];
struct trace_entry *ent;
+ bool ok = true;

ent = trace_entry_idx(tr, data, iter, iter->cpu);
if (!ent || ent->type != TRACE_CONT) {
@@ -1531,10 +1518,14 @@ trace_seq_print_cont(struct trace_seq *s, struct trace_iterator *iter)
}

do {
- trace_seq_printf(s, "%s", ent->cont.buf);
+ if (ok)
+ ok = (trace_seq_printf(s, "%s", ent->cont.buf) > 0);
__trace_iterator_increment(iter, iter->cpu);
ent = trace_entry_idx(tr, data, iter, iter->cpu);
} while (ent && ent->type == TRACE_CONT);
+
+ if (!ok)
+ trace_seq_putc(s, '\n');
}

static int
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index be3b3cf..648433d 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -72,6 +72,23 @@ struct print_entry {
};

/*
+ * 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,
+};
+
+/*
* The trace field - the most basic unit of tracing. This is what
* is printed in the end as a single line in the trace output, such as:
*
@@ -330,6 +347,8 @@ extern int trace_selftest_startup_sysprof(struct tracer *trace,

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);
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index 767d1fa..a108c32 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -245,6 +245,27 @@ static int mmio_print_map(struct trace_iterator *iter)
return 0;
}

+static int mmio_print_mark(struct trace_iterator *iter)
+{
+ struct trace_entry *entry = iter->ent;
+ const char *msg = entry->field.print.buf;
+ struct trace_seq *s = &iter->seq;
+ unsigned long long t = ns2usecs(entry->field.t);
+ unsigned long usec_rem = do_div(t, 1000000ULL);
+ unsigned secs = (unsigned long)t;
+ int ret;
+
+ /* The trailing newline must be in the message. */
+ ret = trace_seq_printf(s, "MARK %lu.%06lu %s", secs, usec_rem, msg);
+ if (!ret)
+ return 0;
+
+ if (entry->field.flags & TRACE_FLAG_CONT)
+ trace_seq_print_cont(s, iter);
+
+ return 1;
+}
+
/* return 0 to abort printing without consuming current entry in pipe mode */
static int mmio_print_line(struct trace_iterator *iter)
{
@@ -253,6 +274,8 @@ static int mmio_print_line(struct trace_iterator *iter)
return mmio_print_rw(iter);
case TRACE_MMIO_MAP:
return mmio_print_map(iter);
+ case TRACE_PRINT:
+ return mmio_print_mark(iter);
default:
return 1; /* ignore unknown entries */
}
--
1.5.6.4


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