The poll_loop code has a feature that, when turned on manually or
automatically (due to high CPU use), logs the source file and line number
of the code that caused a thread to wake up from poll(). Until now, when
a function calls seq_wait(), the source file and line number logged was
the code inside seq_wait(). seq_wait() has many callers, so that
information is not as useful as it could be. This commit changes the
source file and line number used to be that of seq_wait()'s caller.
I found this useful for debugging.
Signed-off-by: Ben Pfaff <b...@nicira.com>
---
lib/seq.c | 20 ++++++++++++--------
lib/seq.h | 7 +++++--
2 files changed, 17 insertions(+), 10 deletions(-)
diff --git a/lib/seq.c b/lib/seq.c
index 7a34244..452d683 100644
--- a/lib/seq.c
+++ b/lib/seq.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2013 Nicira, Inc.
+ * Copyright (c) 2013, 2014 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -125,7 +125,7 @@ seq_read(const struct seq *seq)
}
static void
-seq_wait__(struct seq *seq, uint64_t value)
+seq_wait__(struct seq *seq, uint64_t value, const char *where)
OVS_REQUIRES(seq_mutex)
{
unsigned int id = ovsthread_id_self();
@@ -137,7 +137,7 @@ seq_wait__(struct seq *seq, uint64_t value)
if (waiter->value != value) {
/* The current value is different from the value we've already
* waited for, */
- poll_immediate_wake();
+ poll_immediate_wake_at(where);
} else {
/* Already waiting on 'value', nothing more to do. */
}
@@ -154,7 +154,7 @@ seq_wait__(struct seq *seq, uint64_t value)
list_push_back(&waiter->thread->waiters, &waiter->list_node);
if (!waiter->thread->waiting) {
- latch_wait(&waiter->thread->latch);
+ latch_wait_at(&waiter->thread->latch, where);
waiter->thread->waiting = true;
}
}
@@ -165,18 +165,22 @@ seq_wait__(struct seq *seq, uint64_t value)
*
* seq_read() and seq_wait() can be used together to yield a race-free wakeup
* when an object changes, even without an ability to lock the object. See
- * Usage in seq.h for details. */
+ * Usage in seq.h for details.
+ *
+ * ('where' is used in debug logging. Commonly one would use seq_wait() to
+ * automatically provide the caller's source file and line number for
+ * 'where'.) */
void
-seq_wait(const struct seq *seq_, uint64_t value)
+seq_wait_at(const struct seq *seq_, uint64_t value, const char *where)
OVS_EXCLUDED(seq_mutex)
{
struct seq *seq = CONST_CAST(struct seq *, seq_);
ovs_mutex_lock(&seq_mutex);
if (value == seq->value) {
- seq_wait__(seq, value);
+ seq_wait__(seq, value, where);
} else {
- poll_immediate_wake();
+ poll_immediate_wake_at(where);
}
ovs_mutex_unlock(&seq_mutex);
}
diff --git a/lib/seq.h b/lib/seq.h
index c764809..38c0e52 100644
--- a/lib/seq.h
+++ b/lib/seq.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2013 Nicira, Inc.
+ * Copyright (c) 2013, 2014 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -111,6 +111,7 @@
*/
#include <stdint.h>
+#include "util.h"
/* For implementation of an object with a sequence number attached. */
struct seq *seq_create(void);
@@ -119,7 +120,9 @@ void seq_change(struct seq *);
/* For observers. */
uint64_t seq_read(const struct seq *);
-void seq_wait(const struct seq *, uint64_t value);
+
+void seq_wait_at(const struct seq *, uint64_t value, const char *where);
+#define seq_wait(seq, value) seq_wait_at(seq, value, SOURCE_LOCATOR)
/* For poll_block() internal use. */
void seq_woke(void);
--
1.7.10.4
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