Add tracing mutexes to debug.h.

/*
 * Tracing mutexes are a thin wrapper around the pthread_mutex_t 
 * datatype that tracks and reports when a mutex is locked or unlocked.
 * It also allows you to assert that a mutex has (or has not) been locked
 * by calling tracing_mutex_assert().
 */



git-svn-id: svn://svn.code.sf.net/p/libkqueue/code/trunk@493 fb4e3144-bc1c-4b72-a658-5bcd248dd7f7

src/common/debug.h

@@ -18,11 +18,14 @@
 #define  _DEBUG_H
 
 #include <assert.h>
+#include <stdio.h>
+#include <unistd.h>
 
 extern int DEBUG_ACTIVE;
 extern char *DEBUG_IDENT;
 
 #if defined(__linux__)
+# include <sys/syscall.h>
 # define THREAD_ID ((pid_t)  syscall(__NR_gettid))
 #elif defined(__sun)
 # define THREAD_ID (pthread_self())
@@ -32,7 +35,6 @@ extern char *DEBUG_IDENT;
 # error Unsupported platform
 #endif
 
-
 #ifndef NDEBUG
 #define dbg_puts(str)           do {                                \
     if (DEBUG_ACTIVE)                                                      \
@@ -67,11 +69,46 @@ extern char *DEBUG_IDENT;
       fprintf(stderr, "%s: [%d] %s(): %s: (WSALastError=%d)\n",        \
               DEBUG_IDENT, THREAD_ID, __func__, str, (int)WSAGetLastError());            \
 } while (0)
+
 # else
 #  define dbg_lasterror(str)     ;
 #  define dbg_wsalasterror(str)  ;
 # endif
 
+/*
+ * Tracing mutexes are a thin wrapper around the pthread_mutex_t 
+ * datatype that tracks and reports when a mutex is locked or unlocked.
+ * It also allows you to assert that a mutex has (or has not) been locked
+ * by calling tracing_mutex_assert().
+ */
+
+# define MTX_UNLOCKED    0
+# define MTX_LOCKED      1
+
+typedef struct {
+    pthread_mutex_t mtx_lock; 
+    int mtx_status; 
+} tracing_mutex_t; 
+
+# define tracing_mutex_init(mtx, attr) do { \
+    pthread_mutex_init(&(mtx)->mtx_lock, (attr)); \
+    (mtx)->mtx_status = MTX_UNLOCKED; \
+} while (0)
+
+# define tracing_mutex_assert(x,y)   assert((x)->mtx_status == (y))
+
+# define tracing_mutex_lock(x)  do { \
+    dbg_printf("waiting for %s", #x); \
+    pthread_mutex_lock(&((x)->mtx_lock)); \
+    dbg_printf("locked %s", #x); \
+    (x)->mtx_status = MTX_LOCKED; \
+} while (0)
+
+# define tracing_mutex_unlock(x)  do { \
+    (x)->mtx_status = MTX_UNLOCKED; \
+    pthread_mutex_unlock(&((x)->mtx_lock)); \
+    dbg_printf("unlocked %s", # x); \
+} while (0)
 #else /* NDEBUG */
 # define dbg_puts(str)           do {} while (0)
 # define dbg_printf(fmt,...)     do {} while (0)
@@ -79,6 +116,13 @@ extern char *DEBUG_IDENT;
 # define dbg_lasterror(str)      do {} while (0)
 # define dbg_wsalasterror(str)   do {} while (0)
 # define reset_errno()           do {} while (0)
+# define MTX_UNLOCKED                
+# define MTX_LOCKED                 
+# define tracing_mutex_t            pthread_mutex_t
+# define tracing_mutex_init         pthread_mutex_init
+# define tracing_mutex_assert(x,y)  do {} while (0)
+# define tracing_mutex_lock         pthread_mutex_lock
+# define tracing_mutex_unlock       pthread_mutex_unlock
 #endif 
 
 #endif  /* ! _DEBUG_H */

test/Makefile

@@ -16,7 +16,10 @@
 
 include config.mk
 
-all: kqtest
+all: kqtest lockstat
+
+lockstat: lockstat.c
+	$(CC) -o lockstat $(CFLAGS) lockstat.c $(LDADD)
 
 kqtest: $(SOURCES)
 	$(CC) -o kqtest $(CFLAGS) $(SOURCES) $(LDADD)
@@ -56,5 +59,5 @@ edit:
 	$(EDITOR) *.[ch]
 
 clean:
-	rm -f *.o *.a kqtest
+	rm -f *.o *.a kqtest lockstat
 	for x in libdispatch stress; do cd $$x && make clean && cd ..; done

test/lockstat.c

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2011 Mark Heily <mark@heily.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <pthread.h>
+#include "../src/common/debug.h"
+
+int DEBUG_ACTIVE = 1;
+char * DEBUG_IDENT = "lockstat";
+
+struct foo {
+    tracing_mutex_t foo_lock;
+};
+
+/*
+ * Test the lockstat.h API
+ */
+int main() {
+    struct foo x;
+    
+    tracing_mutex_init(&x.foo_lock, NULL);
+    tracing_mutex_lock(&x.foo_lock);
+    tracing_mutex_assert(&x.foo_lock, MTX_LOCKED);
+    tracing_mutex_unlock(&x.foo_lock);
+    tracing_mutex_assert(&x.foo_lock, MTX_UNLOCKED);
+
+    return (0);
+}