[Qemu-devel] [PATCH 5/7] trace: Trace qemu_malloc() and qemu_vmalloc()

[Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>]

It is often useful to instrument memory management functions in order to
find leaks or performance problems.  This patch adds trace events for
the memory allocation primitives.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
v2:
 * Record pointer result from allocation functions

 osdep.c       |   24 ++++++++++++++++++------
 qemu-malloc.c |   12 ++++++++++--
 trace-events  |   10 ++++++++++
 3 files changed, 38 insertions(+), 8 deletions(-)

diff --git a/osdep.c b/osdep.c
index abbc8a2..a6b7726 100644
--- a/osdep.c
+++ b/osdep.c
@@ -50,6 +50,7 @@
 #endif
 
 #include "qemu-common.h"
+#include "trace.h"
 #include "sysemu.h"
 #include "qemu_socket.h"
 
@@ -71,25 +72,34 @@ static void *oom_check(void *ptr)
 #if defined(_WIN32)
 void *qemu_memalign(size_t alignment, size_t size)
 {
+    void *ptr;
+
     if (!size) {
         abort();
     }
-    return oom_check(VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE));
+    ptr = oom_check(VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE));
+    trace_qemu_memalign(alignment, size, ptr);
+    return ptr;
 }
 
 void *qemu_vmalloc(size_t size)
 {
+    void *ptr;
+
     /* FIXME: this is not exactly optimal solution since VirtualAlloc
        has 64Kb granularity, but at least it guarantees us that the
        memory is page aligned. */
     if (!size) {
         abort();
     }
-    return oom_check(VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE));
+    ptr = oom_check(VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE));
+    trace_qemu_vmalloc(size, ptr);
+    return ptr;
 }
 
 void qemu_vfree(void *ptr)
 {
+    trace_qemu_vfree(ptr);
     VirtualFree(ptr, 0, MEM_RELEASE);
 }
 
@@ -97,21 +107,22 @@ void qemu_vfree(void *ptr)
 
 void *qemu_memalign(size_t alignment, size_t size)
 {
+    void *ptr;
 #if defined(_POSIX_C_SOURCE) && !defined(__sun__)
     int ret;
-    void *ptr;
     ret = posix_memalign(&ptr, alignment, size);
     if (ret != 0) {
         fprintf(stderr, "Failed to allocate %zu B: %s\n",
                 size, strerror(ret));
         abort();
     }
-    return ptr;
 #elif defined(CONFIG_BSD)
-    return oom_check(valloc(size));
+    ptr = oom_check(valloc(size));
 #else
-    return oom_check(memalign(alignment, size));
+    ptr = oom_check(memalign(alignment, size));
 #endif
+    trace_qemu_memalign(alignment, size, ptr);
+    return ptr;
 }
 
 /* alloc shared memory pages */
@@ -122,6 +133,7 @@ void *qemu_vmalloc(size_t size)
 
 void qemu_vfree(void *ptr)
 {
+    trace_qemu_vfree(ptr);
     free(ptr);
 }
 
diff --git a/qemu-malloc.c b/qemu-malloc.c
index 6cdc5de..72de60a 100644
--- a/qemu-malloc.c
+++ b/qemu-malloc.c
@@ -22,6 +22,7 @@
  * THE SOFTWARE.
  */
 #include "qemu-common.h"
+#include "trace.h"
 #include <stdlib.h>
 
 static void *oom_check(void *ptr)
@@ -39,6 +40,7 @@ void *get_mmap_addr(unsigned long size)
 
 void qemu_free(void *ptr)
 {
+    trace_qemu_free(ptr);
     free(ptr);
 }
 
@@ -53,18 +55,24 @@ static int allow_zero_malloc(void)
 
 void *qemu_malloc(size_t size)
 {
+    void *ptr;
     if (!size && !allow_zero_malloc()) {
         abort();
     }
-    return oom_check(malloc(size ? size : 1));
+    ptr = oom_check(malloc(size ? size : 1));
+    trace_qemu_malloc(size, ptr);
+    return ptr;
 }
 
 void *qemu_realloc(void *ptr, size_t size)
 {
+    void *newptr;
     if (!size && !allow_zero_malloc()) {
         abort();
     }
-    return oom_check(realloc(ptr, size ? size : 1));
+    newptr = oom_check(realloc(ptr, size ? size : 1));
+    trace_qemu_realloc(ptr, size, newptr);
+    return newptr;
 }
 
 void *qemu_mallocz(size_t size)
diff --git a/trace-events b/trace-events
index 5efaa86..3fde0c6 100644
--- a/trace-events
+++ b/trace-events
@@ -24,3 +24,13 @@
 # system may not have the necessary headers included.
 #
 # The <format-string> should be a sprintf()-compatible format string.
+
+# qemu-malloc.c
+qemu_malloc(size_t size, void *ptr) "size %zu ptr %p"
+qemu_realloc(void *ptr, size_t size, void *newptr) "ptr %p size %zu newptr %p"
+qemu_free(void *ptr) "ptr %p"
+
+# osdep.c
+qemu_memalign(size_t alignment, size_t size, void *ptr) "alignment %zu size %zu ptr %p"
+qemu_valloc(size_t size, void *ptr) "size %zu ptr %p"
+qemu_vfree(void *ptr) "ptr %p"
-- 
1.7.1