close and re-open sys_exec() scope after migration

2624d3d1 · Nickolai Zeldovich · c99d71b6 · 2624d3d1 · 2624d3d1 · 2624d3d1
--- a/include/kernel.hh
+++ b/include/kernel.hh
@@ -81,7 +81,7 @@ int             e1000tx(void *buf, u32 len);
 void            e1000hwaddr(u8 *hwaddr);

 // exec.c
-int             exec(const char*, char**);
+int             exec(const char*, char**, void* ascope);

 // fs.c
 int             namecmp(const char*, const char*);

--- a/include/kmtrace.hh
+++ b/include/kmtrace.hh
@@ -67,21 +67,43 @@ static inline void mtresume(struct proc *p)
 class mt_ascope
 {
  char name[64];
+  bool active;
 public:
  explicit mt_ascope(const char *fmt, ...)
  {
    va_list ap;

    va_start(ap, fmt);
-    vsnprintf(name, sizeof(name) - 1, fmt, ap);
+    vopen(fmt, ap);
+    va_end(ap);
+  }
+
+  ~mt_ascope()
+  {
+    close();
+  }
+
+  void open(const char *fmt, ...)
+  {
+    va_list ap;
+
+    va_start(ap, fmt);
+    vopen(fmt, ap);
    va_end(ap);
+  }

+  void vopen(const char *fmt, va_list ap)
+  {
+    vsnprintf(name, sizeof(name) - 1, fmt, ap);
    mtrace_ascope_register(0, name);
+    active = true;
  }

-  ~mt_ascope()
+  void close()
  {
-    mtrace_ascope_register(1, name);
+    if (active)
+      mtrace_ascope_register(1, name);
+    active = false;
  }
 };


--- a/kernel/exec.cc
+++ b/kernel/exec.cc
@@ -14,6 +14,7 @@
 #include "cpu.hh"
 #include "wq.hh"
 #include "cilk.hh"
+#include "kmtrace.hh"

 #define BRK (USERTOP >> 1)

@@ -149,7 +150,7 @@ exec_cleanup(vmap *oldvmap, uwq *olduwq)
 }

 int
-exec(const char *path, char **argv)
+exec(const char *path, char **argv, void *ascopev)
 {
  struct inode *ip = nullptr;
  struct vmap *vmp = nullptr;
@@ -166,10 +167,13 @@ exec(const char *path, char **argv)

  myproc()->exec_cpuid_ = mycpuid();

+  mt_ascope *ascope = (mt_ascope*) ascopev;
+  ascope->close();
  myproc()->in_exec_ = 1;
  yield();
  myproc()->in_exec_ = 0;
-  
+  ascope->open("sys_exec2(%s)", path);
+
  if((ip = namei(myproc()->cwd, path)) == 0)
    return -1;


--- a/kernel/sysfile.cc
+++ b/kernel/sysfile.cc
@@ -447,7 +447,7 @@ sys_exec(const char *upath, u64 uargv)
    if(argcheckstr(argv[i]) < 0)
      return -1;
  }
-  return exec(path, argv);
+  return exec(path, argv, &ascope);
 }

 long