Make bulk_free() go faster

Author: jart

.gitignore

@@ -15,3 +15,4 @@ __pycache__
 /tool/emacs/*.elc
 /perf.data
 /perf.data.old
+/qemu*core

libc/cosmo.h

@@ -25,8 +25,8 @@ int cosmo_futex_wake(_COSMO_ATOMIC(int) *, int, char);
 int cosmo_futex_wait(_COSMO_ATOMIC(int) *, int, char, int,
                      const struct timespec *);
 
-errno_t cosmo_stack_alloc(size_t *, size_t *, void **) libcesque;
-errno_t cosmo_stack_free(void *, size_t, size_t) libcesque;
+errno_t cosmo_stack_alloc(unsigned *, unsigned *, void **) libcesque;
+errno_t cosmo_stack_free(void *, unsigned, unsigned) libcesque;
 void cosmo_stack_clear(void) libcesque;
 void cosmo_stack_setmaxstacks(int) libcesque;
 int cosmo_stack_getmaxstacks(void) libcesque;

libc/intrin/stack.c

@@ -42,8 +42,8 @@
 struct CosmoStack {
   struct Dll elem;
   void *stackaddr;
-  size_t stacksize;
-  size_t guardsize;
+  unsigned stacksize;
+  unsigned guardsize;
 };
 
 struct CosmoStacks {
@@ -215,13 +215,13 @@ void cosmo_stack_setmaxstacks(int maxstacks) {
  * This function returns 0 on success, or an errno on error. See the
  * documentation of mmap() for a list possible errors that may occur.
  */
-errno_t cosmo_stack_alloc(size_t *inout_stacksize,  //
-                          size_t *inout_guardsize,  //
+errno_t cosmo_stack_alloc(unsigned *inout_stacksize,  //
+                          unsigned *inout_guardsize,  //
                           void **out_addr) {
 
   // validate arguments
-  size_t stacksize = *inout_stacksize;
-  size_t guardsize = *inout_guardsize;
+  unsigned stacksize = *inout_stacksize;
+  unsigned guardsize = *inout_guardsize;
   stacksize = (stacksize + __gransize - 1) & -__gransize;
   guardsize = (guardsize + __pagesize - 1) & -__pagesize;
   if (guardsize + __pagesize > stacksize)
@@ -283,7 +283,8 @@ static void cosmo_stack_setup(void) {
  * variable is never clobbered. You can only dependably count on this to
  * return an error on failure when you say `cosmo_stack_setmaxstacks(0)`
  */
-errno_t cosmo_stack_free(void *stackaddr, size_t stacksize, size_t guardsize) {
+errno_t cosmo_stack_free(void *stackaddr, unsigned stacksize,
+                         unsigned guardsize) {
   stacksize = (stacksize + __gransize - 1) & -__gransize;
   guardsize = (guardsize + __pagesize - 1) & -__pagesize;
   if (guardsize + __pagesize > stacksize)

libc/thread/mapstack.c

@@ -35,8 +35,8 @@
  */
 void *NewCosmoStack(void) {
   void *stackaddr;
-  size_t stacksize = GetStackSize();
-  size_t guardsize = GetGuardSize();
+  unsigned stacksize = GetStackSize();
+  unsigned guardsize = GetGuardSize();
   errno_t err = cosmo_stack_alloc(&stacksize, &guardsize, &stackaddr);
   if (!err)
     return stackaddr;

libc/thread/posixthread.internal.h

@@ -78,8 +78,7 @@ struct PosixThread {
   atomic_int ptid;            // transitions 0 → tid
   atomic_int pt_refs;         // prevents decimation
   void *(*pt_start)(void *);  // creation callback
-  void *pt_arg;               // start's parameter
-  void *pt_rc;                // start's return value
+  void *pt_val;               // start param / return val
   char *pt_tls;               // bottom of tls allocation
   struct CosmoTib *tib;       // middle of tls allocation
   struct Dll list;            // list of threads
@@ -105,7 +104,6 @@ int _pthread_tid(struct PosixThread *) libcesque;
 intptr_t _pthread_syshand(struct PosixThread *) libcesque;
 long _pthread_cancel_ack(void) libcesque;
 void _pthread_decimate(void) libcesque;
-void _pthread_free(struct PosixThread *) libcesque;
 void _pthread_lock(void) libcesque;
 void _pthread_onfork_child(void) libcesque;
 void _pthread_onfork_parent(void) libcesque;

libc/thread/pthread_atfork.c

@@ -63,11 +63,13 @@ static void _pthread_onfork(int i, const char *op) {
 }
 
 void _pthread_onfork_prepare(void) {
+  pthread_mutex_lock(&_atforks.lock);
   _pthread_onfork(0, "prepare");
 }
 
 void _pthread_onfork_parent(void) {
   _pthread_onfork(1, "parent");
+  pthread_mutex_unlock(&_atforks.lock);
 }
 
 void _pthread_onfork_child(void) {

libc/thread/pthread_create.c

@@ -67,7 +67,7 @@ __static_yoink("_pthread_onfork_prepare");
 __static_yoink("_pthread_onfork_parent");
 __static_yoink("_pthread_onfork_child");
 
-void _pthread_free(struct PosixThread *pt) {
+static void _pthread_free(struct PosixThread *pt) {
 
   // thread must be removed from _pthread_list before calling
   unassert(dll_is_alone(&pt->list) && &pt->list != _pthread_list);
@@ -93,10 +93,13 @@ void _pthread_free(struct PosixThread *pt) {
   }
 
   // free heap memory associated with thread
-  if (pt->pt_flags & PT_OWNSIGALTSTACK)
-    free(pt->pt_attr.__sigaltstackaddr);
-  free(pt->pt_tls);
-  free(pt);
+  bulk_free(
+      (void *[]){
+          pt->pt_flags & PT_OWNSIGALTSTACK ? pt->pt_attr.__sigaltstackaddr : 0,
+          pt->pt_tls,
+          pt,
+      },
+      3);
 }
 
 void _pthread_decimate(void) {
@@ -137,7 +140,6 @@ void _pthread_decimate(void) {
 }
 
 static int PosixThread(void *arg, int tid) {
-  void *rc;
   struct PosixThread *pt = arg;
 
   // setup scheduling
@@ -167,11 +169,11 @@ static int PosixThread(void *arg, int tid) {
     } else {
       sys_sigprocmask(SIG_SETMASK, &pt->pt_attr.__sigmask, 0);
     }
-    rc = pt->pt_start(pt->pt_arg);
+    void *ret = pt->pt_start(pt->pt_val);
     // ensure pthread_cleanup_pop(), and pthread_exit() popped cleanup
     unassert(!pt->pt_cleanup);
     // calling pthread_exit() will either jump back here, or call exit
-    pthread_exit(rc);
+    pthread_exit(ret);
   }
 
   // avoid signal handler being triggered after we trash our own stack
@@ -196,7 +198,7 @@ static errno_t pthread_create_impl(pthread_t *thread,
   dll_init(&pt->list);
   pt->pt_locale = &__global_locale;
   pt->pt_start = start_routine;
-  pt->pt_arg = arg;
+  pt->pt_val = arg;
 
   // create thread local storage memory
   if (!(pt->pt_tls = _mktls(&pt->tib))) {

libc/thread/pthread_exit.c

@@ -88,7 +88,7 @@ wontreturn void pthread_exit(void *rc) {
 
   // set state
   pt->pt_flags |= PT_NOCANCEL | PT_EXITING;
-  pt->pt_rc = rc;
+  pt->pt_val = rc;
 
   // free resources
   __cxa_thread_finalize();

libc/thread/pthread_timedjoin_np.c

@@ -139,7 +139,7 @@ errno_t pthread_timedjoin_np(pthread_t thread, void **value_ptr,
                           memory_order_release);
     _pthread_zombify(pt);
     if (value_ptr)
-      *value_ptr = pt->pt_rc;
+      *value_ptr = pt->pt_val;
   }
 
   _pthread_unref(pt);

libc/thread/thread.h

@@ -130,8 +130,8 @@ typedef struct pthread_attr_s {
   int __contentionscope;
   int __sigaltstacksize;
   uint64_t __sigmask;
-  size_t __guardsize;
-  size_t __stacksize;
+  unsigned __guardsize;
+  unsigned __stacksize;
   void *__stackaddr;
   void *__sigaltstackaddr;
 } pthread_attr_t;