Remove timeout slicing from __timedwait. NFC

This removes the timeout slicing from `__timedwait` and instead relies
on the existing slicing in `emscripten_futex_wait.c`.

This is a followup to #26511 and #26471 (which did the same for the
slicing in `__wait`).

Author: sbc100

system/lib/libc/musl/src/thread/__timedwait.c

@@ -58,41 +58,8 @@ int __timedwait_cp(volatile int *addr, int val,
 	}
 
 #ifdef __EMSCRIPTEN__
-	double msecsToSleep = top ? (top->tv_sec * 1000 + top->tv_nsec / 1000000.0) : INFINITY;
-
-	// cp suffix in the function name means "cancellation point", so this wait can be cancelled
-	// by the user, unless current thread has cancelation disabled (which may be either done
-	// directly, or indirectly, for example in the __timedwait() function).
-	pthread_t self = pthread_self();
-
-	if (self->canceldisable != PTHREAD_CANCEL_DISABLE) {
-		double max_ms_slice_to_sleep = 100;
-		double sleepUntilTime = emscripten_get_now() + msecsToSleep;
-		do {
-			if (self->cancel) {
-				// The thread was canceled by pthread_cancel().
-				// In the case of cancelasync or PTHREAD_CANCEL_ENABLE we can just call
-				// __pthread_testcancel(), which won't return at all.
-				__pthread_testcancel();
-				// If __pthread_testcancel does return here it means that canceldisable
-				// must be set to PTHREAD_CANCEL_MASKED.  In this case we emulate the
-				// behaviour of the futex syscall and return ECANCELLED here.
-				// See pthread_cond_timedwait.c for the only use of this flag.
-				return ECANCELED;
-			}
-			msecsToSleep = sleepUntilTime - emscripten_get_now();
-			if (msecsToSleep <= 0) {
-				return ETIMEDOUT;
-			}
-			// Must wait in slices in case this thread is cancelled in between.
-			if (msecsToSleep > max_ms_slice_to_sleep)
-				msecsToSleep = max_ms_slice_to_sleep;
-			r = -emscripten_futex_wait((void*)addr, val, msecsToSleep);
-		} while (r == ETIMEDOUT);
-	} else {
-		// Can wait in one go.
-		r = -emscripten_futex_wait((void*)addr, val, msecsToSleep);
-	}
+	double msecs_to_sleep = top ? (top->tv_sec * 1000 + top->tv_nsec / 1000000.0) : INFINITY;
+	r = -emscripten_futex_wait((void*)addr, val, msecs_to_sleep);
 #else
 	r = -__futex4_cp(addr, FUTEX_WAIT|priv, val, top);
 #endif

system/lib/pthread/emscripten_futex_wait.c

@@ -132,7 +132,7 @@ int emscripten_futex_wait(volatile void *addr, uint32_t val, double max_wait_ms)
 
 #ifdef __EMSCRIPTEN_PTHREADS__
   pthread_t self = pthread_self();
-  bool cancelable = !self->canceldisable && self->cancelasync;
+  bool cancelable = self->canceldisable != PTHREAD_CANCEL_DISABLE;
 #else
   bool cancelable = false;
 #endif
@@ -215,7 +215,12 @@ int emscripten_futex_wait(volatile void *addr, uint32_t val, double max_wait_ms)
 #ifdef __EMSCRIPTEN_PTHREADS__
     if (cancelable && ret == ATOMICS_WAIT_TIMED_OUT && self->cancel) {
       __pthread_testcancel();
-      break;
+      // If __pthread_testcancel does return here it means that canceldisable
+      // must be set to PTHREAD_CANCEL_MASKED.  In this case we emulate the
+      // behaviour of the futex syscall and return ECANCELLED here.
+      // See pthread_cond_timedwait.c for the only use of this flag.
+      emscripten_conditional_set_current_thread_status(EM_THREAD_STATUS_WAITFUTEX, EM_THREAD_STATUS_RUNNING);
+      return -ECANCELED;
     }
     // If remainder_ns is negative it means we want wait forever, and we don't
     // need to decrement remainder_ns in that case.

test/codesize/test_codesize_minimal_pthreads.json

@@ -1,14 +1,14 @@
 {
   "a.out.js": 7363,
   "a.out.js.gz": 3604,
-  "a.out.nodebug.wasm": 19244,
-  "a.out.nodebug.wasm.gz": 8919,
-  "total": 26607,
-  "total_gz": 12523,
+  "a.out.nodebug.wasm": 19046,
+  "a.out.nodebug.wasm.gz": 8822,
+  "total": 26409,
+  "total_gz": 12426,
   "sent": [
     "a (memory)",
-    "b (emscripten_get_now)",
-    "c (exit)",
+    "b (exit)",
+    "c (emscripten_get_now)",
     "d (_emscripten_thread_set_strongref)",
     "e (_emscripten_receive_on_main_thread_js)",
     "f (emscripten_runtime_keepalive_check)",
@@ -23,8 +23,8 @@
   ],
   "imports": [
     "a (memory)",
-    "b (emscripten_get_now)",
-    "c (exit)",
+    "b (exit)",
+    "c (emscripten_get_now)",
     "d (_emscripten_thread_set_strongref)",
     "e (_emscripten_receive_on_main_thread_js)",
     "f (emscripten_runtime_keepalive_check)",

test/codesize/test_codesize_minimal_pthreads_memgrowth.json

@@ -1,14 +1,14 @@
 {
   "a.out.js": 7765,
   "a.out.js.gz": 3810,
-  "a.out.nodebug.wasm": 19245,
-  "a.out.nodebug.wasm.gz": 8920,
-  "total": 27010,
-  "total_gz": 12730,
+  "a.out.nodebug.wasm": 19047,
+  "a.out.nodebug.wasm.gz": 8823,
+  "total": 26812,
+  "total_gz": 12633,
   "sent": [
     "a (memory)",
-    "b (emscripten_get_now)",
-    "c (exit)",
+    "b (exit)",
+    "c (emscripten_get_now)",
     "d (_emscripten_thread_set_strongref)",
     "e (_emscripten_receive_on_main_thread_js)",
     "f (emscripten_runtime_keepalive_check)",
@@ -23,8 +23,8 @@
   ],
   "imports": [
     "a (memory)",
-    "b (emscripten_get_now)",
-    "c (exit)",
+    "b (exit)",
+    "c (emscripten_get_now)",
     "d (_emscripten_thread_set_strongref)",
     "e (_emscripten_receive_on_main_thread_js)",
     "f (emscripten_runtime_keepalive_check)",