Name worker threads using pthread_setname_np

This helps identify threads in gdb particularly in processes with a
lot of threads.

4 files changed, 17 insertions, 12 deletions

diff --git a/rts/Task.c b/rts/Task.c
index 0370711692..42893fe903 100644
--- a/rts/Task.c
+++ b/rts/Task.c
@@ -462,7 +462,7 @@ startWorkerTask (Capability *cap)
   ASSERT_LOCK_HELD(&cap->lock);
   cap->running_task = task;
 
-  r = createOSThread(&tid, (OSThreadProc*)workerStart, task);
+  r = createOSThread(&tid, "ghc_worker", (OSThreadProc*)workerStart, task);
   if (r != 0) {
     sysErrorBelch("failed to create OS thread");
     stg_exit(EXIT_FAILURE);
diff --git a/rts/posix/OSThreads.c b/rts/posix/OSThreads.c
index e627babd98..e880b891d6 100644
--- a/rts/posix/OSThreads.c
+++ b/rts/posix/OSThreads.c
@@ -129,11 +129,14 @@ shutdownThread(void)
 }
 
 int
-createOSThread (OSThreadId* pId, OSThreadProc *startProc, void *param)
+createOSThread (OSThreadId* pId, char *name,
+                OSThreadProc *startProc, void *param)
 {
   int result = pthread_create(pId, NULL, (void *(*)(void *))startProc, param);
-  if(!result)
+  if (!result) {
     pthread_detach(*pId);
+    pthread_setname_np(*pId, name);
+  }
   return result;
 }
 
diff --git a/rts/sm/GC.c b/rts/sm/GC.c
index dabcd722d7..19d9ab23bc 100644
--- a/rts/sm/GC.c
+++ b/rts/sm/GC.c
@@ -670,6 +670,15 @@ GarbageCollect (nat collect_gen,
   if (major_gc) { gcCAFs(); }
 #endif
 
+  // Update the stable pointer hash table.
+  updateStableTables(major_gc);
+
+  // unlock the StablePtr table.  Must be before scheduleFinalizers(),
+  // because a finalizer may call hs_free_fun_ptr() or
+  // hs_free_stable_ptr(), both of which access the StablePtr table.
+  stableUnlock();
+
+  // Must be after stableUnlock(), because it might free stable ptrs.
   if (major_gc) {
       checkUnload (gct->scavenged_static_objects);
   }
@@ -696,14 +705,6 @@ GarbageCollect (nat collect_gen,
       }
   }
 
-  // Update the stable pointer hash table.
-  updateStableTables(major_gc);
-
-  // unlock the StablePtr table.  Must be before scheduleFinalizers(),
-  // because a finalizer may call hs_free_fun_ptr() or
-  // hs_free_stable_ptr(), both of which access the StablePtr table.
-  stableUnlock();
-
   // Start any pending finalizers.  Must be after
   // updateStableTables() and stableUnlock() (see #4221).
   RELEASE_SM_LOCK;
diff --git a/rts/win32/OSThreads.c b/rts/win32/OSThreads.c
index e336bd20cc..c3d3af64d2 100644
--- a/rts/win32/OSThreads.c
+++ b/rts/win32/OSThreads.c
@@ -98,7 +98,8 @@ shutdownThread()
 }
 
 int
-createOSThread (OSThreadId* pId, OSThreadProc *startProc, void *param)
+createOSThread (OSThreadId* pId, char *name STG_UNUSED,
+                OSThreadProc *startProc, void *param)
 {
     HANDLE h;
     h = CreateThread ( NULL,  /* default security attributes */