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-rw-r--r--REORG.TODO/nptl/pthread_cond_broadcast.c92
1 files changed, 92 insertions, 0 deletions
diff --git a/REORG.TODO/nptl/pthread_cond_broadcast.c b/REORG.TODO/nptl/pthread_cond_broadcast.c
new file mode 100644
index 0000000000..be69451767
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+++ b/REORG.TODO/nptl/pthread_cond_broadcast.c
@@ -0,0 +1,92 @@
+/* Copyright (C) 2003-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <endian.h>
+#include <errno.h>
+#include <sysdep.h>
+#include <futex-internal.h>
+#include <pthread.h>
+#include <pthreadP.h>
+#include <stap-probe.h>
+#include <atomic.h>
+
+#include <shlib-compat.h>
+
+#include "pthread_cond_common.c"
+
+
+/* We do the following steps from __pthread_cond_signal in one critical
+   section: (1) signal all waiters in G1, (2) close G1 so that it can become
+   the new G2 and make G2 the new G1, and (3) signal all waiters in the new
+   G1.  We don't need to do all these steps if there are no waiters in G1
+   and/or G2.  See __pthread_cond_signal for further details.  */
+int
+__pthread_cond_broadcast (pthread_cond_t *cond)
+{
+  LIBC_PROBE (cond_broadcast, 1, cond);
+
+  unsigned int wrefs = atomic_load_relaxed (&cond->__data.__wrefs);
+  if (wrefs >> 3 == 0)
+    return 0;
+  int private = __condvar_get_private (wrefs);
+
+  __condvar_acquire_lock (cond, private);
+
+  unsigned long long int wseq = __condvar_load_wseq_relaxed (cond);
+  unsigned int g2 = wseq & 1;
+  unsigned int g1 = g2 ^ 1;
+  wseq >>= 1;
+  bool do_futex_wake = false;
+
+  /* Step (1): signal all waiters remaining in G1.  */
+  if (cond->__data.__g_size[g1] != 0)
+    {
+      /* Add as many signals as the remaining size of the group.  */
+      atomic_fetch_add_relaxed (cond->__data.__g_signals + g1,
+				cond->__data.__g_size[g1] << 1);
+      cond->__data.__g_size[g1] = 0;
+
+      /* We need to wake G1 waiters before we quiesce G1 below.  */
+      /* TODO Only set it if there are indeed futex waiters.  We could
+	 also try to move this out of the critical section in cases when
+	 G2 is empty (and we don't need to quiesce).  */
+      futex_wake (cond->__data.__g_signals + g1, INT_MAX, private);
+    }
+
+  /* G1 is complete.  Step (2) is next unless there are no waiters in G2, in
+     which case we can stop.  */
+  if (__condvar_quiesce_and_switch_g1 (cond, wseq, &g1, private))
+    {
+      /* Step (3): Send signals to all waiters in the old G2 / new G1.  */
+      atomic_fetch_add_relaxed (cond->__data.__g_signals + g1,
+				cond->__data.__g_size[g1] << 1);
+      cond->__data.__g_size[g1] = 0;
+      /* TODO Only set it if there are indeed futex waiters.  */
+      do_futex_wake = true;
+    }
+
+  __condvar_release_lock (cond, private);
+
+  if (do_futex_wake)
+    futex_wake (cond->__data.__g_signals + g1, INT_MAX, private);
+
+  return 0;
+}
+
+versioned_symbol (libpthread, __pthread_cond_broadcast, pthread_cond_broadcast,
+		  GLIBC_2_3_2);