Prepare for radical source tree reorganization. zack/build-layout-experiment

All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).

1 files changed, 78 insertions, 0 deletions

diff --git a/REORG.TODO/sysdeps/unix/sysv/linux/x86/elision-conf.c b/REORG.TODO/sysdeps/unix/sysv/linux/x86/elision-conf.c
new file mode 100644
index 0000000000..673b0005a7
--- /dev/null
+++ b/REORG.TODO/sysdeps/unix/sysv/linux/x86/elision-conf.c
@@ -0,0 +1,78 @@
+/* elision-conf.c: Lock elision tunable parameters.
+   Copyright (C) 2013-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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 "config.h"
+#include <pthreadP.h>
+#include <init-arch.h>
+#include <elision-conf.h>
+#include <unistd.h>
+
+/* Reasonable initial tuning values, may be revised in the future.
+   This is a conservative initial value.  */
+
+struct elision_config __elision_aconf =
+  {
+    /* How often to not attempt to use elision if a transaction aborted
+       because the lock is already acquired.  Expressed in number of lock
+       acquisition attempts.  */
+    .skip_lock_busy = 3,
+    /* How often to not attempt to use elision if a transaction aborted due
+       to reasons other than other threads' memory accesses.  Expressed in
+       number of lock acquisition attempts.  */
+    .skip_lock_internal_abort = 3,
+    /* How often we retry using elision if there is chance for the transaction
+       to finish execution (e.g., it wasn't aborted due to the lock being
+       already acquired.  */
+    .retry_try_xbegin = 3,
+    /* Same as SKIP_LOCK_INTERNAL_ABORT but for trylock.  */
+    .skip_trylock_internal_abort = 3,
+  };
+
+/* Force elision for all new locks.  This is used to decide whether existing
+   DEFAULT locks should be automatically upgraded to elision in
+   pthread_mutex_lock().  Disabled for suid programs.  Only used when elision
+   is available.  */
+
+int __pthread_force_elision attribute_hidden;
+
+/* Initialize elison.  */
+
+static void
+elision_init (int argc __attribute__ ((unused)),
+	      char **argv  __attribute__ ((unused)),
+	      char **environ)
+{
+  int elision_available = HAS_CPU_FEATURE (RTM);
+#ifdef ENABLE_LOCK_ELISION
+  __pthread_force_elision = __libc_enable_secure ? 0 : elision_available;
+#endif
+  if (!elision_available)
+    __elision_aconf.retry_try_xbegin = 0; /* Disable elision on rwlocks */
+}
+
+#ifdef SHARED
+# define INIT_SECTION ".init_array"
+#else
+# define INIT_SECTION ".preinit_array"
+#endif
+
+void (*const __pthread_init_array []) (int, char **, char **)
+  __attribute__ ((section (INIT_SECTION), aligned (sizeof (void *)))) =
+{
+  &elision_init
+};