Refactor liburcu to support many flavors per compile unit

[urcu.git] / include / urcu / static / urcu-common.h

diff --git a/include/urcu/static/urcu-common.h b/include/urcu/static/urcu-common.h
new file mode 100644 (file)
index 0000000..28d3160
--- /dev/null
+++ b/include/urcu/static/urcu-common.h
@@ -0,0 +1,129 @@
+#ifndef _URCU_COMMON_STATIC_H
+#define _URCU_COMMON_STATIC_H
+
+/*
+ * urcu-common-static.h
+ *
+ * Userspace RCU header.
+ *
+ * TO BE INCLUDED ONLY IN CODE THAT IS TO BE RECOMPILED ON EACH LIBURCU
+ * RELEASE. See urcu.h for linking dynamically with the userspace rcu library.
+ *
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
+ *
+ * This 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.
+ *
+ * This 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * IBM's contributions to this file may be relicensed under LGPLv2 or later.
+ */
+
+#include <stdlib.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <stdint.h>
+
+#include <urcu/config.h>
+#include <urcu/compiler.h>
+#include <urcu/arch.h>
+#include <urcu/system.h>
+#include <urcu/uatomic.h>
+#include <urcu/list.h>
+#include <urcu/futex.h>
+#include <urcu/tls-compat.h>
+#include <urcu/debug.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+enum urcu_state {
+       URCU_READER_ACTIVE_CURRENT,
+       URCU_READER_ACTIVE_OLD,
+       URCU_READER_INACTIVE,
+};
+
+/*
+ * The trick here is that URCU_GP_CTR_PHASE must be a multiple of 8 so
+ * we can use a full 8-bits, 16-bits or 32-bits bitmask for the lower
+ * order bits.
+ */
+#define URCU_GP_COUNT          (1UL << 0)
+/* Use the amount of bits equal to half of the architecture long size */
+#define URCU_GP_CTR_PHASE      (1UL << (sizeof(unsigned long) << 2))
+#define URCU_GP_CTR_NEST_MASK  (URCU_GP_CTR_PHASE - 1)
+
+struct urcu_gp {
+       /*
+        * Global grace period counter.
+        * Contains the current URCU_GP_CTR_PHASE.
+        * Also has a URCU_GP_COUNT of 1, to accelerate the reader fast path.
+        * Written to only by writer with mutex taken.
+        * Read by both writer and readers.
+        */
+       unsigned long ctr;
+
+       int32_t futex;
+} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
+
+struct urcu_reader {
+       /* Data used by both reader and synchronize_rcu() */
+       unsigned long ctr;
+       char need_mb;
+       /* Data used for registry */
+       struct cds_list_head node __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
+       pthread_t tid;
+       /* Reader registered flag, for internal checks. */
+       unsigned int registered:1;
+};
+
+/*
+ * Wake-up waiting synchronize_rcu(). Called from many concurrent threads.
+ */
+static inline void urcu_common_wake_up_gp(struct urcu_gp *gp)
+{
+       if (caa_unlikely(uatomic_read(&gp->futex) == -1)) {
+               uatomic_set(&gp->futex, 0);
+               /*
+                * Ignoring return value until we can make this function
+                * return something (because urcu_die() is not publicly
+                * exposed).
+                */
+               (void) futex_async(&gp->futex, FUTEX_WAKE, 1,
+                               NULL, NULL, 0);
+       }
+}
+
+static inline enum urcu_state urcu_common_reader_state(struct urcu_gp *gp,
+               unsigned long *ctr)
+{
+       unsigned long v;
+
+       /*
+        * Make sure both tests below are done on the same version of *value
+        * to insure consistency.
+        */
+       v = CMM_LOAD_SHARED(*ctr);
+       if (!(v & URCU_GP_CTR_NEST_MASK))
+               return URCU_READER_INACTIVE;
+       if (!((v ^ gp->ctr) & URCU_GP_CTR_PHASE))
+               return URCU_READER_ACTIVE_CURRENT;
+       return URCU_READER_ACTIVE_OLD;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _URCU_COMMON_STATIC_H */