X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu-defer-static.h;h=3e5df3e75b11c31efcd19ec380202d070f824620;hp=25137690465fa9c32ef5939be20d1cec3bdd17ad;hb=2260a36cd53dc882bf83e39180bae4413d64da8f;hpb=786ee85b1676d2a1865b2db7120c45bafdf954d6

diff --git a/urcu-defer-static.h b/urcu-defer-static.h
index 2513769..3e5df3e 100644
--- a/urcu-defer-static.h
+++ b/urcu-defer-static.h
@@ -9,7 +9,7 @@
  * TO BE INCLUDED ONLY IN LGPL-COMPATIBLE CODE. See urcu-defer.h for linking
  * dynamically with the userspace rcu reclamation library.
  *
- * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ * 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
@@ -32,9 +32,15 @@
 #include <stdlib.h>
 #include <pthread.h>
 
-#include <compiler.h>
-#include <arch.h>
+#include <urcu/compiler.h>
+#include <urcu/arch.h>
+#include <urcu/uatomic_arch.h>
+#include <urcu/list.h>
+#include <urcu/system.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 /*
  * Number of entries in the per-thread defer queue. Must be power of 2.
@@ -43,34 +49,21 @@
 #define DEFER_QUEUE_MASK	(DEFER_QUEUE_SIZE - 1)
 
 /*
- * Identify a shared load. A smp_rmc() or smp_mc() should come before the load.
- */
-#define _LOAD_SHARED(p)	       ACCESS_ONCE(p)
-
-/*
- * Load a data from shared memory, doing a cache flush if required.
- */
-#define LOAD_SHARED(p)			\
-	({				\
-		smp_rmc();		\
-		_LOAD_SHARED(p);	\
-	})
-
-/*
- * Identify a shared store. A smp_wmc() or smp_mc() should follow the store.
- */
-#define _STORE_SHARED(x, v)	({ ACCESS_ONCE(x) = (v); })
-
-/*
- * Store v into x, where x is located in shared memory. Performs the required
- * cache flush after writing. Returns v.
+ * Typically, data is aligned at least on the architecture size.
+ * Use lowest bit to indicate that the current callback is changing.
+ * Assumes that (void *)-2L is not used often. Used to encode non-aligned
+ * functions and non-aligned data using extra space.
+ * We encode the (void *)-2L fct as: -2L, fct, data.
+ * We encode the (void *)-2L data as: -2L, fct, data.
+ * Here, DQ_FCT_MARK == ~DQ_FCT_BIT. Required for the test order.
  */
-#define STORE_SHARED(x, v)		\
-	({				\
-		_STORE_SHARED(x, v);	\
-		smp_wmc();		\
-		(v);			\
-	})
+#define DQ_FCT_BIT		(1 << 0)
+#define DQ_IS_FCT_BIT(x)	((unsigned long)(x) & DQ_FCT_BIT)
+#define DQ_SET_FCT_BIT(x)	\
+	(x = (void *)((unsigned long)(x) | DQ_FCT_BIT))
+#define DQ_CLEAR_FCT_BIT(x)	\
+	(x = (void *)((unsigned long)(x) & ~DQ_FCT_BIT))
+#define DQ_FCT_MARK		((void *)(~DQ_FCT_BIT))
 
 /*
  * This code section can only be included in LGPL 2.1 compatible source code.
@@ -86,43 +79,30 @@
 #define rcu_assert(args...)
 #endif
 
+/*
+ * defer queue.
+ * Contains pointers. Encoded to save space when same callback is often used.
+ * When looking up the next item:
+ * - if DQ_FCT_BIT is set, set the current callback to DQ_CLEAR_FCT_BIT(ptr)
+ *   - next element contains pointer to data.
+ * - else if item == DQ_FCT_MARK
+ *   - set the current callback to next element ptr
+ *   - following next element contains pointer to data.
+ * - else current element contains data
+ */
 struct defer_queue {
 	unsigned long head;	/* add element at head */
+	void *last_fct_in;	/* last fct pointer encoded */
 	unsigned long tail;	/* next element to remove at tail */
+	void *last_fct_out;	/* last fct pointer encoded */
 	void **q;
+	/* registry information */
+	unsigned long last_head;
+	struct cds_list_head list;	/* list of thread queues */
 };
 
-extern struct defer_queue __thread defer_queue;
-
-extern void rcu_defer_barrier_thread(void);
-
-/*
- * not signal-safe.
- */
-static inline void _rcu_defer_queue(void *p)
-{
-	unsigned long head, tail;
-
-	/*
-	 * Head is only modified by ourself. Tail can be modified by reclamation
-	 * thread.
-	 */
-	head = defer_queue.head;
-	tail = LOAD_SHARED(defer_queue.tail);
-
-	/*
-	 * If queue is full, empty it ourself.
-	 */
-	if (unlikely(head - tail >= DEFER_QUEUE_SIZE)) {
-		assert(head - tail == DEFER_QUEUE_SIZE);
-		rcu_defer_barrier_thread();
-		assert(head - LOAD_SHARED(defer_queue.tail) == 0);
-	}
-
-	smp_wmb();	/* Publish new pointer before write q[] */
-	_STORE_SHARED(defer_queue.q[head & DEFER_QUEUE_MASK], p);
-	smp_wmb();	/* Write q[] before head. */
-	STORE_SHARED(defer_queue.head, head + 1);
+#ifdef __cplusplus 
 }
+#endif
 
 #endif /* _URCU_DEFER_STATIC_H */