X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;f=formal-model%2Furcu%2Furcu.spin;h=f4d3ea78ade593788bf9d97710e7c8bda5ace2ff;hb=a570e118a8f9ed38d5eaebf8d21b65d2b6f5cf40;hp=cc84e51d09d623b330664a0e8a7ca2fbb8ff97ef;hpb=60a1db9d10aaca98e79a5126f168a37d00151845;p=urcu.git

diff --git a/formal-model/urcu/urcu.spin b/formal-model/urcu/urcu.spin
index cc84e51..f4d3ea7 100644
--- a/formal-model/urcu/urcu.spin
+++ b/formal-model/urcu/urcu.spin
@@ -80,6 +80,68 @@
 	:: 1 -> skip			\
 	fi;
 
+/*
+ * Remote barriers tests the scheme where a signal (or IPI) is sent to all
+ * reader threads to promote their compiler barrier to a smp_mb().
+ */
+#ifdef REMOTE_BARRIERS
+
+inline smp_rmb_pid(i)
+{
+	atomic {
+		CACHE_READ_FROM_MEM(urcu_gp_ctr, i);
+		CACHE_READ_FROM_MEM(urcu_active_readers_one, i);
+		CACHE_READ_FROM_MEM(generation_ptr, i);
+	}
+}
+
+inline smp_wmb_pid(i)
+{
+	atomic {
+		CACHE_WRITE_TO_MEM(urcu_gp_ctr, i);
+		CACHE_WRITE_TO_MEM(urcu_active_readers_one, i);
+		CACHE_WRITE_TO_MEM(generation_ptr, i);
+	}
+}
+
+inline smp_mb_pid(i)
+{
+	atomic {
+#ifndef NO_WMB
+		smp_wmb_pid(i);
+#endif
+#ifndef NO_RMB
+		smp_rmb_pid(i);
+#endif
+		skip;
+	}
+}
+
+/*
+ * Readers do a simple barrier(), writers are doing a smp_mb() _and_ sending a
+ * signal or IPI to have all readers execute a smp_mb.
+ * We are not modeling the whole rendez-vous between readers and writers here,
+ * we just let the writer update each reader's caches remotely.
+ */
+inline smp_mb(i)
+{
+	if
+	:: get_pid() >= NR_READERS ->
+		smp_mb_pid(get_pid());
+		i = 0;
+		do
+		:: i < NR_READERS ->
+			smp_mb_pid(i);
+			i++;
+		:: i >= NR_READERS -> break
+		od;
+		smp_mb_pid(get_pid());
+	:: else -> skip;
+	fi;
+}
+
+#else
+
 inline smp_rmb(i)
 {
 	atomic {
@@ -111,6 +173,8 @@ inline smp_mb(i)
 	}
 }
 
+#endif
+
 /* Keep in sync manually with smp_rmb, wmp_wmb and ooo_mem */
 DECLARE_CACHED_VAR(byte, urcu_gp_ctr, 1);
 /* Note ! currently only one reader */
@@ -123,6 +187,8 @@ bit free_done = 0;
 byte read_generation = 1;
 bit data_access = 0;
 
+bit write_lock = 0;
+
 inline ooo_mem(i)
 {
 	atomic {
@@ -142,16 +208,23 @@ inline ooo_mem(i)
 
 inline wait_for_reader(tmp, id, i)
 {
-	tmp = READ_CACHED_VAR(urcu_active_readers_one);
-	ooo_mem(i);
 	do
-	:: (tmp & RCU_GP_CTR_NEST_MASK) && ((tmp ^ READ_CACHED_VAR(urcu_gp_ctr))
-			& RCU_GP_CTR_BIT)
-		->
-			ooo_mem(i);
+	:: 1 ->
+		ooo_mem(i);
+		tmp = READ_CACHED_VAR(urcu_active_readers_one);
+		ooo_mem(i);
+		if
+		:: (tmp & RCU_GP_CTR_NEST_MASK)
+			&& ((tmp ^ READ_CACHED_VAR(urcu_gp_ctr))
+				& RCU_GP_CTR_BIT) ->
+#ifndef GEN_ERROR_WRITER_PROGRESS
+			smp_mb(i);
+#else
 			skip;
-	:: else	->
+#endif
+		:: else	->
 			break;
+		fi;
 	od;
 }
 
@@ -168,42 +241,76 @@ inline wait_for_quiescent_state(tmp, i, j)
 
 /* Model the RCU read-side critical section. */
 
-active [NR_READERS] proctype urcu_reader()
+inline urcu_one_read(i, nest_i, tmp, tmp2)
 {
-	byte i;
-	byte tmp, tmp2;
-
-	assert(get_pid() < NR_PROCS);
-
-	ooo_mem(i);
-	tmp = READ_CACHED_VAR(urcu_active_readers_one);
-	ooo_mem(i);
-	if
-	:: (!(tmp & RCU_GP_CTR_NEST_MASK))
-		->
-		tmp2 = READ_CACHED_VAR(urcu_gp_ctr);
+	nest_i = 0;
+	do
+	:: nest_i < READER_NEST_LEVEL ->
 		ooo_mem(i);
-		WRITE_CACHED_VAR(urcu_active_readers_one, tmp2);
-	:: else	->
-		WRITE_CACHED_VAR(urcu_active_readers_one, tmp + 1);
-	fi;
+		tmp = READ_CACHED_VAR(urcu_active_readers_one);
+		ooo_mem(i);
+		if
+		:: (!(tmp & RCU_GP_CTR_NEST_MASK))
+			->
+			tmp2 = READ_CACHED_VAR(urcu_gp_ctr);
+			ooo_mem(i);
+			WRITE_CACHED_VAR(urcu_active_readers_one, tmp2);
+		:: else	->
+			WRITE_CACHED_VAR(urcu_active_readers_one,
+					 tmp + 1);
+		fi;
+		ooo_mem(i);
+		smp_mb(i);
+		nest_i++;
+	:: nest_i >= READER_NEST_LEVEL -> break;
+	od;
+
 	ooo_mem(i);
-	smp_mb(i);
 	read_generation = READ_CACHED_VAR(generation_ptr);
 	ooo_mem(i);
 	data_access = 1;
 	ooo_mem(i);
 	data_access = 0;
-	ooo_mem(i);
-	smp_mb(i);
-	ooo_mem(i);
-	tmp2 = READ_CACHED_VAR(urcu_active_readers_one);
-	ooo_mem(i);
-	WRITE_CACHED_VAR(urcu_active_readers_one, tmp2 - 1);
+
+	nest_i = 0;
+	do
+	:: nest_i < READER_NEST_LEVEL ->
+		ooo_mem(i);
+		smp_mb(i);
+		ooo_mem(i);
+		tmp2 = READ_CACHED_VAR(urcu_active_readers_one);
+		ooo_mem(i);
+		WRITE_CACHED_VAR(urcu_active_readers_one, tmp2 - 1);
+		nest_i++;
+	:: nest_i >= READER_NEST_LEVEL -> break;
+	od;
 	ooo_mem(i);
 	//smp_mc(i);	/* added */
 }
 
+active [NR_READERS] proctype urcu_reader()
+{
+	byte i, nest_i;
+	byte tmp, tmp2;
+
+	assert(get_pid() < NR_PROCS);
+
+end_reader:
+	do
+	:: 1 ->
+		/*
+		 * We do not test reader's progress here, because we are mainly
+		 * interested in writer's progress. The reader never blocks
+		 * anyway. We have to test for reader/writer's progress
+		 * separately, otherwise we could think the writer is doing
+		 * progress when it's blocked by an always progressing reader.
+		 */
+#ifdef READER_PROGRESS
+progress_reader:
+#endif
+		urcu_one_read(i, nest_i, tmp, tmp2);
+	od;
+}
 
 /* Model the RCU update process. */
 
@@ -215,35 +322,70 @@ active [NR_WRITERS] proctype urcu_writer()
 
 	assert(get_pid() < NR_PROCS);
 
-	ooo_mem(i);
-	atomic {
-		old_gen = READ_CACHED_VAR(generation_ptr);
-		WRITE_CACHED_VAR(generation_ptr, old_gen + 1);
-	}
-	ooo_mem(i);
+	do
+	:: (READ_CACHED_VAR(generation_ptr) < 5) ->
+#ifdef WRITER_PROGRESS
+progress_writer1:
+#endif
+		ooo_mem(i);
+		atomic {
+			old_gen = READ_CACHED_VAR(generation_ptr);
+			WRITE_CACHED_VAR(generation_ptr, old_gen + 1);
+		}
+		ooo_mem(i);
 
-	smp_mb(i);
-	ooo_mem(i);
-	tmp = READ_CACHED_VAR(urcu_gp_ctr);
-	ooo_mem(i);
-	WRITE_CACHED_VAR(urcu_gp_ctr, tmp ^ RCU_GP_CTR_BIT);
-	ooo_mem(i);
-	//smp_mc(i);
-	wait_for_quiescent_state(tmp, i, j);
-	//smp_mc(i);
-	ooo_mem(i);
-	tmp = READ_CACHED_VAR(urcu_gp_ctr);
-	ooo_mem(i);
-	WRITE_CACHED_VAR(urcu_gp_ctr, tmp ^ RCU_GP_CTR_BIT);
-	//smp_mc(i);
-	ooo_mem(i);
-	wait_for_quiescent_state(tmp, i, j);
-	ooo_mem(i);
-	smp_mb(i);
-	/* free-up step, e.g., kfree(). */
-	ooo_mem(i);
-	atomic {
-		last_free_gen = old_gen;
-		free_done = 1;
-	}
+		do
+		:: 1 ->
+			atomic {
+				if
+				:: write_lock == 0 ->
+					write_lock = 1;
+					break;
+				:: else ->
+					skip;
+				fi;
+			}
+		od;
+		smp_mb(i);
+		ooo_mem(i);
+		tmp = READ_CACHED_VAR(urcu_gp_ctr);
+		ooo_mem(i);
+		WRITE_CACHED_VAR(urcu_gp_ctr, tmp ^ RCU_GP_CTR_BIT);
+		ooo_mem(i);
+		//smp_mc(i);
+		wait_for_quiescent_state(tmp, i, j);
+		//smp_mc(i);
+#ifndef SINGLE_FLIP
+		ooo_mem(i);
+		tmp = READ_CACHED_VAR(urcu_gp_ctr);
+		ooo_mem(i);
+		WRITE_CACHED_VAR(urcu_gp_ctr, tmp ^ RCU_GP_CTR_BIT);
+		//smp_mc(i);
+		ooo_mem(i);
+		wait_for_quiescent_state(tmp, i, j);
+#endif
+		ooo_mem(i);
+		smp_mb(i);
+		ooo_mem(i);
+		write_lock = 0;
+		/* free-up step, e.g., kfree(). */
+		atomic {
+			last_free_gen = old_gen;
+			free_done = 1;
+		}
+	:: else -> break;
+	od;
+	/*
+	 * Given the reader loops infinitely, let the writer also busy-loop
+	 * with progress here so, with weak fairness, we can test the
+	 * writer's progress.
+	 */
+end_writer:
+	do
+	:: 1 ->
+#ifdef WRITER_PROGRESS
+progress_writer2:
+#endif
+		skip;
+	od;
 }