/* Promela validation variables. */
#define NR_READERS 1
-#define NR_WRITERS 2
+#define NR_WRITERS 1
-#define NR_PROCS 3
+#define NR_PROCS 2
#define get_pid() (_pid)
:: 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 {
}
}
+#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 */
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;
}
/* 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. */
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
- :: write_lock == 0 ->
- write_lock = 1;
- break;
- :: else ->
- skip;
- 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);
+ :: (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);
+
+ 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);
+ 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);
- /* free-up step, e.g., kfree(). */
- ooo_mem(i);
- atomic {
- last_free_gen = old_gen;
- free_done = 1;
+ 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;
}
projects / urcu.git / blobdiff