X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=formal-model%2Furcu-controldataflow%2Furcu.spin;h=12f841ce46ed7225be2c8fe83b63d938483a00e6;hb=caeea74ce58faba3ef2bb7d2bd925d9009803086;hp=484205a1dd999a9fd6c97f214e964b9aa2a884ff;hpb=19d8de31dc92430df89d90e8ba76212b764afd44;p=urcu.git diff --git a/formal-model/urcu-controldataflow/urcu.spin b/formal-model/urcu-controldataflow/urcu.spin index 484205a..12f841c 100644 --- a/formal-model/urcu-controldataflow/urcu.spin +++ b/formal-model/urcu-controldataflow/urcu.spin @@ -136,15 +136,19 @@ typedef per_proc_byte { byte val[NR_PROCS]; }; -/* Bitfield has a maximum of 8 procs */ typedef per_proc_bit { + bit val[NR_PROCS]; +}; + +/* Bitfield has a maximum of 8 procs */ +typedef per_proc_bitfield { byte bitfield; }; #define DECLARE_CACHED_VAR(type, x) \ type mem_##x; \ per_proc_##type cached_##x; \ - per_proc_bit cache_dirty_##x; + per_proc_bitfield cache_dirty_##x; #define INIT_CACHED_VAR(x, v, j) \ mem_##x = v; \ @@ -213,7 +217,14 @@ inline smp_rmb(i, j) i++ :: i >= NR_READERS -> break od; - CACHE_READ_FROM_MEM(generation_ptr, get_pid()); + CACHE_READ_FROM_MEM(rcu_ptr, get_pid()); + i = 0; + do + :: i < SLAB_SIZE -> + CACHE_READ_FROM_MEM(rcu_data[i], get_pid()); + i++ + :: i >= SLAB_SIZE -> break + od; } } @@ -229,7 +240,14 @@ inline smp_wmb(i, j) i++ :: i >= NR_READERS -> break od; - CACHE_WRITE_TO_MEM(generation_ptr, get_pid()); + CACHE_WRITE_TO_MEM(rcu_ptr, get_pid()); + i = 0; + do + :: i < SLAB_SIZE -> + CACHE_WRITE_TO_MEM(rcu_data[i], get_pid()); + i++ + :: i >= SLAB_SIZE -> break + od; } } @@ -243,7 +261,6 @@ inline smp_mb(i, j) } } - #ifdef REMOTE_BARRIERS bit reader_barrier[NR_READERS]; @@ -269,55 +286,78 @@ inline smp_mb_recv(i, j) :: (reader_barrier[get_readerid()] == 1) -> smp_mb(i, j); reader_barrier[get_readerid()] = 0; - :: 1 -> skip; - :: 1 -> break; + :: 1 -> + /* We choose to ignore writer's non-progress caused from the + * reader ignoring the writer's mb() requests */ +#ifdef WRITER_PROGRESS +progress_writer_from_reader: +#endif + break; od; } -inline smp_mb_send(i, j) -{ - smp_mb(i, j); - i = 0; - do - :: i < NR_READERS -> - reader_barrier[i] = 1; - do - :: (reader_barrier[i] == 1) -> skip; - :: (reader_barrier[i] == 0) -> break; - od; - i++; - :: i >= NR_READERS -> - break - od; - smp_mb(i, j); +#ifdef WRITER_PROGRESS +//#define PROGRESS_LABEL(progressid) progress_writer_progid_##progressid: +#define PROGRESS_LABEL(progressid) +#else +#define PROGRESS_LABEL(progressid) +#endif + +#define smp_mb_send(i, j, progressid) \ +{ \ + smp_mb(i, j); \ + i = 0; \ + do \ + :: i < NR_READERS -> \ + reader_barrier[i] = 1; \ + /* \ + * Busy-looping waiting for reader barrier handling is of little\ + * interest, given the reader has the ability to totally ignore \ + * barrier requests. \ + */ \ +PROGRESS_LABEL(progressid) \ + do \ + :: (reader_barrier[i] == 1) -> skip; \ + :: (reader_barrier[i] == 0) -> break; \ + od; \ + i++; \ + :: i >= NR_READERS -> \ + break \ + od; \ + smp_mb(i, j); \ } #else -#define smp_mb_send smp_mb +#define smp_mb_send(i, j, progressid) smp_mb(i, j) #define smp_mb_reader smp_mb #define smp_mb_recv(i, j) #endif -/* Keep in sync manually with smp_rmb, wmp_wmb, ooo_mem and init() */ +/* Keep in sync manually with smp_rmb, smp_wmb, ooo_mem and init() */ DECLARE_CACHED_VAR(byte, urcu_gp_ctr); -/* Note ! currently only two readers */ +/* Note ! currently only one reader */ DECLARE_CACHED_VAR(byte, urcu_active_readers[NR_READERS]); -/* pointer generation */ -DECLARE_CACHED_VAR(byte, generation_ptr); - -byte last_free_gen = 0; -bit free_done = 0; -byte read_generation[NR_READERS]; -bit data_access[NR_READERS]; +/* RCU data */ +DECLARE_CACHED_VAR(bit, rcu_data[SLAB_SIZE]); + +/* RCU pointer */ +#if (SLAB_SIZE == 2) +DECLARE_CACHED_VAR(bit, rcu_ptr); +bit ptr_read_first[NR_READERS]; +bit ptr_read_second[NR_READERS]; +#else +DECLARE_CACHED_VAR(byte, rcu_ptr); +byte ptr_read_first[NR_READERS]; +byte ptr_read_second[NR_READERS]; +#endif -bit write_lock = 0; +bit data_read_first[NR_READERS]; +bit data_read_second[NR_READERS]; bit init_done = 0; -bit sighand_exec = 0; - inline wait_init_done() { do @@ -338,7 +378,14 @@ inline ooo_mem(i) i++ :: i >= NR_READERS -> break od; - RANDOM_CACHE_WRITE_TO_MEM(generation_ptr, get_pid()); + RANDOM_CACHE_WRITE_TO_MEM(rcu_ptr, get_pid()); + i = 0; + do + :: i < SLAB_SIZE -> + RANDOM_CACHE_WRITE_TO_MEM(rcu_data[i], get_pid()); + i++ + :: i >= SLAB_SIZE -> break + od; RANDOM_CACHE_READ_FROM_MEM(urcu_gp_ctr, get_pid()); i = 0; do @@ -348,7 +395,14 @@ inline ooo_mem(i) i++ :: i >= NR_READERS -> break od; - RANDOM_CACHE_READ_FROM_MEM(generation_ptr, get_pid()); + RANDOM_CACHE_READ_FROM_MEM(rcu_ptr, get_pid()); + i = 0; + do + :: i < SLAB_SIZE -> + RANDOM_CACHE_READ_FROM_MEM(rcu_data[i], get_pid()); + i++ + :: i >= SLAB_SIZE -> break + od; } } @@ -592,7 +646,7 @@ non_atomic3_end: goto non_atomic3_skip; non_atomic3: - smp_mb_recv(i, j); + smp_mb_recv(i, j); goto non_atomic3_end; non_atomic3_skip: @@ -615,17 +669,18 @@ non_atomic3_skip: READ_PROC_FIRST_MB, /* mb() orders reads */ READ_PROC_READ_GEN) -> ooo_mem(i); - read_generation[get_readerid()] = - READ_CACHED_VAR(generation_ptr); + ptr_read_first[get_readerid()] = READ_CACHED_VAR(rcu_ptr); PRODUCE_TOKENS(proc_urcu_reader, READ_PROC_READ_GEN); :: CONSUME_TOKENS(proc_urcu_reader, READ_PROC_FIRST_MB /* mb() orders reads */ | READ_PROC_READ_GEN, READ_PROC_ACCESS_GEN) -> - ooo_mem(i); - goto non_atomic; -non_atomic_end: + /* smp_read_barrier_depends */ + goto rmb1; +rmb1_end: + data_read_first[get_readerid()] = + READ_CACHED_VAR(rcu_data[ptr_read_first[get_readerid()]]); PRODUCE_TOKENS(proc_urcu_reader, READ_PROC_ACCESS_GEN); @@ -692,8 +747,7 @@ non_atomic_end: | READ_PROC_THIRD_MB, /* mb() orders reads */ READ_PROC_READ_GEN_UNROLL) -> ooo_mem(i); - read_generation[get_readerid()] = - READ_CACHED_VAR(generation_ptr); + ptr_read_second[get_readerid()] = READ_CACHED_VAR(rcu_ptr); PRODUCE_TOKENS(proc_urcu_reader, READ_PROC_READ_GEN_UNROLL); :: CONSUME_TOKENS(proc_urcu_reader, @@ -702,9 +756,11 @@ non_atomic_end: | READ_PROC_SECOND_MB /* mb() orders reads */ | READ_PROC_THIRD_MB, /* mb() orders reads */ READ_PROC_ACCESS_GEN_UNROLL) -> - ooo_mem(i); - goto non_atomic2; -non_atomic2_end: + /* smp_read_barrier_depends */ + goto rmb2; +rmb2_end: + data_read_second[get_readerid()] = + READ_CACHED_VAR(rcu_data[ptr_read_second[get_readerid()]]); PRODUCE_TOKENS(proc_urcu_reader, READ_PROC_ACCESS_GEN_UNROLL); :: CONSUME_TOKENS(proc_urcu_reader, @@ -752,14 +808,20 @@ non_atomic2_end: * to spill its execution on other loop's execution. */ goto end; -non_atomic: - data_access[get_readerid()] = 1; - data_access[get_readerid()] = 0; - goto non_atomic_end; -non_atomic2: - data_access[get_readerid()] = 1; - data_access[get_readerid()] = 0; - goto non_atomic2_end; +rmb1: +#ifndef NO_RMB + smp_rmb(i, j); +#else + ooo_mem(i); +#endif + goto rmb1_end; +rmb2: +#ifndef NO_RMB + smp_rmb(i, j); +#else + ooo_mem(i); +#endif + goto rmb2_end; end: skip; } @@ -808,23 +870,32 @@ int _proc_urcu_writer; #define WRITE_PROD_NONE (1 << 0) -#define WRITE_PROC_FIRST_MB (1 << 1) +#define WRITE_DATA (1 << 1) +#define WRITE_PROC_WMB (1 << 2) +#define WRITE_XCHG_PTR (1 << 3) + +#define WRITE_PROC_FIRST_MB (1 << 4) /* first flip */ -#define WRITE_PROC_FIRST_READ_GP (1 << 2) -#define WRITE_PROC_FIRST_WRITE_GP (1 << 3) -#define WRITE_PROC_FIRST_WAIT (1 << 4) -#define WRITE_PROC_FIRST_WAIT_LOOP (1 << 5) +#define WRITE_PROC_FIRST_READ_GP (1 << 5) +#define WRITE_PROC_FIRST_WRITE_GP (1 << 6) +#define WRITE_PROC_FIRST_WAIT (1 << 7) +#define WRITE_PROC_FIRST_WAIT_LOOP (1 << 8) /* second flip */ -#define WRITE_PROC_SECOND_READ_GP (1 << 6) -#define WRITE_PROC_SECOND_WRITE_GP (1 << 7) -#define WRITE_PROC_SECOND_WAIT (1 << 8) -#define WRITE_PROC_SECOND_WAIT_LOOP (1 << 9) +#define WRITE_PROC_SECOND_READ_GP (1 << 9) +#define WRITE_PROC_SECOND_WRITE_GP (1 << 10) +#define WRITE_PROC_SECOND_WAIT (1 << 11) +#define WRITE_PROC_SECOND_WAIT_LOOP (1 << 12) + +#define WRITE_PROC_SECOND_MB (1 << 13) -#define WRITE_PROC_SECOND_MB (1 << 10) +#define WRITE_FREE (1 << 14) #define WRITE_PROC_ALL_TOKENS (WRITE_PROD_NONE \ + | WRITE_DATA \ + | WRITE_PROC_WMB \ + | WRITE_XCHG_PTR \ | WRITE_PROC_FIRST_MB \ | WRITE_PROC_FIRST_READ_GP \ | WRITE_PROC_FIRST_WRITE_GP \ @@ -832,47 +903,42 @@ int _proc_urcu_writer; | WRITE_PROC_SECOND_READ_GP \ | WRITE_PROC_SECOND_WRITE_GP \ | WRITE_PROC_SECOND_WAIT \ - | WRITE_PROC_SECOND_MB) + | WRITE_PROC_SECOND_MB \ + | WRITE_FREE) -#define WRITE_PROC_ALL_TOKENS_CLEAR ((1 << 11) - 1) +#define WRITE_PROC_ALL_TOKENS_CLEAR ((1 << 15) - 1) +/* + * Mutexes are implied around writer execution. A single writer at a time. + */ active proctype urcu_writer() { byte i, j; byte tmp, tmp2, tmpa; - byte old_gen; + byte cur_data = 0, old_data, loop_nr = 0; + byte cur_gp_val = 0; /* + * Keep a local trace of the current parity so + * we don't add non-existing dependencies on the global + * GP update. Needed to test single flip case. + */ wait_init_done(); assert(get_pid() < NR_PROCS); do - :: (READ_CACHED_VAR(generation_ptr) < 5) -> + :: (loop_nr < 4) -> #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; + loop_nr = loop_nr + 1; PRODUCE_TOKENS(proc_urcu_writer, WRITE_PROD_NONE); +#ifdef NO_WMB + PRODUCE_TOKENS(proc_urcu_writer, WRITE_PROC_WMB); +#endif + #ifdef NO_MB PRODUCE_TOKENS(proc_urcu_writer, WRITE_PROC_FIRST_MB); PRODUCE_TOKENS(proc_urcu_writer, WRITE_PROC_SECOND_MB); @@ -882,13 +948,44 @@ progress_writer1: PRODUCE_TOKENS(proc_urcu_writer, WRITE_PROC_SECOND_READ_GP); PRODUCE_TOKENS(proc_urcu_writer, WRITE_PROC_SECOND_WRITE_GP); PRODUCE_TOKENS(proc_urcu_writer, WRITE_PROC_SECOND_WAIT); + /* For single flip, we need to know the current parity */ + cur_gp_val = cur_gp_val ^ RCU_GP_CTR_BIT; #endif - do + do :: 1 -> + atomic { + if + :: CONSUME_TOKENS(proc_urcu_writer, WRITE_PROD_NONE, + WRITE_DATA) -> + ooo_mem(i); + cur_data = (cur_data + 1) % SLAB_SIZE; + WRITE_CACHED_VAR(rcu_data[cur_data], WINE); + PRODUCE_TOKENS(proc_urcu_writer, WRITE_DATA); + + + :: CONSUME_TOKENS(proc_urcu_writer, + WRITE_DATA, + WRITE_PROC_WMB) -> + smp_wmb(i, j); + PRODUCE_TOKENS(proc_urcu_writer, WRITE_PROC_WMB); + + :: CONSUME_TOKENS(proc_urcu_writer, + WRITE_PROC_WMB, + WRITE_XCHG_PTR) -> + /* rcu_xchg_pointer() */ + atomic { + old_data = READ_CACHED_VAR(rcu_ptr); + WRITE_CACHED_VAR(rcu_ptr, cur_data); + } + PRODUCE_TOKENS(proc_urcu_writer, WRITE_XCHG_PTR); + + :: CONSUME_TOKENS(proc_urcu_writer, + WRITE_DATA | WRITE_PROC_WMB | WRITE_XCHG_PTR, WRITE_PROC_FIRST_MB) -> - smp_mb_send(i, j); + goto smp_mb_send1; +smp_mb_send1_end: PRODUCE_TOKENS(proc_urcu_writer, WRITE_PROC_FIRST_MB); /* first flip */ @@ -898,7 +995,8 @@ progress_writer1: tmpa = READ_CACHED_VAR(urcu_gp_ctr); PRODUCE_TOKENS(proc_urcu_writer, WRITE_PROC_FIRST_READ_GP); :: CONSUME_TOKENS(proc_urcu_writer, - WRITE_PROC_FIRST_MB | WRITE_PROC_FIRST_READ_GP, + WRITE_PROC_FIRST_MB | WRITE_PROC_WMB + | WRITE_PROC_FIRST_READ_GP, WRITE_PROC_FIRST_WRITE_GP) -> ooo_mem(i); WRITE_CACHED_VAR(urcu_gp_ctr, tmpa ^ RCU_GP_CTR_BIT); @@ -911,9 +1009,15 @@ progress_writer1: ooo_mem(i); /* ONLY WAITING FOR READER 0 */ tmp2 = READ_CACHED_VAR(urcu_active_readers[0]); +#ifndef SINGLE_FLIP + /* In normal execution, we are always starting by + * waiting for the even parity. + */ + cur_gp_val = RCU_GP_CTR_BIT; +#endif if :: (tmp2 & RCU_GP_CTR_NEST_MASK) - && ((tmp2 ^ RCU_GP_CTR_BIT) & RCU_GP_CTR_BIT) -> + && ((tmp2 ^ cur_gp_val) & RCU_GP_CTR_BIT) -> PRODUCE_TOKENS(proc_urcu_writer, WRITE_PROC_FIRST_WAIT_LOOP); :: else -> PRODUCE_TOKENS(proc_urcu_writer, WRITE_PROC_FIRST_WAIT); @@ -924,10 +1028,12 @@ progress_writer1: WRITE_PROC_FIRST_WRITE_GP | WRITE_PROC_FIRST_READ_GP | WRITE_PROC_FIRST_WAIT_LOOP + | WRITE_DATA | WRITE_PROC_WMB | WRITE_XCHG_PTR | WRITE_PROC_FIRST_MB, /* can be reordered before/after flips */ 0) -> #ifndef GEN_ERROR_WRITER_PROGRESS - smp_mb_send(i, j); + goto smp_mb_send2; +smp_mb_send2_end: #else ooo_mem(i); #endif @@ -942,12 +1048,12 @@ progress_writer1: | WRITE_PROC_FIRST_READ_GP | WRITE_PROC_FIRST_MB, WRITE_PROC_SECOND_READ_GP) -> - //smp_mb_send(i, j); //TEST ooo_mem(i); tmpa = READ_CACHED_VAR(urcu_gp_ctr); PRODUCE_TOKENS(proc_urcu_writer, WRITE_PROC_SECOND_READ_GP); :: CONSUME_TOKENS(proc_urcu_writer, WRITE_PROC_FIRST_MB + | WRITE_PROC_WMB | WRITE_PROC_FIRST_READ_GP | WRITE_PROC_FIRST_WRITE_GP | WRITE_PROC_SECOND_READ_GP, @@ -979,10 +1085,12 @@ progress_writer1: | WRITE_PROC_SECOND_READ_GP | WRITE_PROC_FIRST_READ_GP | WRITE_PROC_SECOND_WAIT_LOOP + | WRITE_DATA | WRITE_PROC_WMB | WRITE_XCHG_PTR | WRITE_PROC_FIRST_MB, /* can be reordered before/after flips */ 0) -> #ifndef GEN_ERROR_WRITER_PROGRESS - smp_mb_send(i, j); + goto smp_mb_send3; +smp_mb_send3_end: #else ooo_mem(i); #endif @@ -997,22 +1105,40 @@ progress_writer1: | WRITE_PROC_SECOND_READ_GP | WRITE_PROC_FIRST_WRITE_GP | WRITE_PROC_SECOND_WRITE_GP + | WRITE_DATA | WRITE_PROC_WMB | WRITE_XCHG_PTR | WRITE_PROC_FIRST_MB, WRITE_PROC_SECOND_MB) -> - smp_mb_send(i, j); + goto smp_mb_send4; +smp_mb_send4_end: PRODUCE_TOKENS(proc_urcu_writer, WRITE_PROC_SECOND_MB); + :: CONSUME_TOKENS(proc_urcu_writer, + WRITE_XCHG_PTR + | WRITE_PROC_FIRST_WAIT + | WRITE_PROC_SECOND_WAIT + | WRITE_PROC_WMB /* No dependency on + * WRITE_DATA because we + * write to a + * different location. */ + | WRITE_PROC_SECOND_MB + | WRITE_PROC_FIRST_MB, + WRITE_FREE) -> + WRITE_CACHED_VAR(rcu_data[old_data], POISON); + PRODUCE_TOKENS(proc_urcu_writer, WRITE_FREE); + :: CONSUME_TOKENS(proc_urcu_writer, WRITE_PROC_ALL_TOKENS, 0) -> CLEAR_TOKENS(proc_urcu_writer, WRITE_PROC_ALL_TOKENS_CLEAR); break; - od; - - write_lock = 0; - /* free-up step, e.g., kfree(). */ - atomic { - last_free_gen = old_gen; - free_done = 1; + fi; } + od; + /* + * Note : Promela model adds implicit serialization of the + * WRITE_FREE instruction. Normally, it would be permitted to + * spill on the next loop execution. Given the validation we do + * checks for the data entry read to be poisoned, it's ok if + * we do not check "late arriving" memory poisoning. + */ :: else -> break; od; /* @@ -1028,6 +1154,25 @@ progress_writer2: #endif skip; od; + + /* Non-atomic parts of the loop */ + goto end; +smp_mb_send1: + smp_mb_send(i, j, 1); + goto smp_mb_send1_end; +#ifndef GEN_ERROR_WRITER_PROGRESS +smp_mb_send2: + smp_mb_send(i, j, 2); + goto smp_mb_send2_end; +smp_mb_send3: + smp_mb_send(i, j, 3); + goto smp_mb_send3_end; +#endif +smp_mb_send4: + smp_mb_send(i, j, 4); + goto smp_mb_send4_end; +end: + skip; } /* no name clash please */ @@ -1040,17 +1185,28 @@ init { atomic { INIT_CACHED_VAR(urcu_gp_ctr, 1, j); - INIT_CACHED_VAR(generation_ptr, 0, j); + INIT_CACHED_VAR(rcu_ptr, 0, j); i = 0; do :: i < NR_READERS -> INIT_CACHED_VAR(urcu_active_readers[i], 0, j); - read_generation[i] = 1; - data_access[i] = 0; + ptr_read_first[i] = 1; + ptr_read_second[i] = 1; + data_read_first[i] = WINE; + data_read_second[i] = WINE; i++; :: i >= NR_READERS -> break od; + INIT_CACHED_VAR(rcu_data[0], WINE, j); + i = 1; + do + :: i < SLAB_SIZE -> + INIT_CACHED_VAR(rcu_data[i], POISON, j); + i++ + :: i >= SLAB_SIZE -> break + od; + init_done = 1; } }