X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu-bp.c;h=4b3cf01801764c9c132c525876e2cf40ec5895d8;hp=2973574436b7977e491df3a6634e5c99d2ea2a85;hb=fd189fa57fa46b28d59275476993f6a730cde086;hpb=4a52c06932706e3878e6dff6b8c5418641b872e5 diff --git a/urcu-bp.c b/urcu-bp.c index 2973574..4b3cf01 100644 --- a/urcu-bp.c +++ b/urcu-bp.c @@ -24,6 +24,7 @@ */ #define _GNU_SOURCE +#define _LGPL_SOURCE #include #include #include @@ -35,27 +36,77 @@ #include #include +#include "urcu/wfcqueue.h" #include "urcu/map/urcu-bp.h" - #include "urcu/static/urcu-bp.h" +#include "urcu-pointer.h" +#include "urcu/tls-compat.h" + +#include "urcu-die.h" + /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */ +#undef _LGPL_SOURCE #include "urcu-bp.h" +#define _LGPL_SOURCE #ifndef MAP_ANONYMOUS #define MAP_ANONYMOUS MAP_ANON #endif +#ifdef __linux__ +static +void *mremap_wrapper(void *old_address, size_t old_size, + size_t new_size, int flags) +{ + return mremap(old_address, old_size, new_size, flags); +} +#else + +#define MREMAP_MAYMOVE 1 +#define MREMAP_FIXED 2 + +/* + * mremap wrapper for non-Linux systems. Maps a RW, anonymous private mapping. + * This is not generic. +*/ +static +void *mremap_wrapper(void *old_address, size_t old_size, + size_t new_size, int flags) +{ + void *new_address; + + assert(flags & MREMAP_MAYMOVE); + assert(!(flags & MREMAP_FIXED)); + new_address = mmap(old_address, new_size, + PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, + -1, 0); + if (new_address == MAP_FAILED) + return MAP_FAILED; + if (old_address) { + memcpy(new_address, old_address, old_size); + munmap(old_address, old_size); + } + return new_address; +} +#endif + /* Sleep delay in us */ #define RCU_SLEEP_DELAY 1000 #define ARENA_INIT_ALLOC 16 +/* + * Active attempts to check for reader Q.S. before calling sleep(). + */ +#define RCU_QS_ACTIVE_ATTEMPTS 100 + void __attribute__((destructor)) rcu_bp_exit(void); static pthread_mutex_t rcu_gp_lock = PTHREAD_MUTEX_INITIALIZER; #ifdef DEBUG_YIELD -unsigned int yield_active; -unsigned int __thread rand_yield; +unsigned int rcu_yield_active; +DEFINE_URCU_TLS(unsigned int, rcu_rand_yield); #endif /* @@ -70,7 +121,7 @@ long rcu_gp_ctr = RCU_GP_COUNT; * Pointer to registry elements. Written to only by each individual reader. Read * by both the reader and the writers. */ -struct rcu_reader __thread *rcu_reader; +DEFINE_URCU_TLS(struct rcu_reader *, rcu_reader); static CDS_LIST_HEAD(registry); @@ -93,17 +144,12 @@ static void mutex_lock(pthread_mutex_t *mutex) #ifndef DISTRUST_SIGNALS_EXTREME ret = pthread_mutex_lock(mutex); - if (ret) { - perror("Error in pthread mutex lock"); - exit(-1); - } + if (ret) + urcu_die(ret); #else /* #ifndef DISTRUST_SIGNALS_EXTREME */ while ((ret = pthread_mutex_trylock(mutex)) != 0) { - if (ret != EBUSY && ret != EINTR) { - printf("ret = %d, errno = %d\n", ret, errno); - perror("Error in pthread mutex lock"); - exit(-1); - } + if (ret != EBUSY && ret != EINTR) + urcu_die(ret); poll(NULL,0,10); } #endif /* #else #ifndef DISTRUST_SIGNALS_EXTREME */ @@ -114,37 +160,20 @@ static void mutex_unlock(pthread_mutex_t *mutex) int ret; ret = pthread_mutex_unlock(mutex); - if (ret) { - perror("Error in pthread mutex unlock"); - exit(-1); - } + if (ret) + urcu_die(ret); } -void update_counter_and_wait(void) +static void wait_for_readers(void) { CDS_LIST_HEAD(qsreaders); int wait_loops = 0; struct rcu_reader *index, *tmp; - /* Switch parity: 0 -> 1, 1 -> 0 */ - CMM_STORE_SHARED(rcu_gp_ctr, rcu_gp_ctr ^ RCU_GP_CTR_PHASE); - - /* - * Must commit qparity update to memory before waiting for other parity - * quiescent state. Failure to do so could result in the writer waiting - * forever while new readers are always accessing data (no progress). - * Ensured by CMM_STORE_SHARED and CMM_LOAD_SHARED. - */ - - /* - * Adding a cmm_smp_mb() which is _not_ formally required, but makes the - * model easier to understand. It does not have a big performance impact - * anyway, given this is the write-side. - */ - cmm_smp_mb(); - /* - * Wait for each thread rcu_reader.ctr count to become 0. + * Wait for each thread URCU_TLS(rcu_reader).ctr to either + * indicate quiescence (not nested), or observe the current + * rcu_gp_ctr value. */ for (;;) { wait_loops++; @@ -190,9 +219,9 @@ void synchronize_rcu(void) rcu_gc_registry(); /* - * Wait for previous parity to be empty of readers. + * Wait for readers to observe original parity or be quiescent. */ - update_counter_and_wait(); /* 0 -> 1, wait readers in parity 0 */ + wait_for_readers(); /* * Adding a cmm_smp_mb() which is _not_ formally required, but makes the @@ -201,10 +230,27 @@ void synchronize_rcu(void) */ cmm_smp_mb(); + /* Switch parity: 0 -> 1, 1 -> 0 */ + CMM_STORE_SHARED(rcu_gp_ctr, rcu_gp_ctr ^ RCU_GP_CTR_PHASE); + /* - * Wait for previous parity to be empty of readers. + * Must commit qparity update to memory before waiting for other parity + * quiescent state. Failure to do so could result in the writer waiting + * forever while new readers are always accessing data (no progress). + * Ensured by CMM_STORE_SHARED and CMM_LOAD_SHARED. + */ + + /* + * Adding a cmm_smp_mb() which is _not_ formally required, but makes the + * model easier to understand. It does not have a big performance impact + * anyway, given this is the write-side. */ - update_counter_and_wait(); /* 1 -> 0, wait readers in parity 1 */ + cmm_smp_mb(); + + /* + * Wait for readers to observe new parity or be quiescent. + */ + wait_for_readers(); /* * Finish waiting for reader threads before letting the old ptr being @@ -244,8 +290,8 @@ static void resize_arena(struct registry_arena *arena, size_t len) MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); else - new_arena = mremap(arena->p, arena->len, - len, MREMAP_MAYMOVE); + new_arena = mremap_wrapper(arena->p, arena->len, + len, MREMAP_MAYMOVE); assert(new_arena != MAP_FAILED); /* @@ -266,7 +312,7 @@ static void add_thread(void) if (registry_arena.len < registry_arena.used + sizeof(struct rcu_reader)) resize_arena(®istry_arena, - max(registry_arena.len << 1, ARENA_INIT_ALLOC)); + caa_max(registry_arena.len << 1, ARENA_INIT_ALLOC)); /* * Find a free spot. */ @@ -283,7 +329,7 @@ static void add_thread(void) rcu_reader_reg->tid = pthread_self(); assert(rcu_reader_reg->ctr == 0); cds_list_add(&rcu_reader_reg->node, ®istry); - rcu_reader = rcu_reader_reg; + URCU_TLS(rcu_reader) = rcu_reader_reg; } /* Called with signals off and mutex locked */ @@ -324,7 +370,7 @@ void rcu_bp_register(void) /* * Check if a signal concurrently registered our thread since * the check in rcu_read_lock(). */ - if (rcu_reader) + if (URCU_TLS(rcu_reader)) goto end; mutex_lock(&rcu_gp_lock); @@ -335,9 +381,10 @@ end: assert(!ret); } -void rcu_bp_exit() +void rcu_bp_exit(void) { - munmap(registry_arena.p, registry_arena.len); + if (registry_arena.p) + munmap(registry_arena.p, registry_arena.len); } /* @@ -381,5 +428,31 @@ void rcu_bp_after_fork_child(void) assert(!ret); } +void *rcu_dereference_sym_bp(void *p) +{ + return _rcu_dereference(p); +} + +void *rcu_set_pointer_sym_bp(void **p, void *v) +{ + cmm_wmb(); + uatomic_set(p, v); + return v; +} + +void *rcu_xchg_pointer_sym_bp(void **p, void *v) +{ + cmm_wmb(); + return uatomic_xchg(p, v); +} + +void *rcu_cmpxchg_pointer_sym_bp(void **p, void *old, void *_new) +{ + cmm_wmb(); + return uatomic_cmpxchg(p, old, _new); +} + +DEFINE_RCU_FLAVOR(rcu_flavor); + #include "urcu-call-rcu-impl.h" #include "urcu-defer-impl.h"