X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu-bp.c;h=3b2062d6590034ad33619ab1372b137237a9fd1e;hp=b457d2bc8f6e49fee5b55565107219aaf02d6ee9;hb=541d828d3101283ccdb1e25fa5a885e1d1743c1a;hpb=06f22bdbb0c4c4d5db42a2e2dc35818aa61415be diff --git a/urcu-bp.c b/urcu-bp.c index b457d2b..3b2062d 100644 --- a/urcu-bp.c +++ b/urcu-bp.c @@ -24,6 +24,7 @@ */ #define _GNU_SOURCE +#define _LGPL_SOURCE #include #include #include @@ -35,14 +36,58 @@ #include #include -#include "urcu-bp-static.h" +#include "urcu/wfqueue.h" +#include "urcu/map/urcu-bp.h" +#include "urcu/static/urcu-bp.h" +#include "urcu-pointer.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 + +#ifndef __linux__ + +#define MREMAP_MAYMOVE 1 +#define MREMAP_FIXED 2 + +/* + * mremap wrapper for non-Linux systems. Maps a RW, anonymous private mapping. + * This is not generic. +*/ +void *mremap(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; @@ -66,7 +111,7 @@ long rcu_gp_ctr = RCU_GP_COUNT; */ struct rcu_reader __thread *rcu_reader; -static LIST_HEAD(registry); +static CDS_LIST_HEAD(registry); struct registry_arena { void *p; @@ -76,6 +121,9 @@ struct registry_arena { static struct registry_arena registry_arena; +/* Saved fork signal mask, protected by rcu_gp_lock */ +static sigset_t saved_fork_signal_mask; + static void rcu_gc_registry(void); static void mutex_lock(pthread_mutex_t *mutex) @@ -95,11 +143,6 @@ static void mutex_lock(pthread_mutex_t *mutex) perror("Error in pthread mutex lock"); exit(-1); } - if (rcu_reader.need_mb) { - cmm_smp_mb(); - rcu_reader.need_mb = 0; - cmm_smp_mb(); - } poll(NULL,0,10); } #endif /* #else #ifndef DISTRUST_SIGNALS_EXTREME */ @@ -118,18 +161,18 @@ static void mutex_unlock(pthread_mutex_t *mutex) void update_counter_and_wait(void) { - LIST_HEAD(qsreaders); + CDS_LIST_HEAD(qsreaders); int wait_loops = 0; struct rcu_reader *index, *tmp; /* Switch parity: 0 -> 1, 1 -> 0 */ - CAA_STORE_SHARED(rcu_gp_ctr, rcu_gp_ctr ^ RCU_GP_CTR_PHASE); + 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 CAA_STORE_SHARED and CAA_LOAD_SHARED. + * Ensured by CMM_STORE_SHARED and CMM_LOAD_SHARED. */ /* @@ -144,12 +187,12 @@ void update_counter_and_wait(void) */ for (;;) { wait_loops++; - list_for_each_entry_safe(index, tmp, ®istry, node) { + cds_list_for_each_entry_safe(index, tmp, ®istry, node) { if (!rcu_old_gp_ongoing(&index->ctr)) - list_move(&index->node, &qsreaders); + cds_list_move(&index->node, &qsreaders); } - if (list_empty(®istry)) { + if (cds_list_empty(®istry)) { break; } else { if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) @@ -159,7 +202,7 @@ void update_counter_and_wait(void) } } /* put back the reader list in the registry */ - list_splice(&qsreaders, ®istry); + cds_list_splice(&qsreaders, ®istry); } void synchronize_rcu(void) @@ -174,7 +217,7 @@ void synchronize_rcu(void) mutex_lock(&rcu_gp_lock); - if (list_empty(®istry)) + if (cds_list_empty(®istry)) goto out; /* All threads should read qparity before accessing data structure @@ -250,7 +293,6 @@ static void resize_arena(struct registry_arena *arena, size_t len) if (new_arena == arena->p) return; - memcpy(new_arena, arena->p, arena->len); bzero(new_arena + arena->len, len - arena->len); arena->p = new_arena; } @@ -263,7 +305,7 @@ 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. */ @@ -279,7 +321,7 @@ static void add_thread(void) /* Add to registry */ rcu_reader_reg->tid = pthread_self(); assert(rcu_reader_reg->ctr == 0); - list_add(&rcu_reader_reg->node, ®istry); + cds_list_add(&rcu_reader_reg->node, ®istry); rcu_reader = rcu_reader_reg; } @@ -299,7 +341,7 @@ static void rcu_gc_registry(void) ret = pthread_kill(tid, 0); assert(ret != EINVAL); if (ret == ESRCH) { - list_del(&rcu_reader_reg->node); + cds_list_del(&rcu_reader_reg->node); rcu_reader_reg->ctr = 0; rcu_reader_reg->alloc = 0; registry_arena.used -= sizeof(struct rcu_reader); @@ -332,7 +374,54 @@ end: assert(!ret); } -void rcu_bp_exit() +void rcu_bp_exit(void) +{ + if (registry_arena.p) + munmap(registry_arena.p, registry_arena.len); +} + +/* + * Holding the rcu_gp_lock across fork will make sure we fork() don't race with + * a concurrent thread executing with this same lock held. This ensures that the + * registry is in a coherent state in the child. + */ +void rcu_bp_before_fork(void) +{ + sigset_t newmask, oldmask; + int ret; + + ret = sigemptyset(&newmask); + assert(!ret); + ret = pthread_sigmask(SIG_SETMASK, &newmask, &oldmask); + assert(!ret); + mutex_lock(&rcu_gp_lock); + saved_fork_signal_mask = oldmask; +} + +void rcu_bp_after_fork_parent(void) +{ + sigset_t oldmask; + int ret; + + oldmask = saved_fork_signal_mask; + mutex_unlock(&rcu_gp_lock); + ret = pthread_sigmask(SIG_SETMASK, &oldmask, NULL); + assert(!ret); +} + +void rcu_bp_after_fork_child(void) { - munmap(registry_arena.p, registry_arena.len); + sigset_t oldmask; + int ret; + + rcu_gc_registry(); + oldmask = saved_fork_signal_mask; + mutex_unlock(&rcu_gp_lock); + ret = pthread_sigmask(SIG_SETMASK, &oldmask, NULL); + assert(!ret); } + +DEFINE_RCU_FLAVOR() + +#include "urcu-call-rcu-impl.h" +#include "urcu-defer-impl.h"