From f23078cbd302d32649537eedda1769c5685228d8 Mon Sep 17 00:00:00 2001 From: Craig Tiller Date: Fri, 25 Mar 2016 17:07:29 -0700 Subject: Stage #1 of core breakup: move everything under lib --- src/core/lib/support/sync.c | 127 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 127 insertions(+) create mode 100644 src/core/lib/support/sync.c (limited to 'src/core/lib/support/sync.c') diff --git a/src/core/lib/support/sync.c b/src/core/lib/support/sync.c new file mode 100644 index 0000000000..800cf20287 --- /dev/null +++ b/src/core/lib/support/sync.c @@ -0,0 +1,127 @@ +/* + * + * Copyright 2015-2016, Google Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following disclaimer + * in the documentation and/or other materials provided with the + * distribution. + * * Neither the name of Google Inc. nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + */ + +/* Generic implementation of synchronization primitives. */ + +#include +#include +#include + +/* Number of mutexes to allocate for events, to avoid lock contention. + Should be a prime. */ +enum { event_sync_partitions = 31 }; + +/* Events are partitioned by address to avoid lock contention. */ +static struct sync_array_s { + gpr_mu mu; + gpr_cv cv; +} sync_array[event_sync_partitions]; + +/* This routine is executed once on first use, via event_once */ +static gpr_once event_once = GPR_ONCE_INIT; +static void event_initialize(void) { + int i; + for (i = 0; i != event_sync_partitions; i++) { + gpr_mu_init(&sync_array[i].mu); + gpr_cv_init(&sync_array[i].cv); + } +} + +/* Hash ev into an element of sync_array[]. */ +static struct sync_array_s *hash(gpr_event *ev) { + return &sync_array[((uintptr_t)ev) % event_sync_partitions]; +} + +void gpr_event_init(gpr_event *ev) { + gpr_once_init(&event_once, &event_initialize); + ev->state = 0; +} + +void gpr_event_set(gpr_event *ev, void *value) { + struct sync_array_s *s = hash(ev); + gpr_mu_lock(&s->mu); + GPR_ASSERT(gpr_atm_acq_load(&ev->state) == 0); + gpr_atm_rel_store(&ev->state, (gpr_atm)value); + gpr_cv_broadcast(&s->cv); + gpr_mu_unlock(&s->mu); + GPR_ASSERT(value != NULL); +} + +void *gpr_event_get(gpr_event *ev) { + return (void *)gpr_atm_acq_load(&ev->state); +} + +void *gpr_event_wait(gpr_event *ev, gpr_timespec abs_deadline) { + void *result = (void *)gpr_atm_acq_load(&ev->state); + if (result == NULL) { + struct sync_array_s *s = hash(ev); + gpr_mu_lock(&s->mu); + do { + result = (void *)gpr_atm_acq_load(&ev->state); + } while (result == NULL && !gpr_cv_wait(&s->cv, &s->mu, abs_deadline)); + gpr_mu_unlock(&s->mu); + } + return result; +} + +void gpr_ref_init(gpr_refcount *r, int n) { gpr_atm_rel_store(&r->count, n); } + +void gpr_ref(gpr_refcount *r) { gpr_atm_no_barrier_fetch_add(&r->count, 1); } + +void gpr_ref_non_zero(gpr_refcount *r) { + gpr_atm prior = gpr_atm_no_barrier_fetch_add(&r->count, 1); + GPR_ASSERT(prior > 0); +} + +void gpr_refn(gpr_refcount *r, int n) { + gpr_atm_no_barrier_fetch_add(&r->count, n); +} + +int gpr_unref(gpr_refcount *r) { + gpr_atm prior = gpr_atm_full_fetch_add(&r->count, -1); + GPR_ASSERT(prior > 0); + return prior == 1; +} + +void gpr_stats_init(gpr_stats_counter *c, intptr_t n) { + gpr_atm_rel_store(&c->value, n); +} + +void gpr_stats_inc(gpr_stats_counter *c, intptr_t inc) { + gpr_atm_no_barrier_fetch_add(&c->value, inc); +} + +intptr_t gpr_stats_read(const gpr_stats_counter *c) { + /* don't need acquire-load, but we have no no-barrier load yet */ + return gpr_atm_acq_load(&c->value); +} -- cgit v1.2.3