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/*
*
* Copyright 2015, 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.
*
*/
#include "src/core/surface/completion_queue.h"
#include <stdio.h>
#include <string.h>
#include "src/core/iomgr/pollset.h"
#include "src/core/support/string.h"
#include "src/core/surface/call.h"
#include "src/core/surface/event_string.h"
#include "src/core/surface/surface_trace.h"
#include <grpc/support/alloc.h>
#include <grpc/support/atm.h>
#include <grpc/support/log.h>
#define MAX_PLUCKERS 4
typedef struct {
grpc_pollset_worker *worker;
void *tag;
} plucker;
/* Completion queue structure */
struct grpc_completion_queue {
/** completed events */
grpc_cq_completion completed_head;
grpc_cq_completion *completed_tail;
/** Number of pending events (+1 if we're not shutdown) */
gpr_refcount pending_events;
/** Once owning_refs drops to zero, we will destroy the cq */
gpr_refcount owning_refs;
/** the set of low level i/o things that concern this cq */
grpc_pollset pollset;
/** 0 initially, 1 once we've begun shutting down */
int shutdown;
int shutdown_called;
int is_server_cq;
int num_pluckers;
plucker pluckers[MAX_PLUCKERS];
};
grpc_completion_queue *grpc_completion_queue_create(void) {
grpc_completion_queue *cc = gpr_malloc(sizeof(grpc_completion_queue));
memset(cc, 0, sizeof(*cc));
/* Initial ref is dropped by grpc_completion_queue_shutdown */
gpr_ref_init(&cc->pending_events, 1);
/* One for destroy(), one for pollset_shutdown */
gpr_ref_init(&cc->owning_refs, 2);
grpc_pollset_init(&cc->pollset);
cc->completed_tail = &cc->completed_head;
cc->completed_head.next = (gpr_uintptr)cc->completed_tail;
return cc;
}
#ifdef GRPC_CQ_REF_COUNT_DEBUG
void grpc_cq_internal_ref(grpc_completion_queue *cc, const char *reason,
const char *file, int line) {
gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "CQ:%p ref %d -> %d %s", cc,
(int)cc->owning_refs.count, (int)cc->owning_refs.count + 1, reason);
#else
void grpc_cq_internal_ref(grpc_completion_queue *cc) {
#endif
gpr_ref(&cc->owning_refs);
}
static void on_pollset_destroy_done(void *arg) {
grpc_completion_queue *cc = arg;
GRPC_CQ_INTERNAL_UNREF(cc, "pollset_destroy");
}
#ifdef GRPC_CQ_REF_COUNT_DEBUG
void grpc_cq_internal_unref(grpc_completion_queue *cc, const char *reason,
const char *file, int line) {
gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "CQ:%p unref %d -> %d %s", cc,
(int)cc->owning_refs.count, (int)cc->owning_refs.count - 1, reason);
#else
void grpc_cq_internal_unref(grpc_completion_queue *cc) {
#endif
if (gpr_unref(&cc->owning_refs)) {
GPR_ASSERT(cc->completed_head.next == (gpr_uintptr)&cc->completed_head);
grpc_pollset_destroy(&cc->pollset);
gpr_free(cc);
}
}
void grpc_cq_begin_op(grpc_completion_queue *cc) {
gpr_ref(&cc->pending_events);
}
/* Signal the end of an operation - if this is the last waiting-to-be-queued
event, then enter shutdown mode */
/* Queue a GRPC_OP_COMPLETED operation */
void grpc_cq_end_op(grpc_completion_queue *cc, void *tag, int success,
void (*done)(void *done_arg, grpc_cq_completion *storage),
void *done_arg, grpc_cq_completion *storage) {
int shutdown;
int i;
grpc_pollset_worker *pluck_worker;
storage->tag = tag;
storage->done = done;
storage->done_arg = done_arg;
storage->next =
((gpr_uintptr)&cc->completed_head) | ((gpr_uintptr)(success != 0));
gpr_mu_lock(GRPC_POLLSET_MU(&cc->pollset));
shutdown = gpr_unref(&cc->pending_events);
if (!shutdown) {
cc->completed_tail->next =
((gpr_uintptr)storage) | (1u & (gpr_uintptr)cc->completed_tail->next);
cc->completed_tail = storage;
pluck_worker = NULL;
for (i = 0; i < cc->num_pluckers; i++) {
if (cc->pluckers[i].tag == tag) {
pluck_worker = cc->pluckers[i].worker;
break;
}
}
grpc_pollset_kick(&cc->pollset, pluck_worker);
gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
} else {
cc->completed_tail->next =
((gpr_uintptr)storage) | (1u & (gpr_uintptr)cc->completed_tail->next);
cc->completed_tail = storage;
GPR_ASSERT(!cc->shutdown);
GPR_ASSERT(cc->shutdown_called);
cc->shutdown = 1;
gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
grpc_pollset_shutdown(&cc->pollset, on_pollset_destroy_done, cc);
}
}
grpc_event grpc_completion_queue_next(grpc_completion_queue *cc,
gpr_timespec deadline) {
grpc_event ret;
grpc_pollset_worker worker;
deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
GRPC_CQ_INTERNAL_REF(cc, "next");
gpr_mu_lock(GRPC_POLLSET_MU(&cc->pollset));
for (;;) {
if (cc->completed_tail != &cc->completed_head) {
grpc_cq_completion *c = (grpc_cq_completion *)cc->completed_head.next;
cc->completed_head.next = c->next & ~(gpr_uintptr)1;
if (c == cc->completed_tail) {
cc->completed_tail = &cc->completed_head;
}
gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
ret.type = GRPC_OP_COMPLETE;
ret.success = c->next & 1u;
ret.tag = c->tag;
c->done(c->done_arg, c);
break;
}
if (cc->shutdown) {
gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
memset(&ret, 0, sizeof(ret));
ret.type = GRPC_QUEUE_SHUTDOWN;
break;
}
if (!grpc_pollset_work(&cc->pollset, &worker, deadline)) {
gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
memset(&ret, 0, sizeof(ret));
ret.type = GRPC_QUEUE_TIMEOUT;
break;
}
}
GRPC_SURFACE_TRACE_RETURNED_EVENT(cc, &ret);
GRPC_CQ_INTERNAL_UNREF(cc, "next");
return ret;
}
static void add_plucker(grpc_completion_queue *cc, void *tag,
grpc_pollset_worker *worker) {
GPR_ASSERT(cc->num_pluckers != MAX_PLUCKERS);
cc->pluckers[cc->num_pluckers].tag = tag;
cc->pluckers[cc->num_pluckers].worker = worker;
cc->num_pluckers++;
}
static void del_plucker(grpc_completion_queue *cc, void *tag,
grpc_pollset_worker *worker) {
int i;
for (i = 0; i < cc->num_pluckers; i++) {
if (cc->pluckers[i].tag == tag && cc->pluckers[i].worker == worker) {
cc->num_pluckers--;
GPR_SWAP(plucker, cc->pluckers[i], cc->pluckers[cc->num_pluckers]);
return;
}
}
gpr_log(GPR_ERROR, "should never reach here");
abort();
}
grpc_event grpc_completion_queue_pluck(grpc_completion_queue *cc, void *tag,
gpr_timespec deadline) {
grpc_event ret;
grpc_cq_completion *c;
grpc_cq_completion *prev;
grpc_pollset_worker worker;
deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
GRPC_CQ_INTERNAL_REF(cc, "pluck");
gpr_mu_lock(GRPC_POLLSET_MU(&cc->pollset));
for (;;) {
prev = &cc->completed_head;
while ((c = (grpc_cq_completion *)(prev->next & ~(gpr_uintptr)1)) !=
&cc->completed_head) {
if (c->tag == tag) {
prev->next =
(prev->next & (gpr_uintptr)1) | (c->next & ~(gpr_uintptr)1);
if (c == cc->completed_tail) {
cc->completed_tail = prev;
}
gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
ret.type = GRPC_OP_COMPLETE;
ret.success = c->next & 1u;
ret.tag = c->tag;
c->done(c->done_arg, c);
goto done;
}
prev = c;
}
if (cc->shutdown) {
gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
memset(&ret, 0, sizeof(ret));
ret.type = GRPC_QUEUE_SHUTDOWN;
break;
}
add_plucker(cc, tag, &worker);
if (!grpc_pollset_work(&cc->pollset, &worker, deadline)) {
del_plucker(cc, tag, &worker);
gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
memset(&ret, 0, sizeof(ret));
ret.type = GRPC_QUEUE_TIMEOUT;
break;
}
del_plucker(cc, tag, &worker);
}
done:
GRPC_SURFACE_TRACE_RETURNED_EVENT(cc, &ret);
GRPC_CQ_INTERNAL_UNREF(cc, "pluck");
return ret;
}
/* Shutdown simply drops a ref that we reserved at creation time; if we drop
to zero here, then enter shutdown mode and wake up any waiters */
void grpc_completion_queue_shutdown(grpc_completion_queue *cc) {
gpr_mu_lock(GRPC_POLLSET_MU(&cc->pollset));
if (cc->shutdown_called) {
gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
return;
}
cc->shutdown_called = 1;
gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
if (gpr_unref(&cc->pending_events)) {
gpr_mu_lock(GRPC_POLLSET_MU(&cc->pollset));
GPR_ASSERT(!cc->shutdown);
cc->shutdown = 1;
gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
grpc_pollset_shutdown(&cc->pollset, on_pollset_destroy_done, cc);
}
}
void grpc_completion_queue_destroy(grpc_completion_queue *cc) {
grpc_completion_queue_shutdown(cc);
GRPC_CQ_INTERNAL_UNREF(cc, "destroy");
}
grpc_pollset *grpc_cq_pollset(grpc_completion_queue *cc) {
return &cc->pollset;
}
void grpc_cq_mark_server_cq(grpc_completion_queue *cc) { cc->is_server_cq = 1; }
int grpc_cq_is_server_cq(grpc_completion_queue *cc) { return cc->is_server_cq; }
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