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Diffstat (limited to 'src/core/lib/iomgr/ev_poll_posix.c')
-rw-r--r--src/core/lib/iomgr/ev_poll_posix.c241
1 files changed, 240 insertions, 1 deletions
diff --git a/src/core/lib/iomgr/ev_poll_posix.c b/src/core/lib/iomgr/ev_poll_posix.c
index 16a5e3083e..f137e4dacc 100644
--- a/src/core/lib/iomgr/ev_poll_posix.c
+++ b/src/core/lib/iomgr/ev_poll_posix.c
@@ -47,10 +47,12 @@
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/string_util.h>
+#include <grpc/support/thd.h>
#include <grpc/support/tls.h>
#include <grpc/support/useful.h>
#include "src/core/lib/iomgr/iomgr_internal.h"
+#include "src/core/lib/iomgr/wakeup_fd_cv.h"
#include "src/core/lib/iomgr/wakeup_fd_posix.h"
#include "src/core/lib/profiling/timers.h"
#include "src/core/lib/support/block_annotate.h"
@@ -246,6 +248,28 @@ struct grpc_pollset_set {
};
/*******************************************************************************
+ * condition variable polling definitions
+ */
+
+#define CV_POLL_PERIOD_MS 1000
+#define CV_DEFAULT_TABLE_SIZE 16
+
+typedef enum poll_status_t { INPROGRESS, COMPLETED, CANCELLED } poll_status_t;
+
+typedef struct poll_args {
+ gpr_refcount refcount;
+ gpr_cv *cv;
+ struct pollfd *fds;
+ nfds_t nfds;
+ int timeout;
+ int retval;
+ int err;
+ gpr_atm status;
+} poll_args;
+
+cv_fd_table g_cvfds;
+
+/*******************************************************************************
* fd_posix.c
*/
@@ -1236,10 +1260,211 @@ static void pollset_set_del_fd(grpc_exec_ctx *exec_ctx,
}
/*******************************************************************************
+ * Condition Variable polling extensions
+ */
+
+static void decref_poll_args(poll_args *args) {
+ if (gpr_unref(&args->refcount)) {
+ gpr_free(args->fds);
+ gpr_cv_destroy(args->cv);
+ gpr_free(args->cv);
+ gpr_free(args);
+ }
+}
+
+// Poll in a background thread
+static void run_poll(void *arg) {
+ int timeout, retval;
+ poll_args *pargs = (poll_args *)arg;
+ while (gpr_atm_no_barrier_load(&pargs->status) == INPROGRESS) {
+ if (pargs->timeout < 0) {
+ timeout = CV_POLL_PERIOD_MS;
+ } else {
+ timeout = GPR_MIN(CV_POLL_PERIOD_MS, pargs->timeout);
+ pargs->timeout -= timeout;
+ }
+ retval = g_cvfds.poll(pargs->fds, pargs->nfds, timeout);
+ if (retval != 0 || pargs->timeout == 0) {
+ pargs->retval = retval;
+ pargs->err = errno;
+ break;
+ }
+ }
+ gpr_mu_lock(&g_cvfds.mu);
+ if (gpr_atm_no_barrier_load(&pargs->status) == INPROGRESS) {
+ // Signal main thread that the poll completed
+ gpr_atm_no_barrier_store(&pargs->status, COMPLETED);
+ gpr_cv_signal(pargs->cv);
+ }
+ decref_poll_args(pargs);
+ g_cvfds.pollcount--;
+ if (g_cvfds.shutdown && g_cvfds.pollcount == 0) {
+ gpr_cv_signal(&g_cvfds.shutdown_complete);
+ }
+ gpr_mu_unlock(&g_cvfds.mu);
+}
+
+// This function overrides poll() to handle condition variable wakeup fds
+static int cvfd_poll(struct pollfd *fds, nfds_t nfds, int timeout) {
+ unsigned int i;
+ int res, idx;
+ gpr_cv *pollcv;
+ cv_node *cvn, *prev;
+ nfds_t nsockfds = 0;
+ gpr_thd_id t_id;
+ gpr_thd_options opt;
+ poll_args *pargs = NULL;
+ gpr_mu_lock(&g_cvfds.mu);
+ pollcv = gpr_malloc(sizeof(gpr_cv));
+ gpr_cv_init(pollcv);
+ for (i = 0; i < nfds; i++) {
+ fds[i].revents = 0;
+ if (fds[i].fd < 0 && (fds[i].events & POLLIN)) {
+ idx = FD_TO_IDX(fds[i].fd);
+ cvn = gpr_malloc(sizeof(cv_node));
+ cvn->cv = pollcv;
+ cvn->next = g_cvfds.cvfds[idx].cvs;
+ g_cvfds.cvfds[idx].cvs = cvn;
+ // We should return immediately if there are pending events,
+ // but we still need to call poll() to check for socket events
+ if (g_cvfds.cvfds[idx].is_set) {
+ timeout = 0;
+ }
+ } else if (fds[i].fd >= 0) {
+ nsockfds++;
+ }
+ }
+
+ if (nsockfds > 0) {
+ pargs = gpr_malloc(sizeof(struct poll_args));
+ // Both the main thread and calling thread get a reference
+ gpr_ref_init(&pargs->refcount, 2);
+ pargs->cv = pollcv;
+ pargs->fds = gpr_malloc(sizeof(struct pollfd) * nsockfds);
+ pargs->nfds = nsockfds;
+ pargs->timeout = timeout;
+ pargs->retval = 0;
+ pargs->err = 0;
+ gpr_atm_no_barrier_store(&pargs->status, INPROGRESS);
+ idx = 0;
+ for (i = 0; i < nfds; i++) {
+ if (fds[i].fd >= 0) {
+ pargs->fds[idx].fd = fds[i].fd;
+ pargs->fds[idx].events = fds[i].events;
+ pargs->fds[idx].revents = 0;
+ idx++;
+ }
+ }
+ g_cvfds.pollcount++;
+ opt = gpr_thd_options_default();
+ gpr_thd_options_set_detached(&opt);
+ gpr_thd_new(&t_id, &run_poll, pargs, &opt);
+ // We want the poll() thread to trigger the deadline, so wait forever here
+ gpr_cv_wait(pollcv, &g_cvfds.mu, gpr_inf_future(GPR_CLOCK_MONOTONIC));
+ if (gpr_atm_no_barrier_load(&pargs->status) == COMPLETED) {
+ res = pargs->retval;
+ errno = pargs->err;
+ } else {
+ res = 0;
+ errno = 0;
+ gpr_atm_no_barrier_store(&pargs->status, CANCELLED);
+ }
+ } else {
+ gpr_timespec deadline = gpr_now(GPR_CLOCK_REALTIME);
+ deadline =
+ gpr_time_add(deadline, gpr_time_from_millis(timeout, GPR_TIMESPAN));
+ gpr_cv_wait(pollcv, &g_cvfds.mu, deadline);
+ res = 0;
+ }
+
+ idx = 0;
+ for (i = 0; i < nfds; i++) {
+ if (fds[i].fd < 0 && (fds[i].events & POLLIN)) {
+ cvn = g_cvfds.cvfds[FD_TO_IDX(fds[i].fd)].cvs;
+ prev = NULL;
+ while (cvn->cv != pollcv) {
+ prev = cvn;
+ cvn = cvn->next;
+ GPR_ASSERT(cvn);
+ }
+ if (!prev) {
+ g_cvfds.cvfds[FD_TO_IDX(fds[i].fd)].cvs = cvn->next;
+ } else {
+ prev->next = cvn->next;
+ }
+ gpr_free(cvn);
+
+ if (g_cvfds.cvfds[FD_TO_IDX(fds[i].fd)].is_set) {
+ fds[i].revents = POLLIN;
+ if (res >= 0) res++;
+ }
+ } else if (fds[i].fd >= 0 &&
+ gpr_atm_no_barrier_load(&pargs->status) == COMPLETED) {
+ fds[i].revents = pargs->fds[idx].revents;
+ idx++;
+ }
+ }
+
+ if (pargs) {
+ decref_poll_args(pargs);
+ } else {
+ gpr_cv_destroy(pollcv);
+ gpr_free(pollcv);
+ }
+ gpr_mu_unlock(&g_cvfds.mu);
+
+ return res;
+}
+
+static void global_cv_fd_table_init() {
+ gpr_mu_init(&g_cvfds.mu);
+ gpr_mu_lock(&g_cvfds.mu);
+ gpr_cv_init(&g_cvfds.shutdown_complete);
+ g_cvfds.shutdown = 0;
+ g_cvfds.pollcount = 0;
+ g_cvfds.size = CV_DEFAULT_TABLE_SIZE;
+ g_cvfds.cvfds = gpr_malloc(sizeof(fd_node) * CV_DEFAULT_TABLE_SIZE);
+ g_cvfds.free_fds = NULL;
+ for (int i = 0; i < CV_DEFAULT_TABLE_SIZE; i++) {
+ g_cvfds.cvfds[i].is_set = 0;
+ g_cvfds.cvfds[i].cvs = NULL;
+ g_cvfds.cvfds[i].next_free = g_cvfds.free_fds;
+ g_cvfds.free_fds = &g_cvfds.cvfds[i];
+ }
+ // Override the poll function with one that supports cvfds
+ g_cvfds.poll = grpc_poll_function;
+ grpc_poll_function = &cvfd_poll;
+ gpr_mu_unlock(&g_cvfds.mu);
+}
+
+static void global_cv_fd_table_shutdown() {
+ gpr_mu_lock(&g_cvfds.mu);
+ g_cvfds.shutdown = 1;
+ // Attempt to wait for all abandoned poll() threads to terminate
+ // Not doing so will result in reported memory leaks
+ if (g_cvfds.pollcount > 0) {
+ int res = gpr_cv_wait(&g_cvfds.shutdown_complete, &g_cvfds.mu,
+ gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
+ gpr_time_from_seconds(3, GPR_TIMESPAN)));
+ GPR_ASSERT(res == 0);
+ }
+ gpr_cv_destroy(&g_cvfds.shutdown_complete);
+ grpc_poll_function = g_cvfds.poll;
+ gpr_free(g_cvfds.cvfds);
+ gpr_mu_unlock(&g_cvfds.mu);
+ gpr_mu_destroy(&g_cvfds.mu);
+}
+
+/*******************************************************************************
* event engine binding
*/
-static void shutdown_engine(void) { pollset_global_shutdown(); }
+static void shutdown_engine(void) {
+ pollset_global_shutdown();
+ if (grpc_cv_wakeup_fds_enabled()) {
+ global_cv_fd_table_shutdown();
+ }
+}
static const grpc_event_engine_vtable vtable = {
.pollset_size = sizeof(grpc_pollset),
@@ -1277,7 +1502,21 @@ static const grpc_event_engine_vtable vtable = {
};
const grpc_event_engine_vtable *grpc_init_poll_posix(void) {
+ if (!grpc_has_wakeup_fd()) {
+ return NULL;
+ }
+ if (!GRPC_LOG_IF_ERROR("pollset_global_init", pollset_global_init())) {
+ return NULL;
+ }
+ return &vtable;
+}
+
+const grpc_event_engine_vtable *grpc_init_poll_cv_posix(void) {
+ global_cv_fd_table_init();
+ grpc_enable_cv_wakeup_fds(1);
if (!GRPC_LOG_IF_ERROR("pollset_global_init", pollset_global_init())) {
+ global_cv_fd_table_shutdown();
+ grpc_enable_cv_wakeup_fds(0);
return NULL;
}
return &vtable;
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-03 10:45:37 +0000