--- /dev/null
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/iomgr/port.h"
+
+#include <grpc/support/log.h>
+
+/* This polling engine is only relevant on linux kernels supporting epoll() */
+#ifdef GRPC_LINUX_EPOLL_CREATE1
+
+#include "src/core/lib/iomgr/ev_epollex_linux.h"
+
+#include <assert.h>
+#include <errno.h>
+#include <limits.h>
+#include <poll.h>
+#include <pthread.h>
+#include <string.h>
+#include <sys/epoll.h>
+#include <sys/socket.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/lib/debug/stats.h"
+#include "src/core/lib/gpr/spinlock.h"
+#include "src/core/lib/gpr/tls.h"
+#include "src/core/lib/gpr/useful.h"
+#include "src/core/lib/gprpp/inlined_vector.h"
+#include "src/core/lib/gprpp/manual_constructor.h"
+#include "src/core/lib/gprpp/ref_counted.h"
+#include "src/core/lib/gprpp/sync.h"
+#include "src/core/lib/iomgr/block_annotate.h"
+#include "src/core/lib/iomgr/iomgr_internal.h"
+#include "src/core/lib/iomgr/is_epollexclusive_available.h"
+#include "src/core/lib/iomgr/lockfree_event.h"
+#include "src/core/lib/iomgr/sys_epoll_wrapper.h"
+#include "src/core/lib/iomgr/timer.h"
+#include "src/core/lib/iomgr/wakeup_fd_posix.h"
+#include "src/core/lib/profiling/timers.h"
+
+// debug aid: create workers on the heap (allows asan to spot
+// use-after-destruction)
+//#define GRPC_EPOLLEX_CREATE_WORKERS_ON_HEAP 1
+
+#define MAX_EPOLL_EVENTS 100
+// TODO(juanlishen): We use a greater-than-one value here as a workaround fix to
+// a keepalive ping timeout issue. We may want to revert https://github
+// .com/grpc/grpc/pull/14943 once we figure out the root cause.
+#define MAX_EPOLL_EVENTS_HANDLED_EACH_POLL_CALL 16
+#define MAX_FDS_IN_CACHE 32
+
+grpc_core::DebugOnlyTraceFlag grpc_trace_pollable_refcount(false,
+ "pollable_refcount");
+
+/*******************************************************************************
+ * pollable Declarations
+ */
+
+typedef enum { PO_MULTI, PO_FD, PO_EMPTY } pollable_type;
+
+typedef struct pollable pollable;
+
+/// A pollable is something that can be polled: it has an epoll set to poll on,
+/// and a wakeup fd for kicks
+/// There are three broad types:
+/// - PO_EMPTY - the empty pollable, used before file descriptors are added to
+/// a pollset
+/// - PO_FD - a pollable containing only one FD - used to optimize single-fd
+/// pollsets (which are common with synchronous api usage)
+/// - PO_MULTI - a pollable containing many fds
+struct pollable {
+ pollable_type type; // immutable
+ grpc_core::RefCount refs;
+
+ int epfd;
+ grpc_wakeup_fd wakeup;
+
+ // The following are relevant only for type PO_FD
+ grpc_fd* owner_fd; // Set to the owner_fd if the type is PO_FD
+ gpr_mu owner_orphan_mu; // Synchronizes access to owner_orphaned field
+ bool owner_orphaned; // Is the owner fd orphaned
+
+ grpc_pollset_set* pollset_set;
+ pollable* next;
+ pollable* prev;
+
+ gpr_mu mu;
+ grpc_pollset_worker* root_worker;
+
+ int event_cursor;
+ int event_count;
+ struct epoll_event events[MAX_EPOLL_EVENTS];
+};
+
+static const char* pollable_type_string(pollable_type t) {
+ switch (t) {
+ case PO_MULTI:
+ return "pollset";
+ case PO_FD:
+ return "fd";
+ case PO_EMPTY:
+ return "empty";
+ }
+ return "<invalid>";
+}
+
+static char* pollable_desc(pollable* p) {
+ char* out;
+ gpr_asprintf(&out, "type=%s epfd=%d wakeup=%d", pollable_type_string(p->type),
+ p->epfd, p->wakeup.read_fd);
+ return out;
+}
+
+/// Shared empty pollable - used by pollset to poll on until the first fd is
+/// added
+static pollable* g_empty_pollable;
+
+static grpc_error* pollable_create(pollable_type type, pollable** p);
+static pollable* pollable_ref(pollable* p,
+ const grpc_core::DebugLocation& dbg_loc,
+ const char* reason) {
+ p->refs.Ref(dbg_loc, reason);
+ return p;
+}
+static void pollable_unref(pollable* p, const grpc_core::DebugLocation& dbg_loc,
+ const char* reason) {
+ if (p == nullptr) return;
+ if (GPR_UNLIKELY(p != nullptr && p->refs.Unref(dbg_loc, reason))) {
+ GRPC_FD_TRACE("pollable_unref: Closing epfd: %d", p->epfd);
+ close(p->epfd);
+ grpc_wakeup_fd_destroy(&p->wakeup);
+ gpr_mu_destroy(&p->owner_orphan_mu);
+ gpr_mu_destroy(&p->mu);
+ gpr_free(p);
+ }
+}
+#define POLLABLE_REF(p, r) pollable_ref((p), DEBUG_LOCATION, (r))
+#define POLLABLE_UNREF(p, r) pollable_unref((p), DEBUG_LOCATION, (r))
+
+/*******************************************************************************
+ * Fd Declarations
+ */
+
+struct grpc_fd {
+ grpc_fd(int fd, const char* name, bool track_err)
+ : fd(fd), track_err(track_err) {
+ gpr_mu_init(&orphan_mu);
+ gpr_mu_init(&pollable_mu);
+ read_closure.InitEvent();
+ write_closure.InitEvent();
+ error_closure.InitEvent();
+
+ char* fd_name;
+ gpr_asprintf(&fd_name, "%s fd=%d", name, fd);
+ grpc_iomgr_register_object(&iomgr_object, fd_name);
+#ifndef NDEBUG
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_trace_fd_refcount)) {
+ gpr_log(GPR_DEBUG, "FD %d %p create %s", fd, this, fd_name);
+ }
+#endif
+ gpr_free(fd_name);
+ }
+
+ // This is really the dtor, but the poller threads waking up from
+ // epoll_wait() may access the (read|write|error)_closure after destruction.
+ // Since the object will be added to the free pool, this behavior is
+ // not going to cause issues, except spurious events if the FD is reused
+ // while the race happens.
+ void destroy() {
+ grpc_iomgr_unregister_object(&iomgr_object);
+
+ POLLABLE_UNREF(pollable_obj, "fd_pollable");
+ pollset_fds.clear();
+ gpr_mu_destroy(&pollable_mu);
+ gpr_mu_destroy(&orphan_mu);
+
+ read_closure.DestroyEvent();
+ write_closure.DestroyEvent();
+ error_closure.DestroyEvent();
+
+ invalidate();
+ }
+
+#ifndef NDEBUG
+ /* Since an fd is never really destroyed (i.e gpr_free() is not called), it is
+ * hard-to-debug cases where fd fields are accessed even after calling
+ * fd_destroy(). The following invalidates fd fields to make catching such
+ * errors easier */
+ void invalidate() {
+ fd = -1;
+ gpr_atm_no_barrier_store(&refst, -1);
+ memset(&orphan_mu, -1, sizeof(orphan_mu));
+ memset(&pollable_mu, -1, sizeof(pollable_mu));
+ pollable_obj = nullptr;
+ on_done_closure = nullptr;
+ memset(&iomgr_object, -1, sizeof(iomgr_object));
+ track_err = false;
+ }
+#else
+ void invalidate() {}
+#endif
+
+ int fd;
+
+ // refst format:
+ // bit 0 : 1=Active / 0=Orphaned
+ // bits 1-n : refcount
+ // Ref/Unref by two to avoid altering the orphaned bit
+ gpr_atm refst = 1;
+
+ gpr_mu orphan_mu;
+
+ // Protects pollable_obj and pollset_fds.
+ gpr_mu pollable_mu;
+ grpc_core::InlinedVector<int, 1> pollset_fds; // Used in PO_MULTI.
+ pollable* pollable_obj = nullptr; // Used in PO_FD.
+
+ grpc_core::LockfreeEvent read_closure;
+ grpc_core::LockfreeEvent write_closure;
+ grpc_core::LockfreeEvent error_closure;
+
+ struct grpc_fd* freelist_next = nullptr;
+ grpc_closure* on_done_closure = nullptr;
+
+ grpc_iomgr_object iomgr_object;
+
+ // Do we need to track EPOLLERR events separately?
+ bool track_err;
+};
+
+static void fd_global_init(void);
+static void fd_global_shutdown(void);
+
+/*******************************************************************************
+ * Pollset Declarations
+ */
+
+typedef struct {
+ grpc_pollset_worker* next;
+ grpc_pollset_worker* prev;
+} pwlink;
+
+typedef enum { PWLINK_POLLABLE = 0, PWLINK_POLLSET, PWLINK_COUNT } pwlinks;
+
+struct grpc_pollset_worker {
+ bool kicked;
+ bool initialized_cv;
+#ifndef NDEBUG
+ // debug aid: which thread started this worker
+ pid_t originator;
+#endif
+ gpr_cv cv;
+ grpc_pollset* pollset;
+ pollable* pollable_obj;
+
+ pwlink links[PWLINK_COUNT];
+};
+
+struct grpc_pollset {
+ gpr_mu mu;
+ gpr_atm worker_count;
+ gpr_atm active_pollable_type;
+ pollable* active_pollable;
+ bool kicked_without_poller;
+ grpc_closure* shutdown_closure;
+ bool already_shutdown;
+ grpc_pollset_worker* root_worker;
+ int containing_pollset_set_count;
+};
+
+/*******************************************************************************
+ * Pollset-set Declarations
+ */
+
+struct grpc_pollset_set {
+ grpc_core::RefCount refs;
+ gpr_mu mu;
+ grpc_pollset_set* parent;
+
+ size_t pollset_count;
+ size_t pollset_capacity;
+ grpc_pollset** pollsets;
+
+ size_t fd_count;
+ size_t fd_capacity;
+ grpc_fd** fds;
+};
+
+/*******************************************************************************
+ * Common helpers
+ */
+
+static bool append_error(grpc_error** composite, grpc_error* error,
+ const char* desc) {
+ if (error == GRPC_ERROR_NONE) return true;
+ if (*composite == GRPC_ERROR_NONE) {
+ *composite = GRPC_ERROR_CREATE_FROM_COPIED_STRING(desc);
+ }
+ *composite = grpc_error_add_child(*composite, error);
+ return false;
+}
+
+/*******************************************************************************
+ * Fd Definitions
+ */
+
+/* We need to keep a freelist not because of any concerns of malloc performance
+ * but instead so that implementations with multiple threads in (for example)
+ * epoll_wait deal with the race between pollset removal and incoming poll
+ * notifications.
+ *
+ * The problem is that the poller ultimately holds a reference to this
+ * object, so it is very difficult to know when is safe to free it, at least
+ * without some expensive synchronization.
+ *
+ * If we keep the object freelisted, in the worst case losing this race just
+ * becomes a spurious read notification on a reused fd.
+ */
+
+static grpc_fd* fd_freelist = nullptr;
+static gpr_mu fd_freelist_mu;
+
+#ifndef NDEBUG
+#define REF_BY(fd, n, reason) ref_by(fd, n, reason, __FILE__, __LINE__)
+#define UNREF_BY(fd, n, reason) unref_by(fd, n, reason, __FILE__, __LINE__)
+static void ref_by(grpc_fd* fd, int n, const char* reason, const char* file,
+ int line) {
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_trace_fd_refcount)) {
+ gpr_log(GPR_DEBUG,
+ "FD %d %p ref %d %" PRIdPTR " -> %" PRIdPTR " [%s; %s:%d]",
+ fd->fd, fd, n, gpr_atm_no_barrier_load(&fd->refst),
+ gpr_atm_no_barrier_load(&fd->refst) + n, reason, file, line);
+ }
+#else
+#define REF_BY(fd, n, reason) ref_by(fd, n)
+#define UNREF_BY(fd, n, reason) unref_by(fd, n)
+static void ref_by(grpc_fd* fd, int n) {
+#endif
+ GPR_ASSERT(gpr_atm_no_barrier_fetch_add(&fd->refst, n) > 0);
+}
+
+/* Uninitialize and add to the freelist */
+static void fd_destroy(void* arg, grpc_error* error) {
+ grpc_fd* fd = static_cast<grpc_fd*>(arg);
+ fd->destroy();
+
+ /* Add the fd to the freelist */
+ gpr_mu_lock(&fd_freelist_mu);
+ fd->freelist_next = fd_freelist;
+ fd_freelist = fd;
+ gpr_mu_unlock(&fd_freelist_mu);
+}
+
+#ifndef NDEBUG
+static void unref_by(grpc_fd* fd, int n, const char* reason, const char* file,
+ int line) {
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_trace_fd_refcount)) {
+ gpr_log(GPR_DEBUG,
+ "FD %d %p unref %d %" PRIdPTR " -> %" PRIdPTR " [%s; %s:%d]",
+ fd->fd, fd, n, gpr_atm_no_barrier_load(&fd->refst),
+ gpr_atm_no_barrier_load(&fd->refst) - n, reason, file, line);
+ }
+#else
+static void unref_by(grpc_fd* fd, int n) {
+#endif
+ gpr_atm old = gpr_atm_full_fetch_add(&fd->refst, -n);
+ if (old == n) {
+ GRPC_CLOSURE_SCHED(
+ GRPC_CLOSURE_CREATE(fd_destroy, fd, grpc_schedule_on_exec_ctx),
+ GRPC_ERROR_NONE);
+ } else {
+ GPR_ASSERT(old > n);
+ }
+}
+
+static void fd_global_init(void) { gpr_mu_init(&fd_freelist_mu); }
+
+static void fd_global_shutdown(void) {
+ // TODO(guantaol): We don't have a reasonable explanation about this
+ // lock()/unlock() pattern. It can be a valid barrier if there is at most one
+ // pending lock() at this point. Otherwise, there is still a possibility of
+ // use-after-free race. Need to reason about the code and/or clean it up.
+ gpr_mu_lock(&fd_freelist_mu);
+ gpr_mu_unlock(&fd_freelist_mu);
+ while (fd_freelist != nullptr) {
+ grpc_fd* fd = fd_freelist;
+ fd_freelist = fd_freelist->freelist_next;
+ gpr_free(fd);
+ }
+ gpr_mu_destroy(&fd_freelist_mu);
+}
+
+static grpc_fd* fd_create(int fd, const char* name, bool track_err) {
+ grpc_fd* new_fd = nullptr;
+
+ gpr_mu_lock(&fd_freelist_mu);
+ if (fd_freelist != nullptr) {
+ new_fd = fd_freelist;
+ fd_freelist = fd_freelist->freelist_next;
+ }
+ gpr_mu_unlock(&fd_freelist_mu);
+
+ if (new_fd == nullptr) {
+ new_fd = static_cast<grpc_fd*>(gpr_malloc(sizeof(grpc_fd)));
+ }
+
+ return new (new_fd) grpc_fd(fd, name, track_err);
+}
+
+static int fd_wrapped_fd(grpc_fd* fd) {
+ int ret_fd = fd->fd;
+ return (gpr_atm_acq_load(&fd->refst) & 1) ? ret_fd : -1;
+}
+
+static void fd_orphan(grpc_fd* fd, grpc_closure* on_done, int* release_fd,
+ const char* reason) {
+ bool is_fd_closed = false;
+
+ gpr_mu_lock(&fd->orphan_mu);
+
+ // Get the fd->pollable_obj and set the owner_orphaned on that pollable to
+ // true so that the pollable will no longer access its owner_fd field.
+ gpr_mu_lock(&fd->pollable_mu);
+ pollable* pollable_obj = fd->pollable_obj;
+
+ if (pollable_obj) {
+ gpr_mu_lock(&pollable_obj->owner_orphan_mu);
+ pollable_obj->owner_orphaned = true;
+ }
+
+ fd->on_done_closure = on_done;
+
+ /* If release_fd is not NULL, we should be relinquishing control of the file
+ descriptor fd->fd (but we still own the grpc_fd structure). */
+ if (release_fd != nullptr) {
+ // Remove the FD from all epolls sets, before releasing it.
+ // Otherwise, we will receive epoll events after we release the FD.
+ epoll_event ev_fd;
+ memset(&ev_fd, 0, sizeof(ev_fd));
+ if (pollable_obj != nullptr) { // For PO_FD.
+ epoll_ctl(pollable_obj->epfd, EPOLL_CTL_DEL, fd->fd, &ev_fd);
+ }
+ for (size_t i = 0; i < fd->pollset_fds.size(); ++i) { // For PO_MULTI.
+ const int epfd = fd->pollset_fds[i];
+ epoll_ctl(epfd, EPOLL_CTL_DEL, fd->fd, &ev_fd);
+ }
+ *release_fd = fd->fd;
+ } else {
+ close(fd->fd);
+ is_fd_closed = true;
+ }
+
+ // TODO(sreek): handle fd removal (where is_fd_closed=false)
+ if (!is_fd_closed) {
+ GRPC_FD_TRACE("epoll_fd %p (%d) was orphaned but not closed.", fd, fd->fd);
+ }
+
+ /* Remove the active status but keep referenced. We want this grpc_fd struct
+ to be alive (and not added to freelist) until the end of this function */
+ REF_BY(fd, 1, reason);
+
+ GRPC_CLOSURE_SCHED(fd->on_done_closure, GRPC_ERROR_NONE);
+
+ if (pollable_obj) {
+ gpr_mu_unlock(&pollable_obj->owner_orphan_mu);
+ }
+
+ gpr_mu_unlock(&fd->pollable_mu);
+ gpr_mu_unlock(&fd->orphan_mu);
+
+ UNREF_BY(fd, 2, reason); /* Drop the reference */
+}
+
+static bool fd_is_shutdown(grpc_fd* fd) {
+ return fd->read_closure.IsShutdown();
+}
+
+/* Might be called multiple times */
+static void fd_shutdown(grpc_fd* fd, grpc_error* why) {
+ if (fd->read_closure.SetShutdown(GRPC_ERROR_REF(why))) {
+ if (shutdown(fd->fd, SHUT_RDWR)) {
+ if (errno != ENOTCONN) {
+ gpr_log(GPR_ERROR, "Error shutting down fd %d. errno: %d",
+ grpc_fd_wrapped_fd(fd), errno);
+ }
+ }
+ fd->write_closure.SetShutdown(GRPC_ERROR_REF(why));
+ fd->error_closure.SetShutdown(GRPC_ERROR_REF(why));
+ }
+ GRPC_ERROR_UNREF(why);
+}
+
+static void fd_notify_on_read(grpc_fd* fd, grpc_closure* closure) {
+ fd->read_closure.NotifyOn(closure);
+}
+
+static void fd_notify_on_write(grpc_fd* fd, grpc_closure* closure) {
+ fd->write_closure.NotifyOn(closure);
+}
+
+static void fd_notify_on_error(grpc_fd* fd, grpc_closure* closure) {
+ fd->error_closure.NotifyOn(closure);
+}
+
+static bool fd_has_pollset(grpc_fd* fd, grpc_pollset* pollset) {
+ const int epfd = pollset->active_pollable->epfd;
+ grpc_core::MutexLock lock(&fd->pollable_mu);
+ for (size_t i = 0; i < fd->pollset_fds.size(); ++i) {
+ if (fd->pollset_fds[i] == epfd) {
+ return true;
+ }
+ }
+ return false;
+}
+
+static void fd_add_pollset(grpc_fd* fd, grpc_pollset* pollset) {
+ const int epfd = pollset->active_pollable->epfd;
+ grpc_core::MutexLock lock(&fd->pollable_mu);
+ fd->pollset_fds.push_back(epfd);
+}
+
+/*******************************************************************************
+ * Pollable Definitions
+ */
+
+static grpc_error* pollable_create(pollable_type type, pollable** p) {
+ *p = nullptr;
+
+ int epfd = epoll_create1(EPOLL_CLOEXEC);
+ if (epfd == -1) {
+ return GRPC_OS_ERROR(errno, "epoll_create1");
+ }
+ GRPC_FD_TRACE("Pollable_create: created epfd: %d (type: %d)", epfd, type);
+ *p = static_cast<pollable*>(gpr_malloc(sizeof(**p)));
+ grpc_error* err = grpc_wakeup_fd_init(&(*p)->wakeup);
+ if (err != GRPC_ERROR_NONE) {
+ GRPC_FD_TRACE(
+ "Pollable_create: closed epfd: %d (type: %d). wakeupfd_init error",
+ epfd, type);
+ close(epfd);
+ gpr_free(*p);
+ *p = nullptr;
+ return err;
+ }
+ struct epoll_event ev;
+ ev.events = static_cast<uint32_t>(EPOLLIN | EPOLLET);
+ ev.data.ptr = (void*)(1 | (intptr_t) & (*p)->wakeup);
+ if (epoll_ctl(epfd, EPOLL_CTL_ADD, (*p)->wakeup.read_fd, &ev) != 0) {
+ err = GRPC_OS_ERROR(errno, "epoll_ctl");
+ GRPC_FD_TRACE(
+ "Pollable_create: closed epfd: %d (type: %d). epoll_ctl error", epfd,
+ type);
+ close(epfd);
+ grpc_wakeup_fd_destroy(&(*p)->wakeup);
+ gpr_free(*p);
+ *p = nullptr;
+ return err;
+ }
+
+ (*p)->type = type;
+ new (&(*p)->refs) grpc_core::RefCount(1, &grpc_trace_pollable_refcount);
+ gpr_mu_init(&(*p)->mu);
+ (*p)->epfd = epfd;
+ (*p)->owner_fd = nullptr;
+ gpr_mu_init(&(*p)->owner_orphan_mu);
+ (*p)->owner_orphaned = false;
+ (*p)->pollset_set = nullptr;
+ (*p)->next = (*p)->prev = *p;
+ (*p)->root_worker = nullptr;
+ (*p)->event_cursor = 0;
+ (*p)->event_count = 0;
+ return GRPC_ERROR_NONE;
+}
+
+static grpc_error* pollable_add_fd(pollable* p, grpc_fd* fd) {
+ grpc_error* error = GRPC_ERROR_NONE;
+ static const char* err_desc = "pollable_add_fd";
+ const int epfd = p->epfd;
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "add fd %p (%d) to pollable %p", fd, fd->fd, p);
+ }
+
+ struct epoll_event ev_fd;
+ ev_fd.events =
+ static_cast<uint32_t>(EPOLLET | EPOLLIN | EPOLLOUT | EPOLLEXCLUSIVE);
+ /* Use the second least significant bit of ev_fd.data.ptr to store track_err
+ * to avoid synchronization issues when accessing it after receiving an event.
+ * Accessing fd would be a data race there because the fd might have been
+ * returned to the free list at that point. */
+ ev_fd.data.ptr = reinterpret_cast<void*>(reinterpret_cast<intptr_t>(fd) |
+ (fd->track_err ? 2 : 0));
+ GRPC_STATS_INC_SYSCALL_EPOLL_CTL();
+ if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd->fd, &ev_fd) != 0) {
+ switch (errno) {
+ case EEXIST:
+ break;
+ default:
+ append_error(&error, GRPC_OS_ERROR(errno, "epoll_ctl"), err_desc);
+ }
+ }
+
+ return error;
+}
+
+/*******************************************************************************
+ * Pollset Definitions
+ */
+
+GPR_TLS_DECL(g_current_thread_pollset);
+GPR_TLS_DECL(g_current_thread_worker);
+
+/* Global state management */
+static grpc_error* pollset_global_init(void) {
+ gpr_tls_init(&g_current_thread_pollset);
+ gpr_tls_init(&g_current_thread_worker);
+ return pollable_create(PO_EMPTY, &g_empty_pollable);
+}
+
+static void pollset_global_shutdown(void) {
+ POLLABLE_UNREF(g_empty_pollable, "g_empty_pollable");
+ gpr_tls_destroy(&g_current_thread_pollset);
+ gpr_tls_destroy(&g_current_thread_worker);
+}
+
+/* pollset->mu must be held while calling this function */
+static void pollset_maybe_finish_shutdown(grpc_pollset* pollset) {
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO,
+ "PS:%p (pollable:%p) maybe_finish_shutdown sc=%p (target:!NULL) "
+ "rw=%p (target:NULL) cpsc=%d (target:0)",
+ pollset, pollset->active_pollable, pollset->shutdown_closure,
+ pollset->root_worker, pollset->containing_pollset_set_count);
+ }
+ if (pollset->shutdown_closure != nullptr && pollset->root_worker == nullptr &&
+ pollset->containing_pollset_set_count == 0) {
+ GPR_TIMER_MARK("pollset_finish_shutdown", 0);
+ GRPC_CLOSURE_SCHED(pollset->shutdown_closure, GRPC_ERROR_NONE);
+ pollset->shutdown_closure = nullptr;
+ pollset->already_shutdown = true;
+ }
+}
+
+/* pollset->mu must be held before calling this function,
+ * pollset->active_pollable->mu & specific_worker->pollable_obj->mu must not be
+ * held */
+static grpc_error* kick_one_worker(grpc_pollset_worker* specific_worker) {
+ GPR_TIMER_SCOPE("kick_one_worker", 0);
+ pollable* p = specific_worker->pollable_obj;
+ grpc_core::MutexLock lock(&p->mu);
+ GPR_ASSERT(specific_worker != nullptr);
+ if (specific_worker->kicked) {
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PS:%p kicked_specific_but_already_kicked", p);
+ }
+ GRPC_STATS_INC_POLLSET_KICKED_AGAIN();
+ return GRPC_ERROR_NONE;
+ }
+ if (gpr_tls_get(&g_current_thread_worker) == (intptr_t)specific_worker) {
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PS:%p kicked_specific_but_awake", p);
+ }
+ GRPC_STATS_INC_POLLSET_KICK_OWN_THREAD();
+ specific_worker->kicked = true;
+ return GRPC_ERROR_NONE;
+ }
+ if (specific_worker == p->root_worker) {
+ GRPC_STATS_INC_POLLSET_KICK_WAKEUP_FD();
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PS:%p kicked_specific_via_wakeup_fd", p);
+ }
+ specific_worker->kicked = true;
+ grpc_error* error = grpc_wakeup_fd_wakeup(&p->wakeup);
+ return error;
+ }
+ if (specific_worker->initialized_cv) {
+ GRPC_STATS_INC_POLLSET_KICK_WAKEUP_CV();
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PS:%p kicked_specific_via_cv", p);
+ }
+ specific_worker->kicked = true;
+ gpr_cv_signal(&specific_worker->cv);
+ return GRPC_ERROR_NONE;
+ }
+ // we can get here during end_worker after removing specific_worker from the
+ // pollable list but before removing it from the pollset list
+ return GRPC_ERROR_NONE;
+}
+
+static grpc_error* pollset_kick(grpc_pollset* pollset,
+ grpc_pollset_worker* specific_worker) {
+ GPR_TIMER_SCOPE("pollset_kick", 0);
+ GRPC_STATS_INC_POLLSET_KICK();
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO,
+ "PS:%p kick %p tls_pollset=%p tls_worker=%p pollset.root_worker=%p",
+ pollset, specific_worker,
+ (void*)gpr_tls_get(&g_current_thread_pollset),
+ (void*)gpr_tls_get(&g_current_thread_worker), pollset->root_worker);
+ }
+ if (specific_worker == nullptr) {
+ if (gpr_tls_get(&g_current_thread_pollset) != (intptr_t)pollset) {
+ if (pollset->root_worker == nullptr) {
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PS:%p kicked_any_without_poller", pollset);
+ }
+ GRPC_STATS_INC_POLLSET_KICKED_WITHOUT_POLLER();
+ pollset->kicked_without_poller = true;
+ return GRPC_ERROR_NONE;
+ } else {
+ // We've been asked to kick a poller, but we haven't been told which one
+ // ... any will do
+ // We look at the pollset worker list because:
+ // 1. the pollable list may include workers from other pollers, so we'd
+ // need to do an O(N) search
+ // 2. we'd additionally need to take the pollable lock, which we've so
+ // far avoided
+ // Now, we would prefer to wake a poller in cv_wait, and not in
+ // epoll_wait (since the latter would imply the need to do an additional
+ // wakeup)
+ // We know that if a worker is at the root of a pollable, it's (likely)
+ // also the root of a pollset, and we know that if a worker is NOT at
+ // the root of a pollset, it's (likely) not at the root of a pollable,
+ // so we take our chances and choose the SECOND worker enqueued against
+ // the pollset as a worker that's likely to be in cv_wait
+ return kick_one_worker(
+ pollset->root_worker->links[PWLINK_POLLSET].next);
+ }
+ } else {
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PS:%p kicked_any_but_awake", pollset);
+ }
+ GRPC_STATS_INC_POLLSET_KICK_OWN_THREAD();
+ return GRPC_ERROR_NONE;
+ }
+ } else {
+ return kick_one_worker(specific_worker);
+ }
+}
+
+static grpc_error* pollset_kick_all(grpc_pollset* pollset) {
+ GPR_TIMER_SCOPE("pollset_kick_all", 0);
+ grpc_error* error = GRPC_ERROR_NONE;
+ const char* err_desc = "pollset_kick_all";
+ grpc_pollset_worker* w = pollset->root_worker;
+ if (w != nullptr) {
+ do {
+ GRPC_STATS_INC_POLLSET_KICK();
+ append_error(&error, kick_one_worker(w), err_desc);
+ w = w->links[PWLINK_POLLSET].next;
+ } while (w != pollset->root_worker);
+ }
+ return error;
+}
+
+static void pollset_init(grpc_pollset* pollset, gpr_mu** mu) {
+ gpr_mu_init(&pollset->mu);
+ gpr_atm_no_barrier_store(&pollset->worker_count, 0);
+ gpr_atm_no_barrier_store(&pollset->active_pollable_type, PO_EMPTY);
+ pollset->active_pollable = POLLABLE_REF(g_empty_pollable, "pollset");
+ pollset->kicked_without_poller = false;
+ pollset->shutdown_closure = nullptr;
+ pollset->already_shutdown = false;
+ pollset->root_worker = nullptr;
+ pollset->containing_pollset_set_count = 0;
+ *mu = &pollset->mu;
+}
+
+static int poll_deadline_to_millis_timeout(grpc_millis millis) {
+ if (millis == GRPC_MILLIS_INF_FUTURE) return -1;
+ grpc_millis delta = millis - grpc_core::ExecCtx::Get()->Now();
+ if (delta > INT_MAX)
+ return INT_MAX;
+ else if (delta < 0)
+ return 0;
+ else
+ return static_cast<int>(delta);
+}
+
+static void fd_become_readable(grpc_fd* fd) { fd->read_closure.SetReady(); }
+
+static void fd_become_writable(grpc_fd* fd) { fd->write_closure.SetReady(); }
+
+static void fd_has_errors(grpc_fd* fd) { fd->error_closure.SetReady(); }
+
+/* Get the pollable_obj attached to this fd. If none is attached, create a new
+ * pollable object (of type PO_FD), attach it to the fd and return it
+ *
+ * Note that if a pollable object is already attached to the fd, it may be of
+ * either PO_FD or PO_MULTI type */
+static grpc_error* get_fd_pollable(grpc_fd* fd, pollable** p) {
+ gpr_mu_lock(&fd->pollable_mu);
+ grpc_error* error = GRPC_ERROR_NONE;
+ static const char* err_desc = "get_fd_pollable";
+ if (fd->pollable_obj == nullptr) {
+ if (append_error(&error, pollable_create(PO_FD, &fd->pollable_obj),
+ err_desc)) {
+ fd->pollable_obj->owner_fd = fd;
+ if (!append_error(&error, pollable_add_fd(fd->pollable_obj, fd),
+ err_desc)) {
+ POLLABLE_UNREF(fd->pollable_obj, "fd_pollable");
+ fd->pollable_obj = nullptr;
+ }
+ }
+ }
+ if (error == GRPC_ERROR_NONE) {
+ GPR_ASSERT(fd->pollable_obj != nullptr);
+ *p = POLLABLE_REF(fd->pollable_obj, "pollset");
+ } else {
+ GPR_ASSERT(fd->pollable_obj == nullptr);
+ *p = nullptr;
+ }
+ gpr_mu_unlock(&fd->pollable_mu);
+ return error;
+}
+
+/* pollset->po.mu lock must be held by the caller before calling this */
+static void pollset_shutdown(grpc_pollset* pollset, grpc_closure* closure) {
+ GPR_TIMER_SCOPE("pollset_shutdown", 0);
+ GPR_ASSERT(pollset->shutdown_closure == nullptr);
+ pollset->shutdown_closure = closure;
+ GRPC_LOG_IF_ERROR("pollset_shutdown", pollset_kick_all(pollset));
+ pollset_maybe_finish_shutdown(pollset);
+}
+
+static grpc_error* pollable_process_events(grpc_pollset* pollset,
+ pollable* pollable_obj, bool drain) {
+ GPR_TIMER_SCOPE("pollable_process_events", 0);
+ static const char* err_desc = "pollset_process_events";
+ // Use a simple heuristic to determine how many fd events to process
+ // per loop iteration. (events/workers)
+ int handle_count = 1;
+ int worker_count = gpr_atm_no_barrier_load(&pollset->worker_count);
+ GPR_ASSERT(worker_count > 0);
+ handle_count =
+ (pollable_obj->event_count - pollable_obj->event_cursor) / worker_count;
+ if (handle_count == 0) {
+ handle_count = 1;
+ } else if (handle_count > MAX_EPOLL_EVENTS_HANDLED_EACH_POLL_CALL) {
+ handle_count = MAX_EPOLL_EVENTS_HANDLED_EACH_POLL_CALL;
+ }
+ grpc_error* error = GRPC_ERROR_NONE;
+ for (int i = 0; (drain || i < handle_count) &&
+ pollable_obj->event_cursor != pollable_obj->event_count;
+ i++) {
+ int n = pollable_obj->event_cursor++;
+ struct epoll_event* ev = &pollable_obj->events[n];
+ void* data_ptr = ev->data.ptr;
+ if (1 & (intptr_t)data_ptr) {
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PS:%p got pollset_wakeup %p", pollset, data_ptr);
+ }
+ append_error(&error,
+ grpc_wakeup_fd_consume_wakeup(
+ (grpc_wakeup_fd*)((~static_cast<intptr_t>(1)) &
+ (intptr_t)data_ptr)),
+ err_desc);
+ } else {
+ grpc_fd* fd =
+ reinterpret_cast<grpc_fd*>(reinterpret_cast<intptr_t>(data_ptr) & ~2);
+ bool track_err = reinterpret_cast<intptr_t>(data_ptr) & 2;
+ bool cancel = (ev->events & EPOLLHUP) != 0;
+ bool error = (ev->events & EPOLLERR) != 0;
+ bool read_ev = (ev->events & (EPOLLIN | EPOLLPRI)) != 0;
+ bool write_ev = (ev->events & EPOLLOUT) != 0;
+ bool err_fallback = error && !track_err;
+
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO,
+ "PS:%p got fd %p: cancel=%d read=%d "
+ "write=%d",
+ pollset, fd, cancel, read_ev, write_ev);
+ }
+ if (error && !err_fallback) {
+ fd_has_errors(fd);
+ }
+ if (read_ev || cancel || err_fallback) {
+ fd_become_readable(fd);
+ }
+ if (write_ev || cancel || err_fallback) {
+ fd_become_writable(fd);
+ }
+ }
+ }
+
+ return error;
+}
+
+/* pollset_shutdown is guaranteed to be called before pollset_destroy. */
+static void pollset_destroy(grpc_pollset* pollset) {
+ POLLABLE_UNREF(pollset->active_pollable, "pollset");
+ pollset->active_pollable = nullptr;
+ gpr_mu_destroy(&pollset->mu);
+}
+
+static grpc_error* pollable_epoll(pollable* p, grpc_millis deadline) {
+ GPR_TIMER_SCOPE("pollable_epoll", 0);
+ int timeout = poll_deadline_to_millis_timeout(deadline);
+
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ char* desc = pollable_desc(p);
+ gpr_log(GPR_INFO, "POLLABLE:%p[%s] poll for %dms", p, desc, timeout);
+ gpr_free(desc);
+ }
+
+ if (timeout != 0) {
+ GRPC_SCHEDULING_START_BLOCKING_REGION;
+ }
+ int r;
+ do {
+ GRPC_STATS_INC_SYSCALL_POLL();
+ r = epoll_wait(p->epfd, p->events, MAX_EPOLL_EVENTS, timeout);
+ } while (r < 0 && errno == EINTR);
+ if (timeout != 0) {
+ GRPC_SCHEDULING_END_BLOCKING_REGION;
+ }
+
+ if (r < 0) return GRPC_OS_ERROR(errno, "epoll_wait");
+
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "POLLABLE:%p got %d events", p, r);
+ }
+
+ p->event_cursor = 0;
+ p->event_count = r;
+
+ return GRPC_ERROR_NONE;
+}
+
+/* Return true if first in list */
+static bool worker_insert(grpc_pollset_worker** root_worker,
+ grpc_pollset_worker* worker, pwlinks link) {
+ if (*root_worker == nullptr) {
+ *root_worker = worker;
+ worker->links[link].next = worker->links[link].prev = worker;
+ return true;
+ } else {
+ worker->links[link].next = *root_worker;
+ worker->links[link].prev = worker->links[link].next->links[link].prev;
+ worker->links[link].next->links[link].prev = worker;
+ worker->links[link].prev->links[link].next = worker;
+ return false;
+ }
+}
+
+/* returns the new root IFF the root changed */
+typedef enum { WRR_NEW_ROOT, WRR_EMPTIED, WRR_REMOVED } worker_remove_result;
+
+static worker_remove_result worker_remove(grpc_pollset_worker** root_worker,
+ grpc_pollset_worker* worker,
+ pwlinks link) {
+ if (worker == *root_worker) {
+ if (worker == worker->links[link].next) {
+ *root_worker = nullptr;
+ return WRR_EMPTIED;
+ } else {
+ *root_worker = worker->links[link].next;
+ worker->links[link].prev->links[link].next = worker->links[link].next;
+ worker->links[link].next->links[link].prev = worker->links[link].prev;
+ return WRR_NEW_ROOT;
+ }
+ } else {
+ worker->links[link].prev->links[link].next = worker->links[link].next;
+ worker->links[link].next->links[link].prev = worker->links[link].prev;
+ return WRR_REMOVED;
+ }
+}
+
+/* Return true if this thread should poll */
+static bool begin_worker(grpc_pollset* pollset, grpc_pollset_worker* worker,
+ grpc_pollset_worker** worker_hdl,
+ grpc_millis deadline) {
+ GPR_TIMER_SCOPE("begin_worker", 0);
+ bool do_poll =
+ (pollset->shutdown_closure == nullptr && !pollset->already_shutdown);
+ gpr_atm_no_barrier_fetch_add(&pollset->worker_count, 1);
+ if (worker_hdl != nullptr) *worker_hdl = worker;
+ worker->initialized_cv = false;
+ worker->kicked = false;
+ worker->pollset = pollset;
+ worker->pollable_obj =
+ POLLABLE_REF(pollset->active_pollable, "pollset_worker");
+ worker_insert(&pollset->root_worker, worker, PWLINK_POLLSET);
+ gpr_mu_lock(&worker->pollable_obj->mu);
+ if (!worker_insert(&worker->pollable_obj->root_worker, worker,
+ PWLINK_POLLABLE)) {
+ worker->initialized_cv = true;
+ gpr_cv_init(&worker->cv);
+ gpr_mu_unlock(&pollset->mu);
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace) &&
+ worker->pollable_obj->root_worker != worker) {
+ gpr_log(GPR_INFO, "PS:%p wait %p w=%p for %dms", pollset,
+ worker->pollable_obj, worker,
+ poll_deadline_to_millis_timeout(deadline));
+ }
+ while (do_poll && worker->pollable_obj->root_worker != worker) {
+ if (gpr_cv_wait(&worker->cv, &worker->pollable_obj->mu,
+ grpc_millis_to_timespec(deadline, GPR_CLOCK_REALTIME))) {
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PS:%p timeout_wait %p w=%p", pollset,
+ worker->pollable_obj, worker);
+ }
+ do_poll = false;
+ } else if (worker->kicked) {
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PS:%p wakeup %p w=%p", pollset,
+ worker->pollable_obj, worker);
+ }
+ do_poll = false;
+ } else if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace) &&
+ worker->pollable_obj->root_worker != worker) {
+ gpr_log(GPR_INFO, "PS:%p spurious_wakeup %p w=%p", pollset,
+ worker->pollable_obj, worker);
+ }
+ }
+ grpc_core::ExecCtx::Get()->InvalidateNow();
+ } else {
+ gpr_mu_unlock(&pollset->mu);
+ }
+ gpr_mu_unlock(&worker->pollable_obj->mu);
+
+ return do_poll;
+}
+
+static void end_worker(grpc_pollset* pollset, grpc_pollset_worker* worker,
+ grpc_pollset_worker** worker_hdl) {
+ GPR_TIMER_SCOPE("end_worker", 0);
+ gpr_mu_lock(&pollset->mu);
+ gpr_mu_lock(&worker->pollable_obj->mu);
+ switch (worker_remove(&worker->pollable_obj->root_worker, worker,
+ PWLINK_POLLABLE)) {
+ case WRR_NEW_ROOT: {
+ // wakeup new poller
+ grpc_pollset_worker* new_root = worker->pollable_obj->root_worker;
+ GPR_ASSERT(new_root->initialized_cv);
+ gpr_cv_signal(&new_root->cv);
+ break;
+ }
+ case WRR_EMPTIED:
+ if (pollset->active_pollable != worker->pollable_obj) {
+ // pollable no longer being polled: flush events
+ pollable_process_events(pollset, worker->pollable_obj, true);
+ }
+ break;
+ case WRR_REMOVED:
+ break;
+ }
+ gpr_mu_unlock(&worker->pollable_obj->mu);
+ POLLABLE_UNREF(worker->pollable_obj, "pollset_worker");
+ if (worker_remove(&pollset->root_worker, worker, PWLINK_POLLSET) ==
+ WRR_EMPTIED) {
+ pollset_maybe_finish_shutdown(pollset);
+ }
+ if (worker->initialized_cv) {
+ gpr_cv_destroy(&worker->cv);
+ }
+ gpr_atm_no_barrier_fetch_add(&pollset->worker_count, -1);
+}
+
+#ifndef NDEBUG
+static long sys_gettid(void) { return syscall(__NR_gettid); }
+#endif
+
+/* pollset->mu lock must be held by the caller before calling this.
+ The function pollset_work() may temporarily release the lock (pollset->po.mu)
+ during the course of its execution but it will always re-acquire the lock and
+ ensure that it is held by the time the function returns */
+static grpc_error* pollset_work(grpc_pollset* pollset,
+ grpc_pollset_worker** worker_hdl,
+ grpc_millis deadline) {
+ GPR_TIMER_SCOPE("pollset_work", 0);
+#ifdef GRPC_EPOLLEX_CREATE_WORKERS_ON_HEAP
+ grpc_pollset_worker* worker =
+ (grpc_pollset_worker*)gpr_malloc(sizeof(*worker));
+#define WORKER_PTR (worker)
+#else
+ grpc_pollset_worker worker;
+#define WORKER_PTR (&worker)
+#endif
+#ifndef NDEBUG
+ WORKER_PTR->originator = sys_gettid();
+#endif
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO,
+ "PS:%p work hdl=%p worker=%p now=%" PRId64 " deadline=%" PRId64
+ " kwp=%d pollable=%p",
+ pollset, worker_hdl, WORKER_PTR, grpc_core::ExecCtx::Get()->Now(),
+ deadline, pollset->kicked_without_poller, pollset->active_pollable);
+ }
+ static const char* err_desc = "pollset_work";
+ grpc_error* error = GRPC_ERROR_NONE;
+ if (pollset->kicked_without_poller) {
+ pollset->kicked_without_poller = false;
+ } else {
+ if (begin_worker(pollset, WORKER_PTR, worker_hdl, deadline)) {
+ gpr_tls_set(&g_current_thread_pollset, (intptr_t)pollset);
+ gpr_tls_set(&g_current_thread_worker, (intptr_t)WORKER_PTR);
+ if (WORKER_PTR->pollable_obj->event_cursor ==
+ WORKER_PTR->pollable_obj->event_count) {
+ append_error(&error, pollable_epoll(WORKER_PTR->pollable_obj, deadline),
+ err_desc);
+ }
+ append_error(
+ &error,
+ pollable_process_events(pollset, WORKER_PTR->pollable_obj, false),
+ err_desc);
+ grpc_core::ExecCtx::Get()->Flush();
+ gpr_tls_set(&g_current_thread_pollset, 0);
+ gpr_tls_set(&g_current_thread_worker, 0);
+ }
+ end_worker(pollset, WORKER_PTR, worker_hdl);
+ }
+#ifdef GRPC_EPOLLEX_CREATE_WORKERS_ON_HEAP
+ gpr_free(worker);
+#endif
+#undef WORKER_PTR
+ return error;
+}
+
+static grpc_error* pollset_transition_pollable_from_empty_to_fd_locked(
+ grpc_pollset* pollset, grpc_fd* fd) {
+ static const char* err_desc = "pollset_transition_pollable_from_empty_to_fd";
+ grpc_error* error = GRPC_ERROR_NONE;
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO,
+ "PS:%p add fd %p (%d); transition pollable from empty to fd",
+ pollset, fd, fd->fd);
+ }
+ append_error(&error, pollset_kick_all(pollset), err_desc);
+ POLLABLE_UNREF(pollset->active_pollable, "pollset");
+ append_error(&error, get_fd_pollable(fd, &pollset->active_pollable),
+ err_desc);
+ return error;
+}
+
+static grpc_error* pollset_transition_pollable_from_fd_to_multi_locked(
+ grpc_pollset* pollset, grpc_fd* and_add_fd) {
+ static const char* err_desc = "pollset_transition_pollable_from_fd_to_multi";
+ grpc_error* error = GRPC_ERROR_NONE;
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(
+ GPR_INFO,
+ "PS:%p add fd %p (%d); transition pollable from fd %p to multipoller",
+ pollset, and_add_fd, and_add_fd ? and_add_fd->fd : -1,
+ pollset->active_pollable->owner_fd);
+ }
+ append_error(&error, pollset_kick_all(pollset), err_desc);
+ grpc_fd* initial_fd = pollset->active_pollable->owner_fd;
+ POLLABLE_UNREF(pollset->active_pollable, "pollset");
+ pollset->active_pollable = nullptr;
+ if (append_error(&error, pollable_create(PO_MULTI, &pollset->active_pollable),
+ err_desc)) {
+ append_error(&error, pollable_add_fd(pollset->active_pollable, initial_fd),
+ err_desc);
+ if (and_add_fd != nullptr) {
+ append_error(&error,
+ pollable_add_fd(pollset->active_pollable, and_add_fd),
+ err_desc);
+ }
+ }
+ return error;
+}
+
+/* expects pollsets locked, flag whether fd is locked or not */
+static grpc_error* pollset_add_fd_locked(grpc_pollset* pollset, grpc_fd* fd) {
+ grpc_error* error = GRPC_ERROR_NONE;
+ pollable* po_at_start =
+ POLLABLE_REF(pollset->active_pollable, "pollset_add_fd");
+ switch (pollset->active_pollable->type) {
+ case PO_EMPTY:
+ /* empty pollable --> single fd pollable */
+ error = pollset_transition_pollable_from_empty_to_fd_locked(pollset, fd);
+ break;
+ case PO_FD:
+ gpr_mu_lock(&po_at_start->owner_orphan_mu);
+ if (po_at_start->owner_orphaned) {
+ error =
+ pollset_transition_pollable_from_empty_to_fd_locked(pollset, fd);
+ } else {
+ /* fd --> multipoller */
+ error =
+ pollset_transition_pollable_from_fd_to_multi_locked(pollset, fd);
+ }
+ gpr_mu_unlock(&po_at_start->owner_orphan_mu);
+ break;
+ case PO_MULTI:
+ error = pollable_add_fd(pollset->active_pollable, fd);
+ break;
+ }
+ if (error != GRPC_ERROR_NONE) {
+ POLLABLE_UNREF(pollset->active_pollable, "pollset");
+ pollset->active_pollable = po_at_start;
+ } else {
+ gpr_atm_rel_store(&pollset->active_pollable_type,
+ pollset->active_pollable->type);
+ POLLABLE_UNREF(po_at_start, "pollset_add_fd");
+ }
+ return error;
+}
+
+static grpc_error* pollset_as_multipollable_locked(grpc_pollset* pollset,
+ pollable** pollable_obj) {
+ grpc_error* error = GRPC_ERROR_NONE;
+ pollable* po_at_start =
+ POLLABLE_REF(pollset->active_pollable, "pollset_as_multipollable");
+ switch (pollset->active_pollable->type) {
+ case PO_EMPTY:
+ POLLABLE_UNREF(pollset->active_pollable, "pollset");
+ error = pollable_create(PO_MULTI, &pollset->active_pollable);
+ /* Any workers currently polling on this pollset must now be woked up so
+ * that they can pick up the new active_pollable */
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO,
+ "PS:%p active pollable transition from empty to multi",
+ pollset);
+ }
+ static const char* err_desc =
+ "pollset_as_multipollable_locked: empty -> multi";
+ append_error(&error, pollset_kick_all(pollset), err_desc);
+ break;
+ case PO_FD:
+ gpr_mu_lock(&po_at_start->owner_orphan_mu);
+ if (po_at_start->owner_orphaned) {
+ // Unlock before Unref'ing the pollable
+ gpr_mu_unlock(&po_at_start->owner_orphan_mu);
+ POLLABLE_UNREF(pollset->active_pollable, "pollset");
+ error = pollable_create(PO_MULTI, &pollset->active_pollable);
+ } else {
+ error = pollset_transition_pollable_from_fd_to_multi_locked(pollset,
+ nullptr);
+ gpr_mu_unlock(&po_at_start->owner_orphan_mu);
+ }
+ break;
+ case PO_MULTI:
+ break;
+ }
+ if (error != GRPC_ERROR_NONE) {
+ POLLABLE_UNREF(pollset->active_pollable, "pollset");
+ pollset->active_pollable = po_at_start;
+ *pollable_obj = nullptr;
+ } else {
+ gpr_atm_rel_store(&pollset->active_pollable_type,
+ pollset->active_pollable->type);
+ *pollable_obj = POLLABLE_REF(pollset->active_pollable, "pollset_set");
+ POLLABLE_UNREF(po_at_start, "pollset_as_multipollable");
+ }
+ return error;
+}
+
+static void pollset_add_fd(grpc_pollset* pollset, grpc_fd* fd) {
+ GPR_TIMER_SCOPE("pollset_add_fd", 0);
+
+ // We never transition from PO_MULTI to other modes (i.e., PO_FD or PO_EMPTY)
+ // and, thus, it is safe to simply store and check whether the FD has already
+ // been added to the active pollable previously.
+ if (gpr_atm_acq_load(&pollset->active_pollable_type) == PO_MULTI &&
+ fd_has_pollset(fd, pollset)) {
+ return;
+ }
+
+ grpc_core::MutexLock lock(&pollset->mu);
+ grpc_error* error = pollset_add_fd_locked(pollset, fd);
+
+ // If we are in PO_MULTI mode, we should update the pollsets of the FD.
+ if (gpr_atm_no_barrier_load(&pollset->active_pollable_type) == PO_MULTI) {
+ fd_add_pollset(fd, pollset);
+ }
+
+ GRPC_LOG_IF_ERROR("pollset_add_fd", error);
+}
+
+/*******************************************************************************
+ * Pollset-set Definitions
+ */
+
+static grpc_pollset_set* pss_lock_adam(grpc_pollset_set* pss) {
+ gpr_mu_lock(&pss->mu);
+ while (pss->parent != nullptr) {
+ gpr_mu_unlock(&pss->mu);
+ pss = pss->parent;
+ gpr_mu_lock(&pss->mu);
+ }
+ return pss;
+}
+
+static grpc_pollset_set* pollset_set_create(void) {
+ grpc_pollset_set* pss =
+ static_cast<grpc_pollset_set*>(gpr_zalloc(sizeof(*pss)));
+ gpr_mu_init(&pss->mu);
+ new (&pss->refs) grpc_core::RefCount();
+ return pss;
+}
+
+static void pollset_set_unref(grpc_pollset_set* pss) {
+ if (pss == nullptr) return;
+ if (GPR_LIKELY(!pss->refs.Unref())) return;
+ pollset_set_unref(pss->parent);
+ gpr_mu_destroy(&pss->mu);
+ for (size_t i = 0; i < pss->pollset_count; i++) {
+ gpr_mu_lock(&pss->pollsets[i]->mu);
+ if (0 == --pss->pollsets[i]->containing_pollset_set_count) {
+ pollset_maybe_finish_shutdown(pss->pollsets[i]);
+ }
+ gpr_mu_unlock(&pss->pollsets[i]->mu);
+ }
+ for (size_t i = 0; i < pss->fd_count; i++) {
+ UNREF_BY(pss->fds[i], 2, "pollset_set");
+ }
+ gpr_free(pss->pollsets);
+ gpr_free(pss->fds);
+ gpr_free(pss);
+}
+
+static void pollset_set_add_fd(grpc_pollset_set* pss, grpc_fd* fd) {
+ GPR_TIMER_SCOPE("pollset_set_add_fd", 0);
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PSS:%p: add fd %p (%d)", pss, fd, fd->fd);
+ }
+ grpc_error* error = GRPC_ERROR_NONE;
+ static const char* err_desc = "pollset_set_add_fd";
+ pss = pss_lock_adam(pss);
+ for (size_t i = 0; i < pss->pollset_count; i++) {
+ append_error(&error, pollable_add_fd(pss->pollsets[i]->active_pollable, fd),
+ err_desc);
+ }
+ if (pss->fd_count == pss->fd_capacity) {
+ pss->fd_capacity = GPR_MAX(pss->fd_capacity * 2, 8);
+ pss->fds = static_cast<grpc_fd**>(
+ gpr_realloc(pss->fds, pss->fd_capacity * sizeof(*pss->fds)));
+ }
+ REF_BY(fd, 2, "pollset_set");
+ pss->fds[pss->fd_count++] = fd;
+ gpr_mu_unlock(&pss->mu);
+
+ GRPC_LOG_IF_ERROR(err_desc, error);
+}
+
+static void pollset_set_del_fd(grpc_pollset_set* pss, grpc_fd* fd) {
+ GPR_TIMER_SCOPE("pollset_set_del_fd", 0);
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PSS:%p: del fd %p", pss, fd);
+ }
+ pss = pss_lock_adam(pss);
+ size_t i;
+ for (i = 0; i < pss->fd_count; i++) {
+ if (pss->fds[i] == fd) {
+ UNREF_BY(fd, 2, "pollset_set");
+ break;
+ }
+ }
+ GPR_ASSERT(i != pss->fd_count);
+ for (; i < pss->fd_count - 1; i++) {
+ pss->fds[i] = pss->fds[i + 1];
+ }
+ pss->fd_count--;
+ gpr_mu_unlock(&pss->mu);
+}
+
+static void pollset_set_del_pollset(grpc_pollset_set* pss, grpc_pollset* ps) {
+ GPR_TIMER_SCOPE("pollset_set_del_pollset", 0);
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PSS:%p: del pollset %p", pss, ps);
+ }
+ pss = pss_lock_adam(pss);
+ size_t i;
+ for (i = 0; i < pss->pollset_count; i++) {
+ if (pss->pollsets[i] == ps) {
+ break;
+ }
+ }
+ GPR_ASSERT(i != pss->pollset_count);
+ for (; i < pss->pollset_count - 1; i++) {
+ pss->pollsets[i] = pss->pollsets[i + 1];
+ }
+ pss->pollset_count--;
+ gpr_mu_unlock(&pss->mu);
+ gpr_mu_lock(&ps->mu);
+ if (0 == --ps->containing_pollset_set_count) {
+ pollset_maybe_finish_shutdown(ps);
+ }
+ gpr_mu_unlock(&ps->mu);
+}
+
+// add all fds to pollables, and output a new array of unorphaned out_fds
+// assumes pollsets are multipollable
+static grpc_error* add_fds_to_pollsets(grpc_fd** fds, size_t fd_count,
+ grpc_pollset** pollsets,
+ size_t pollset_count,
+ const char* err_desc, grpc_fd** out_fds,
+ size_t* out_fd_count) {
+ GPR_TIMER_SCOPE("add_fds_to_pollsets", 0);
+ grpc_error* error = GRPC_ERROR_NONE;
+ for (size_t i = 0; i < fd_count; i++) {
+ gpr_mu_lock(&fds[i]->orphan_mu);
+ if ((gpr_atm_no_barrier_load(&fds[i]->refst) & 1) == 0) {
+ gpr_mu_unlock(&fds[i]->orphan_mu);
+ UNREF_BY(fds[i], 2, "pollset_set");
+ } else {
+ for (size_t j = 0; j < pollset_count; j++) {
+ append_error(&error,
+ pollable_add_fd(pollsets[j]->active_pollable, fds[i]),
+ err_desc);
+ }
+ gpr_mu_unlock(&fds[i]->orphan_mu);
+ out_fds[(*out_fd_count)++] = fds[i];
+ }
+ }
+ return error;
+}
+
+static void pollset_set_add_pollset(grpc_pollset_set* pss, grpc_pollset* ps) {
+ GPR_TIMER_SCOPE("pollset_set_add_pollset", 0);
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PSS:%p: add pollset %p", pss, ps);
+ }
+ grpc_error* error = GRPC_ERROR_NONE;
+ static const char* err_desc = "pollset_set_add_pollset";
+ pollable* pollable_obj = nullptr;
+ gpr_mu_lock(&ps->mu);
+ if (!GRPC_LOG_IF_ERROR(err_desc,
+ pollset_as_multipollable_locked(ps, &pollable_obj))) {
+ GPR_ASSERT(pollable_obj == nullptr);
+ gpr_mu_unlock(&ps->mu);
+ return;
+ }
+ ps->containing_pollset_set_count++;
+ gpr_mu_unlock(&ps->mu);
+ pss = pss_lock_adam(pss);
+ size_t initial_fd_count = pss->fd_count;
+ pss->fd_count = 0;
+ append_error(&error,
+ add_fds_to_pollsets(pss->fds, initial_fd_count, &ps, 1, err_desc,
+ pss->fds, &pss->fd_count),
+ err_desc);
+ if (pss->pollset_count == pss->pollset_capacity) {
+ pss->pollset_capacity = GPR_MAX(pss->pollset_capacity * 2, 8);
+ pss->pollsets = static_cast<grpc_pollset**>(gpr_realloc(
+ pss->pollsets, pss->pollset_capacity * sizeof(*pss->pollsets)));
+ }
+ pss->pollsets[pss->pollset_count++] = ps;
+ gpr_mu_unlock(&pss->mu);
+ POLLABLE_UNREF(pollable_obj, "pollset_set");
+
+ GRPC_LOG_IF_ERROR(err_desc, error);
+}
+
+static void pollset_set_add_pollset_set(grpc_pollset_set* a,
+ grpc_pollset_set* b) {
+ GPR_TIMER_SCOPE("pollset_set_add_pollset_set", 0);
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PSS: merge (%p, %p)", a, b);
+ }
+ grpc_error* error = GRPC_ERROR_NONE;
+ static const char* err_desc = "pollset_set_add_fd";
+ for (;;) {
+ if (a == b) {
+ // pollset ancestors are the same: nothing to do
+ return;
+ }
+ if (a > b) {
+ GPR_SWAP(grpc_pollset_set*, a, b);
+ }
+ gpr_mu* a_mu = &a->mu;
+ gpr_mu* b_mu = &b->mu;
+ gpr_mu_lock(a_mu);
+ gpr_mu_lock(b_mu);
+ if (a->parent != nullptr) {
+ a = a->parent;
+ } else if (b->parent != nullptr) {
+ b = b->parent;
+ } else {
+ break; // exit loop, both pollsets locked
+ }
+ gpr_mu_unlock(a_mu);
+ gpr_mu_unlock(b_mu);
+ }
+ // try to do the least copying possible
+ // TODO(sreek): there's probably a better heuristic here
+ const size_t a_size = a->fd_count + a->pollset_count;
+ const size_t b_size = b->fd_count + b->pollset_count;
+ if (b_size > a_size) {
+ GPR_SWAP(grpc_pollset_set*, a, b);
+ }
+ if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_trace)) {
+ gpr_log(GPR_INFO, "PSS: parent %p to %p", b, a);
+ }
+ a->refs.Ref();
+ b->parent = a;
+ if (a->fd_capacity < a->fd_count + b->fd_count) {
+ a->fd_capacity = GPR_MAX(2 * a->fd_capacity, a->fd_count + b->fd_count);
+ a->fds = static_cast<grpc_fd**>(
+ gpr_realloc(a->fds, a->fd_capacity * sizeof(*a->fds)));
+ }
+ size_t initial_a_fd_count = a->fd_count;
+ a->fd_count = 0;
+ append_error(
+ &error,
+ add_fds_to_pollsets(a->fds, initial_a_fd_count, b->pollsets,
+ b->pollset_count, "merge_a2b", a->fds, &a->fd_count),
+ err_desc);
+ append_error(
+ &error,
+ add_fds_to_pollsets(b->fds, b->fd_count, a->pollsets, a->pollset_count,
+ "merge_b2a", a->fds, &a->fd_count),
+ err_desc);
+ if (a->pollset_capacity < a->pollset_count + b->pollset_count) {
+ a->pollset_capacity =
+ GPR_MAX(2 * a->pollset_capacity, a->pollset_count + b->pollset_count);
+ a->pollsets = static_cast<grpc_pollset**>(
+ gpr_realloc(a->pollsets, a->pollset_capacity * sizeof(*a->pollsets)));
+ }
+ if (b->pollset_count > 0) {
+ memcpy(a->pollsets + a->pollset_count, b->pollsets,
+ b->pollset_count * sizeof(*b->pollsets));
+ }
+ a->pollset_count += b->pollset_count;
+ gpr_free(b->fds);
+ gpr_free(b->pollsets);
+ b->fds = nullptr;
+ b->pollsets = nullptr;
+ b->fd_count = b->fd_capacity = b->pollset_count = b->pollset_capacity = 0;
+ gpr_mu_unlock(&a->mu);
+ gpr_mu_unlock(&b->mu);
+}
+
+static void pollset_set_del_pollset_set(grpc_pollset_set* bag,
+ grpc_pollset_set* item) {}
+
+/*******************************************************************************
+ * Event engine binding
+ */
+
+static bool is_any_background_poller_thread(void) { return false; }
+
+static void shutdown_background_closure(void) {}
+
+static bool add_closure_to_background_poller(grpc_closure* closure,
+ grpc_error* error) {
+ return false;
+}
+
+static void shutdown_engine(void) {
+ fd_global_shutdown();
+ pollset_global_shutdown();
+}
+
+static const grpc_event_engine_vtable vtable = {
+ sizeof(grpc_pollset),
+ true,
+ false,
+
+ fd_create,
+ fd_wrapped_fd,
+ fd_orphan,
+ fd_shutdown,
+ fd_notify_on_read,
+ fd_notify_on_write,
+ fd_notify_on_error,
+ fd_become_readable,
+ fd_become_writable,
+ fd_has_errors,
+ fd_is_shutdown,
+
+ pollset_init,
+ pollset_shutdown,
+ pollset_destroy,
+ pollset_work,
+ pollset_kick,
+ pollset_add_fd,
+
+ pollset_set_create,
+ pollset_set_unref, // destroy ==> unref 1 public ref
+ pollset_set_add_pollset,
+ pollset_set_del_pollset,
+ pollset_set_add_pollset_set,
+ pollset_set_del_pollset_set,
+ pollset_set_add_fd,
+ pollset_set_del_fd,
+
+ is_any_background_poller_thread,
+ shutdown_background_closure,
+ shutdown_engine,
+ add_closure_to_background_poller,
+};
+
+const grpc_event_engine_vtable* grpc_init_epollex_linux(
+ bool explicitly_requested) {
+ if (!grpc_has_wakeup_fd()) {
+ gpr_log(GPR_ERROR, "Skipping epollex because of no wakeup fd.");
+ return nullptr;
+ }
+
+ if (!grpc_is_epollexclusive_available()) {
+ gpr_log(GPR_INFO, "Skipping epollex because it is not supported.");
+ return nullptr;
+ }
+
+ fd_global_init();
+
+ if (!GRPC_LOG_IF_ERROR("pollset_global_init", pollset_global_init())) {
+ pollset_global_shutdown();
+ fd_global_shutdown();
+ return nullptr;
+ }
+
+ return &vtable;
+}
+
+#else /* defined(GRPC_LINUX_EPOLL_CREATE1) */
+#if defined(GRPC_POSIX_SOCKET_EV_EPOLLEX)
+#include "src/core/lib/iomgr/ev_epollex_linux.h"
+/* If GRPC_LINUX_EPOLL_CREATE1 is not defined, it means
+ epoll_create1 is not available. Return NULL */
+const grpc_event_engine_vtable* grpc_init_epollex_linux(
+ bool explicitly_requested) {
+ return nullptr;
+}
+#endif /* defined(GRPC_POSIX_SOCKET_EV_EPOLLEX) */
+
+#endif /* !defined(GRPC_LINUX_EPOLL_CREATE1) */
git://repos.xcallymotion.com / motion2.git / blobdiff