| /* |
| * |
| * 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 |
| epoll_create() or epoll_create1() */ |
| #ifdef GRPC_LINUX_EPOLL |
| #include "src/core/lib/iomgr/ev_epoll1_linux.h" |
| |
| #include <assert.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <limits.h> |
| #include <poll.h> |
| #include <pthread.h> |
| #include <string.h> |
| #include <sys/epoll.h> |
| #include <sys/socket.h> |
| #include <unistd.h> |
| |
| #include <grpc/support/alloc.h> |
| #include <grpc/support/cpu.h> |
| #include <grpc/support/string_util.h> |
| |
| #include "src/core/lib/debug/stats.h" |
| #include "src/core/lib/gpr/string.h" |
| #include "src/core/lib/gpr/tls.h" |
| #include "src/core/lib/gpr/useful.h" |
| #include "src/core/lib/gprpp/manual_constructor.h" |
| #include "src/core/lib/iomgr/block_annotate.h" |
| #include "src/core/lib/iomgr/ev_posix.h" |
| #include "src/core/lib/iomgr/iomgr_internal.h" |
| #include "src/core/lib/iomgr/lockfree_event.h" |
| #include "src/core/lib/iomgr/wakeup_fd_posix.h" |
| #include "src/core/lib/profiling/timers.h" |
| |
| static grpc_wakeup_fd global_wakeup_fd; |
| |
| /******************************************************************************* |
| * Singleton epoll set related fields |
| */ |
| |
| #define MAX_EPOLL_EVENTS 100 |
| #define MAX_EPOLL_EVENTS_HANDLED_PER_ITERATION 1 |
| |
| /* NOTE ON SYNCHRONIZATION: |
| * - Fields in this struct are only modified by the designated poller. Hence |
| * there is no need for any locks to protect the struct. |
| * - num_events and cursor fields have to be of atomic type to provide memory |
| * visibility guarantees only. i.e In case of multiple pollers, the designated |
| * polling thread keeps changing; the thread that wrote these values may be |
| * different from the thread reading the values |
| */ |
| typedef struct epoll_set { |
| int epfd; |
| |
| /* The epoll_events after the last call to epoll_wait() */ |
| struct epoll_event events[MAX_EPOLL_EVENTS]; |
| |
| /* The number of epoll_events after the last call to epoll_wait() */ |
| gpr_atm num_events; |
| |
| /* Index of the first event in epoll_events that has to be processed. This |
| * field is only valid if num_events > 0 */ |
| gpr_atm cursor; |
| } epoll_set; |
| |
| /* The global singleton epoll set */ |
| static epoll_set g_epoll_set; |
| |
| static int epoll_create_and_cloexec() { |
| #ifdef GRPC_LINUX_EPOLL_CREATE1 |
| int fd = epoll_create1(EPOLL_CLOEXEC); |
| if (fd < 0) { |
| gpr_log(GPR_ERROR, "epoll_create1 unavailable"); |
| } |
| #else |
| int fd = epoll_create(MAX_EPOLL_EVENTS); |
| if (fd < 0) { |
| gpr_log(GPR_ERROR, "epoll_create unavailable"); |
| } else if (fcntl(fd, F_SETFD, FD_CLOEXEC) != 0) { |
| gpr_log(GPR_ERROR, "fcntl following epoll_create failed"); |
| return -1; |
| } |
| #endif |
| return fd; |
| } |
| |
| /* Must be called *only* once */ |
| static bool epoll_set_init() { |
| g_epoll_set.epfd = epoll_create_and_cloexec(); |
| if (g_epoll_set.epfd < 0) { |
| return false; |
| } |
| |
| gpr_log(GPR_INFO, "grpc epoll fd: %d", g_epoll_set.epfd); |
| gpr_atm_no_barrier_store(&g_epoll_set.num_events, 0); |
| gpr_atm_no_barrier_store(&g_epoll_set.cursor, 0); |
| return true; |
| } |
| |
| /* epoll_set_init() MUST be called before calling this. */ |
| static void epoll_set_shutdown() { |
| if (g_epoll_set.epfd >= 0) { |
| close(g_epoll_set.epfd); |
| g_epoll_set.epfd = -1; |
| } |
| } |
| |
| /******************************************************************************* |
| * Fd Declarations |
| */ |
| |
| /* Only used when GRPC_ENABLE_FORK_SUPPORT=1 */ |
| struct grpc_fork_fd_list { |
| grpc_fd* fd; |
| grpc_fd* next; |
| grpc_fd* prev; |
| }; |
| |
| struct grpc_fd { |
| int fd; |
| |
| grpc_core::ManualConstructor<grpc_core::LockfreeEvent> read_closure; |
| grpc_core::ManualConstructor<grpc_core::LockfreeEvent> write_closure; |
| grpc_core::ManualConstructor<grpc_core::LockfreeEvent> error_closure; |
| |
| struct grpc_fd* freelist_next; |
| |
| grpc_iomgr_object iomgr_object; |
| |
| /* Only used when GRPC_ENABLE_FORK_SUPPORT=1 */ |
| grpc_fork_fd_list* fork_fd_list; |
| }; |
| |
| static void fd_global_init(void); |
| static void fd_global_shutdown(void); |
| |
| /******************************************************************************* |
| * Pollset Declarations |
| */ |
| |
| typedef enum { UNKICKED, KICKED, DESIGNATED_POLLER } kick_state; |
| |
| static const char* kick_state_string(kick_state st) { |
| switch (st) { |
| case UNKICKED: |
| return "UNKICKED"; |
| case KICKED: |
| return "KICKED"; |
| case DESIGNATED_POLLER: |
| return "DESIGNATED_POLLER"; |
| } |
| GPR_UNREACHABLE_CODE(return "UNKNOWN"); |
| } |
| |
| struct grpc_pollset_worker { |
| kick_state state; |
| int kick_state_mutator; // which line of code last changed kick state |
| bool initialized_cv; |
| grpc_pollset_worker* next; |
| grpc_pollset_worker* prev; |
| gpr_cv cv; |
| grpc_closure_list schedule_on_end_work; |
| }; |
| |
| #define SET_KICK_STATE(worker, kick_state) \ |
| do { \ |
| (worker)->state = (kick_state); \ |
| (worker)->kick_state_mutator = __LINE__; \ |
| } while (false) |
| |
| #define MAX_NEIGHBORHOODS 1024 |
| |
| typedef struct pollset_neighborhood { |
| union { |
| char pad[GPR_CACHELINE_SIZE]; |
| struct { |
| gpr_mu mu; |
| grpc_pollset* active_root; |
| }; |
| }; |
| } pollset_neighborhood; |
| |
| struct grpc_pollset { |
| gpr_mu mu; |
| pollset_neighborhood* neighborhood; |
| bool reassigning_neighborhood; |
| grpc_pollset_worker* root_worker; |
| bool kicked_without_poller; |
| |
| /* Set to true if the pollset is observed to have no workers available to |
| poll */ |
| bool seen_inactive; |
| bool shutting_down; /* Is the pollset shutting down ? */ |
| grpc_closure* shutdown_closure; /* Called after after shutdown is complete */ |
| |
| /* Number of workers who are *about-to* attach themselves to the pollset |
| * worker list */ |
| int begin_refs; |
| |
| grpc_pollset* next; |
| grpc_pollset* prev; |
| }; |
| |
| /******************************************************************************* |
| * Pollset-set Declarations |
| */ |
| |
| struct grpc_pollset_set { |
| char unused; |
| }; |
| |
| /******************************************************************************* |
| * 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. |
| */ |
| |
| /* The alarm system needs to be able to wakeup 'some poller' sometimes |
| * (specifically when a new alarm needs to be triggered earlier than the next |
| * alarm 'epoch'). This wakeup_fd gives us something to alert on when such a |
| * case occurs. */ |
| |
| static grpc_fd* fd_freelist = nullptr; |
| static gpr_mu fd_freelist_mu; |
| |
| /* Only used when GRPC_ENABLE_FORK_SUPPORT=1 */ |
| static grpc_fd* fork_fd_list_head = nullptr; |
| static gpr_mu fork_fd_list_mu; |
| |
| 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 void fork_fd_list_add_grpc_fd(grpc_fd* fd) { |
| if (grpc_core::Fork::Enabled()) { |
| gpr_mu_lock(&fork_fd_list_mu); |
| fd->fork_fd_list = |
| static_cast<grpc_fork_fd_list*>(gpr_malloc(sizeof(grpc_fork_fd_list))); |
| fd->fork_fd_list->next = fork_fd_list_head; |
| fd->fork_fd_list->prev = nullptr; |
| if (fork_fd_list_head != nullptr) { |
| fork_fd_list_head->fork_fd_list->prev = fd; |
| } |
| fork_fd_list_head = fd; |
| gpr_mu_unlock(&fork_fd_list_mu); |
| } |
| } |
| |
| static void fork_fd_list_remove_grpc_fd(grpc_fd* fd) { |
| if (grpc_core::Fork::Enabled()) { |
| gpr_mu_lock(&fork_fd_list_mu); |
| if (fork_fd_list_head == fd) { |
| fork_fd_list_head = fd->fork_fd_list->next; |
| } |
| if (fd->fork_fd_list->prev != nullptr) { |
| fd->fork_fd_list->prev->fork_fd_list->next = fd->fork_fd_list->next; |
| } |
| if (fd->fork_fd_list->next != nullptr) { |
| fd->fork_fd_list->next->fork_fd_list->prev = fd->fork_fd_list->prev; |
| } |
| gpr_free(fd->fork_fd_list); |
| gpr_mu_unlock(&fork_fd_list_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))); |
| new_fd->read_closure.Init(); |
| new_fd->write_closure.Init(); |
| new_fd->error_closure.Init(); |
| } |
| new_fd->fd = fd; |
| new_fd->read_closure->InitEvent(); |
| new_fd->write_closure->InitEvent(); |
| new_fd->error_closure->InitEvent(); |
| |
| new_fd->freelist_next = nullptr; |
| |
| char* fd_name; |
| gpr_asprintf(&fd_name, "%s fd=%d", name, fd); |
| grpc_iomgr_register_object(&new_fd->iomgr_object, fd_name); |
| fork_fd_list_add_grpc_fd(new_fd); |
| #ifndef NDEBUG |
| if (grpc_trace_fd_refcount.enabled()) { |
| gpr_log(GPR_DEBUG, "FD %d %p create %s", fd, new_fd, fd_name); |
| } |
| #endif |
| gpr_free(fd_name); |
| |
| struct epoll_event ev; |
| ev.events = static_cast<uint32_t>(EPOLLIN | EPOLLOUT | EPOLLET); |
| /* Use the least significant bit of ev.data.ptr to store track_err. We expect |
| * the addresses to be word aligned. We need 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.data.ptr = reinterpret_cast<void*>(reinterpret_cast<intptr_t>(new_fd) | |
| (track_err ? 1 : 0)); |
| if (epoll_ctl(g_epoll_set.epfd, EPOLL_CTL_ADD, fd, &ev) != 0) { |
| gpr_log(GPR_ERROR, "epoll_ctl failed: %s", strerror(errno)); |
| } |
| |
| return new_fd; |
| } |
| |
| static int fd_wrapped_fd(grpc_fd* fd) { return fd->fd; } |
| |
| /* if 'releasing_fd' is true, it means that we are going to detach the internal |
| * fd from grpc_fd structure (i.e which means we should not be calling |
| * shutdown() syscall on that fd) */ |
| static void fd_shutdown_internal(grpc_fd* fd, grpc_error* why, |
| bool releasing_fd) { |
| if (fd->read_closure->SetShutdown(GRPC_ERROR_REF(why))) { |
| if (!releasing_fd) { |
| shutdown(fd->fd, SHUT_RDWR); |
| } |
| fd->write_closure->SetShutdown(GRPC_ERROR_REF(why)); |
| fd->error_closure->SetShutdown(GRPC_ERROR_REF(why)); |
| } |
| GRPC_ERROR_UNREF(why); |
| } |
| |
| /* Might be called multiple times */ |
| static void fd_shutdown(grpc_fd* fd, grpc_error* why) { |
| fd_shutdown_internal(fd, why, false); |
| } |
| |
| static void fd_orphan(grpc_fd* fd, grpc_closure* on_done, int* release_fd, |
| const char* reason) { |
| grpc_error* error = GRPC_ERROR_NONE; |
| bool is_release_fd = (release_fd != nullptr); |
| |
| if (!fd->read_closure->IsShutdown()) { |
| fd_shutdown_internal(fd, GRPC_ERROR_CREATE_FROM_COPIED_STRING(reason), |
| is_release_fd); |
| } |
| |
| /* 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 (is_release_fd) { |
| *release_fd = fd->fd; |
| } else { |
| close(fd->fd); |
| } |
| |
| GRPC_CLOSURE_SCHED(on_done, GRPC_ERROR_REF(error)); |
| |
| grpc_iomgr_unregister_object(&fd->iomgr_object); |
| fork_fd_list_remove_grpc_fd(fd); |
| fd->read_closure->DestroyEvent(); |
| fd->write_closure->DestroyEvent(); |
| fd->error_closure->DestroyEvent(); |
| |
| gpr_mu_lock(&fd_freelist_mu); |
| fd->freelist_next = fd_freelist; |
| fd_freelist = fd; |
| gpr_mu_unlock(&fd_freelist_mu); |
| } |
| |
| static bool fd_is_shutdown(grpc_fd* fd) { |
| return fd->read_closure->IsShutdown(); |
| } |
| |
| 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 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(); } |
| |
| /******************************************************************************* |
| * Pollset Definitions |
| */ |
| |
| GPR_TLS_DECL(g_current_thread_pollset); |
| GPR_TLS_DECL(g_current_thread_worker); |
| |
| /* The designated poller */ |
| static gpr_atm g_active_poller; |
| |
| static pollset_neighborhood* g_neighborhoods; |
| static size_t g_num_neighborhoods; |
| |
| /* Return true if first in list */ |
| static bool worker_insert(grpc_pollset* pollset, grpc_pollset_worker* worker) { |
| if (pollset->root_worker == nullptr) { |
| pollset->root_worker = worker; |
| worker->next = worker->prev = worker; |
| return true; |
| } else { |
| worker->next = pollset->root_worker; |
| worker->prev = worker->next->prev; |
| worker->next->prev = worker; |
| worker->prev->next = worker; |
| return false; |
| } |
| } |
| |
| /* Return true if last in list */ |
| typedef enum { EMPTIED, NEW_ROOT, REMOVED } worker_remove_result; |
| |
| static worker_remove_result worker_remove(grpc_pollset* pollset, |
| grpc_pollset_worker* worker) { |
| if (worker == pollset->root_worker) { |
| if (worker == worker->next) { |
| pollset->root_worker = nullptr; |
| return EMPTIED; |
| } else { |
| pollset->root_worker = worker->next; |
| worker->prev->next = worker->next; |
| worker->next->prev = worker->prev; |
| return NEW_ROOT; |
| } |
| } else { |
| worker->prev->next = worker->next; |
| worker->next->prev = worker->prev; |
| return REMOVED; |
| } |
| } |
| |
| static size_t choose_neighborhood(void) { |
| return static_cast<size_t>(gpr_cpu_current_cpu()) % g_num_neighborhoods; |
| } |
| |
| static grpc_error* pollset_global_init(void) { |
| gpr_tls_init(&g_current_thread_pollset); |
| gpr_tls_init(&g_current_thread_worker); |
| gpr_atm_no_barrier_store(&g_active_poller, 0); |
| global_wakeup_fd.read_fd = -1; |
| grpc_error* err = grpc_wakeup_fd_init(&global_wakeup_fd); |
| if (err != GRPC_ERROR_NONE) return err; |
| struct epoll_event ev; |
| ev.events = static_cast<uint32_t>(EPOLLIN | EPOLLET); |
| ev.data.ptr = &global_wakeup_fd; |
| if (epoll_ctl(g_epoll_set.epfd, EPOLL_CTL_ADD, global_wakeup_fd.read_fd, |
| &ev) != 0) { |
| return GRPC_OS_ERROR(errno, "epoll_ctl"); |
| } |
| g_num_neighborhoods = GPR_CLAMP(gpr_cpu_num_cores(), 1, MAX_NEIGHBORHOODS); |
| g_neighborhoods = static_cast<pollset_neighborhood*>( |
| gpr_zalloc(sizeof(*g_neighborhoods) * g_num_neighborhoods)); |
| for (size_t i = 0; i < g_num_neighborhoods; i++) { |
| gpr_mu_init(&g_neighborhoods[i].mu); |
| } |
| return GRPC_ERROR_NONE; |
| } |
| |
| static void pollset_global_shutdown(void) { |
| gpr_tls_destroy(&g_current_thread_pollset); |
| gpr_tls_destroy(&g_current_thread_worker); |
| if (global_wakeup_fd.read_fd != -1) grpc_wakeup_fd_destroy(&global_wakeup_fd); |
| for (size_t i = 0; i < g_num_neighborhoods; i++) { |
| gpr_mu_destroy(&g_neighborhoods[i].mu); |
| } |
| gpr_free(g_neighborhoods); |
| } |
| |
| static void pollset_init(grpc_pollset* pollset, gpr_mu** mu) { |
| gpr_mu_init(&pollset->mu); |
| *mu = &pollset->mu; |
| pollset->neighborhood = &g_neighborhoods[choose_neighborhood()]; |
| pollset->reassigning_neighborhood = false; |
| pollset->root_worker = nullptr; |
| pollset->kicked_without_poller = false; |
| pollset->seen_inactive = true; |
| pollset->shutting_down = false; |
| pollset->shutdown_closure = nullptr; |
| pollset->begin_refs = 0; |
| pollset->next = pollset->prev = nullptr; |
| } |
| |
| static void pollset_destroy(grpc_pollset* pollset) { |
| gpr_mu_lock(&pollset->mu); |
| if (!pollset->seen_inactive) { |
| pollset_neighborhood* neighborhood = pollset->neighborhood; |
| gpr_mu_unlock(&pollset->mu); |
| retry_lock_neighborhood: |
| gpr_mu_lock(&neighborhood->mu); |
| gpr_mu_lock(&pollset->mu); |
| if (!pollset->seen_inactive) { |
| if (pollset->neighborhood != neighborhood) { |
| gpr_mu_unlock(&neighborhood->mu); |
| neighborhood = pollset->neighborhood; |
| gpr_mu_unlock(&pollset->mu); |
| goto retry_lock_neighborhood; |
| } |
| pollset->prev->next = pollset->next; |
| pollset->next->prev = pollset->prev; |
| if (pollset == pollset->neighborhood->active_root) { |
| pollset->neighborhood->active_root = |
| pollset->next == pollset ? nullptr : pollset->next; |
| } |
| } |
| gpr_mu_unlock(&pollset->neighborhood->mu); |
| } |
| gpr_mu_unlock(&pollset->mu); |
| gpr_mu_destroy(&pollset->mu); |
| } |
| |
| static grpc_error* pollset_kick_all(grpc_pollset* pollset) { |
| GPR_TIMER_SCOPE("pollset_kick_all", 0); |
| grpc_error* error = GRPC_ERROR_NONE; |
| if (pollset->root_worker != nullptr) { |
| grpc_pollset_worker* worker = pollset->root_worker; |
| do { |
| GRPC_STATS_INC_POLLSET_KICK(); |
| switch (worker->state) { |
| case KICKED: |
| GRPC_STATS_INC_POLLSET_KICKED_AGAIN(); |
| break; |
| case UNKICKED: |
| SET_KICK_STATE(worker, KICKED); |
| if (worker->initialized_cv) { |
| GRPC_STATS_INC_POLLSET_KICK_WAKEUP_CV(); |
| gpr_cv_signal(&worker->cv); |
| } |
| break; |
| case DESIGNATED_POLLER: |
| GRPC_STATS_INC_POLLSET_KICK_WAKEUP_FD(); |
| SET_KICK_STATE(worker, KICKED); |
| append_error(&error, grpc_wakeup_fd_wakeup(&global_wakeup_fd), |
| "pollset_kick_all"); |
| break; |
| } |
| |
| worker = worker->next; |
| } while (worker != pollset->root_worker); |
| } |
| // TODO: sreek. Check if we need to set 'kicked_without_poller' to true here |
| // in the else case |
| return error; |
| } |
| |
| static void pollset_maybe_finish_shutdown(grpc_pollset* pollset) { |
| if (pollset->shutdown_closure != nullptr && pollset->root_worker == nullptr && |
| pollset->begin_refs == 0) { |
| GPR_TIMER_MARK("pollset_finish_shutdown", 0); |
| GRPC_CLOSURE_SCHED(pollset->shutdown_closure, GRPC_ERROR_NONE); |
| pollset->shutdown_closure = nullptr; |
| } |
| } |
| |
| static void pollset_shutdown(grpc_pollset* pollset, grpc_closure* closure) { |
| GPR_TIMER_SCOPE("pollset_shutdown", 0); |
| GPR_ASSERT(pollset->shutdown_closure == nullptr); |
| GPR_ASSERT(!pollset->shutting_down); |
| pollset->shutdown_closure = closure; |
| pollset->shutting_down = true; |
| GRPC_LOG_IF_ERROR("pollset_shutdown", pollset_kick_all(pollset)); |
| pollset_maybe_finish_shutdown(pollset); |
| } |
| |
| 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); |
| } |
| } |
| |
| /* Process the epoll events found by do_epoll_wait() function. |
| - g_epoll_set.cursor points to the index of the first event to be processed |
| - This function then processes up-to MAX_EPOLL_EVENTS_PER_ITERATION and |
| updates the g_epoll_set.cursor |
| |
| NOTE ON SYNCRHONIZATION: Similar to do_epoll_wait(), this function is only |
| called by g_active_poller thread. So there is no need for synchronization |
| when accessing fields in g_epoll_set */ |
| static grpc_error* process_epoll_events(grpc_pollset* pollset) { |
| GPR_TIMER_SCOPE("process_epoll_events", 0); |
| |
| static const char* err_desc = "process_events"; |
| grpc_error* error = GRPC_ERROR_NONE; |
| long num_events = gpr_atm_acq_load(&g_epoll_set.num_events); |
| long cursor = gpr_atm_acq_load(&g_epoll_set.cursor); |
| for (int idx = 0; |
| (idx < MAX_EPOLL_EVENTS_HANDLED_PER_ITERATION) && cursor != num_events; |
| idx++) { |
| long c = cursor++; |
| struct epoll_event* ev = &g_epoll_set.events[c]; |
| void* data_ptr = ev->data.ptr; |
| |
| if (data_ptr == &global_wakeup_fd) { |
| append_error(&error, grpc_wakeup_fd_consume_wakeup(&global_wakeup_fd), |
| err_desc); |
| } else { |
| grpc_fd* fd = reinterpret_cast<grpc_fd*>( |
| reinterpret_cast<intptr_t>(data_ptr) & ~static_cast<intptr_t>(1)); |
| bool track_err = |
| reinterpret_cast<intptr_t>(data_ptr) & static_cast<intptr_t>(1); |
| 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 (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); |
| } |
| } |
| } |
| gpr_atm_rel_store(&g_epoll_set.cursor, cursor); |
| return error; |
| } |
| |
| /* Do epoll_wait and store the events in g_epoll_set.events field. This does not |
| "process" any of the events yet; that is done in process_epoll_events(). |
| *See process_epoll_events() function for more details. |
| |
| NOTE ON SYNCHRONIZATION: At any point of time, only the g_active_poller |
| (i.e the designated poller thread) will be calling this function. So there is |
| no need for any synchronization when accesing fields in g_epoll_set */ |
| static grpc_error* do_epoll_wait(grpc_pollset* ps, grpc_millis deadline) { |
| GPR_TIMER_SCOPE("do_epoll_wait", 0); |
| |
| int r; |
| int timeout = poll_deadline_to_millis_timeout(deadline); |
| if (timeout != 0) { |
| GRPC_SCHEDULING_START_BLOCKING_REGION; |
| } |
| do { |
| GRPC_STATS_INC_SYSCALL_POLL(); |
| r = epoll_wait(g_epoll_set.epfd, g_epoll_set.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"); |
| |
| GRPC_STATS_INC_POLL_EVENTS_RETURNED(r); |
| |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, "ps: %p poll got %d events", ps, r); |
| } |
| |
| gpr_atm_rel_store(&g_epoll_set.num_events, r); |
| gpr_atm_rel_store(&g_epoll_set.cursor, 0); |
| |
| return GRPC_ERROR_NONE; |
| } |
| |
| 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); |
| if (worker_hdl != nullptr) *worker_hdl = worker; |
| worker->initialized_cv = false; |
| SET_KICK_STATE(worker, UNKICKED); |
| worker->schedule_on_end_work = (grpc_closure_list)GRPC_CLOSURE_LIST_INIT; |
| pollset->begin_refs++; |
| |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, "PS:%p BEGIN_STARTS:%p", pollset, worker); |
| } |
| |
| if (pollset->seen_inactive) { |
| // pollset has been observed to be inactive, we need to move back to the |
| // active list |
| bool is_reassigning = false; |
| if (!pollset->reassigning_neighborhood) { |
| is_reassigning = true; |
| pollset->reassigning_neighborhood = true; |
| pollset->neighborhood = &g_neighborhoods[choose_neighborhood()]; |
| } |
| pollset_neighborhood* neighborhood = pollset->neighborhood; |
| gpr_mu_unlock(&pollset->mu); |
| // pollset unlocked: state may change (even worker->kick_state) |
| retry_lock_neighborhood: |
| gpr_mu_lock(&neighborhood->mu); |
| gpr_mu_lock(&pollset->mu); |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, "PS:%p BEGIN_REORG:%p kick_state=%s is_reassigning=%d", |
| pollset, worker, kick_state_string(worker->state), |
| is_reassigning); |
| } |
| if (pollset->seen_inactive) { |
| if (neighborhood != pollset->neighborhood) { |
| gpr_mu_unlock(&neighborhood->mu); |
| neighborhood = pollset->neighborhood; |
| gpr_mu_unlock(&pollset->mu); |
| goto retry_lock_neighborhood; |
| } |
| |
| /* In the brief time we released the pollset locks above, the worker MAY |
| have been kicked. In this case, the worker should get out of this |
| pollset ASAP and hence this should neither add the pollset to |
| neighborhood nor mark the pollset as active. |
| |
| On a side note, the only way a worker's kick state could have changed |
| at this point is if it were "kicked specifically". Since the worker has |
| not added itself to the pollset yet (by calling worker_insert()), it is |
| not visible in the "kick any" path yet */ |
| if (worker->state == UNKICKED) { |
| pollset->seen_inactive = false; |
| if (neighborhood->active_root == nullptr) { |
| neighborhood->active_root = pollset->next = pollset->prev = pollset; |
| /* Make this the designated poller if there isn't one already */ |
| if (worker->state == UNKICKED && |
| gpr_atm_no_barrier_cas(&g_active_poller, 0, (gpr_atm)worker)) { |
| SET_KICK_STATE(worker, DESIGNATED_POLLER); |
| } |
| } else { |
| pollset->next = neighborhood->active_root; |
| pollset->prev = pollset->next->prev; |
| pollset->next->prev = pollset->prev->next = pollset; |
| } |
| } |
| } |
| if (is_reassigning) { |
| GPR_ASSERT(pollset->reassigning_neighborhood); |
| pollset->reassigning_neighborhood = false; |
| } |
| gpr_mu_unlock(&neighborhood->mu); |
| } |
| |
| worker_insert(pollset, worker); |
| pollset->begin_refs--; |
| if (worker->state == UNKICKED && !pollset->kicked_without_poller) { |
| GPR_ASSERT(gpr_atm_no_barrier_load(&g_active_poller) != (gpr_atm)worker); |
| worker->initialized_cv = true; |
| gpr_cv_init(&worker->cv); |
| while (worker->state == UNKICKED && !pollset->shutting_down) { |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, "PS:%p BEGIN_WAIT:%p kick_state=%s shutdown=%d", |
| pollset, worker, kick_state_string(worker->state), |
| pollset->shutting_down); |
| } |
| |
| if (gpr_cv_wait(&worker->cv, &pollset->mu, |
| grpc_millis_to_timespec(deadline, GPR_CLOCK_MONOTONIC)) && |
| worker->state == UNKICKED) { |
| /* If gpr_cv_wait returns true (i.e a timeout), pretend that the worker |
| received a kick */ |
| SET_KICK_STATE(worker, KICKED); |
| } |
| } |
| grpc_core::ExecCtx::Get()->InvalidateNow(); |
| } |
| |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, |
| "PS:%p BEGIN_DONE:%p kick_state=%s shutdown=%d " |
| "kicked_without_poller: %d", |
| pollset, worker, kick_state_string(worker->state), |
| pollset->shutting_down, pollset->kicked_without_poller); |
| } |
| |
| /* We release pollset lock in this function at a couple of places: |
| * 1. Briefly when assigning pollset to a neighborhood |
| * 2. When doing gpr_cv_wait() |
| * It is possible that 'kicked_without_poller' was set to true during (1) and |
| * 'shutting_down' is set to true during (1) or (2). If either of them is |
| * true, this worker cannot do polling */ |
| /* TODO(sreek): Perhaps there is a better way to handle kicked_without_poller |
| * case; especially when the worker is the DESIGNATED_POLLER */ |
| |
| if (pollset->kicked_without_poller) { |
| pollset->kicked_without_poller = false; |
| return false; |
| } |
| |
| return worker->state == DESIGNATED_POLLER && !pollset->shutting_down; |
| } |
| |
| static bool check_neighborhood_for_available_poller( |
| pollset_neighborhood* neighborhood) { |
| GPR_TIMER_SCOPE("check_neighborhood_for_available_poller", 0); |
| bool found_worker = false; |
| do { |
| grpc_pollset* inspect = neighborhood->active_root; |
| if (inspect == nullptr) { |
| break; |
| } |
| gpr_mu_lock(&inspect->mu); |
| GPR_ASSERT(!inspect->seen_inactive); |
| grpc_pollset_worker* inspect_worker = inspect->root_worker; |
| if (inspect_worker != nullptr) { |
| do { |
| switch (inspect_worker->state) { |
| case UNKICKED: |
| if (gpr_atm_no_barrier_cas(&g_active_poller, 0, |
| (gpr_atm)inspect_worker)) { |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. choose next poller to be %p", |
| inspect_worker); |
| } |
| SET_KICK_STATE(inspect_worker, DESIGNATED_POLLER); |
| if (inspect_worker->initialized_cv) { |
| GPR_TIMER_MARK("signal worker", 0); |
| GRPC_STATS_INC_POLLSET_KICK_WAKEUP_CV(); |
| gpr_cv_signal(&inspect_worker->cv); |
| } |
| } else { |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. beaten to choose next poller"); |
| } |
| } |
| // even if we didn't win the cas, there's a worker, we can stop |
| found_worker = true; |
| break; |
| case KICKED: |
| break; |
| case DESIGNATED_POLLER: |
| found_worker = true; // ok, so someone else found the worker, but |
| // we'll accept that |
| break; |
| } |
| inspect_worker = inspect_worker->next; |
| } while (!found_worker && inspect_worker != inspect->root_worker); |
| } |
| if (!found_worker) { |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. mark pollset %p inactive", inspect); |
| } |
| inspect->seen_inactive = true; |
| if (inspect == neighborhood->active_root) { |
| neighborhood->active_root = |
| inspect->next == inspect ? nullptr : inspect->next; |
| } |
| inspect->next->prev = inspect->prev; |
| inspect->prev->next = inspect->next; |
| inspect->next = inspect->prev = nullptr; |
| } |
| gpr_mu_unlock(&inspect->mu); |
| } while (!found_worker); |
| return found_worker; |
| } |
| |
| static void end_worker(grpc_pollset* pollset, grpc_pollset_worker* worker, |
| grpc_pollset_worker** worker_hdl) { |
| GPR_TIMER_SCOPE("end_worker", 0); |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, "PS:%p END_WORKER:%p", pollset, worker); |
| } |
| if (worker_hdl != nullptr) *worker_hdl = nullptr; |
| /* Make sure we appear kicked */ |
| SET_KICK_STATE(worker, KICKED); |
| grpc_closure_list_move(&worker->schedule_on_end_work, |
| grpc_core::ExecCtx::Get()->closure_list()); |
| if (gpr_atm_no_barrier_load(&g_active_poller) == (gpr_atm)worker) { |
| if (worker->next != worker && worker->next->state == UNKICKED) { |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. choose next poller to be peer %p", worker); |
| } |
| GPR_ASSERT(worker->next->initialized_cv); |
| gpr_atm_no_barrier_store(&g_active_poller, (gpr_atm)worker->next); |
| SET_KICK_STATE(worker->next, DESIGNATED_POLLER); |
| GRPC_STATS_INC_POLLSET_KICK_WAKEUP_CV(); |
| gpr_cv_signal(&worker->next->cv); |
| if (grpc_core::ExecCtx::Get()->HasWork()) { |
| gpr_mu_unlock(&pollset->mu); |
| grpc_core::ExecCtx::Get()->Flush(); |
| gpr_mu_lock(&pollset->mu); |
| } |
| } else { |
| gpr_atm_no_barrier_store(&g_active_poller, 0); |
| size_t poller_neighborhood_idx = |
| static_cast<size_t>(pollset->neighborhood - g_neighborhoods); |
| gpr_mu_unlock(&pollset->mu); |
| bool found_worker = false; |
| bool scan_state[MAX_NEIGHBORHOODS]; |
| for (size_t i = 0; !found_worker && i < g_num_neighborhoods; i++) { |
| pollset_neighborhood* neighborhood = |
| &g_neighborhoods[(poller_neighborhood_idx + i) % |
| g_num_neighborhoods]; |
| if (gpr_mu_trylock(&neighborhood->mu)) { |
| found_worker = check_neighborhood_for_available_poller(neighborhood); |
| gpr_mu_unlock(&neighborhood->mu); |
| scan_state[i] = true; |
| } else { |
| scan_state[i] = false; |
| } |
| } |
| for (size_t i = 0; !found_worker && i < g_num_neighborhoods; i++) { |
| if (scan_state[i]) continue; |
| pollset_neighborhood* neighborhood = |
| &g_neighborhoods[(poller_neighborhood_idx + i) % |
| g_num_neighborhoods]; |
| gpr_mu_lock(&neighborhood->mu); |
| found_worker = check_neighborhood_for_available_poller(neighborhood); |
| gpr_mu_unlock(&neighborhood->mu); |
| } |
| grpc_core::ExecCtx::Get()->Flush(); |
| gpr_mu_lock(&pollset->mu); |
| } |
| } else if (grpc_core::ExecCtx::Get()->HasWork()) { |
| gpr_mu_unlock(&pollset->mu); |
| grpc_core::ExecCtx::Get()->Flush(); |
| gpr_mu_lock(&pollset->mu); |
| } |
| if (worker->initialized_cv) { |
| gpr_cv_destroy(&worker->cv); |
| } |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. remove worker"); |
| } |
| if (EMPTIED == worker_remove(pollset, worker)) { |
| pollset_maybe_finish_shutdown(pollset); |
| } |
| GPR_ASSERT(gpr_atm_no_barrier_load(&g_active_poller) != (gpr_atm)worker); |
| } |
| |
| /* pollset->po.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* ps, |
| grpc_pollset_worker** worker_hdl, |
| grpc_millis deadline) { |
| GPR_TIMER_SCOPE("pollset_work", 0); |
| grpc_pollset_worker worker; |
| grpc_error* error = GRPC_ERROR_NONE; |
| static const char* err_desc = "pollset_work"; |
| if (ps->kicked_without_poller) { |
| ps->kicked_without_poller = false; |
| return GRPC_ERROR_NONE; |
| } |
| |
| if (begin_worker(ps, &worker, worker_hdl, deadline)) { |
| gpr_tls_set(&g_current_thread_pollset, (intptr_t)ps); |
| gpr_tls_set(&g_current_thread_worker, (intptr_t)&worker); |
| GPR_ASSERT(!ps->shutting_down); |
| GPR_ASSERT(!ps->seen_inactive); |
| |
| gpr_mu_unlock(&ps->mu); /* unlock */ |
| /* This is the designated polling thread at this point and should ideally do |
| polling. However, if there are unprocessed events left from a previous |
| call to do_epoll_wait(), skip calling epoll_wait() in this iteration and |
| process the pending epoll events. |
| |
| The reason for decoupling do_epoll_wait and process_epoll_events is to |
| better distrubute the work (i.e handling epoll events) across multiple |
| threads |
| |
| process_epoll_events() returns very quickly: It just queues the work on |
| exec_ctx but does not execute it (the actual exectution or more |
| accurately grpc_core::ExecCtx::Get()->Flush() happens in end_worker() |
| AFTER selecting a designated poller). So we are not waiting long periods |
| without a designated poller */ |
| if (gpr_atm_acq_load(&g_epoll_set.cursor) == |
| gpr_atm_acq_load(&g_epoll_set.num_events)) { |
| append_error(&error, do_epoll_wait(ps, deadline), err_desc); |
| } |
| append_error(&error, process_epoll_events(ps), err_desc); |
| |
| gpr_mu_lock(&ps->mu); /* lock */ |
| |
| gpr_tls_set(&g_current_thread_worker, 0); |
| } else { |
| gpr_tls_set(&g_current_thread_pollset, (intptr_t)ps); |
| } |
| end_worker(ps, &worker, worker_hdl); |
| |
| gpr_tls_set(&g_current_thread_pollset, 0); |
| return error; |
| } |
| |
| static grpc_error* pollset_kick(grpc_pollset* pollset, |
| grpc_pollset_worker* specific_worker) { |
| GPR_TIMER_SCOPE("pollset_kick", 0); |
| GRPC_STATS_INC_POLLSET_KICK(); |
| grpc_error* ret_err = GRPC_ERROR_NONE; |
| if (grpc_polling_trace.enabled()) { |
| gpr_strvec log; |
| gpr_strvec_init(&log); |
| char* tmp; |
| gpr_asprintf(&tmp, "PS:%p KICK:%p curps=%p curworker=%p root=%p", pollset, |
| specific_worker, (void*)gpr_tls_get(&g_current_thread_pollset), |
| (void*)gpr_tls_get(&g_current_thread_worker), |
| pollset->root_worker); |
| gpr_strvec_add(&log, tmp); |
| if (pollset->root_worker != nullptr) { |
| gpr_asprintf(&tmp, " {kick_state=%s next=%p {kick_state=%s}}", |
| kick_state_string(pollset->root_worker->state), |
| pollset->root_worker->next, |
| kick_state_string(pollset->root_worker->next->state)); |
| gpr_strvec_add(&log, tmp); |
| } |
| if (specific_worker != nullptr) { |
| gpr_asprintf(&tmp, " worker_kick_state=%s", |
| kick_state_string(specific_worker->state)); |
| gpr_strvec_add(&log, tmp); |
| } |
| tmp = gpr_strvec_flatten(&log, nullptr); |
| gpr_strvec_destroy(&log); |
| gpr_log(GPR_DEBUG, "%s", tmp); |
| gpr_free(tmp); |
| } |
| |
| if (specific_worker == nullptr) { |
| if (gpr_tls_get(&g_current_thread_pollset) != (intptr_t)pollset) { |
| grpc_pollset_worker* root_worker = pollset->root_worker; |
| if (root_worker == nullptr) { |
| GRPC_STATS_INC_POLLSET_KICKED_WITHOUT_POLLER(); |
| pollset->kicked_without_poller = true; |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. kicked_without_poller"); |
| } |
| goto done; |
| } |
| grpc_pollset_worker* next_worker = root_worker->next; |
| if (root_worker->state == KICKED) { |
| GRPC_STATS_INC_POLLSET_KICKED_AGAIN(); |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. already kicked %p", root_worker); |
| } |
| SET_KICK_STATE(root_worker, KICKED); |
| goto done; |
| } else if (next_worker->state == KICKED) { |
| GRPC_STATS_INC_POLLSET_KICKED_AGAIN(); |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. already kicked %p", next_worker); |
| } |
| SET_KICK_STATE(next_worker, KICKED); |
| goto done; |
| } else if (root_worker == |
| next_worker && // only try and wake up a poller if |
| // there is no next worker |
| root_worker == (grpc_pollset_worker*)gpr_atm_no_barrier_load( |
| &g_active_poller)) { |
| GRPC_STATS_INC_POLLSET_KICK_WAKEUP_FD(); |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. kicked %p", root_worker); |
| } |
| SET_KICK_STATE(root_worker, KICKED); |
| ret_err = grpc_wakeup_fd_wakeup(&global_wakeup_fd); |
| goto done; |
| } else if (next_worker->state == UNKICKED) { |
| GRPC_STATS_INC_POLLSET_KICK_WAKEUP_CV(); |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. kicked %p", next_worker); |
| } |
| GPR_ASSERT(next_worker->initialized_cv); |
| SET_KICK_STATE(next_worker, KICKED); |
| gpr_cv_signal(&next_worker->cv); |
| goto done; |
| } else if (next_worker->state == DESIGNATED_POLLER) { |
| if (root_worker->state != DESIGNATED_POLLER) { |
| if (grpc_polling_trace.enabled()) { |
| gpr_log( |
| GPR_INFO, |
| " .. kicked root non-poller %p (initialized_cv=%d) (poller=%p)", |
| root_worker, root_worker->initialized_cv, next_worker); |
| } |
| SET_KICK_STATE(root_worker, KICKED); |
| if (root_worker->initialized_cv) { |
| GRPC_STATS_INC_POLLSET_KICK_WAKEUP_CV(); |
| gpr_cv_signal(&root_worker->cv); |
| } |
| goto done; |
| } else { |
| GRPC_STATS_INC_POLLSET_KICK_WAKEUP_FD(); |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. non-root poller %p (root=%p)", next_worker, |
| root_worker); |
| } |
| SET_KICK_STATE(next_worker, KICKED); |
| ret_err = grpc_wakeup_fd_wakeup(&global_wakeup_fd); |
| goto done; |
| } |
| } else { |
| GRPC_STATS_INC_POLLSET_KICKED_AGAIN(); |
| GPR_ASSERT(next_worker->state == KICKED); |
| SET_KICK_STATE(next_worker, KICKED); |
| goto done; |
| } |
| } else { |
| GRPC_STATS_INC_POLLSET_KICK_OWN_THREAD(); |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. kicked while waking up"); |
| } |
| goto done; |
| } |
| |
| GPR_UNREACHABLE_CODE(goto done); |
| } |
| |
| if (specific_worker->state == KICKED) { |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. specific worker already kicked"); |
| } |
| goto done; |
| } else if (gpr_tls_get(&g_current_thread_worker) == |
| (intptr_t)specific_worker) { |
| GRPC_STATS_INC_POLLSET_KICK_OWN_THREAD(); |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. mark %p kicked", specific_worker); |
| } |
| SET_KICK_STATE(specific_worker, KICKED); |
| goto done; |
| } else if (specific_worker == |
| (grpc_pollset_worker*)gpr_atm_no_barrier_load(&g_active_poller)) { |
| GRPC_STATS_INC_POLLSET_KICK_WAKEUP_FD(); |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. kick active poller"); |
| } |
| SET_KICK_STATE(specific_worker, KICKED); |
| ret_err = grpc_wakeup_fd_wakeup(&global_wakeup_fd); |
| goto done; |
| } else if (specific_worker->initialized_cv) { |
| GRPC_STATS_INC_POLLSET_KICK_WAKEUP_CV(); |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. kick waiting worker"); |
| } |
| SET_KICK_STATE(specific_worker, KICKED); |
| gpr_cv_signal(&specific_worker->cv); |
| goto done; |
| } else { |
| GRPC_STATS_INC_POLLSET_KICKED_AGAIN(); |
| if (grpc_polling_trace.enabled()) { |
| gpr_log(GPR_INFO, " .. kick non-waiting worker"); |
| } |
| SET_KICK_STATE(specific_worker, KICKED); |
| goto done; |
| } |
| done: |
| return ret_err; |
| } |
| |
| static void pollset_add_fd(grpc_pollset* pollset, grpc_fd* fd) {} |
| |
| /******************************************************************************* |
| * Pollset-set Definitions |
| */ |
| |
| static grpc_pollset_set* pollset_set_create(void) { |
| return (grpc_pollset_set*)(static_cast<intptr_t>(0xdeafbeef)); |
| } |
| |
| static void pollset_set_destroy(grpc_pollset_set* pss) {} |
| |
| static void pollset_set_add_fd(grpc_pollset_set* pss, grpc_fd* fd) {} |
| |
| static void pollset_set_del_fd(grpc_pollset_set* pss, grpc_fd* fd) {} |
| |
| static void pollset_set_add_pollset(grpc_pollset_set* pss, grpc_pollset* ps) {} |
| |
| static void pollset_set_del_pollset(grpc_pollset_set* pss, grpc_pollset* ps) {} |
| |
| static void pollset_set_add_pollset_set(grpc_pollset_set* bag, |
| grpc_pollset_set* item) {} |
| |
| static void pollset_set_del_pollset_set(grpc_pollset_set* bag, |
| grpc_pollset_set* item) {} |
| |
| /******************************************************************************* |
| * Event engine binding |
| */ |
| |
| static void shutdown_background_closure(void) {} |
| |
| static void shutdown_engine(void) { |
| fd_global_shutdown(); |
| pollset_global_shutdown(); |
| epoll_set_shutdown(); |
| if (grpc_core::Fork::Enabled()) { |
| gpr_mu_destroy(&fork_fd_list_mu); |
| grpc_core::Fork::SetResetChildPollingEngineFunc(nullptr); |
| } |
| } |
| |
| 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_destroy, |
| 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, |
| |
| shutdown_background_closure, |
| shutdown_engine, |
| }; |
| |
| /* Called by the child process's post-fork handler to close open fds, including |
| * the global epoll fd. This allows gRPC to shutdown in the child process |
| * without interfering with connections or RPCs ongoing in the parent. */ |
| static void reset_event_manager_on_fork() { |
| gpr_mu_lock(&fork_fd_list_mu); |
| while (fork_fd_list_head != nullptr) { |
| close(fork_fd_list_head->fd); |
| fork_fd_list_head->fd = -1; |
| fork_fd_list_head = fork_fd_list_head->fork_fd_list->next; |
| } |
| gpr_mu_unlock(&fork_fd_list_mu); |
| shutdown_engine(); |
| grpc_init_epoll1_linux(true); |
| } |
| |
| /* It is possible that GLIBC has epoll but the underlying kernel doesn't. |
| * Create epoll_fd (epoll_set_init() takes care of that) to make sure epoll |
| * support is available */ |
| const grpc_event_engine_vtable* grpc_init_epoll1_linux(bool explicit_request) { |
| if (!grpc_has_wakeup_fd()) { |
| gpr_log(GPR_ERROR, "Skipping epoll1 because of no wakeup fd."); |
| return nullptr; |
| } |
| |
| if (!epoll_set_init()) { |
| return nullptr; |
| } |
| |
| fd_global_init(); |
| |
| if (!GRPC_LOG_IF_ERROR("pollset_global_init", pollset_global_init())) { |
| fd_global_shutdown(); |
| epoll_set_shutdown(); |
| return nullptr; |
| } |
| |
| if (grpc_core::Fork::Enabled()) { |
| gpr_mu_init(&fork_fd_list_mu); |
| grpc_core::Fork::SetResetChildPollingEngineFunc( |
| reset_event_manager_on_fork); |
| } |
| return &vtable; |
| } |
| |
| #else /* defined(GRPC_LINUX_EPOLL) */ |
| #if defined(GRPC_POSIX_SOCKET_EV_EPOLL1) |
| #include "src/core/lib/iomgr/ev_epoll1_linux.h" |
| /* If GRPC_LINUX_EPOLL is not defined, it means epoll is not available. Return |
| * NULL */ |
| const grpc_event_engine_vtable* grpc_init_epoll1_linux(bool explicit_request) { |
| return nullptr; |
| } |
| #endif /* defined(GRPC_POSIX_SOCKET_EV_EPOLL1) */ |
| #endif /* !defined(GRPC_LINUX_EPOLL) */ |