| /* |
| * |
| * Copyright 2017, Google Inc. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following disclaimer |
| * in the documentation and/or other materials provided with the |
| * distribution. |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| */ |
| |
| #include "src/core/lib/iomgr/port.h" |
| |
| /* This polling engine is only relevant on linux kernels supporting epoll() */ |
| #ifdef GRPC_LINUX_EPOLL |
| |
| #include "src/core/lib/iomgr/ev_epoll1_linux.h" |
| |
| #include <assert.h> |
| #include <errno.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/log.h> |
| #include <grpc/support/string_util.h> |
| #include <grpc/support/tls.h> |
| #include <grpc/support/useful.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/iomgr/workqueue.h" |
| #include "src/core/lib/profiling/timers.h" |
| #include "src/core/lib/support/block_annotate.h" |
| #include "src/core/lib/support/string.h" |
| |
| static grpc_wakeup_fd global_wakeup_fd; |
| static int g_epfd; |
| |
| /******************************************************************************* |
| * Fd Declarations |
| */ |
| |
| struct grpc_fd { |
| int fd; |
| |
| gpr_atm read_closure; |
| gpr_atm write_closure; |
| |
| struct grpc_fd *freelist_next; |
| |
| /* The pollset that last noticed that the fd is readable. The actual type |
| * stored in this is (grpc_pollset *) */ |
| gpr_atm read_notifier_pollset; |
| |
| grpc_iomgr_object iomgr_object; |
| }; |
| |
| static void fd_global_init(void); |
| static void fd_global_shutdown(void); |
| |
| /******************************************************************************* |
| * Pollset Declarations |
| */ |
| |
| typedef enum { UNKICKED, KICKED, DESIGNATED_POLLER } kick_state; |
| |
| struct grpc_pollset_worker { |
| kick_state kick_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, state) \ |
| do { \ |
| (worker)->kick_state = (state); \ |
| (worker)->kick_state_mutator = __LINE__; \ |
| } while (false) |
| |
| #define MAX_NEIGHBOURHOODS 1024 |
| |
| typedef struct pollset_neighbourhood { |
| gpr_mu mu; |
| grpc_pollset *active_root; |
| char pad[GPR_CACHELINE_SIZE]; |
| } pollset_neighbourhood; |
| |
| struct grpc_pollset { |
| gpr_mu mu; |
| pollset_neighbourhood *neighbourhood; |
| bool reassigning_neighbourhood; |
| grpc_pollset_worker *root_worker; |
| bool kicked_without_poller; |
| bool seen_inactive; |
| bool shutting_down; /* Is the pollset shutting down ? */ |
| bool finish_shutdown_called; /* Is the 'finish_shutdown_locked()' called ? */ |
| grpc_closure *shutdown_closure; /* Called after after shutdown is complete */ |
| int begin_refs; |
| |
| grpc_pollset *next; |
| grpc_pollset *prev; |
| }; |
| |
| /******************************************************************************* |
| * Pollset-set Declarations |
| */ |
| |
| struct grpc_pollset_set {}; |
| |
| /******************************************************************************* |
| * 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 = NULL; |
| static gpr_mu fd_freelist_mu; |
| |
| static void fd_global_init(void) { gpr_mu_init(&fd_freelist_mu); } |
| |
| static void fd_global_shutdown(void) { |
| gpr_mu_lock(&fd_freelist_mu); |
| gpr_mu_unlock(&fd_freelist_mu); |
| while (fd_freelist != NULL) { |
| 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) { |
| grpc_fd *new_fd = NULL; |
| |
| gpr_mu_lock(&fd_freelist_mu); |
| if (fd_freelist != NULL) { |
| new_fd = fd_freelist; |
| fd_freelist = fd_freelist->freelist_next; |
| } |
| gpr_mu_unlock(&fd_freelist_mu); |
| |
| if (new_fd == NULL) { |
| new_fd = gpr_malloc(sizeof(grpc_fd)); |
| } |
| |
| new_fd->fd = fd; |
| grpc_lfev_init(&new_fd->read_closure); |
| grpc_lfev_init(&new_fd->write_closure); |
| gpr_atm_no_barrier_store(&new_fd->read_notifier_pollset, (gpr_atm)NULL); |
| |
| new_fd->freelist_next = NULL; |
| |
| char *fd_name; |
| gpr_asprintf(&fd_name, "%s fd=%d", name, fd); |
| grpc_iomgr_register_object(&new_fd->iomgr_object, fd_name); |
| #ifdef GRPC_FD_REF_COUNT_DEBUG |
| gpr_log(GPR_DEBUG, "FD %d %p create %s", fd, (void *)new_fd, fd_name); |
| #endif |
| gpr_free(fd_name); |
| |
| struct epoll_event ev = {.events = (uint32_t)(EPOLLIN | EPOLLOUT | EPOLLET), |
| .data.ptr = new_fd}; |
| if (epoll_ctl(g_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; } |
| |
| /* Might be called multiple times */ |
| static void fd_shutdown(grpc_exec_ctx *exec_ctx, grpc_fd *fd, grpc_error *why) { |
| if (grpc_lfev_set_shutdown(exec_ctx, &fd->read_closure, |
| GRPC_ERROR_REF(why))) { |
| shutdown(fd->fd, SHUT_RDWR); |
| grpc_lfev_set_shutdown(exec_ctx, &fd->write_closure, GRPC_ERROR_REF(why)); |
| } |
| GRPC_ERROR_UNREF(why); |
| } |
| |
| static void fd_orphan(grpc_exec_ctx *exec_ctx, grpc_fd *fd, |
| grpc_closure *on_done, int *release_fd, |
| const char *reason) { |
| grpc_error *error = GRPC_ERROR_NONE; |
| |
| if (!grpc_lfev_is_shutdown(&fd->read_closure)) { |
| fd_shutdown(exec_ctx, fd, GRPC_ERROR_CREATE_FROM_COPIED_STRING(reason)); |
| } |
| |
| /* 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 != NULL) { |
| *release_fd = fd->fd; |
| } else { |
| close(fd->fd); |
| } |
| |
| grpc_closure_sched(exec_ctx, on_done, GRPC_ERROR_REF(error)); |
| |
| grpc_iomgr_unregister_object(&fd->iomgr_object); |
| grpc_lfev_destroy(&fd->read_closure); |
| grpc_lfev_destroy(&fd->write_closure); |
| |
| gpr_mu_lock(&fd_freelist_mu); |
| fd->freelist_next = fd_freelist; |
| fd_freelist = fd; |
| gpr_mu_unlock(&fd_freelist_mu); |
| } |
| |
| static grpc_pollset *fd_get_read_notifier_pollset(grpc_exec_ctx *exec_ctx, |
| grpc_fd *fd) { |
| gpr_atm notifier = gpr_atm_acq_load(&fd->read_notifier_pollset); |
| return (grpc_pollset *)notifier; |
| } |
| |
| static bool fd_is_shutdown(grpc_fd *fd) { |
| return grpc_lfev_is_shutdown(&fd->read_closure); |
| } |
| |
| static void fd_notify_on_read(grpc_exec_ctx *exec_ctx, grpc_fd *fd, |
| grpc_closure *closure) { |
| grpc_lfev_notify_on(exec_ctx, &fd->read_closure, closure); |
| } |
| |
| static void fd_notify_on_write(grpc_exec_ctx *exec_ctx, grpc_fd *fd, |
| grpc_closure *closure) { |
| grpc_lfev_notify_on(exec_ctx, &fd->write_closure, closure); |
| } |
| |
| static grpc_workqueue *fd_get_workqueue(grpc_fd *fd) { |
| return (grpc_workqueue *)0xb0b51ed; |
| } |
| |
| static void fd_become_readable(grpc_exec_ctx *exec_ctx, grpc_fd *fd, |
| grpc_pollset *notifier) { |
| grpc_lfev_set_ready(exec_ctx, &fd->read_closure); |
| |
| /* Note, it is possible that fd_become_readable might be called twice with |
| different 'notifier's when an fd becomes readable and it is in two epoll |
| sets (This can happen briefly during polling island merges). In such cases |
| it does not really matter which notifer is set as the read_notifier_pollset |
| (They would both point to the same polling island anyway) */ |
| /* Use release store to match with acquire load in fd_get_read_notifier */ |
| gpr_atm_rel_store(&fd->read_notifier_pollset, (gpr_atm)notifier); |
| } |
| |
| static void fd_become_writable(grpc_exec_ctx *exec_ctx, grpc_fd *fd) { |
| grpc_lfev_set_ready(exec_ctx, &fd->write_closure); |
| } |
| |
| /******************************************************************************* |
| * Pollset Definitions |
| */ |
| |
| GPR_TLS_DECL(g_current_thread_pollset); |
| GPR_TLS_DECL(g_current_thread_worker); |
| static gpr_atm g_active_poller; |
| static pollset_neighbourhood *g_neighbourhoods; |
| static size_t g_num_neighbourhoods; |
| static gpr_mu g_wq_mu; |
| static grpc_closure_list g_wq_items; |
| |
| /* Return true if first in list */ |
| static bool worker_insert(grpc_pollset *pollset, grpc_pollset_worker *worker) { |
| if (pollset->root_worker == NULL) { |
| 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 = NULL; |
| 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_neighbourhood(void) { |
| return (size_t)gpr_cpu_current_cpu() % g_num_neighbourhoods; |
| } |
| |
| 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); |
| gpr_mu_init(&g_wq_mu); |
| g_wq_items = (grpc_closure_list)GRPC_CLOSURE_LIST_INIT; |
| if (err != GRPC_ERROR_NONE) return err; |
| struct epoll_event ev = {.events = (uint32_t)(EPOLLIN | EPOLLET), |
| .data.ptr = &global_wakeup_fd}; |
| if (epoll_ctl(g_epfd, EPOLL_CTL_ADD, global_wakeup_fd.read_fd, &ev) != 0) { |
| return GRPC_OS_ERROR(errno, "epoll_ctl"); |
| } |
| g_num_neighbourhoods = GPR_CLAMP(gpr_cpu_num_cores(), 1, MAX_NEIGHBOURHOODS); |
| g_neighbourhoods = |
| gpr_zalloc(sizeof(*g_neighbourhoods) * g_num_neighbourhoods); |
| for (size_t i = 0; i < g_num_neighbourhoods; i++) { |
| gpr_mu_init(&g_neighbourhoods[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); |
| gpr_mu_destroy(&g_wq_mu); |
| if (global_wakeup_fd.read_fd != -1) grpc_wakeup_fd_destroy(&global_wakeup_fd); |
| for (size_t i = 0; i < g_num_neighbourhoods; i++) { |
| gpr_mu_destroy(&g_neighbourhoods[i].mu); |
| } |
| gpr_free(g_neighbourhoods); |
| } |
| |
| static void pollset_init(grpc_pollset *pollset, gpr_mu **mu) { |
| gpr_mu_init(&pollset->mu); |
| *mu = &pollset->mu; |
| pollset->neighbourhood = &g_neighbourhoods[choose_neighbourhood()]; |
| pollset->seen_inactive = true; |
| } |
| |
| static void pollset_destroy(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset) { |
| gpr_mu_lock(&pollset->mu); |
| if (!pollset->seen_inactive) { |
| pollset_neighbourhood *neighbourhood = pollset->neighbourhood; |
| gpr_mu_unlock(&pollset->mu); |
| retry_lock_neighbourhood: |
| gpr_mu_lock(&neighbourhood->mu); |
| gpr_mu_lock(&pollset->mu); |
| if (!pollset->seen_inactive) { |
| if (pollset->neighbourhood != neighbourhood) { |
| gpr_mu_unlock(&neighbourhood->mu); |
| neighbourhood = pollset->neighbourhood; |
| gpr_mu_unlock(&pollset->mu); |
| goto retry_lock_neighbourhood; |
| } |
| pollset->prev->next = pollset->next; |
| pollset->next->prev = pollset->prev; |
| if (pollset == pollset->neighbourhood->active_root) { |
| pollset->neighbourhood->active_root = |
| pollset->next == pollset ? NULL : pollset->next; |
| } |
| } |
| gpr_mu_unlock(&pollset->neighbourhood->mu); |
| } |
| gpr_mu_unlock(&pollset->mu); |
| gpr_mu_destroy(&pollset->mu); |
| } |
| |
| static grpc_error *pollset_kick_all(grpc_pollset *pollset) { |
| grpc_error *error = GRPC_ERROR_NONE; |
| if (pollset->root_worker != NULL) { |
| grpc_pollset_worker *worker = pollset->root_worker; |
| do { |
| switch (worker->kick_state) { |
| case KICKED: |
| break; |
| case UNKICKED: |
| SET_KICK_STATE(worker, KICKED); |
| if (worker->initialized_cv) { |
| gpr_cv_signal(&worker->cv); |
| } |
| break; |
| case DESIGNATED_POLLER: |
| SET_KICK_STATE(worker, KICKED); |
| append_error(&error, grpc_wakeup_fd_wakeup(&global_wakeup_fd), |
| "pollset_shutdown"); |
| break; |
| } |
| |
| worker = worker->next; |
| } while (worker != pollset->root_worker); |
| } |
| return error; |
| } |
| |
| static void pollset_maybe_finish_shutdown(grpc_exec_ctx *exec_ctx, |
| grpc_pollset *pollset) { |
| if (pollset->shutdown_closure != NULL && pollset->root_worker == NULL && |
| pollset->begin_refs == 0) { |
| grpc_closure_sched(exec_ctx, pollset->shutdown_closure, GRPC_ERROR_NONE); |
| pollset->shutdown_closure = NULL; |
| } |
| } |
| |
| static void pollset_shutdown(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset, |
| grpc_closure *closure) { |
| GPR_ASSERT(pollset->shutdown_closure == NULL); |
| pollset->shutdown_closure = closure; |
| GRPC_LOG_IF_ERROR("pollset_shutdown", pollset_kick_all(pollset)); |
| pollset_maybe_finish_shutdown(exec_ctx, pollset); |
| } |
| |
| #define MAX_EPOLL_EVENTS 100 |
| |
| static int poll_deadline_to_millis_timeout(gpr_timespec deadline, |
| gpr_timespec now) { |
| gpr_timespec timeout; |
| if (gpr_time_cmp(deadline, gpr_inf_future(deadline.clock_type)) == 0) { |
| return -1; |
| } |
| |
| if (gpr_time_cmp(deadline, now) <= 0) { |
| return 0; |
| } |
| |
| static const gpr_timespec round_up = { |
| .clock_type = GPR_TIMESPAN, .tv_sec = 0, .tv_nsec = GPR_NS_PER_MS - 1}; |
| timeout = gpr_time_sub(deadline, now); |
| int millis = gpr_time_to_millis(gpr_time_add(timeout, round_up)); |
| return millis >= 1 ? millis : 1; |
| } |
| |
| static grpc_error *pollset_epoll(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset, |
| gpr_timespec now, gpr_timespec deadline) { |
| struct epoll_event events[MAX_EPOLL_EVENTS]; |
| static const char *err_desc = "pollset_poll"; |
| |
| int timeout = poll_deadline_to_millis_timeout(deadline, now); |
| |
| if (timeout != 0) { |
| GRPC_SCHEDULING_START_BLOCKING_REGION; |
| } |
| int r; |
| do { |
| r = epoll_wait(g_epfd, 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_error *error = GRPC_ERROR_NONE; |
| for (int i = 0; i < r; i++) { |
| void *data_ptr = events[i].data.ptr; |
| if (data_ptr == &global_wakeup_fd) { |
| gpr_mu_lock(&g_wq_mu); |
| grpc_closure_list_move(&g_wq_items, &exec_ctx->closure_list); |
| gpr_mu_unlock(&g_wq_mu); |
| append_error(&error, grpc_wakeup_fd_consume_wakeup(&global_wakeup_fd), |
| err_desc); |
| } else { |
| grpc_fd *fd = (grpc_fd *)(data_ptr); |
| bool cancel = (events[i].events & (EPOLLERR | EPOLLHUP)) != 0; |
| bool read_ev = (events[i].events & (EPOLLIN | EPOLLPRI)) != 0; |
| bool write_ev = (events[i].events & EPOLLOUT) != 0; |
| if (read_ev || cancel) { |
| fd_become_readable(exec_ctx, fd, pollset); |
| } |
| if (write_ev || cancel) { |
| fd_become_writable(exec_ctx, fd); |
| } |
| } |
| } |
| |
| return error; |
| } |
| |
| static bool begin_worker(grpc_pollset *pollset, grpc_pollset_worker *worker, |
| grpc_pollset_worker **worker_hdl, gpr_timespec *now, |
| gpr_timespec deadline) { |
| if (worker_hdl != NULL) *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 (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_neighbourhood) { |
| is_reassigning = true; |
| pollset->reassigning_neighbourhood = true; |
| pollset->neighbourhood = &g_neighbourhoods[choose_neighbourhood()]; |
| } |
| pollset_neighbourhood *neighbourhood = pollset->neighbourhood; |
| gpr_mu_unlock(&pollset->mu); |
| // pollset unlocked: state may change (even worker->kick_state) |
| retry_lock_neighbourhood: |
| gpr_mu_lock(&neighbourhood->mu); |
| gpr_mu_lock(&pollset->mu); |
| if (pollset->seen_inactive) { |
| if (neighbourhood != pollset->neighbourhood) { |
| gpr_mu_unlock(&neighbourhood->mu); |
| neighbourhood = pollset->neighbourhood; |
| gpr_mu_unlock(&pollset->mu); |
| goto retry_lock_neighbourhood; |
| } |
| pollset->seen_inactive = false; |
| if (neighbourhood->active_root == NULL) { |
| neighbourhood->active_root = pollset->next = pollset->prev = pollset; |
| if (worker->kick_state == UNKICKED && |
| gpr_atm_no_barrier_cas(&g_active_poller, 0, (gpr_atm)worker)) { |
| SET_KICK_STATE(worker, DESIGNATED_POLLER); |
| } |
| } else { |
| pollset->next = neighbourhood->active_root; |
| pollset->prev = pollset->next->prev; |
| pollset->next->prev = pollset->prev->next = pollset; |
| } |
| } |
| if (is_reassigning) { |
| GPR_ASSERT(pollset->reassigning_neighbourhood); |
| pollset->reassigning_neighbourhood = false; |
| } |
| gpr_mu_unlock(&neighbourhood->mu); |
| } |
| worker_insert(pollset, worker); |
| pollset->begin_refs--; |
| if (worker->kick_state == UNKICKED) { |
| GPR_ASSERT(gpr_atm_no_barrier_load(&g_active_poller) != (gpr_atm)worker); |
| worker->initialized_cv = true; |
| gpr_cv_init(&worker->cv); |
| while (worker->kick_state == UNKICKED && |
| pollset->shutdown_closure == NULL) { |
| if (gpr_cv_wait(&worker->cv, &pollset->mu, deadline) && |
| worker->kick_state == UNKICKED) { |
| SET_KICK_STATE(worker, KICKED); |
| } |
| } |
| *now = gpr_now(now->clock_type); |
| } |
| |
| return worker->kick_state == DESIGNATED_POLLER && |
| pollset->shutdown_closure == NULL; |
| } |
| |
| static bool check_neighbourhood_for_available_poller( |
| pollset_neighbourhood *neighbourhood) { |
| bool found_worker = false; |
| do { |
| grpc_pollset *inspect = neighbourhood->active_root; |
| if (inspect == NULL) { |
| break; |
| } |
| gpr_mu_lock(&inspect->mu); |
| GPR_ASSERT(!inspect->seen_inactive); |
| grpc_pollset_worker *inspect_worker = inspect->root_worker; |
| if (inspect_worker != NULL) { |
| do { |
| switch (inspect_worker->kick_state) { |
| case UNKICKED: |
| if (gpr_atm_no_barrier_cas(&g_active_poller, 0, |
| (gpr_atm)inspect_worker)) { |
| SET_KICK_STATE(inspect_worker, DESIGNATED_POLLER); |
| if (inspect_worker->initialized_cv) { |
| gpr_cv_signal(&inspect_worker->cv); |
| } |
| } |
| // 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 (inspect_worker != inspect->root_worker); |
| } |
| if (!found_worker) { |
| inspect->seen_inactive = true; |
| if (inspect == neighbourhood->active_root) { |
| neighbourhood->active_root = |
| inspect->next == inspect ? NULL : inspect->next; |
| } |
| inspect->next->prev = inspect->prev; |
| inspect->prev->next = inspect->next; |
| inspect->next = inspect->prev = NULL; |
| } |
| gpr_mu_unlock(&inspect->mu); |
| } while (!found_worker); |
| return found_worker; |
| } |
| |
| static void end_worker(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset, |
| grpc_pollset_worker *worker, |
| grpc_pollset_worker **worker_hdl) { |
| if (worker_hdl != NULL) *worker_hdl = NULL; |
| SET_KICK_STATE(worker, KICKED); |
| grpc_closure_list_move(&worker->schedule_on_end_work, |
| &exec_ctx->closure_list); |
| if (gpr_atm_no_barrier_load(&g_active_poller) == (gpr_atm)worker) { |
| if (worker->next != worker && worker->next->kick_state == UNKICKED) { |
| 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); |
| gpr_cv_signal(&worker->next->cv); |
| if (grpc_exec_ctx_has_work(exec_ctx)) { |
| gpr_mu_unlock(&pollset->mu); |
| grpc_exec_ctx_flush(exec_ctx); |
| gpr_mu_lock(&pollset->mu); |
| } |
| } else { |
| gpr_atm_no_barrier_store(&g_active_poller, 0); |
| size_t poller_neighbourhood_idx = |
| (size_t)(pollset->neighbourhood - g_neighbourhoods); |
| gpr_mu_unlock(&pollset->mu); |
| bool found_worker = false; |
| bool scan_state[MAX_NEIGHBOURHOODS]; |
| for (size_t i = 0; !found_worker && i < g_num_neighbourhoods; i++) { |
| pollset_neighbourhood *neighbourhood = |
| &g_neighbourhoods[(poller_neighbourhood_idx + i) % |
| g_num_neighbourhoods]; |
| if (gpr_mu_trylock(&neighbourhood->mu)) { |
| found_worker = |
| check_neighbourhood_for_available_poller(neighbourhood); |
| gpr_mu_unlock(&neighbourhood->mu); |
| scan_state[i] = true; |
| } else { |
| scan_state[i] = false; |
| } |
| } |
| for (size_t i = 0; !found_worker && i < g_num_neighbourhoods; i++) { |
| if (scan_state[i]) continue; |
| pollset_neighbourhood *neighbourhood = |
| &g_neighbourhoods[(poller_neighbourhood_idx + i) % |
| g_num_neighbourhoods]; |
| gpr_mu_lock(&neighbourhood->mu); |
| found_worker = check_neighbourhood_for_available_poller(neighbourhood); |
| gpr_mu_unlock(&neighbourhood->mu); |
| } |
| grpc_exec_ctx_flush(exec_ctx); |
| gpr_mu_lock(&pollset->mu); |
| } |
| } else if (grpc_exec_ctx_has_work(exec_ctx)) { |
| gpr_mu_unlock(&pollset->mu); |
| grpc_exec_ctx_flush(exec_ctx); |
| gpr_mu_lock(&pollset->mu); |
| } |
| if (worker->initialized_cv) { |
| gpr_cv_destroy(&worker->cv); |
| } |
| if (EMPTIED == worker_remove(pollset, worker)) { |
| pollset_maybe_finish_shutdown(exec_ctx, 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_exec_ctx *exec_ctx, grpc_pollset *pollset, |
| grpc_pollset_worker **worker_hdl, |
| gpr_timespec now, gpr_timespec deadline) { |
| grpc_pollset_worker worker; |
| grpc_error *error = GRPC_ERROR_NONE; |
| static const char *err_desc = "pollset_work"; |
| if (pollset->kicked_without_poller) { |
| pollset->kicked_without_poller = false; |
| return GRPC_ERROR_NONE; |
| } |
| gpr_tls_set(&g_current_thread_pollset, (intptr_t)pollset); |
| if (begin_worker(pollset, &worker, worker_hdl, &now, deadline)) { |
| gpr_tls_set(&g_current_thread_worker, (intptr_t)&worker); |
| GPR_ASSERT(!pollset->shutdown_closure); |
| GPR_ASSERT(!pollset->seen_inactive); |
| gpr_mu_unlock(&pollset->mu); |
| append_error(&error, pollset_epoll(exec_ctx, pollset, now, deadline), |
| err_desc); |
| gpr_mu_lock(&pollset->mu); |
| gpr_tls_set(&g_current_thread_worker, 0); |
| } |
| end_worker(exec_ctx, pollset, &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) { |
| if (GRPC_TRACER_ON(grpc_polling_trace)) { |
| 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 != NULL) { |
| gpr_asprintf(&tmp, " {kicked=%d next=%p {kicked=%d}}", |
| pollset->root_worker->kick_state, pollset->root_worker->next, |
| pollset->root_worker->next->kick_state); |
| gpr_strvec_add(&log, tmp); |
| } |
| if (specific_worker != NULL) { |
| gpr_asprintf(&tmp, " worker_kicked=%d", specific_worker->kick_state); |
| gpr_strvec_add(&log, tmp); |
| } |
| tmp = gpr_strvec_flatten(&log, NULL); |
| gpr_strvec_destroy(&log); |
| gpr_log(GPR_DEBUG, "%s", tmp); |
| gpr_free(tmp); |
| } |
| if (specific_worker == NULL) { |
| if (gpr_tls_get(&g_current_thread_pollset) != (intptr_t)pollset) { |
| grpc_pollset_worker *root_worker = pollset->root_worker; |
| if (root_worker == NULL) { |
| pollset->kicked_without_poller = true; |
| if (GRPC_TRACER_ON(grpc_polling_trace)) { |
| gpr_log(GPR_DEBUG, " .. kicked_without_poller"); |
| } |
| return GRPC_ERROR_NONE; |
| } |
| grpc_pollset_worker *next_worker = root_worker->next; |
| 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)) { |
| if (GRPC_TRACER_ON(grpc_polling_trace)) { |
| gpr_log(GPR_DEBUG, " .. kicked %p", root_worker); |
| } |
| SET_KICK_STATE(root_worker, KICKED); |
| return grpc_wakeup_fd_wakeup(&global_wakeup_fd); |
| } else if (next_worker->kick_state == UNKICKED) { |
| if (GRPC_TRACER_ON(grpc_polling_trace)) { |
| gpr_log(GPR_DEBUG, " .. kicked %p", next_worker); |
| } |
| GPR_ASSERT(next_worker->initialized_cv); |
| SET_KICK_STATE(next_worker, KICKED); |
| gpr_cv_signal(&next_worker->cv); |
| return GRPC_ERROR_NONE; |
| } else if (next_worker->kick_state == DESIGNATED_POLLER) { |
| if (root_worker->kick_state != DESIGNATED_POLLER) { |
| if (GRPC_TRACER_ON(grpc_polling_trace)) { |
| gpr_log(GPR_DEBUG, " .. kicked root non-poller %p", next_worker); |
| } |
| SET_KICK_STATE(root_worker, KICKED); |
| if (root_worker->initialized_cv) { |
| gpr_cv_signal(&root_worker->cv); |
| } |
| return GRPC_ERROR_NONE; |
| } else { |
| if (GRPC_TRACER_ON(grpc_polling_trace)) { |
| gpr_log(GPR_DEBUG, " .. non-root poller %p (root=%p)", next_worker, |
| root_worker); |
| } |
| SET_KICK_STATE(next_worker, KICKED); |
| return grpc_wakeup_fd_wakeup(&global_wakeup_fd); |
| } |
| } else { |
| GPR_ASSERT(next_worker->kick_state == KICKED); |
| SET_KICK_STATE(next_worker, KICKED); |
| return GRPC_ERROR_NONE; |
| } |
| } else { |
| GPR_ASSERT(false); |
| return GRPC_ERROR_NONE; |
| } |
| } else if (specific_worker->kick_state == KICKED) { |
| if (GRPC_TRACER_ON(grpc_polling_trace)) { |
| gpr_log(GPR_DEBUG, " .. specific worker already kicked"); |
| } |
| return GRPC_ERROR_NONE; |
| } else if (gpr_tls_get(&g_current_thread_worker) == |
| (intptr_t)specific_worker) { |
| if (GRPC_TRACER_ON(grpc_polling_trace)) { |
| gpr_log(GPR_DEBUG, " .. mark %p kicked", specific_worker); |
| } |
| SET_KICK_STATE(specific_worker, KICKED); |
| return GRPC_ERROR_NONE; |
| } else if (specific_worker == |
| (grpc_pollset_worker *)gpr_atm_no_barrier_load(&g_active_poller)) { |
| if (GRPC_TRACER_ON(grpc_polling_trace)) { |
| gpr_log(GPR_DEBUG, " .. kick active poller"); |
| } |
| SET_KICK_STATE(specific_worker, KICKED); |
| return grpc_wakeup_fd_wakeup(&global_wakeup_fd); |
| } else if (specific_worker->initialized_cv) { |
| if (GRPC_TRACER_ON(grpc_polling_trace)) { |
| gpr_log(GPR_DEBUG, " .. kick waiting worker"); |
| } |
| SET_KICK_STATE(specific_worker, KICKED); |
| gpr_cv_signal(&specific_worker->cv); |
| return GRPC_ERROR_NONE; |
| } else { |
| if (GRPC_TRACER_ON(grpc_polling_trace)) { |
| gpr_log(GPR_DEBUG, " .. kick non-waiting worker"); |
| } |
| SET_KICK_STATE(specific_worker, KICKED); |
| return GRPC_ERROR_NONE; |
| } |
| } |
| |
| static void pollset_add_fd(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset, |
| grpc_fd *fd) {} |
| |
| /******************************************************************************* |
| * Workqueue Definitions |
| */ |
| |
| #ifdef GRPC_WORKQUEUE_REFCOUNT_DEBUG |
| static grpc_workqueue *workqueue_ref(grpc_workqueue *workqueue, |
| const char *file, int line, |
| const char *reason) { |
| return workqueue; |
| } |
| |
| static void workqueue_unref(grpc_exec_ctx *exec_ctx, grpc_workqueue *workqueue, |
| const char *file, int line, const char *reason) {} |
| #else |
| static grpc_workqueue *workqueue_ref(grpc_workqueue *workqueue) { |
| return workqueue; |
| } |
| |
| static void workqueue_unref(grpc_exec_ctx *exec_ctx, |
| grpc_workqueue *workqueue) {} |
| #endif |
| |
| static void wq_sched(grpc_exec_ctx *exec_ctx, grpc_closure *closure, |
| grpc_error *error) { |
| // find a neighbourhood to wakeup |
| bool scheduled = false; |
| size_t initial_neighbourhood = choose_neighbourhood(); |
| for (size_t i = 0; !scheduled && i < g_num_neighbourhoods; i++) { |
| pollset_neighbourhood *neighbourhood = |
| &g_neighbourhoods[(initial_neighbourhood + i) % g_num_neighbourhoods]; |
| if (gpr_mu_trylock(&neighbourhood->mu)) { |
| if (neighbourhood->active_root != NULL) { |
| grpc_pollset *inspect = neighbourhood->active_root; |
| do { |
| if (gpr_mu_trylock(&inspect->mu)) { |
| if (inspect->root_worker != NULL) { |
| grpc_pollset_worker *inspect_worker = inspect->root_worker; |
| do { |
| if (inspect_worker->kick_state == UNKICKED) { |
| SET_KICK_STATE(inspect_worker, KICKED); |
| grpc_closure_list_append( |
| &inspect_worker->schedule_on_end_work, closure, error); |
| if (inspect_worker->initialized_cv) { |
| gpr_cv_signal(&inspect_worker->cv); |
| } |
| scheduled = true; |
| } |
| inspect_worker = inspect_worker->next; |
| } while (!scheduled && inspect_worker != inspect->root_worker); |
| } |
| gpr_mu_unlock(&inspect->mu); |
| } |
| inspect = inspect->next; |
| } while (!scheduled && inspect != neighbourhood->active_root); |
| } |
| gpr_mu_unlock(&neighbourhood->mu); |
| } |
| } |
| if (!scheduled) { |
| gpr_mu_lock(&g_wq_mu); |
| grpc_closure_list_append(&g_wq_items, closure, error); |
| gpr_mu_unlock(&g_wq_mu); |
| GRPC_LOG_IF_ERROR("workqueue_scheduler", |
| grpc_wakeup_fd_wakeup(&global_wakeup_fd)); |
| } |
| } |
| |
| static const grpc_closure_scheduler_vtable |
| singleton_workqueue_scheduler_vtable = {wq_sched, wq_sched, |
| "epoll1_workqueue"}; |
| |
| static grpc_closure_scheduler singleton_workqueue_scheduler = { |
| &singleton_workqueue_scheduler_vtable}; |
| |
| static grpc_closure_scheduler *workqueue_scheduler(grpc_workqueue *workqueue) { |
| return &singleton_workqueue_scheduler; |
| } |
| |
| /******************************************************************************* |
| * Pollset-set Definitions |
| */ |
| |
| static grpc_pollset_set *pollset_set_create(void) { |
| return (grpc_pollset_set *)((intptr_t)0xdeafbeef); |
| } |
| |
| static void pollset_set_destroy(grpc_exec_ctx *exec_ctx, |
| grpc_pollset_set *pss) {} |
| |
| static void pollset_set_add_fd(grpc_exec_ctx *exec_ctx, grpc_pollset_set *pss, |
| grpc_fd *fd) {} |
| |
| static void pollset_set_del_fd(grpc_exec_ctx *exec_ctx, grpc_pollset_set *pss, |
| grpc_fd *fd) {} |
| |
| static void pollset_set_add_pollset(grpc_exec_ctx *exec_ctx, |
| grpc_pollset_set *pss, grpc_pollset *ps) {} |
| |
| static void pollset_set_del_pollset(grpc_exec_ctx *exec_ctx, |
| grpc_pollset_set *pss, grpc_pollset *ps) {} |
| |
| static void pollset_set_add_pollset_set(grpc_exec_ctx *exec_ctx, |
| grpc_pollset_set *bag, |
| grpc_pollset_set *item) {} |
| |
| static void pollset_set_del_pollset_set(grpc_exec_ctx *exec_ctx, |
| grpc_pollset_set *bag, |
| grpc_pollset_set *item) {} |
| |
| /******************************************************************************* |
| * Event engine binding |
| */ |
| |
| static void shutdown_engine(void) { |
| fd_global_shutdown(); |
| pollset_global_shutdown(); |
| } |
| |
| static const grpc_event_engine_vtable vtable = { |
| .pollset_size = sizeof(grpc_pollset), |
| |
| .fd_create = fd_create, |
| .fd_wrapped_fd = fd_wrapped_fd, |
| .fd_orphan = fd_orphan, |
| .fd_shutdown = fd_shutdown, |
| .fd_is_shutdown = fd_is_shutdown, |
| .fd_notify_on_read = fd_notify_on_read, |
| .fd_notify_on_write = fd_notify_on_write, |
| .fd_get_read_notifier_pollset = fd_get_read_notifier_pollset, |
| .fd_get_workqueue = fd_get_workqueue, |
| |
| .pollset_init = pollset_init, |
| .pollset_shutdown = pollset_shutdown, |
| .pollset_destroy = pollset_destroy, |
| .pollset_work = pollset_work, |
| .pollset_kick = pollset_kick, |
| .pollset_add_fd = pollset_add_fd, |
| |
| .pollset_set_create = pollset_set_create, |
| .pollset_set_destroy = pollset_set_destroy, |
| .pollset_set_add_pollset = pollset_set_add_pollset, |
| .pollset_set_del_pollset = pollset_set_del_pollset, |
| .pollset_set_add_pollset_set = pollset_set_add_pollset_set, |
| .pollset_set_del_pollset_set = pollset_set_del_pollset_set, |
| .pollset_set_add_fd = pollset_set_add_fd, |
| .pollset_set_del_fd = pollset_set_del_fd, |
| |
| .workqueue_ref = workqueue_ref, |
| .workqueue_unref = workqueue_unref, |
| .workqueue_scheduler = workqueue_scheduler, |
| |
| .shutdown_engine = shutdown_engine, |
| }; |
| |
| /* It is possible that GLIBC has epoll but the underlying kernel doesn't. |
| * Create a dummy epoll_fd to make sure epoll support is available */ |
| const grpc_event_engine_vtable *grpc_init_epoll1_linux(bool explicit_request) { |
| if (!grpc_has_wakeup_fd()) { |
| return NULL; |
| } |
| |
| g_epfd = epoll_create1(EPOLL_CLOEXEC); |
| if (g_epfd < 0) { |
| gpr_log(GPR_ERROR, "epoll unavailable"); |
| return NULL; |
| } |
| |
| fd_global_init(); |
| |
| if (!GRPC_LOG_IF_ERROR("pollset_global_init", pollset_global_init())) { |
| close(g_epfd); |
| fd_global_shutdown(); |
| return NULL; |
| } |
| |
| return &vtable; |
| } |
| |
| #else /* defined(GRPC_LINUX_EPOLL) */ |
| #if defined(GRPC_POSIX_SOCKET) |
| #include "src/core/lib/iomgr/ev_posix.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 NULL; |
| } |
| #endif /* defined(GRPC_POSIX_SOCKET) */ |
| #endif /* !defined(GRPC_LINUX_EPOLL) */ |