/* * * 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 #include "src/core/lib/iomgr/port.h" #include /* 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 #include #include #include #include #include #include #include #include #include #include #include #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/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 gpr_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 ""; } 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); #ifdef NDEBUG static pollable* pollable_ref(pollable* p); static void pollable_unref(pollable* p); #define POLLABLE_REF(p, r) pollable_ref(p) #define POLLABLE_UNREF(p, r) pollable_unref(p) #else static pollable* pollable_ref(pollable* p, int line, const char* reason); static void pollable_unref(pollable* p, int line, const char* reason); #define POLLABLE_REF(p, r) pollable_ref((p), __LINE__, (r)) #define POLLABLE_UNREF(p, r) pollable_unref((p), __LINE__, (r)) #endif /******************************************************************************* * 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 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 { gpr_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(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(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(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(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; gpr_ref_init(&(*p)->refs, 1); 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; } #ifdef NDEBUG static pollable* pollable_ref(pollable* p) { #else static pollable* pollable_ref(pollable* p, int line, const char* reason) { if (GRPC_TRACE_FLAG_ENABLED(grpc_trace_pollable_refcount)) { int r = static_cast gpr_atm_no_barrier_load(&p->refs.count); gpr_log(__FILE__, line, GPR_LOG_SEVERITY_DEBUG, "POLLABLE:%p ref %d->%d %s", p, r, r + 1, reason); } #endif gpr_ref(&p->refs); return p; } #ifdef NDEBUG static void pollable_unref(pollable* p) { #else static void pollable_unref(pollable* p, int line, const char* reason) { if (p == nullptr) return; if (GRPC_TRACE_FLAG_ENABLED(grpc_trace_pollable_refcount)) { int r = static_cast gpr_atm_no_barrier_load(&p->refs.count); gpr_log(__FILE__, line, GPR_LOG_SEVERITY_DEBUG, "POLLABLE:%p unref %d->%d %s", p, r, r - 1, reason); } #endif if (p != nullptr && gpr_unref(&p->refs)) { 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); } } 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(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(reinterpret_cast(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(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(1)) & (intptr_t)data_ptr)), err_desc); } else { grpc_fd* fd = reinterpret_cast(reinterpret_cast(data_ptr) & ~2); bool track_err = reinterpret_cast(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 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 = 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(gpr_zalloc(sizeof(*pss))); gpr_mu_init(&pss->mu); gpr_ref_init(&pss->refs, 1); return pss; } static void pollset_set_unref(grpc_pollset_set* pss) { if (pss == nullptr) return; if (!gpr_unref(&pss->refs)) 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( 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(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); } gpr_ref(&a->refs); 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( 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( 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) */