From fbf61bbc1abe671d9e5b1a8177a6be2abf9d5e23 Mon Sep 17 00:00:00 2001 From: Craig Tiller Date: Wed, 8 Nov 2017 11:50:14 -0800 Subject: [PATCH] Revert "Revert "Class-ify lockfree event"" --- src/core/lib/iomgr/ev_epoll1_linux.cc | 30 +++---- src/core/lib/iomgr/ev_epollex_linux.cc | 28 +++--- src/core/lib/iomgr/ev_epollsig_linux.cc | 28 +++--- src/core/lib/iomgr/lockfree_event.cc | 115 +++++++++++------------- src/core/lib/iomgr/lockfree_event.h | 44 +++++---- 5 files changed, 120 insertions(+), 125 deletions(-) diff --git a/src/core/lib/iomgr/ev_epoll1_linux.cc b/src/core/lib/iomgr/ev_epoll1_linux.cc index 504c6598749..9e3643fa286 100644 --- a/src/core/lib/iomgr/ev_epoll1_linux.cc +++ b/src/core/lib/iomgr/ev_epoll1_linux.cc @@ -46,6 +46,7 @@ #include "src/core/lib/iomgr/lockfree_event.h" #include "src/core/lib/iomgr/wakeup_fd_posix.h" #include "src/core/lib/profiling/timers.h" +#include "src/core/lib/support/manual_constructor.h" #include "src/core/lib/support/string.h" static grpc_wakeup_fd global_wakeup_fd; @@ -111,8 +112,8 @@ static void epoll_set_shutdown() { struct grpc_fd { int fd; - gpr_atm read_closure; - gpr_atm write_closure; + grpc_core::ManualConstructor read_closure; + grpc_core::ManualConstructor write_closure; struct grpc_fd* freelist_next; @@ -264,8 +265,8 @@ static grpc_fd* fd_create(int fd, const char* name) { } new_fd->fd = fd; - grpc_lfev_init(&new_fd->read_closure); - grpc_lfev_init(&new_fd->write_closure); + new_fd->read_closure.Init(); + new_fd->write_closure.Init(); gpr_atm_no_barrier_store(&new_fd->read_notifier_pollset, (gpr_atm)NULL); new_fd->freelist_next = NULL; @@ -297,12 +298,11 @@ static int fd_wrapped_fd(grpc_fd* fd) { return fd->fd; } * shutdown() syscall on that fd) */ static void fd_shutdown_internal(grpc_exec_ctx* exec_ctx, grpc_fd* fd, grpc_error* why, bool releasing_fd) { - if (grpc_lfev_set_shutdown(exec_ctx, &fd->read_closure, - GRPC_ERROR_REF(why))) { + if (fd->read_closure->SetShutdown(exec_ctx, GRPC_ERROR_REF(why))) { if (!releasing_fd) { shutdown(fd->fd, SHUT_RDWR); } - grpc_lfev_set_shutdown(exec_ctx, &fd->write_closure, GRPC_ERROR_REF(why)); + fd->write_closure->SetShutdown(exec_ctx, GRPC_ERROR_REF(why)); } GRPC_ERROR_UNREF(why); } @@ -318,7 +318,7 @@ static void fd_orphan(grpc_exec_ctx* exec_ctx, grpc_fd* fd, grpc_error* error = GRPC_ERROR_NONE; bool is_release_fd = (release_fd != NULL); - if (!grpc_lfev_is_shutdown(&fd->read_closure)) { + if (!fd->read_closure->IsShutdown()) { fd_shutdown_internal(exec_ctx, fd, GRPC_ERROR_CREATE_FROM_COPIED_STRING(reason), is_release_fd); @@ -335,8 +335,8 @@ static void fd_orphan(grpc_exec_ctx* exec_ctx, grpc_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); + fd->read_closure.Destroy(); + fd->write_closure.Destroy(); gpr_mu_lock(&fd_freelist_mu); fd->freelist_next = fd_freelist; @@ -351,28 +351,28 @@ static grpc_pollset* fd_get_read_notifier_pollset(grpc_exec_ctx* exec_ctx, } static bool fd_is_shutdown(grpc_fd* fd) { - return grpc_lfev_is_shutdown(&fd->read_closure); + return fd->read_closure->IsShutdown(); } 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, "read"); + fd->read_closure->NotifyOn(exec_ctx, 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, "write"); + fd->write_closure->NotifyOn(exec_ctx, closure); } 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, "read"); + fd->read_closure->SetReady(exec_ctx); /* 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, "write"); + fd->write_closure->SetReady(exec_ctx); } /******************************************************************************* diff --git a/src/core/lib/iomgr/ev_epollex_linux.cc b/src/core/lib/iomgr/ev_epollex_linux.cc index aafdd690c73..26ed1f67472 100644 --- a/src/core/lib/iomgr/ev_epollex_linux.cc +++ b/src/core/lib/iomgr/ev_epollex_linux.cc @@ -48,6 +48,7 @@ #include "src/core/lib/iomgr/timer.h" #include "src/core/lib/iomgr/wakeup_fd_posix.h" #include "src/core/lib/profiling/timers.h" +#include "src/core/lib/support/manual_constructor.h" #include "src/core/lib/support/spinlock.h" // debug aid: create workers on the heap (allows asan to spot @@ -153,8 +154,8 @@ struct grpc_fd { gpr_mu pollable_mu; pollable* pollable_obj; - gpr_atm read_closure; - gpr_atm write_closure; + grpc_core::ManualConstructor read_closure; + grpc_core::ManualConstructor write_closure; struct grpc_fd* freelist_next; grpc_closure* on_done_closure; @@ -286,8 +287,8 @@ static void fd_destroy(grpc_exec_ctx* exec_ctx, void* arg, grpc_error* error) { fd->freelist_next = fd_freelist; fd_freelist = fd; - grpc_lfev_destroy(&fd->read_closure); - grpc_lfev_destroy(&fd->write_closure); + fd->read_closure.Destroy(); + fd->write_closure.Destroy(); gpr_mu_unlock(&fd_freelist_mu); } @@ -347,8 +348,8 @@ static grpc_fd* fd_create(int fd, const char* name) { new_fd->pollable_obj = NULL; gpr_atm_rel_store(&new_fd->refst, (gpr_atm)1); new_fd->fd = fd; - grpc_lfev_init(&new_fd->read_closure); - grpc_lfev_init(&new_fd->write_closure); + new_fd->read_closure.Init(); + new_fd->write_closure.Init(); gpr_atm_no_barrier_store(&new_fd->read_notifier_pollset, (gpr_atm)NULL); new_fd->freelist_next = NULL; @@ -411,27 +412,26 @@ static grpc_pollset* fd_get_read_notifier_pollset(grpc_exec_ctx* exec_ctx, } static bool fd_is_shutdown(grpc_fd* fd) { - return grpc_lfev_is_shutdown(&fd->read_closure); + return fd->read_closure->IsShutdown(); } /* 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))) { + if (fd->read_closure->SetShutdown(exec_ctx, GRPC_ERROR_REF(why))) { shutdown(fd->fd, SHUT_RDWR); - grpc_lfev_set_shutdown(exec_ctx, &fd->write_closure, GRPC_ERROR_REF(why)); + fd->write_closure->SetShutdown(exec_ctx, GRPC_ERROR_REF(why)); } GRPC_ERROR_UNREF(why); } 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, "read"); + fd->read_closure->NotifyOn(exec_ctx, 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, "write"); + fd->write_closure->NotifyOn(exec_ctx, closure); } /******************************************************************************* @@ -702,7 +702,7 @@ static int poll_deadline_to_millis_timeout(grpc_exec_ctx* exec_ctx, 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, "read"); + fd->read_closure->SetReady(exec_ctx); /* 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 @@ -714,7 +714,7 @@ static void fd_become_readable(grpc_exec_ctx* exec_ctx, grpc_fd* fd, } static void fd_become_writable(grpc_exec_ctx* exec_ctx, grpc_fd* fd) { - grpc_lfev_set_ready(exec_ctx, &fd->write_closure, "write"); + fd->write_closure->SetReady(exec_ctx); } static grpc_error* fd_get_or_become_pollable(grpc_fd* fd, pollable** p) { diff --git a/src/core/lib/iomgr/ev_epollsig_linux.cc b/src/core/lib/iomgr/ev_epollsig_linux.cc index d5f3122abc5..9a127806fa1 100644 --- a/src/core/lib/iomgr/ev_epollsig_linux.cc +++ b/src/core/lib/iomgr/ev_epollsig_linux.cc @@ -50,6 +50,7 @@ #include "src/core/lib/iomgr/timer.h" #include "src/core/lib/iomgr/wakeup_fd_posix.h" #include "src/core/lib/profiling/timers.h" +#include "src/core/lib/support/manual_constructor.h" #define GRPC_POLLSET_KICK_BROADCAST ((grpc_pollset_worker*)1) @@ -127,8 +128,8 @@ struct grpc_fd { valid */ bool orphaned; - gpr_atm read_closure; - gpr_atm write_closure; + grpc_core::ManualConstructor read_closure; + grpc_core::ManualConstructor write_closure; struct grpc_fd* freelist_next; grpc_closure* on_done_closure; @@ -766,8 +767,8 @@ static void unref_by(grpc_fd* fd, int n) { fd_freelist = fd; grpc_iomgr_unregister_object(&fd->iomgr_object); - grpc_lfev_destroy(&fd->read_closure); - grpc_lfev_destroy(&fd->write_closure); + fd->read_closure.Destroy(); + fd->write_closure.Destroy(); gpr_mu_unlock(&fd_freelist_mu); } else { @@ -832,8 +833,8 @@ static grpc_fd* fd_create(int fd, const char* name) { gpr_atm_rel_store(&new_fd->refst, (gpr_atm)1); new_fd->fd = fd; new_fd->orphaned = false; - grpc_lfev_init(&new_fd->read_closure); - grpc_lfev_init(&new_fd->write_closure); + new_fd->read_closure.Init(); + new_fd->write_closure.Init(); gpr_atm_no_barrier_store(&new_fd->read_notifier_pollset, (gpr_atm)NULL); new_fd->freelist_next = NULL; @@ -924,27 +925,26 @@ static grpc_pollset* fd_get_read_notifier_pollset(grpc_exec_ctx* exec_ctx, } static bool fd_is_shutdown(grpc_fd* fd) { - return grpc_lfev_is_shutdown(&fd->read_closure); + return fd->read_closure->IsShutdown(); } /* 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))) { + if (fd->read_closure->SetShutdown(exec_ctx, GRPC_ERROR_REF(why))) { shutdown(fd->fd, SHUT_RDWR); - grpc_lfev_set_shutdown(exec_ctx, &fd->write_closure, GRPC_ERROR_REF(why)); + fd->write_closure->SetShutdown(exec_ctx, GRPC_ERROR_REF(why)); } GRPC_ERROR_UNREF(why); } 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, "read"); + fd->read_closure->NotifyOn(exec_ctx, 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, "write"); + fd->write_closure->NotifyOn(exec_ctx, closure); } /******************************************************************************* @@ -1108,7 +1108,7 @@ static int poll_deadline_to_millis_timeout(grpc_exec_ctx* exec_ctx, 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, "read"); + fd->read_closure->SetReady(exec_ctx); /* 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 @@ -1120,7 +1120,7 @@ static void fd_become_readable(grpc_exec_ctx* exec_ctx, grpc_fd* fd, } static void fd_become_writable(grpc_exec_ctx* exec_ctx, grpc_fd* fd) { - grpc_lfev_set_ready(exec_ctx, &fd->write_closure, "write"); + fd->write_closure->SetReady(exec_ctx); } static void pollset_release_polling_island(grpc_exec_ctx* exec_ctx, diff --git a/src/core/lib/iomgr/lockfree_event.cc b/src/core/lib/iomgr/lockfree_event.cc index 443a8375b28..98e19f89df3 100644 --- a/src/core/lib/iomgr/lockfree_event.cc +++ b/src/core/lib/iomgr/lockfree_event.cc @@ -26,92 +26,79 @@ extern grpc_tracer_flag grpc_polling_trace; /* 'state' holds the to call when the fd is readable or writable respectively. It can contain one of the following values: - CLOSURE_READY : The fd has an I/O event of interest but there is no + kClosureReady : The fd has an I/O event of interest but there is no closure yet to execute - CLOSURE_NOT_READY : The fd has no I/O event of interest + kClosureNotReady : The fd has no I/O event of interest closure ptr : The closure to be executed when the fd has an I/O event of interest - shutdown_error | FD_SHUTDOWN_BIT : - 'shutdown_error' field ORed with FD_SHUTDOWN_BIT. + shutdown_error | kShutdownBit : + 'shutdown_error' field ORed with kShutdownBit. This indicates that the fd is shutdown. Since all memory allocations are word-aligned, the lower two bits of the shutdown_error pointer are always 0. So - it is safe to OR these with FD_SHUTDOWN_BIT + it is safe to OR these with kShutdownBit Valid state transitions: - <-----3------ CLOSURE_NOT_READY ----1----> CLOSURE_READY + <-----3------ kClosureNotReady -----1-------> kClosureReady | | ^ | ^ | | | | | | | | | | +--------------4----------+ 6 +---------2---------------+ | | | | | v | - +-----5-------> [shutdown_error | FD_SHUTDOWN_BIT] <----7---------+ + +-----5-------> [shutdown_error | kShutdownBit] <-------7---------+ - For 1, 4 : See grpc_lfev_set_ready() function - For 2, 3 : See grpc_lfev_notify_on() function - For 5,6,7: See grpc_lfev_set_shutdown() function */ + For 1, 4 : See SetReady() function + For 2, 3 : See NotifyOn() function + For 5,6,7: See SetShutdown() function */ -#define CLOSURE_NOT_READY ((gpr_atm)0) -#define CLOSURE_READY ((gpr_atm)2) +namespace grpc_core { -#define FD_SHUTDOWN_BIT ((gpr_atm)1) - -void grpc_lfev_init(gpr_atm* state) { - gpr_atm_no_barrier_store(state, CLOSURE_NOT_READY); -} - -void grpc_lfev_destroy(gpr_atm* state) { - gpr_atm curr = gpr_atm_no_barrier_load(state); - if (curr & FD_SHUTDOWN_BIT) { - GRPC_ERROR_UNREF((grpc_error*)(curr & ~FD_SHUTDOWN_BIT)); +LockfreeEvent::~LockfreeEvent() { + gpr_atm curr = gpr_atm_no_barrier_load(&state_); + if (curr & kShutdownBit) { + GRPC_ERROR_UNREF((grpc_error*)(curr & ~kShutdownBit)); } else { - GPR_ASSERT(curr == CLOSURE_NOT_READY || curr == CLOSURE_READY); + GPR_ASSERT(curr == kClosureNotReady || curr == kClosureReady); } } -bool grpc_lfev_is_shutdown(gpr_atm* state) { - gpr_atm curr = gpr_atm_no_barrier_load(state); - return (curr & FD_SHUTDOWN_BIT) != 0; -} - -void grpc_lfev_notify_on(grpc_exec_ctx* exec_ctx, gpr_atm* state, - grpc_closure* closure, const char* variable) { +void LockfreeEvent::NotifyOn(grpc_exec_ctx* exec_ctx, grpc_closure* closure) { while (true) { - gpr_atm curr = gpr_atm_no_barrier_load(state); + gpr_atm curr = gpr_atm_no_barrier_load(&state_); if (GRPC_TRACER_ON(grpc_polling_trace)) { - gpr_log(GPR_ERROR, "lfev_notify_on[%s]: %p curr=%p closure=%p", variable, - state, (void*)curr, closure); + gpr_log(GPR_ERROR, "LockfreeEvent::NotifyOn: %p curr=%p closure=%p", this, + (void*)curr, closure); } switch (curr) { - case CLOSURE_NOT_READY: { - /* CLOSURE_NOT_READY -> . + case kClosureNotReady: { + /* kClosureNotReady -> . We're guaranteed by API that there's an acquire barrier before here, so there's no need to double-dip and this can be a release-only. The release itself pairs with the acquire half of a set_ready full barrier. */ - if (gpr_atm_rel_cas(state, CLOSURE_NOT_READY, (gpr_atm)closure)) { + if (gpr_atm_rel_cas(&state_, kClosureNotReady, (gpr_atm)closure)) { return; /* Successful. Return */ } break; /* retry */ } - case CLOSURE_READY: { - /* Change the state to CLOSURE_NOT_READY. Schedule the closure if + case kClosureReady: { + /* Change the state to kClosureNotReady. Schedule the closure if successful. If not, the state most likely transitioned to shutdown. We should retry. This can be a no-barrier cas since the state is being transitioned to - CLOSURE_NOT_READY; set_ready and set_shutdown do not schedule any + kClosureNotReady; set_ready and set_shutdown do not schedule any closure when transitioning out of CLOSURE_NO_READY state (i.e there is no other code that needs to 'happen-after' this) */ - if (gpr_atm_no_barrier_cas(state, CLOSURE_READY, CLOSURE_NOT_READY)) { + if (gpr_atm_no_barrier_cas(&state_, kClosureReady, kClosureNotReady)) { GRPC_CLOSURE_SCHED(exec_ctx, closure, GRPC_ERROR_NONE); return; /* Successful. Return */ } @@ -123,8 +110,8 @@ void grpc_lfev_notify_on(grpc_exec_ctx* exec_ctx, gpr_atm* state, /* 'curr' is either a closure or the fd is shutdown(in which case 'curr' contains a pointer to the shutdown-error). If the fd is shutdown, schedule the closure with the shutdown error */ - if ((curr & FD_SHUTDOWN_BIT) > 0) { - grpc_error* shutdown_err = (grpc_error*)(curr & ~FD_SHUTDOWN_BIT); + if ((curr & kShutdownBit) > 0) { + grpc_error* shutdown_err = (grpc_error*)(curr & ~kShutdownBit); GRPC_CLOSURE_SCHED(exec_ctx, closure, GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( "FD Shutdown", &shutdown_err, 1)); @@ -133,7 +120,8 @@ void grpc_lfev_notify_on(grpc_exec_ctx* exec_ctx, gpr_atm* state, /* There is already a closure!. This indicates a bug in the code */ gpr_log(GPR_ERROR, - "notify_on called with a previous callback still pending"); + "LockfreeEvent::NotifyOn: notify_on called with a previous " + "callback still pending"); abort(); } } @@ -142,22 +130,22 @@ void grpc_lfev_notify_on(grpc_exec_ctx* exec_ctx, gpr_atm* state, GPR_UNREACHABLE_CODE(return ); } -bool grpc_lfev_set_shutdown(grpc_exec_ctx* exec_ctx, gpr_atm* state, - grpc_error* shutdown_err) { - gpr_atm new_state = (gpr_atm)shutdown_err | FD_SHUTDOWN_BIT; +bool LockfreeEvent::SetShutdown(grpc_exec_ctx* exec_ctx, + grpc_error* shutdown_err) { + gpr_atm new_state = (gpr_atm)shutdown_err | kShutdownBit; while (true) { - gpr_atm curr = gpr_atm_no_barrier_load(state); + gpr_atm curr = gpr_atm_no_barrier_load(&state_); if (GRPC_TRACER_ON(grpc_polling_trace)) { - gpr_log(GPR_ERROR, "lfev_set_shutdown: %p curr=%p err=%s", state, - (void*)curr, grpc_error_string(shutdown_err)); + gpr_log(GPR_ERROR, "LockfreeEvent::SetShutdown: %p curr=%p err=%s", + &state_, (void*)curr, grpc_error_string(shutdown_err)); } switch (curr) { - case CLOSURE_READY: - case CLOSURE_NOT_READY: + case kClosureReady: + case kClosureNotReady: /* Need a full barrier here so that the initial load in notify_on doesn't need a barrier */ - if (gpr_atm_full_cas(state, curr, new_state)) { + if (gpr_atm_full_cas(&state_, curr, new_state)) { return true; /* early out */ } break; /* retry */ @@ -166,7 +154,7 @@ bool grpc_lfev_set_shutdown(grpc_exec_ctx* exec_ctx, gpr_atm* state, /* 'curr' is either a closure or the fd is already shutdown */ /* If fd is already shutdown, we are done */ - if ((curr & FD_SHUTDOWN_BIT) > 0) { + if ((curr & kShutdownBit) > 0) { GRPC_ERROR_UNREF(shutdown_err); return false; } @@ -176,7 +164,7 @@ bool grpc_lfev_set_shutdown(grpc_exec_ctx* exec_ctx, gpr_atm* state, Needs an acquire to pair with setting the closure (and get a happens-after on that edge), and a release to pair with anything loading the shutdown state. */ - if (gpr_atm_full_cas(state, curr, new_state)) { + if (gpr_atm_full_cas(&state_, curr, new_state)) { GRPC_CLOSURE_SCHED(exec_ctx, (grpc_closure*)curr, GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( "FD Shutdown", &shutdown_err, 1)); @@ -193,26 +181,25 @@ bool grpc_lfev_set_shutdown(grpc_exec_ctx* exec_ctx, gpr_atm* state, GPR_UNREACHABLE_CODE(return false); } -void grpc_lfev_set_ready(grpc_exec_ctx* exec_ctx, gpr_atm* state, - const char* variable) { +void LockfreeEvent::SetReady(grpc_exec_ctx* exec_ctx) { while (true) { - gpr_atm curr = gpr_atm_no_barrier_load(state); + gpr_atm curr = gpr_atm_no_barrier_load(&state_); if (GRPC_TRACER_ON(grpc_polling_trace)) { - gpr_log(GPR_ERROR, "lfev_set_ready[%s]: %p curr=%p", variable, state, + gpr_log(GPR_ERROR, "LockfreeEvent::SetReady: %p curr=%p", &state_, (void*)curr); } switch (curr) { - case CLOSURE_READY: { + case kClosureReady: { /* Already ready. We are done here */ return; } - case CLOSURE_NOT_READY: { + case kClosureNotReady: { /* No barrier required as we're transitioning to a state that does not involve a closure */ - if (gpr_atm_no_barrier_cas(state, CLOSURE_NOT_READY, CLOSURE_READY)) { + if (gpr_atm_no_barrier_cas(&state_, kClosureNotReady, kClosureReady)) { return; /* early out */ } break; /* retry */ @@ -220,14 +207,14 @@ void grpc_lfev_set_ready(grpc_exec_ctx* exec_ctx, gpr_atm* state, default: { /* 'curr' is either a closure or the fd is shutdown */ - if ((curr & FD_SHUTDOWN_BIT) > 0) { + if ((curr & kShutdownBit) > 0) { /* The fd is shutdown. Do nothing */ return; } /* Full cas: acquire pairs with this cas' release in the event of a spurious set_ready; release pairs with this or the acquire in notify_on (or set_shutdown) */ - else if (gpr_atm_full_cas(state, curr, CLOSURE_NOT_READY)) { + else if (gpr_atm_full_cas(&state_, curr, kClosureNotReady)) { GRPC_CLOSURE_SCHED(exec_ctx, (grpc_closure*)curr, GRPC_ERROR_NONE); return; } @@ -239,3 +226,5 @@ void grpc_lfev_set_ready(grpc_exec_ctx* exec_ctx, gpr_atm* state, } } } + +} // namespace grpc_core diff --git a/src/core/lib/iomgr/lockfree_event.h b/src/core/lib/iomgr/lockfree_event.h index 75526d6b9f9..47d0089c01d 100644 --- a/src/core/lib/iomgr/lockfree_event.h +++ b/src/core/lib/iomgr/lockfree_event.h @@ -25,24 +25,30 @@ #include "src/core/lib/iomgr/exec_ctx.h" -#ifdef __cplusplus -extern "C" { -#endif - -void grpc_lfev_init(gpr_atm* state); -void grpc_lfev_destroy(gpr_atm* state); -bool grpc_lfev_is_shutdown(gpr_atm* state); - -void grpc_lfev_notify_on(grpc_exec_ctx* exec_ctx, gpr_atm* state, - grpc_closure* closure, const char* variable); -/* Returns true on first successful shutdown */ -bool grpc_lfev_set_shutdown(grpc_exec_ctx* exec_ctx, gpr_atm* state, - grpc_error* shutdown_err); -void grpc_lfev_set_ready(grpc_exec_ctx* exec_ctx, gpr_atm* state, - const char* variable); - -#ifdef __cplusplus -} -#endif +namespace grpc_core { + +class LockfreeEvent { + public: + LockfreeEvent() = default; + ~LockfreeEvent(); + + LockfreeEvent(const LockfreeEvent&) = delete; + LockfreeEvent& operator=(const LockfreeEvent&) = delete; + + bool IsShutdown() const { + return (gpr_atm_no_barrier_load(&state_) & kShutdownBit) != 0; + } + + void NotifyOn(grpc_exec_ctx* exec_ctx, grpc_closure* closure); + bool SetShutdown(grpc_exec_ctx* exec_ctx, grpc_error* error); + void SetReady(grpc_exec_ctx* exec_ctx); + + private: + enum State { kClosureNotReady = 0, kClosureReady = 2, kShutdownBit = 1 }; + + gpr_atm state_ = kClosureNotReady; +}; + +} // namespace grpc_core #endif /* GRPC_CORE_LIB_IOMGR_LOCKFREE_EVENT_H */