diff --git a/src/core/lib/iomgr/ev_epoll_linux.c b/src/core/lib/iomgr/ev_epoll_linux.c index 108cf5a6130..2a0b8917e8e 100644 --- a/src/core/lib/iomgr/ev_epoll_linux.c +++ b/src/core/lib/iomgr/ev_epoll_linux.c @@ -1108,7 +1108,9 @@ static void notify_on(grpc_exec_ctx *exec_ctx, grpc_fd *fd, gpr_atm *state, grpc_closure *closure) { while (true) { /* Fast-path: CLOSURE_NOT_READY -> */ - if (gpr_atm_acq_cas(state, CLOSURE_NOT_READY, (gpr_atm)closure)) { + /* Also do a release-cas here so that there is a 'happen-before' established + with acquire loads in set_ready() / set_shutdown() */ + if (gpr_atm_rel_cas(state, CLOSURE_NOT_READY, (gpr_atm)closure)) { return; /* Fast-path successful. Return */ } @@ -1163,7 +1165,7 @@ static void set_shutdown(grpc_exec_ctx *exec_ctx, grpc_fd *fd, gpr_atm *state, gpr_atm new_state = (gpr_atm)shutdown_err | FD_SHUTDOWN_BIT; while (true) { - if (gpr_atm_acq_cas(state, curr, new_state)) { + if (gpr_atm_rel_cas(state, curr, new_state)) { return; /* Fast-path successful. Return */ } @@ -1206,9 +1208,9 @@ static void set_shutdown(grpc_exec_ctx *exec_ctx, grpc_fd *fd, gpr_atm *state, } static void set_ready(grpc_exec_ctx *exec_ctx, grpc_fd *fd, gpr_atm *state) { - /* Try the fast-path first (i.e expect the current value to be - * CLOSURE_NOT_READY */ - if (gpr_atm_acq_cas(state, CLOSURE_NOT_READY, CLOSURE_READY)) { + /* Try an optimistic case first (i.e assume current state is + CLOSURE_NOT_READY) */ + if (gpr_atm_rel_cas(state, CLOSURE_NOT_READY, CLOSURE_READY)) { return; /* early out */ } @@ -1247,7 +1249,7 @@ static void set_ready(grpc_exec_ctx *exec_ctx, grpc_fd *fd, gpr_atm *state) { static grpc_pollset *fd_get_read_notifier_pollset(grpc_exec_ctx *exec_ctx, grpc_fd *fd) { - gpr_atm notifier = gpr_atm_no_barrier_load(&fd->read_closure); + gpr_atm notifier = gpr_atm_acq_load(&fd->read_notifier_pollset); return (grpc_pollset *)notifier; } @@ -1259,7 +1261,7 @@ static bool fd_is_shutdown(grpc_fd *fd) { /* Might be called multiple times */ static void fd_shutdown(grpc_exec_ctx *exec_ctx, grpc_fd *fd, grpc_error *why) { /* Store the shutdown error ORed with FD_SHUTDOWN_BIT in fd->shutdown_error */ - if (gpr_atm_acq_cas(&fd->shutdown_error, (gpr_atm)GRPC_ERROR_NONE, + if (gpr_atm_rel_cas(&fd->shutdown_error, (gpr_atm)GRPC_ERROR_NONE, (gpr_atm)why | FD_SHUTDOWN_BIT)) { shutdown(fd->fd, SHUT_RDWR); @@ -1474,7 +1476,8 @@ static void fd_become_readable(grpc_exec_ctx *exec_ctx, grpc_fd *fd, 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) */ - gpr_atm_no_barrier_store(&fd->read_notifier_pollset, (gpr_atm)notifier); + /* 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) {