diff options
Diffstat (limited to 'erts/emulator/sys/common/erl_poll.c')
| -rw-r--r-- | erts/emulator/sys/common/erl_poll.c | 78 |
1 files changed, 66 insertions, 12 deletions
diff --git a/erts/emulator/sys/common/erl_poll.c b/erts/emulator/sys/common/erl_poll.c index fc32dbf370..30a595c17a 100644 --- a/erts/emulator/sys/common/erl_poll.c +++ b/erts/emulator/sys/common/erl_poll.c @@ -186,6 +186,8 @@ int ERTS_SELECT(int nfds, ERTS_fd_set *readfds, ERTS_fd_set *writefds, #define ERTS_POLL_USE_CONCURRENT_UPDATE (ERTS_POLL_USE_EPOLL || ERTS_POLL_USE_KQUEUE) +#define ERTS_POLL_USE_WAKEUP_PIPE (!ERTS_POLL_USE_CONCURRENT_UPDATE) + #if !ERTS_POLL_USE_CONCURRENT_UPDATE #define ERTS_POLLSET_SET_HAVE_UPDATE_REQUESTS(PS) \ @@ -279,9 +281,12 @@ struct ERTS_POLL_EXPORT(erts_pollset) { ErtsPollSetUpdateRequestsBlock *curr_upd_req_block; erts_atomic32_t have_update_requests; erts_mtx_t mtx; - int wake_fds[2]; erts_atomic32_t wakeup_state; #endif + +#if ERTS_POLL_USE_WAKEUP_PIPE + int wake_fds[2]; +#endif }; void erts_silence_warn_unused_result(long unused); @@ -397,11 +402,12 @@ woke_up(ErtsPollSet *ps) * --- Wakeup pipe ----------------------------------------------------------- */ -#if !ERTS_POLL_USE_CONCURRENT_UPDATE +#if ERTS_POLL_USE_WAKEUP_PIPE static ERTS_INLINE void wake_poller(ErtsPollSet *ps, int interrupted) { +#if !ERTS_POLL_USE_CONCURRENT_UPDATE int wake; erts_aint32_t wakeup_state; if (!interrupted) @@ -413,7 +419,9 @@ wake_poller(ErtsPollSet *ps, int interrupted) ERTS_POLL_WOKEN_INTR); wake = wakeup_state == ERTS_POLL_NOT_WOKEN; - if (wake) { + if (wake) +#endif + { ssize_t res; if (ps->wake_fds[1] < 0) return; /* Not initialized yet */ @@ -452,8 +460,10 @@ cleanup_wakeup_pipe(ErtsPollSet *ps) fd, erl_errno_id(errno), errno); } +#if !ERTS_POLL_USE_CONCURRENT_UPDATE if (intr) erts_atomic32_set_nob(&ps->wakeup_state, ERTS_POLL_WOKEN_INTR); +#endif } static void @@ -489,11 +499,14 @@ create_wakeup_pipe(ErtsPollSet *ps) ps->wake_fds[1] = wake_fds[1]; } +#endif /* * --- Poll set update requests ---------------------------------------------- */ +#if !ERTS_POLL_USE_CONCURRENT_UPDATE + static ERTS_INLINE void enqueue_update_request(ErtsPollSet *ps, int fd) { @@ -893,9 +906,9 @@ update_pollset(ErtsPollSet *ps, int fd, ErtsPollOp op, ErtsPollEvents events) #endif if (op == ERTS_POLL_OP_ADD) erts_atomic_dec_nob(&ps->no_of_user_fds); - return ERTS_POLL_EV_NVAL; - } - return 0; + events = ERTS_POLL_EV_NVAL; + } else + events = 0; } return events; } @@ -1216,7 +1229,7 @@ poll_control(ErtsPollSet *ps, int fd, ErtsPollOp op, goto done; } #endif -#if !ERTS_POLL_USE_CONCURRENT_UPDATE +#if ERTS_POLL_USE_WAKEUP_PIPE if (fd == ps->wake_fds[0] || fd == ps->wake_fds[1]) { new_events = ERTS_POLL_EV_NVAL; goto done; @@ -1294,10 +1307,10 @@ ERTS_POLL_EXPORT(erts_poll_control)(ErtsPollSet *ps, static ERTS_INLINE int ERTS_POLL_EXPORT(save_result)(ErtsPollSet *ps, ErtsPollResFd pr[], int max_res, int chk_fds_res, int ebadf) { -#if !ERTS_POLL_USE_CONCURRENT_UPDATE || ERTS_POLL_DEBUG_PRINT +#if !ERTS_POLL_USE_CONCURRENT_UPDATE || ERTS_POLL_DEBUG_PRINT || ERTS_POLL_USE_WAKEUP_PIPE int n = chk_fds_res < max_res ? chk_fds_res : max_res, i; int res = n; -#if !ERTS_POLL_USE_CONCURRENT_UPDATE +#if ERTS_POLL_USE_WAKEUP_PIPE int wake_fd = ps->wake_fds[0]; #endif @@ -1318,12 +1331,16 @@ ERTS_POLL_EXPORT(save_result)(ErtsPollSet *ps, ErtsPollResFd pr[], int max_res, #endif ); -#if !ERTS_POLL_USE_CONCURRENT_UPDATE - +#if ERTS_POLL_USE_WAKEUP_PIPE if (fd == wake_fd) { cleanup_wakeup_pipe(ps); ERTS_POLL_RES_SET_EVTS(&pr[i], ERTS_POLL_EV_NONE); - } else { + if (n == 1) + return 0; + } +#endif +#if !ERTS_POLL_USE_CONCURRENT_UPDATE + else { /* Reset the events to emulate ONESHOT semantics */ ps->fds_status[fd].events = 0; enqueue_update_request(ps, fd); @@ -1820,6 +1837,43 @@ ERTS_POLL_EXPORT(erts_poll_create_pollset)(int id) handle_update_requests(ps, NULL, 0); cleanup_wakeup_pipe(ps); #endif +#if ERTS_POLL_USE_KERNEL_POLL && (defined(__DARWIN__) || defined(__APPLE__) && defined(__MACH__)) + { + /* + * Using kqueue on OS X is a mess of brokenness... + * + * On OS X version older than 15.6 (i.e. OS X El Capitan released in July 2015), + * a thread waiting in kevent is not woken if an event is inserted into the kqueue + * by another thread and the event becomes ready. However if a new call to kevent + * is done by the waiting thread, the new event is found. + * + * So on effected OS X versions we could trigger the wakeup pipe so that + * the waiters will be woken and re-issue the kevent. However... + * + * On OS X version older then 16 (i.e. OS X Sierra released in September 2016), + * running the emulator driver_SUITE smp_select testcase consistently causes a + * kernel panic. I don't know why or what events that trigger it. But it seems + * like updates of the pollset while another thread is sleeping in it Creates + * some kind of race that triggers the kernel panic. + * + * So to deal with this, the erts configure check what OS X version is run + * and only enabled kernel poll on OS X 16 or newer. In addition, if someone + * attempts to compile Erlang on OS X 16 and then run it on OS X 15, we do the + * run-time check below to disallow this. + */ + int major, minor, build; + os_version(&major,&minor,&build); + if (major < 16) { + erts_fprintf(stderr,"BROKEN KQUEUE!\n" + "Erlang has been compiled with kernel-poll support,\n" + "but this OS X version is known to have kernel bugs\n" + "when using kernel-poll. You have two options:\n" + " 1) update to a newer OS X version (OS X Sierra or newer)\n" + " 2) recompile erlang without kernel-poll support\n"); + erts_exit(1, ""); + } + } +#endif erts_atomic_set_nob(&ps->no_of_user_fds, 0); /* Don't count wakeup pipe and fallback fd */ return ps; |