diff options
Diffstat (limited to 'erts/emulator/beam/erl_process_lock.c')
| -rw-r--r-- | erts/emulator/beam/erl_process_lock.c | 261 |
1 files changed, 183 insertions, 78 deletions
diff --git a/erts/emulator/beam/erl_process_lock.c b/erts/emulator/beam/erl_process_lock.c index 3e52a8767f..b864340782 100644 --- a/erts/emulator/beam/erl_process_lock.c +++ b/erts/emulator/beam/erl_process_lock.c @@ -67,7 +67,7 @@ #include "erl_process.h" -const Process erts_proc_lock_busy; +const Process erts_proc_lock_busy = {ERTS_INVALID_PID}; #ifdef ERTS_SMP @@ -671,12 +671,11 @@ erts_proc_lock_prepare_proc_lock_waiter(void) */ static void -proc_safelock(Process *a_proc, - erts_pix_lock_t *a_pix_lck, +proc_safelock(int is_sched, + Process *a_proc, ErtsProcLocks a_have_locks, ErtsProcLocks a_need_locks, Process *b_proc, - erts_pix_lock_t *b_pix_lck, ErtsProcLocks b_have_locks, ErtsProcLocks b_need_locks) { @@ -684,7 +683,6 @@ proc_safelock(Process *a_proc, #ifdef ERTS_ENABLE_LOCK_CHECK Eterm pid1, pid2; #endif - erts_pix_lock_t *pix_lck1, *pix_lck2; ErtsProcLocks need_locks1, have_locks1, need_locks2, have_locks2; ErtsProcLocks unlock_mask; int lock_no, refc1 = 0, refc2 = 0; @@ -701,14 +699,12 @@ proc_safelock(Process *a_proc, #ifdef ERTS_ENABLE_LOCK_CHECK pid1 = a_proc->id; #endif - pix_lck1 = a_pix_lck; need_locks1 = a_need_locks; have_locks1 = a_have_locks; p2 = b_proc; #ifdef ERTS_ENABLE_LOCK_CHECK pid2 = b_proc->id; #endif - pix_lck2 = b_pix_lck; need_locks2 = b_need_locks; have_locks2 = b_have_locks; } @@ -717,14 +713,12 @@ proc_safelock(Process *a_proc, #ifdef ERTS_ENABLE_LOCK_CHECK pid1 = b_proc->id; #endif - pix_lck1 = b_pix_lck; need_locks1 = b_need_locks; have_locks1 = b_have_locks; p2 = a_proc; #ifdef ERTS_ENABLE_LOCK_CHECK pid2 = a_proc->id; #endif - pix_lck2 = a_pix_lck; need_locks2 = a_need_locks; have_locks2 = a_have_locks; } @@ -735,14 +729,12 @@ proc_safelock(Process *a_proc, #ifdef ERTS_ENABLE_LOCK_CHECK pid1 = a_proc->id; #endif - pix_lck1 = a_pix_lck; need_locks1 = a_need_locks | b_need_locks; have_locks1 = a_have_locks | b_have_locks; p2 = NULL; #ifdef ERTS_ENABLE_LOCK_CHECK pid2 = 0; #endif - pix_lck2 = NULL; need_locks2 = 0; have_locks2 = 0; } @@ -752,14 +744,12 @@ proc_safelock(Process *a_proc, #ifdef ERTS_ENABLE_LOCK_CHECK pid1 = b_proc->id; #endif - pix_lck1 = b_pix_lck; need_locks1 = b_need_locks; have_locks1 = b_have_locks; p2 = NULL; #ifdef ERTS_ENABLE_LOCK_CHECK pid2 = 0; #endif - pix_lck2 = NULL; need_locks2 = 0; have_locks2 = 0; #ifdef ERTS_ENABLE_LOCK_CHECK @@ -807,21 +797,21 @@ proc_safelock(Process *a_proc, if (unlock_locks) { have_locks1 &= ~unlock_locks; need_locks1 |= unlock_locks; - if (!have_locks1) { + if (!is_sched && !have_locks1) { refc1 = 1; erts_smp_proc_inc_refc(p1); } - erts_smp_proc_unlock__(p1, pix_lck1, unlock_locks); + erts_smp_proc_unlock(p1, unlock_locks); } unlock_locks = unlock_mask & have_locks2; if (unlock_locks) { have_locks2 &= ~unlock_locks; need_locks2 |= unlock_locks; - if (!have_locks2) { + if (!is_sched && !have_locks2) { refc2 = 1; erts_smp_proc_inc_refc(p2); } - erts_smp_proc_unlock__(p2, pix_lck2, unlock_locks); + erts_smp_proc_unlock(p2, unlock_locks); } } @@ -852,7 +842,7 @@ proc_safelock(Process *a_proc, if (need_locks2 & lock) lock_no--; locks = need_locks1 & lock_mask; - erts_smp_proc_lock__(p1, pix_lck1, locks); + erts_smp_proc_lock(p1, locks); have_locks1 |= locks; need_locks1 &= ~locks; } @@ -863,7 +853,7 @@ proc_safelock(Process *a_proc, lock = (1 << ++lock_no); } locks = need_locks2 & lock_mask; - erts_smp_proc_lock__(p2, pix_lck2, locks); + erts_smp_proc_lock(p2, locks); have_locks2 |= locks; need_locks2 &= ~locks; } @@ -898,10 +888,12 @@ proc_safelock(Process *a_proc, } #endif - if (refc1) - erts_smp_proc_dec_refc(p1); - if (refc2) - erts_smp_proc_dec_refc(p2); + if (!is_sched) { + if (refc1) + erts_smp_proc_dec_refc(p1); + if (refc2) + erts_smp_proc_dec_refc(p2); + } } void @@ -912,72 +904,185 @@ erts_proc_safelock(Process *a_proc, ErtsProcLocks b_have_locks, ErtsProcLocks b_need_locks) { - proc_safelock(a_proc, - a_proc ? ERTS_PID2PIXLOCK(a_proc->id) : NULL, + proc_safelock(erts_get_scheduler_id() != 0, + a_proc, a_have_locks, a_need_locks, b_proc, - b_proc ? ERTS_PID2PIXLOCK(b_proc->id) : NULL, b_have_locks, b_need_locks); } -/* - * erts_pid2proc_safelock() is called from erts_pid2proc_opt() when - * it wasn't possible to trylock all locks needed. - * c_p - current process - * c_p_have_locks - locks held on c_p - * pid - process id of process we are looking up - * proc - process struct of process we are looking - * up (both in and out argument) - * need_locks - all locks we need (including have_locks) - * pix_lock - pix lock for process we are looking up - * flags - option flags - */ -void -erts_pid2proc_safelock(Process *c_p, - ErtsProcLocks c_p_have_locks, - Process **proc, - ErtsProcLocks need_locks, - erts_pix_lock_t *pix_lock, - int flags) +Process * +erts_pid2proc_opt(Process *c_p, + ErtsProcLocks c_p_have_locks, + Eterm pid, + ErtsProcLocks pid_need_locks, + int flags) { - Process *p = *proc; - ERTS_LC_ASSERT(p->lock.refc > 0); - ERTS_LC_ASSERT(process_tab[internal_pid_index(p->id)] == p); - p->lock.refc++; - erts_pix_unlock(pix_lock); - - proc_safelock(c_p, - c_p ? ERTS_PID2PIXLOCK(c_p->id) : NULL, - c_p_have_locks, - c_p_have_locks, - p, - pix_lock, - 0, - need_locks); + Process *dec_refc_proc = NULL; + int need_ptl; + ErtsProcLocks need_locks; + Uint pix; + Process *proc; +#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_COUNT) + ErtsProcLocks lcnt_locks; +#endif - erts_pix_lock(pix_lock); +#ifdef ERTS_ENABLE_LOCK_CHECK + if (c_p) { + ErtsProcLocks might_unlock = c_p_have_locks & pid_need_locks; + if (might_unlock) + erts_proc_lc_might_unlock(c_p, might_unlock); + } +#endif - if (!p->is_exiting - || ((flags & ERTS_P2P_FLG_ALLOW_OTHER_X) - && process_tab[internal_pid_index(p->id)] == p)) { - ERTS_LC_ASSERT(p->lock.refc > 1); - p->lock.refc--; + if (is_not_internal_pid(pid)) + return NULL; + pix = internal_pid_index(pid); + + ERTS_LC_ASSERT((pid_need_locks & ERTS_PROC_LOCKS_ALL) == pid_need_locks); + need_locks = pid_need_locks; + + if (c_p && c_p->id == pid) { + ASSERT(c_p->id != ERTS_INVALID_PID); + ASSERT(c_p == erts_pix2proc(pix)); + + if (!(flags & ERTS_P2P_FLG_ALLOW_OTHER_X) + && ERTS_PROC_IS_EXITING(c_p)) + return NULL; + need_locks &= ~c_p_have_locks; + if (!need_locks) { + if (flags & ERTS_P2P_FLG_SMP_INC_REFC) + erts_smp_proc_inc_refc(c_p); + return c_p; + } } - else { - /* No proc. Note, we need to keep refc until after process unlock */ - erts_pix_unlock(pix_lock); - erts_smp_proc_unlock__(p, pix_lock, need_locks); - *proc = NULL; - erts_pix_lock(pix_lock); - ERTS_LC_ASSERT(p->lock.refc > 0); - if (--p->lock.refc == 0) { - erts_pix_unlock(pix_lock); - erts_free_proc(p); - erts_pix_lock(pix_lock); + + need_ptl = !erts_get_scheduler_id(); + + if (need_ptl) + erts_smp_rwmtx_rwlock(&erts_proc_tab_rwmtx); + + proc = (Process *) erts_smp_atomic_read_ddrb(&erts_proc.tab[pix]); + + if (proc) { + if (proc->id != pid) + proc = NULL; + else if (!need_locks) { + if (flags & ERTS_P2P_FLG_SMP_INC_REFC) + erts_smp_proc_inc_refc(proc); } + else { + int busy; + +#if ERTS_PROC_LOCK_OWN_IMPL +#ifdef ERTS_ENABLE_LOCK_COUNT + lcnt_locks = need_locks; + if (!(flags & ERTS_P2P_FLG_TRY_LOCK)) { + erts_lcnt_proc_lock(&proc->lock, need_locks); + } +#endif + +#ifdef ERTS_ENABLE_LOCK_CHECK + /* Make sure erts_pid2proc_safelock() is enough to handle + a potential lock order violation situation... */ + busy = erts_proc_lc_trylock_force_busy(proc, need_locks); + if (!busy) +#endif +#endif /* ERTS_PROC_LOCK_OWN_IMPL */ + { + /* Try a quick trylock to grab all the locks we need. */ + busy = (int) erts_smp_proc_raw_trylock__(proc, need_locks); + +#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_CHECK) + erts_proc_lc_trylock(proc, need_locks, !busy); +#endif +#ifdef ERTS_PROC_LOCK_DEBUG + if (!busy) + erts_proc_lock_op_debug(proc, need_locks, 1); +#endif + } + +#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_COUNT) + if (flags & ERTS_P2P_FLG_TRY_LOCK) + erts_lcnt_proc_trylock(&proc->lock, need_locks, + busy ? EBUSY : 0); +#endif + + if (!busy) { + if (flags & ERTS_P2P_FLG_SMP_INC_REFC) + erts_smp_proc_inc_refc(proc); + +#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_COUNT) + /* all is great */ + if (!(flags & ERTS_P2P_FLG_TRY_LOCK)) + erts_lcnt_proc_lock_post_x(&proc->lock, lcnt_locks, + __FILE__, __LINE__); +#endif + + } + else { + if (flags & ERTS_P2P_FLG_TRY_LOCK) + proc = ERTS_PROC_LOCK_BUSY; + else { + if (flags & ERTS_P2P_FLG_SMP_INC_REFC) + erts_smp_proc_inc_refc(proc); + +#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_COUNT) + erts_lcnt_proc_lock_unaquire(&proc->lock, lcnt_locks); +#endif + + if (need_ptl) { + erts_smp_proc_inc_refc(proc); + dec_refc_proc = proc; + erts_smp_rwmtx_rwunlock(&erts_proc_tab_rwmtx); + need_ptl = 0; + } + + proc_safelock(!need_ptl, + c_p, + c_p_have_locks, + c_p_have_locks, + proc, + 0, + need_locks); + } + } + } } + + if (need_ptl) + erts_smp_rwmtx_rwunlock(&erts_proc_tab_rwmtx); + + if (need_locks + && proc + && proc != ERTS_PROC_LOCK_BUSY + && (!(flags & ERTS_P2P_FLG_ALLOW_OTHER_X) + ? ERTS_PROC_IS_EXITING(proc) + : (proc + != (Process *) erts_smp_atomic_read_nob(&erts_proc.tab[pix])))) { + + erts_smp_proc_unlock(proc, need_locks); + + if (flags & ERTS_P2P_FLG_SMP_INC_REFC) + dec_refc_proc = proc; + proc = NULL; + + } + + if (dec_refc_proc) + erts_smp_proc_dec_refc(dec_refc_proc); + +#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_PROC_LOCK_DEBUG) + ERTS_LC_ASSERT(!proc + || proc == ERTS_PROC_LOCK_BUSY + || (pid_need_locks == + (ERTS_PROC_LOCK_FLGS_READ_(&proc->lock) + & pid_need_locks))); +#endif + + return proc; } void @@ -1017,7 +1122,7 @@ erts_proc_lock_init(Process *p) erts_lc_trylock(1, &p->lock.status.lc); #endif #endif - p->lock.refc = 1; + erts_atomic32_init_nob(&p->lock.refc, 1); #ifdef ERTS_PROC_LOCK_DEBUG { int i; @@ -1590,4 +1695,4 @@ check_queue(erts_proc_lock_t *lck) } #endif -#endif /* ERTS_SMP (the whole file) */ +#endif /* ERTS_SMP */ |