From 2dc14df8ce5d56df3974aa57a61b3c1a0bfd3149 Mon Sep 17 00:00:00 2001 From: Rickard Green Date: Wed, 21 Mar 2018 17:34:38 +0100 Subject: Fix signal handling priority elevation --- erts/emulator/beam/erl_process.c | 104 +++++++++++++++++++++++++-------------- 1 file changed, 66 insertions(+), 38 deletions(-) (limited to 'erts/emulator/beam') diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c index 7969025f57..374583ec47 100644 --- a/erts/emulator/beam/erl_process.c +++ b/erts/emulator/beam/erl_process.c @@ -10501,6 +10501,8 @@ done: return st; } + +static void exit_permanent_prio_elevation(Process *c_p, erts_aint32_t state); static void save_gc_task(Process *c_p, ErtsProcSysTask *st, int prio); static void save_dirty_task(Process *c_p, ErtsProcSysTask *st); @@ -10633,8 +10635,10 @@ execute_sys_tasks(Process *c_p, erts_aint32_t *statep, int in_reds) reds, local_only); reds -= sig_reds; - if (state & ERTS_PSFLG_EXITING) - goto perm_elevate_prio; + if (state & ERTS_PSFLG_EXITING) { + exit_permanent_prio_elevation(c_p, state); + break; + } if (sig_res) break; @@ -10648,37 +10652,8 @@ execute_sys_tasks(Process *c_p, erts_aint32_t *statep, int in_reds) st = NULL; } else { - erts_aint32_t a; - state = erts_atomic32_read_nob(&c_p->state); - - perm_elevate_prio: - - /* - * we are about to terminate; permanently elevate - * prio in order to ensure high prio signal - * handling... - */ - - a = state; - while (1) { - erts_aint32_t aprio, uprio, n, e; - ASSERT(!(a & ERTS_PSFLG_FREE)); - aprio = ERTS_PSFLGS_GET_ACT_PRIO(a); - uprio = ERTS_PSFLGS_GET_USR_PRIO(a); - if (aprio >= uprio) - break; /* user prio >= actual prio */ - /* - * actual prio is higher than user prio; raise - * user prio to actual prio... - */ - n = e = a; - n &= ~ERTS_PSFLGS_USR_PRIO_MASK; - n |= aprio << ERTS_PSFLGS_USR_PRIO_OFFSET; - a = erts_atomic32_cmpxchg_mb(&c_p->state, n, e); - if (a == e) - break; - } + exit_permanent_prio_elevation(c_p, state); } break; } @@ -10730,12 +10705,15 @@ cleanup_sys_tasks(Process *c_p, erts_aint32_t in_state, int in_reds) } switch (st->type) { + case ERTS_PSTT_PRIO_SIG: + state = erts_atomic32_read_nob(&c_p->state); + exit_permanent_prio_elevation(c_p, state); + /* fall through... */ case ERTS_PSTT_GC_MAJOR: case ERTS_PSTT_GC_MINOR: case ERTS_PSTT_CPC: case ERTS_PSTT_COHMQ: case ERTS_PSTT_ETS_FREE_FIXATION: - case ERTS_PSTT_PRIO_SIG: st_res = am_false; break; case ERTS_PSTT_CLA: @@ -10759,6 +10737,36 @@ cleanup_sys_tasks(Process *c_p, erts_aint32_t in_state, int in_reds) return reds; } +static void +exit_permanent_prio_elevation(Process *c_p, erts_aint32_t state) +{ + erts_aint32_t a; + /* + * we are about to terminate; permanently elevate + * prio in order to ensure high prio signal + * handling... + */ + a = state; + while (1) { + erts_aint32_t aprio, uprio, n, e; + ASSERT(a & ERTS_PSFLG_EXITING); + ASSERT(!(a & ERTS_PSFLG_FREE)); + aprio = ERTS_PSFLGS_GET_ACT_PRIO(a); + uprio = ERTS_PSFLGS_GET_USR_PRIO(a); + if (aprio >= uprio) + break; /* user prio >= actual prio */ + /* + * actual prio is higher than user prio; raise + * user prio to actual prio... + */ + n = e = a; + n &= ~ERTS_PSFLGS_USR_PRIO_MASK; + n |= aprio << ERTS_PSFLGS_USR_PRIO_OFFSET; + a = erts_atomic32_cmpxchg_mb(&c_p->state, n, e); + if (a == e) + break; + } +} void erts_execute_dirty_system_task(Process *c_p) @@ -12752,16 +12760,13 @@ erts_continue_exit_process(Process *p) erts_set_gc_state(p, 1); state = erts_atomic32_read_acqb(&p->state); - if ((state & ERTS_PSFLG_SYS_TASKS) - || p->dirty_sys_tasks - ) { + if ((state & ERTS_PSFLG_SYS_TASKS) || p->dirty_sys_tasks) { if (cleanup_sys_tasks(p, state, CONTEXT_REDS) >= CONTEXT_REDS/2) goto yield; } #ifdef DEBUG erts_proc_lock(p, ERTS_PROC_LOCK_STATUS); - ASSERT(p->sys_task_qs == NULL); ASSERT(ERTS_PROC_GET_DELAYED_GC_TASK_QS(p) == NULL); ASSERT(p->dirty_sys_tasks == NULL); erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS); @@ -12873,7 +12878,30 @@ erts_continue_exit_process(Process *p) ? ERTS_PROC_SET_DIST_ENTRY(p, NULL) : NULL); - erts_proc_unlock(p, ERTS_PROC_LOCKS_ALL); + + /* + * It might show up signal prio elevation tasks until we + * have entered free state. Cleanup such tasks now. + */ + state = erts_atomic32_read_acqb(&p->state); + if (!(state & ERTS_PSFLG_SYS_TASKS)) + erts_proc_unlock(p, ERTS_PROC_LOCKS_ALL); + else { + erts_proc_unlock(p, ERTS_PROC_LOCKS_ALL_MINOR); + + do { + (void) cleanup_sys_tasks(p, state, CONTEXT_REDS); + state = erts_atomic32_read_acqb(&p->state); + } while (state & ERTS_PSFLG_SYS_TASKS); + + erts_proc_unlock(p, ERTS_PROC_LOCK_MAIN); + } + +#ifdef DEBUG + erts_proc_lock(p, ERTS_PROC_LOCK_STATUS); + ASSERT(p->sys_task_qs == NULL); + erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS); +#endif if (dep) { erts_do_net_exits(dep, (reason == am_kill) ? am_killed : reason); -- cgit v1.2.3