From 4458257e5c9c48d43fa0ea4fa981436f364e14e2 Mon Sep 17 00:00:00 2001 From: Rickard Green Date: Wed, 6 Apr 2011 09:53:04 +0200 Subject: Only set status P_WAITING when needed The status of a process was unnecessarily set to waiting before the process was enqueued in a run queue. This bug was harmless up until OTP-R14B01. In OTP-R14B02 erlang:hibernate/3 was fixed (OTP-9125). After the introduction of OTP-9125, the previously harmless process status bug sometimes caused erroneous badarg exceptions from process_info(). --- erts/emulator/beam/beam_emu.c | 3 ++- erts/emulator/beam/erl_process.c | 8 +++----- 2 files changed, 5 insertions(+), 6 deletions(-) (limited to 'erts/emulator/beam') diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c index 7b2aac0908..df9d067727 100644 --- a/erts/emulator/beam/beam_emu.c +++ b/erts/emulator/beam/beam_emu.c @@ -6276,12 +6276,13 @@ erts_hibernate(Process* c_p, Eterm module, Eterm function, Eterm args, Eterm* re PROCESS_MAIN_CHK_LOCKS(c_p); erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS); ASSERT(!ERTS_PROC_IS_EXITING(c_p)); - c_p->status = P_WAITING; #ifdef ERTS_SMP ERTS_SMP_MSGQ_MV_INQ2PRIVQ(c_p); if (c_p->msg.len > 0) erts_add_to_runq(c_p); + else #endif + c_p->status = P_WAITING; } erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS); c_p->current = bif_export[BIF_hibernate_3]->code; diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c index 428ca12eb1..f6e4e9df11 100644 --- a/erts/emulator/beam/erl_process.c +++ b/erts/emulator/beam/erl_process.c @@ -2857,7 +2857,6 @@ resume_process(Process *p) return; switch(p->rstatus) { case P_RUNABLE: - *statusp = P_WAITING; /* make erts_add_to_runq work */ erts_add_to_runq(p); break; case P_WAITING: @@ -4653,7 +4652,7 @@ internal_add_to_runq(ErtsRunQueue *runq, Process *p) if (p->status_flags & ERTS_PROC_SFLG_INRUNQ) return NULL; else if (p->runq_flags & ERTS_PROC_RUNQ_FLG_RUNNING) { - ASSERT(p->status != P_SUSPENDED); + ASSERT(p->rcount == 0); ERTS_DBG_CHK_PROCS_RUNQ_NOPROC(runq, p); p->status_flags |= ERTS_PROC_SFLG_PENDADD2SCHEDQ; return NULL; @@ -4664,9 +4663,8 @@ internal_add_to_runq(ErtsRunQueue *runq, Process *p) ERTS_DBG_CHK_PROCS_RUNQ_NOPROC(runq, p); #ifndef ERTS_SMP /* Never schedule a suspended process (ok in smp case) */ - ASSERT(p->status != P_SUSPENDED); + ASSERT(p->rcount == 0); add_runq = runq; - #else ASSERT(!p->bound_runq || p->bound_runq == p->run_queue); if (p->bound_runq) { @@ -5166,7 +5164,7 @@ Process *schedule(Process *p, int calls) handle_pending_suspend(p, ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_STATUS); ASSERT(!(p->status_flags & ERTS_PROC_SFLG_PENDADD2SCHEDQ) - || p->status != P_SUSPENDED); + || p->rcount == 0); } #endif erts_smp_runq_lock(rq); -- cgit v1.2.3 From e63eb63e2e8b8298826f2df7192e982a4e272749 Mon Sep 17 00:00:00 2001 From: Rickard Green Date: Fri, 8 Apr 2011 15:11:46 +0200 Subject: Fix lost wakeup when process garbage collected by other --- erts/emulator/beam/erl_process.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) (limited to 'erts/emulator/beam') diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c index f6e4e9df11..21625921d5 100644 --- a/erts/emulator/beam/erl_process.c +++ b/erts/emulator/beam/erl_process.c @@ -7609,10 +7609,28 @@ timeout_proc(Process* p) p->flags |= F_TIMO; p->flags &= ~F_INSLPQUEUE; - if (p->status == P_WAITING) - erts_add_to_runq(p); - if (p->status == P_SUSPENDED) + switch (p->status) { + case P_GARBING: + switch (p->gcstatus) { + case P_SUSPENDED: + goto suspended; + case P_WAITING: + goto waiting; + default: + break; + } + break; + case P_WAITING: + waiting: + erts_add_to_runq(p); + break; + case P_SUSPENDED: + suspended: p->rstatus = P_RUNABLE; /* MUST set resume status to runnable */ + break; + default: + break; + } } -- cgit v1.2.3 From b7ecdcd1ae9e11b8f75e11b82d94da32837932bc Mon Sep 17 00:00:00 2001 From: Rickard Green Date: Thu, 7 Apr 2011 11:54:37 +0200 Subject: Fix thread unsafe access Fix thread unsafe access to process status field introduced in OTP-9125. --- erts/emulator/beam/beam_emu.c | 5 ++++- erts/emulator/beam/erl_process.h | 1 + 2 files changed, 5 insertions(+), 1 deletion(-) (limited to 'erts/emulator/beam') diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c index df9d067727..47bff4a427 100644 --- a/erts/emulator/beam/beam_emu.c +++ b/erts/emulator/beam/beam_emu.c @@ -3419,7 +3419,8 @@ void process_main(void) r(0) = c_p->def_arg_reg[0]; x(1) = c_p->def_arg_reg[1]; x(2) = c_p->def_arg_reg[2]; - if (c_p->status == P_WAITING) { + if (c_p->flags & F_HIBERNATE_SCHED) { + c_p->flags &= ~F_HIBERNATE_SCHED; goto do_schedule; } Dispatch(); @@ -5224,6 +5225,7 @@ void process_main(void) OpCase(i_hibernate): { SWAPOUT; if (erts_hibernate(c_p, r(0), x(1), x(2), reg)) { + c_p->flags &= ~F_HIBERNATE_SCHED; goto do_schedule; } else { I = handle_error(c_p, I, reg, hibernate_3); @@ -6286,6 +6288,7 @@ erts_hibernate(Process* c_p, Eterm module, Eterm function, Eterm args, Eterm* re } erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS); c_p->current = bif_export[BIF_hibernate_3]->code; + c_p->flags |= F_HIBERNATE_SCHED; /* Needed also when woken! */ return 1; } diff --git a/erts/emulator/beam/erl_process.h b/erts/emulator/beam/erl_process.h index 8f78a7d76e..334ae5573f 100644 --- a/erts/emulator/beam/erl_process.h +++ b/erts/emulator/beam/erl_process.h @@ -895,6 +895,7 @@ extern struct erts_system_profile_flags_t erts_system_profile_flags; #define F_HAVE_BLCKD_MSCHED (1 << 8) /* Process has blocked multi-scheduling */ #define F_P2PNR_RESCHED (1 << 9) /* Process has been rescheduled via erts_pid2proc_not_running() */ #define F_FORCE_GC (1 << 10) /* Force gc at process in-scheduling */ +#define F_HIBERNATE_SCHED (1 << 11) /* Schedule out after hibernate op */ /* process trace_flags */ #define F_SENSITIVE (1 << 0) -- cgit v1.2.3