C++ (Cpp) erts_lcnt_proc_trylock Examples

Example #1

File: erl_process_lock.c Project: AugHu/otp

Process *
erts_pid2proc_opt(Process *c_p,
		  ErtsProcLocks c_p_have_locks,
		  Eterm pid,
		  ErtsProcLocks pid_need_locks,
		  int flags)
{
    Process *dec_refc_proc = NULL;
    ErtsThrPrgrDelayHandle dhndl;
    ErtsProcLocks need_locks;
    Uint pix;
    Process *proc;
#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_COUNT)
    ErtsProcLocks lcnt_locks;
#endif

#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 (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->common.id == pid) {
	ASSERT(c_p->common.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_INC_REFC)
		erts_proc_inc_refc(c_p);
	    return c_p;
	}
    }

    dhndl = erts_thr_progress_unmanaged_delay();

    proc = (Process *) erts_ptab_pix2intptr_ddrb(&erts_proc, pix);

    if (proc) {
	if (proc->common.id != pid)
	    proc = NULL;
	else if (!need_locks) {
	    if (flags & ERTS_P2P_FLG_INC_REFC)
		erts_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, __FILE__,__LINE__);
#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_INC_REFC)
		    erts_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 {
		    int managed;
		    if (flags & ERTS_P2P_FLG_INC_REFC)
			erts_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

		    managed = dhndl == ERTS_THR_PRGR_DHANDLE_MANAGED;
		    if (!managed) {
			erts_proc_inc_refc(proc);
			erts_thr_progress_unmanaged_continue(dhndl);
			dec_refc_proc = proc;

			/*
			 * We don't want to call
			 * erts_thr_progress_unmanaged_continue()
			 * again.
			 */
			dhndl = ERTS_THR_PRGR_DHANDLE_MANAGED;
		    }

		    proc_safelock(managed,
				  c_p,
				  c_p_have_locks,
				  c_p_have_locks,
				  proc,
				  0,
				  need_locks);
		}
	    }
        }
    }

    if (dhndl != ERTS_THR_PRGR_DHANDLE_MANAGED)
	erts_thr_progress_unmanaged_continue(dhndl);

    if (need_locks
	&& proc
	&& proc != ERTS_PROC_LOCK_BUSY
	&& (!(flags & ERTS_P2P_FLG_ALLOW_OTHER_X)
	    ? ERTS_PROC_IS_EXITING(proc)
	    : (proc
	       != (Process *) erts_ptab_pix2intptr_nob(&erts_proc, pix)))) {

	erts_smp_proc_unlock(proc, need_locks);

	if (flags & ERTS_P2P_FLG_INC_REFC)
	    dec_refc_proc = proc;
	proc = NULL;

    }

    if (dec_refc_proc)
	erts_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;
}

Example #2

File: erl_process_lock.c Project: PiotrSikora/otp

Process *
erts_pid2proc_opt(Process *c_p,
		  ErtsProcLocks c_p_have_locks,
		  Eterm pid,
		  ErtsProcLocks pid_need_locks,
		  int flags)
{
    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

#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 (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;
	}
    }

    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;
}