fis-gtm/sr_port/op_zalloc2.c

/****************************************************************
 *								*
 *	Copyright 2001, 2010 Fidelity Information Services, Inc	*
 *								*
 *	This source code contains the intellectual property	*
 *	of its copyright holder(s), and is made available	*
 *	under a license.  If you do not know the terms of	*
 *	the license, please stop and do not read further.	*
 *								*
 ****************************************************************/

#include "mdef.h"

#include "cdb_sc.h"
#include "cmidef.h"
#include "hashtab_mname.h"	/* needed for cmmdef.h */
#include "cmmdef.h"
#include "gdsroot.h"
#include "gt_timer.h"
#include "iotimer.h"
#include "locklits.h"
#include "mlkdef.h"
#include "t_retry.h"
#include "op.h"
#include "mlk_lock.h"
#include "mlk_bckout.h"
#include "mlk_pvtblk_delete.h"
#include "mlk_unlock.h"
#include "mlk_unpend.h"
#include "outofband.h"
#include "lk_check_own.h"
#include "gvcmx.h"
#include "gvcmz.h"
#include "rel_quant.h"
#include "lckclr.h"
#include "wake_alarm.h"

GBLREF	bool		out_of_time;
GBLREF	bool		remlkreq;
GBLREF	unsigned char	cm_action;
GBLREF	unsigned short	lks_this_cmd;
GBLREF	uint4		dollar_tlevel;
GBLREF	unsigned int	t_tries;
GBLREF	uint4		process_id;
GBLREF	int4		outofband;
GBLREF	mlk_pvtblk	*mlk_pvt_root;
GBLREF	mlk_stats_t	mlk_stats;			/* Process-private M-lock statistics */

/* -----------------------------------------------
 *
 * Maintain in parallel with op_lock2
 *
 * Arguments:
 *	timeout	- max. time to wait for locks before giving up
 *      auxown - auxillary owner field for use by servers
 *
 * Return:
 *	1 - if not timeout specified
 *	if timeout specified:
 *		!= 0 - all the locks int the list obtained, or
 *		0 - blocked
 *	The return result is suited to be placed directly into
 *	the $T variable by the caller if timeout is specified.
 * -----------------------------------------------
 */
int	op_zalloc2(int4 timeout, UINTPTR_T auxown)	/* timeout in seconds */
{
	bool		blocked, timer_on;
	signed char	gotit;
	unsigned short	locks_bckout, locks_done;
	int4		msec_timeout;	/* timeout in milliseconds */
	mlk_pvtblk	*pvt_ptr1, *pvt_ptr2, **prior;

	gotit = -1;
	cm_action = CM_ZALLOCATES;
	timer_on = (NO_M_TIMEOUT != timeout);
	out_of_time = FALSE;
	if (!timer_on)
		msec_timeout = NO_M_TIMEOUT;
	else
	{
		msec_timeout = timeout2msec(timeout);
		if (0 == msec_timeout)
			out_of_time = TRUE;
		else
			start_timer((TID)&timer_on, msec_timeout, wake_alarm, 0, NULL);
	}
	lckclr();
	for (blocked = FALSE;  !blocked;)
	{
		/* if this is a request for a remote node */
		if (remlkreq)
		{
			if (gotit >= 0)
				gotit = gvcmx_resremlk(cm_action);
			else
				gotit = gvcmx_reqremlk(cm_action, timeout);

			if (!gotit)
			{
				/* only REQIMMED returns false */
				blocked = TRUE;
				break;
			}
		}
		for (pvt_ptr1 = mlk_pvt_root, locks_done = 0;  locks_done < lks_this_cmd;  pvt_ptr1 = pvt_ptr1->next, locks_done++)
		{	/* Go thru the list of all locks to be obtained attempting to lock
			 * each one. If any lock could not be obtained, break out of the loop */
			if (pvt_ptr1->old  &&  !pvt_ptr1->zalloc)
				pvt_ptr1->old = FALSE;
			if (!mlk_lock(pvt_ptr1, auxown, TRUE))
			{	/* If lock is obtained */
				pvt_ptr1->granted = TRUE;
				pvt_ptr1->zalloc = TRUE;
			} else
			{
				blocked = TRUE;
				break;
			}
		}
		/* If we did not get blocked, we are all done */
		if (!blocked)
			break;
		/* We got blocked and need to keep retrying after some time interval */
		if (remlkreq)
			gvcmx_susremlk(cm_action);

		for (pvt_ptr2 = mlk_pvt_root, locks_bckout = 0;  locks_bckout < locks_done;
			pvt_ptr2 = pvt_ptr2->next, locks_bckout++)
		{
			assert(pvt_ptr2->granted && (pvt_ptr2 != pvt_ptr1));
			mlk_bckout(pvt_ptr2, ZALLOCATED);
		}
		if (dollar_tlevel && (CDB_STAGNATE <= t_tries))
		{
			mlk_unpend(pvt_ptr1);		/* Eliminated the dangling request block */
			if (timer_on)
				cancel_timer((TID)&timer_on);
			t_retry(cdb_sc_needlock);	/* release crit to prevent a deadlock */
		}

		for (;;)
		{
			if (out_of_time || outofband)
			{	/* if time expired  ||  control-c encountered */
				if (outofband || !lk_check_own(pvt_ptr1))
				{	/* If CTL-C, check lock owner */
					if (pvt_ptr1->nodptr)		/* Get off pending list to be sent a wake */
						mlk_unpend(pvt_ptr1);
					/* Cancel all remote locks obtained so far */
					if (remlkreq)
					{
						gvcmx_canremlk();
						gvcmz_clrlkreq();
						remlkreq = FALSE;
					}
					if (outofband)
					{
						cancel_timer((TID)&timer_on);
						outofband_action(FALSE);
					}
					break;
				}
			}
			if (!mlk_lock(pvt_ptr1, 0, FALSE))
			{	/* If we got the lock, break out of timer loop */
				blocked = FALSE;
				if (pvt_ptr1 != mlk_pvt_root)
				{
					rel_quant();		/* attempt to get a full timeslice for maximum chance to get all */
					mlk_unlock(pvt_ptr1);
				}
				break;
			}
			if (pvt_ptr1->nodptr)
				lk_check_own(pvt_ptr1);		/* clear an abandoned owner */
			hiber_start_wait_any(LOCK_SELF_WAKE);
		}
		if (blocked  &&  out_of_time)
			break;
	}
	if (remlkreq)
	{
		gvcmz_clrlkreq();
		remlkreq = FALSE;
	}
	if (timer_on)
	{
		cancel_timer((TID)&timer_on);
		if (blocked)
		{
			for (prior = &mlk_pvt_root;  *prior;)
			{
				if (!(*prior)->granted)
				{	/* if entry was never granted, delete list entry */
					mlk_pvtblk_delete(prior);
				} else
					prior = &((*prior)->next);
			}
			mlk_stats.n_user_locks_fail++;
			return (FALSE);
		}
	}
	mlk_stats.n_user_locks_success++;
	return (TRUE);
}