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/*************************************************************************
* *
* YAP Prolog *
* *
* Yap Prolog was developed at NCCUP - Universidade do Porto *
* *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
* *
**************************************************************************
* *
* File: or.cowengine.c *
* Last rev: *
* mods: *
* comments: *
* *
*************************************************************************/
/* ------------------ **
** Includes **
** ------------------ */
#include "Yap.h"
#ifdef ACOW
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include "Yatom.h"
#include "Heap.h"
#include "or.macros.h"
/* ------------------------------------- **
** Local functions declaration **
** ------------------------------------- */
static void share_private_nodes(int worker_q);
/* ----------------------- **
** Local inlines **
** ----------------------- */
STD_PROTO(static inline void PUT_BUSY, (int));
static inline
void PUT_BUSY(int worker_num) {
LOCK(GLOBAL_LOCKS_bm_idle_workers);
BITMAP_delete(GLOBAL_bm_idle_workers, worker_num);
UNLOCK(GLOBAL_LOCKS_bm_idle_workers);
return;
}
/* -------------------------- **
** Global functions **
** -------------------------- */
void make_root_choice_point(void) {
if (worker_id == 0) {
LOCAL_top_cp = GLOBAL_root_cp = OrFr_node(GLOBAL_root_or_fr) = B;
} else {
B = LOCAL_top_cp = GLOBAL_root_cp;
B->cp_tr = TR = ((choiceptr) (worker_offset(0) + (CELL)(B)))->cp_tr;
}
B->cp_h = H0;
B->cp_ap = GETWORK;
B->cp_or_fr = GLOBAL_root_or_fr;
LOCAL_top_or_fr = GLOBAL_root_or_fr;
LOCAL_load = 0;
LOCAL_prune_request = NULL;
BRANCH(worker_id, 0) = 0;
return;
}
void free_root_choice_point(void) {
B = LOCAL_top_cp->cp_b;
LOCAL_top_cp = B_BASE;
return;
}
int p_share_work(void) {
int worker_q = LOCAL_share_request;
int son;
if (! BITMAP_member(OrFr_members(REMOTE_top_or_fr(worker_q)), worker_id) ||
B == REMOTE_top_cp(worker_q) ||
(LOCAL_load <= DELAYED_RELEASE_LOAD && OrFr_nearest_livenode(LOCAL_top_or_fr) == NULL)) {
/* refuse sharing request */
REMOTE_reply_signal(LOCAL_share_request) = no_sharing;
LOCAL_share_request = MAX_WORKERS;
PUT_OUT_REQUESTABLE(worker_id);
return TRUE;
}
/* sharing request accepted */
REMOTE_reply_signal(worker_q) = sharing;
share_private_nodes(worker_q);
if ((son = fork()) == 0) {
worker_id = worker_q; /* child becomes requesting worker */
LOCAL = REMOTE + worker_id;
LOCAL_reply_signal = ready;
PUT_IN_REQUESTABLE(worker_id);
PUT_BUSY(worker_id);
return FALSE;
} else {
worker_pid(worker_q) = son;
LOCAL_share_request = MAX_WORKERS;
PUT_IN_REQUESTABLE(worker_id);
return TRUE;
}
}
int q_share_work(int worker_p) {
LOCK_OR_FRAME(LOCAL_top_or_fr);
if (REMOTE_prune_request(worker_p)) {
/* worker p with prune request */
UNLOCK_OR_FRAME(LOCAL_top_or_fr);
return FALSE;
}
#ifdef YAPOR_ERRORS
if (OrFr_pend_prune_cp(LOCAL_top_or_fr) &&
BRANCH_LTT(worker_p, OrFr_depth(LOCAL_top_or_fr)) < OrFr_pend_prune_ltt(LOCAL_top_or_fr))
YAPOR_ERROR_MESSAGE("prune ltt > worker_p branch ltt (q_share_work)");
#endif /* YAPOR_ERRORS */
/* there is no pending prune with worker p at right --> safe move to worker p branch */
BRANCH(worker_id, OrFr_depth(LOCAL_top_or_fr)) = BRANCH(worker_p, OrFr_depth(LOCAL_top_or_fr));
LOCAL_prune_request = NULL;
UNLOCK_OR_FRAME(LOCAL_top_or_fr);
/* make sharing request */
LOCK_WORKER(worker_p);
if (BITMAP_member(GLOBAL_bm_idle_workers, worker_p) ||
REMOTE_share_request(worker_p) != MAX_WORKERS) {
/* worker p is idle or has another request */
UNLOCK_WORKER(worker_p);
return FALSE;
}
REMOTE_share_request(worker_p) = worker_id;
UNLOCK_WORKER(worker_p);
/* wait for an answer */
while (LOCAL_reply_signal == ready);
if (LOCAL_reply_signal == no_sharing) {
/* sharing request refused */
LOCAL_reply_signal = ready;
return FALSE;
}
/* exit this process */
exit(0);
}
/* ------------------------- **
** Local functions **
** ------------------------- */
static
void share_private_nodes(int worker_q) {
int depth;
choiceptr AuxB;
or_fr_ptr or_frame, previous_or_frame;
/* initialize auxiliary variables */
AuxB = B;
previous_or_frame = NULL;
depth = OrFr_depth(LOCAL_top_or_fr);
/* sharing loop */
while (AuxB != LOCAL_top_cp) {
depth++;
ALLOC_OR_FRAME(or_frame);
INIT_LOCK(OrFr_lock(or_frame));
OrFr_node(or_frame) = AuxB;
OrFr_alternative(or_frame) = AuxB->cp_ap;
OrFr_pend_prune_cp(or_frame) = NULL;
OrFr_nearest_leftnode(or_frame) = LOCAL_top_or_fr;
OrFr_qg_solutions(or_frame) = NULL;
BITMAP_clear(OrFr_members(or_frame));
BITMAP_insert(OrFr_members(or_frame), worker_id);
BITMAP_insert(OrFr_members(or_frame), worker_q);
if (AuxB->cp_ap && YAMOP_SEQ(AuxB->cp_ap)) {
AuxB->cp_ap = GETWORK_SEQ;
} else {
AuxB->cp_ap = GETWORK;
}
AuxB->cp_or_fr = or_frame;
AuxB = AuxB->cp_b;
if (previous_or_frame) {
OrFr_nearest_livenode(previous_or_frame) = OrFr_next(previous_or_frame) = or_frame;
}
previous_or_frame = or_frame;
}
/* initialize last or-frame pointer */
or_frame = AuxB->cp_or_fr;
if (previous_or_frame) {
OrFr_nearest_livenode(previous_or_frame) = OrFr_next(previous_or_frame) = or_frame;
}
/* update depth */
if (depth >= MAX_DEPTH)
Yap_Error(INTERNAL_ERROR, TermNil, "maximum depth exceded (share_private_nodes)");
or_frame = B->cp_or_fr;
while (or_frame != LOCAL_top_or_fr) {
unsigned int branch;
if (OrFr_alternative(or_frame)) {
branch = YAMOP_OR_ARG(OrFr_alternative(or_frame)) + 1;
} else {
branch = 1;
}
branch |= YAMOP_CUT_FLAG; /* in doubt, assume cut */
BRANCH(worker_id, depth) = BRANCH(worker_q, depth) = branch;
OrFr_depth(or_frame) = depth--;
or_frame = OrFr_next_on_stack(or_frame);
}
/* update old shared nodes */
while (or_frame != REMOTE_top_or_fr(worker_q)) {
LOCK_OR_FRAME(or_frame);
BRANCH(worker_q, OrFr_depth(or_frame)) = BRANCH(worker_id, OrFr_depth(or_frame));
BITMAP_insert(OrFr_members(or_frame), worker_q);
UNLOCK_OR_FRAME(or_frame);
or_frame = OrFr_next_on_stack(or_frame);
}
/* update top shared nodes */
REMOTE_top_cp(worker_q) = LOCAL_top_cp = B;
REMOTE_top_or_fr(worker_q) = LOCAL_top_or_fr = LOCAL_top_cp->cp_or_fr;
/* update prune request */
if (LOCAL_prune_request) {
CUT_send_prune_request(worker_q, LOCAL_prune_request);
}
/* update load and return */
REMOTE_load(worker_q) = LOCAL_load = 0;
return;
}
#endif /* ACOW */
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