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#include "stdinc.h"
#include "dat.h"
#include "fns.h"
typedef struct LumpQueue LumpQueue;
typedef struct WLump WLump;
enum
{
MaxLumpQ = 1 << 3 /* max. lumps on a single write queue, must be pow 2 */
};
struct WLump
{
Lump *u;
Packet *p;
int creator;
int gen;
};
struct LumpQueue
{
QLock lock;
Rendez flush;
Rendez full;
Rendez empty;
WLump q[MaxLumpQ];
int w;
int r;
};
static LumpQueue *lumpqs;
static int nqs;
static QLock glk;
static int gen;
static void queueproc(void *vq);
int
initlumpqueues(int nq)
{
LumpQueue *q;
int i;
nqs = nq;
lumpqs = MKNZ(LumpQueue, nq);
for(i = 0; i < nq; i++){
q = &lumpqs[i];
q->full.l = &q->lock;
q->empty.l = &q->lock;
q->flush.l = &q->lock;
if(vtproc(queueproc, q) < 0){
seterr(EOk, "can't start write queue slave: %r");
return -1;
}
}
return 0;
}
/*
* queue a lump & it's packet data for writing
*/
int
queuewrite(Lump *u, Packet *p, int creator)
{
LumpQueue *q;
int i;
i = indexsect(mainindex, u->score);
if(i < 0 || i >= nqs){
seterr(EBug, "internal error: illegal index section in queuewrite");
return -1;
}
q = &lumpqs[i];
qlock(&q->lock);
while(q->r == ((q->w + 1) & (MaxLumpQ - 1)))
rsleep(&q->full);
q->q[q->w].u = u;
q->q[q->w].p = p;
q->q[q->w].creator = creator;
q->q[q->w].gen = gen;
q->w = (q->w + 1) & (MaxLumpQ - 1);
rwakeup(&q->empty);
qunlock(&q->lock);
return 0;
}
void
flushqueue(void)
{
int i;
LumpQueue *q;
if(!lumpqs)
return;
qlock(&glk);
gen++;
qunlock(&glk);
for(i=0; i<mainindex->nsects; i++){
q = &lumpqs[i];
qlock(&q->lock);
while(q->w != q->r && gen - q->q[q->r].gen > 0)
rsleep(&q->flush);
qunlock(&q->lock);
}
}
static void
queueproc(void *vq)
{
LumpQueue *q;
Lump *u;
Packet *p;
int creator;
q = vq;
for(;;){
qlock(&q->lock);
while(q->w == q->r)
rsleep(&q->empty);
u = q->q[q->r].u;
p = q->q[q->r].p;
creator = q->q[q->r].creator;
rwakeup(&q->full);
qunlock(&q->lock);
if(writeqlump(u, p, creator) < 0)
fprint(2, "failed to write lump for %V: %r", u->score);
qlock(&q->lock);
q->r = (q->r + 1) & (MaxLumpQ - 1);
rwakeup(&q->flush);
qunlock(&q->lock);
putlump(u);
}
}
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