1 /* kern_synch.c 4.7 02/26/81 */ 2 3 #include "../h/param.h" 4 #include "../h/systm.h" 5 #include "../h/dir.h" 6 #include "../h/user.h" 7 #include "../h/proc.h" 8 #include "../h/file.h" 9 #include "../h/inode.h" 10 #include "../h/vm.h" 11 #include "../h/pte.h" 12 #include "../h/inline.h" 13 #include "../h/mtpr.h" 14 15 #define SQSIZE 0100 /* Must be power of 2 */ 16 #define HASH(x) (( (int) x >> 5) & (SQSIZE-1)) 17 struct proc *slpque[SQSIZE]; 18 19 /* 20 * Give up the processor till a wakeup occurs 21 * on chan, at which time the process 22 * enters the scheduling queue at priority pri. 23 * The most important effect of pri is that when 24 * pri<=PZERO a signal cannot disturb the sleep; 25 * if pri>PZERO signals will be processed. 26 * Callers of this routine must be prepared for 27 * premature return, and check that the reason for 28 * sleeping has gone away. 29 */ 30 sleep(chan, pri) 31 caddr_t chan; 32 { 33 register struct proc *rp, **hp; 34 register s; 35 36 rp = u.u_procp; 37 s = spl6(); 38 if (chan==0 || rp->p_stat != SRUN || rp->p_rlink) 39 panic("sleep"); 40 rp->p_wchan = chan; 41 rp->p_slptime = 0; 42 rp->p_pri = pri; 43 hp = &slpque[HASH(chan)]; 44 rp->p_link = *hp; 45 *hp = rp; 46 if(pri > PZERO) { 47 if(ISSIG(rp)) { 48 if (rp->p_wchan) 49 unsleep(rp); 50 rp->p_stat = SRUN; 51 (void) spl0(); 52 goto psig; 53 } 54 if (rp->p_wchan == 0) 55 goto out; 56 rp->p_stat = SSLEEP; 57 (void) spl0(); 58 swtch(); 59 if(ISSIG(rp)) 60 goto psig; 61 } else { 62 rp->p_stat = SSLEEP; 63 (void) spl0(); 64 swtch(); 65 } 66 out: 67 splx(s); 68 return; 69 70 /* 71 * If priority was low (>PZERO) and 72 * there has been a signal, 73 * execute non-local goto to 74 * the qsav location. 75 * (see trap1/trap.c) 76 */ 77 psig: 78 longjmp(u.u_qsav); 79 /*NOTREACHED*/ 80 } 81 82 /* 83 * Sleep on chan at pri. 84 * Return in no more than the indicated number of seconds. 85 * (If seconds==0, no timeout implied) 86 * Return TS_OK if chan was awakened normally 87 * TS_TIME if timeout occurred 88 * TS_SIG if asynchronous signal occurred 89 */ 90 tsleep(chan, pri, seconds) 91 caddr_t chan; 92 { 93 label_t lqsav; 94 register struct proc *pp; 95 register sec, n, rval; 96 97 pp = u.u_procp; 98 n = spl7(); 99 sec = 0; 100 rval = 0; 101 if (pp->p_clktim && pp->p_clktim<seconds) 102 seconds = 0; 103 if (seconds) { 104 pp->p_flag |= STIMO; 105 sec = pp->p_clktim-seconds; 106 pp->p_clktim = seconds; 107 } 108 bcopy((caddr_t)u.u_qsav, (caddr_t)lqsav, sizeof (label_t)); 109 if (setjmp(u.u_qsav)) 110 rval = TS_SIG; 111 else { 112 sleep(chan, pri); 113 if ((pp->p_flag&STIMO)==0 && seconds) 114 rval = TS_TIME; 115 else 116 rval = TS_OK; 117 } 118 pp->p_flag &= ~STIMO; 119 bcopy((caddr_t)lqsav, (caddr_t)u.u_qsav, sizeof (label_t)); 120 if (sec > 0) 121 pp->p_clktim += sec; 122 else 123 pp->p_clktim = 0; 124 splx(n); 125 return(rval); 126 } 127 128 /* 129 * Remove a process from its wait queue 130 */ 131 unsleep(p) 132 register struct proc *p; 133 { 134 register struct proc **hp; 135 register s; 136 137 s = spl6(); 138 if (p->p_wchan) { 139 hp = &slpque[HASH(p->p_wchan)]; 140 while (*hp != p) 141 hp = &(*hp)->p_link; 142 *hp = p->p_link; 143 p->p_wchan = 0; 144 } 145 splx(s); 146 } 147 148 /* 149 * Wake up all processes sleeping on chan. 150 */ 151 wakeup(chan) 152 register caddr_t chan; 153 { 154 register struct proc *p, **q, **h; 155 int s; 156 157 s = spl6(); 158 h = &slpque[HASH(chan)]; 159 restart: 160 for (q = h; p = *q; ) { 161 if (p->p_rlink || p->p_stat != SSLEEP && p->p_stat != SSTOP) 162 panic("wakeup"); 163 if (p->p_wchan==chan) { 164 p->p_wchan = 0; 165 *q = p->p_link; 166 p->p_slptime = 0; 167 if (p->p_stat == SSLEEP) { 168 /* OPTIMIZED INLINE EXPANSION OF setrun(p) */ 169 p->p_stat = SRUN; 170 if (p->p_flag & SLOAD) 171 setrq(p); 172 if(p->p_pri < curpri) { 173 runrun++; 174 aston(); 175 } 176 if(runout != 0 && (p->p_flag&SLOAD) == 0) { 177 runout = 0; 178 wakeup((caddr_t)&runout); 179 } 180 /* END INLINE EXPANSION */ 181 goto restart; 182 } 183 } else 184 q = &p->p_link; 185 } 186 splx(s); 187 } 188 189 /* 190 * Initialize the (doubly-linked) run queues 191 * to be empty. 192 */ 193 rqinit() 194 { 195 register int i; 196 197 for (i = 0; i < NQS; i++) 198 qs[i].ph_link = qs[i].ph_rlink = (struct proc *)&qs[i]; 199 } 200 201 /* 202 * Set the process running; 203 * arrange for it to be swapped in if necessary. 204 */ 205 setrun(p) 206 register struct proc *p; 207 { 208 register s; 209 210 s = spl6(); 211 switch (p->p_stat) { 212 213 case 0: 214 case SWAIT: 215 case SRUN: 216 case SZOMB: 217 default: 218 panic("setrun"); 219 220 case SSTOP: 221 case SSLEEP: 222 unsleep(p); /* e.g. when sending signals */ 223 break; 224 225 case SIDL: 226 break; 227 } 228 p->p_stat = SRUN; 229 if (p->p_flag & SLOAD) 230 setrq(p); 231 splx(s); 232 if(p->p_pri < curpri) { 233 runrun++; 234 aston(); 235 } 236 if(runout != 0 && (p->p_flag&SLOAD) == 0) { 237 runout = 0; 238 wakeup((caddr_t)&runout); 239 } 240 } 241 242 /* 243 * Set user priority. 244 * The rescheduling flag (runrun) 245 * is set if the priority is better 246 * than the currently running process. 247 */ 248 setpri(pp) 249 register struct proc *pp; 250 { 251 register p; 252 253 p = (pp->p_cpu & 0377)/16; 254 p += PUSER + 2*(pp->p_nice - NZERO); 255 if(p > 127) 256 p = 127; 257 if(p < curpri) { 258 runrun++; 259 aston(); 260 } 261 pp->p_usrpri = p; 262 return(p); 263 } 264 265 /* 266 * Create a new process-- the internal version of 267 * sys fork. 268 * It returns 1 in the new process, 0 in the old. 269 */ 270 newproc(isvfork) 271 { 272 register struct proc *p; 273 register struct proc *rpp, *rip; 274 register int n; 275 276 p = NULL; 277 /* 278 * First, just locate a slot for a process 279 * and copy the useful info from this process into it. 280 * The panic "cannot happen" because fork has already 281 * checked for the existence of a slot. 282 */ 283 retry: 284 mpid++; 285 if(mpid >= 30000) { 286 mpid = 0; 287 goto retry; 288 } 289 for(rpp = &proc[0]; rpp < &proc[NPROC]; rpp++) { 290 if(rpp->p_stat == NULL && p==NULL) 291 p = rpp; 292 if (rpp->p_pid==mpid || rpp->p_pgrp==mpid) 293 goto retry; 294 } 295 if ((rpp = p)==NULL) 296 panic("no procs"); 297 298 /* 299 * make proc entry for new proc 300 */ 301 302 rip = u.u_procp; 303 rpp->p_stat = SIDL; 304 rpp->p_clktim = 0; 305 rpp->p_flag = SLOAD | (rip->p_flag & (SPAGI|SDETACH|SNUSIG)); 306 if (isvfork) { 307 rpp->p_flag |= SVFORK; 308 rpp->p_ndx = rip->p_ndx; 309 } else 310 rpp->p_ndx = rpp - proc; 311 rpp->p_uid = rip->p_uid; 312 rpp->p_pgrp = rip->p_pgrp; 313 rpp->p_nice = rip->p_nice; 314 rpp->p_textp = isvfork ? 0 : rip->p_textp; 315 rpp->p_pid = mpid; 316 rpp->p_ppid = rip->p_pid; 317 rpp->p_pptr = rip; 318 rpp->p_time = 0; 319 rpp->p_cpu = 0; 320 rpp->p_siga0 = rip->p_siga0; 321 rpp->p_siga1 = rip->p_siga1; 322 /* take along any pending signals, like stops? */ 323 if (isvfork) { 324 rpp->p_tsize = rpp->p_dsize = rpp->p_ssize = 0; 325 rpp->p_szpt = clrnd(ctopt(UPAGES)); 326 forkstat.cntvfork++; 327 forkstat.sizvfork += rip->p_dsize + rip->p_ssize; 328 } else { 329 rpp->p_tsize = rip->p_tsize; 330 rpp->p_dsize = rip->p_dsize; 331 rpp->p_ssize = rip->p_ssize; 332 rpp->p_szpt = rip->p_szpt; 333 forkstat.cntfork++; 334 forkstat.sizfork += rip->p_dsize + rip->p_ssize; 335 } 336 rpp->p_rssize = 0; 337 rpp->p_wchan = 0; 338 rpp->p_slptime = 0; 339 rpp->p_pctcpu = 0; 340 rpp->p_cpticks = 0; 341 n = PIDHASH(rpp->p_pid); 342 p->p_idhash = pidhash[n]; 343 pidhash[n] = rpp - proc; 344 345 /* 346 * make duplicate entries 347 * where needed 348 */ 349 350 multprog++; 351 352 for(n=0; n<NOFILE; n++) 353 if(u.u_ofile[n] != NULL) { 354 #ifdef UCBIPC 355 if (u.u_pofile[n] & ISPORT) 356 u.u_oport[n]->pt_count++; 357 else { 358 #endif 359 u.u_ofile[n]->f_count++; 360 if(!isvfork && u.u_vrpages[n]) 361 u.u_ofile[n]->f_inode->i_vfdcnt++; 362 #ifdef UCBIPC 363 } 364 #endif UCBIPC 365 } 366 367 u.u_cdir->i_count++; 368 if (u.u_rdir) 369 u.u_rdir->i_count++; 370 /* 371 * Partially simulate the environment 372 * of the new process so that when it is actually 373 * created (by copying) it will look right. 374 */ 375 376 rip->p_flag |= SKEEP; /* prevent parent from being swapped */ 377 378 if (procdup(rpp, isvfork)) 379 return (1); 380 381 (void) spl6(); 382 rpp->p_stat = SRUN; 383 setrq(rpp); 384 (void) spl0(); 385 /* SSWAP NOT NEEDED IN THIS CASE AS u.u_pcb.pcb_sswap SUFFICES */ 386 /* rpp->p_flag |= SSWAP; */ 387 rip->p_flag &= ~SKEEP; 388 if (isvfork) { 389 u.u_procp->p_xlink = rpp; 390 u.u_procp->p_flag |= SNOVM; 391 while (rpp->p_flag & SVFORK) 392 sleep((caddr_t)rpp, PZERO - 1); 393 if ((rpp->p_flag & SLOAD) == 0) 394 panic("newproc vfork"); 395 uaccess(rpp, Vfmap, &vfutl); 396 u.u_procp->p_xlink = 0; 397 vpassvm(rpp, u.u_procp, &vfutl, &u, Vfmap); 398 for (n = 0; n < NOFILE; n++) 399 if (vfutl.u_vrpages[n]) { 400 if ((u.u_vrpages[n] = vfutl.u_vrpages[n] - 1) == 0) 401 if (--u.u_ofile[n]->f_inode->i_vfdcnt < 0) 402 panic("newproc i_vfdcnt"); 403 vfutl.u_vrpages[n] = 0; 404 } 405 u.u_procp->p_flag &= ~SNOVM; 406 rpp->p_ndx = rpp - proc; 407 rpp->p_flag |= SVFDONE; 408 wakeup((caddr_t)rpp); 409 } 410 return (0); 411 } 412