sys/kern/kern_usched.c

   1 /*
   2  * Copyright (c) 2005 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Sergey Glushchenko <deen@smz.com.ua>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  */
  35
  36 #include <sys/cpumask.h>
  37 #include <sys/errno.h>
  38 #include <sys/globaldata.h>             /* curthread */
  39 #include <sys/proc.h>
  40 #include <sys/priv.h>
  41 #include <sys/sysproto.h>               /* struct usched_set_args */
  42 #include <sys/systm.h>                  /* strcmp() */
  43 #include <sys/usched.h>
  44
  45 #include <machine/smp.h>
  46
  47 static TAILQ_HEAD(, usched) usched_list = TAILQ_HEAD_INITIALIZER(usched_list);
  48
  49 cpumask_t usched_mastermask = CPUMASK_INITIALIZER_ALLONES;
  50
  51 static int setaffinity_lp(struct lwp *lp, cpumask_t *mask);
  52
  53 /*
  54  * Called from very low level boot code, sys/kern/init_main.c:mi_proc0init().
  55  * We cannot do anything fancy.  no malloc's, no nothing other then
  56  * static initialization.
  57  */
  58 struct usched *
  59 usched_init(void)
  60 {
  61         const char *defsched;
  62
  63         defsched = kgetenv("kern.user_scheduler");
  64
  65         /*
  66          * Add various userland schedulers to the system.
  67          */
  68         usched_ctl(&usched_bsd4, USCH_ADD);
  69         usched_ctl(&usched_dfly, USCH_ADD);
  70         usched_ctl(&usched_dummy, USCH_ADD);
  71         if (defsched == NULL )
  72                 return(&usched_dfly);
  73         if (strcmp(defsched, "bsd4") == 0)
  74                 return(&usched_bsd4);
  75         if (strcmp(defsched, "dfly") == 0)
  76                 return(&usched_dfly);
  77         kprintf("WARNING: Running dummy userland scheduler\n");
  78         return(&usched_dummy);
  79 }
  80
  81 /*
  82  * USCHED_CTL
  83  *
  84  * SYNOPSIS:
  85  *      Add/remove usched to/from list.
  86  *
  87  * ARGUMENTS:
  88  *      usched - pointer to target scheduler
  89  *      action - addition or removal ?
  90  *
  91  * RETURN VALUES:
  92  *      0 - success
  93  *      EINVAL - error
  94  */
  95 int
  96 usched_ctl(struct usched *usched, int action)
  97 {
  98         struct usched *item;    /* temporaly for TAILQ processing */
  99         int error = 0;
 100
 101         switch(action) {
 102         case USCH_ADD:
 103                 /*
 104                  * Make sure it isn't already on the list
 105                  */
 106 #ifdef INVARIANTS
 107                 TAILQ_FOREACH(item, &usched_list, entry) {
 108                         KKASSERT(item != usched);
 109                 }
 110 #endif
 111                 /*
 112                  * Optional callback to the scheduler before we officially
 113                  * add it to the list.
 114                  */
 115                 if (usched->usched_register)
 116                         usched->usched_register();
 117                 TAILQ_INSERT_TAIL(&usched_list, usched, entry);
 118                 break;
 119         case USCH_REM:
 120                 /*
 121                  * Do not allow the default scheduler to be removed
 122                  */
 123                 if (strcmp(usched->name, "bsd4") == 0) {
 124                         error = EINVAL;
 125                         break;
 126                 }
 127                 TAILQ_FOREACH(item, &usched_list, entry) {
 128                         if (item == usched)
 129                                 break;
 130                 }
 131                 if (item) {
 132                         if (item->usched_unregister)
 133                                 item->usched_unregister();
 134                         TAILQ_REMOVE(&usched_list, item, entry);
 135                 } else {
 136                         error = EINVAL;
 137                 }
 138                 break;
 139         default:
 140                 error = EINVAL;
 141                 break;
 142         }
 143         return (error);
 144 }
 145
 146 /*
 147  * Called from the scheduler clock on each cpu independently at the
 148  * common scheduling rate.  If th scheduler clock interrupted a running
 149  * lwp the lp will be non-NULL.
 150  */
 151 void
 152 usched_schedulerclock(struct lwp *lp, sysclock_t periodic, sysclock_t time)
 153 {
 154         struct usched *item;
 155
 156         TAILQ_FOREACH(item, &usched_list, entry) {
 157                 if (lp && lp->lwp_proc->p_usched == item)
 158                         item->schedulerclock(lp, periodic, time);
 159                 else
 160                         item->schedulerclock(NULL, periodic, time);
 161         }
 162 }
 163
 164 /*
 165  * USCHED_SET(syscall)
 166  *
 167  * SYNOPSIS:
 168  *      Setting up a proc's usched.
 169  *
 170  * ARGUMENTS:
 171  *      pid     -
 172  *      cmd     -
 173  *      data    -
 174  *      bytes   -
 175  * RETURN VALUES:
 176  *      0 - success
 177  *      EFBIG  - error (invalid cpu#)
 178  *      EPERM  - error (failed to delete cpu#)
 179  *      EINVAL - error (other reasons)
 180  *
 181  * MPALMOSTSAFE
 182  */
 183 int
 184 sys_usched_set(struct usched_set_args *uap)
 185 {
 186         struct proc *p = curthread->td_proc;
 187         struct usched *item;    /* temporaly for TAILQ processing */
 188         int error;
 189         char buffer[NAME_LENGTH];
 190         cpumask_t mask;
 191         struct lwp *lp;
 192         int cpuid;
 193
 194         if (uap->pid != 0 && uap->pid != curthread->td_proc->p_pid)
 195                 return (EINVAL);
 196
 197         lp = curthread->td_lwp;
 198         lwkt_gettoken(&lp->lwp_token);
 199
 200         switch (uap->cmd) {
 201         case USCHED_SET_SCHEDULER:
 202                 if ((error = priv_check(curthread, PRIV_SCHED_SET)) != 0)
 203                         break;
 204                 error = copyinstr(uap->data, buffer, sizeof(buffer), NULL);
 205                 if (error)
 206                         break;
 207                 TAILQ_FOREACH(item, &usched_list, entry) {
 208                         if ((strcmp(item->name, buffer) == 0))
 209                                 break;
 210                 }
 211
 212                 /*
 213                  * If the scheduler for a process is being changed, disassociate
 214                  * the old scheduler before switching to the new one.
 215                  *
 216                  * XXX we might have to add an additional ABI call to do a 'full
 217                  * disassociation' and another ABI call to do a 'full
 218                  * reassociation'
 219                  */
 220                 /* XXX lwp have to deal with multiple lwps here */
 221                 if (p->p_nthreads != 1) {
 222                         error = EINVAL;
 223                         break;
 224                 }
 225                 if (item && item != p->p_usched) {
 226                         /* XXX lwp */
 227                         p->p_usched->release_curproc(ONLY_LWP_IN_PROC(p));
 228                         p->p_usched->heuristic_exiting(ONLY_LWP_IN_PROC(p), p);
 229                         p->p_usched = item;
 230                 } else if (item == NULL) {
 231                         error = EINVAL;
 232                 }
 233                 break;
 234         case USCHED_SET_CPU:
 235                 if ((error = priv_check(curthread, PRIV_SCHED_CPUSET)) != 0)
 236                         break;
 237                 if (uap->bytes != sizeof(int)) {
 238                         error = EINVAL;
 239                         break;
 240                 }
 241                 error = copyin(uap->data, &cpuid, sizeof(int));
 242                 if (error)
 243                         break;
 244                 if (cpuid < 0 || cpuid >= ncpus) {
 245                         error = EFBIG;
 246                         break;
 247                 }
 248                 if (CPUMASK_TESTBIT(smp_active_mask, cpuid) == 0) {
 249                         error = EINVAL;
 250                         break;
 251                 }
 252                 CPUMASK_ASSBIT(lp->lwp_cpumask, cpuid);
 253                 if (cpuid != mycpu->gd_cpuid) {
 254                         lwkt_migratecpu(cpuid);
 255                         p->p_usched->changedcpu(lp);
 256                 }
 257                 break;
 258         case USCHED_GET_CPU:
 259                 /* USCHED_GET_CPU doesn't require special privileges. */
 260                 if (uap->bytes != sizeof(int)) {
 261                         error = EINVAL;
 262                         break;
 263                 }
 264                 error = copyout(&(mycpu->gd_cpuid), uap->data, sizeof(int));
 265                 break;
 266         case USCHED_GET_CPUMASK:
 267                 /* USCHED_GET_CPUMASK doesn't require special privileges. */
 268                 if (uap->bytes != sizeof(cpumask_t)) {
 269                         error = EINVAL;
 270                         break;
 271                 }
 272                 mask = lp->lwp_cpumask;
 273                 CPUMASK_ANDMASK(mask, smp_active_mask);
 274                 error = copyout(&mask, uap->data, sizeof(cpumask_t));
 275                 break;
 276         case USCHED_ADD_CPU:
 277                 if ((error = priv_check(curthread, PRIV_SCHED_CPUSET)) != 0)
 278                         break;
 279                 if (uap->bytes != sizeof(int)) {
 280                         error = EINVAL;
 281                         break;
 282                 }
 283                 error = copyin(uap->data, &cpuid, sizeof(int));
 284                 if (error)
 285                         break;
 286                 if (cpuid < 0 || cpuid >= ncpus) {
 287                         error = EFBIG;
 288                         break;
 289                 }
 290                 if (CPUMASK_TESTBIT(smp_active_mask, cpuid) == 0) {
 291                         error = EINVAL;
 292                         break;
 293                 }
 294                 CPUMASK_ORBIT(lp->lwp_cpumask, cpuid);
 295                 break;
 296         case USCHED_DEL_CPU:
 297                 /* USCHED_DEL_CPU doesn't require special privileges. */
 298                 if (uap->bytes != sizeof(int)) {
 299                         error = EINVAL;
 300                         break;
 301                 }
 302                 error = copyin(uap->data, &cpuid, sizeof(int));
 303                 if (error)
 304                         break;
 305                 if (cpuid < 0 || cpuid >= ncpus) {
 306                         error = EFBIG;
 307                         break;
 308                 }
 309                 lp = curthread->td_lwp;
 310                 mask = lp->lwp_cpumask;
 311                 CPUMASK_ANDMASK(mask, smp_active_mask);
 312                 CPUMASK_NANDBIT(mask, cpuid);
 313                 if (CPUMASK_TESTZERO(mask)) {
 314                         error = EPERM;
 315                 } else {
 316                         CPUMASK_NANDBIT(lp->lwp_cpumask, cpuid);
 317                         if (CPUMASK_TESTMASK(lp->lwp_cpumask,
 318                                             mycpu->gd_cpumask) == 0) {
 319                                 mask = lp->lwp_cpumask;
 320                                 CPUMASK_ANDMASK(mask, smp_active_mask);
 321                                 cpuid = BSFCPUMASK(mask);
 322                                 lwkt_migratecpu(cpuid);
 323                                 p->p_usched->changedcpu(lp);
 324                         }
 325                 }
 326                 break;
 327         case USCHED_SET_CPUMASK:
 328                 if ((error = priv_check(curthread, PRIV_SCHED_CPUSET)) != 0)
 329                         break;
 330                 if (uap->bytes != sizeof(mask)) {
 331                         error = EINVAL;
 332                         break;
 333                 }
 334                 error = copyin(uap->data, &mask, sizeof(mask));
 335                 if (error)
 336                         break;
 337
 338                 CPUMASK_ANDMASK(mask, smp_active_mask);
 339                 if (CPUMASK_TESTZERO(mask)) {
 340                         error = EPERM;
 341                         break;
 342                 }
 343                 /* Commit the new cpumask. */
 344                 lp->lwp_cpumask = mask;
 345
 346                 /* Migrate if necessary. */
 347                 if (CPUMASK_TESTMASK(lp->lwp_cpumask, mycpu->gd_cpumask) == 0) {
 348                         cpuid = BSFCPUMASK(lp->lwp_cpumask);
 349                         lwkt_migratecpu(cpuid);
 350                         p->p_usched->changedcpu(lp);
 351                 }
 352                 break;
 353         default:
 354                 error = EINVAL;
 355                 break;
 356         }
 357         lwkt_reltoken(&lp->lwp_token);
 358
 359         return (error);
 360 }
 361
 362 int
 363 sys_lwp_getaffinity(struct lwp_getaffinity_args *uap)
 364 {
 365         struct proc *p;
 366         cpumask_t mask;
 367         struct lwp *lp;
 368         int error = 0;
 369
 370         if (uap->pid < 0)
 371                 return (EINVAL);
 372
 373         if (uap->pid == 0) {
 374                 p = curproc;
 375                 PHOLD(p);
 376         } else {
 377                 p = pfind(uap->pid);    /* pfind() holds (p) */
 378                 if (p == NULL)
 379                         return (ESRCH);
 380         }
 381         lwkt_gettoken(&p->p_token);
 382
 383         if (uap->tid < 0) {
 384                 lp = RB_FIRST(lwp_rb_tree, &p->p_lwp_tree);
 385         } else {
 386                 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, uap->tid);
 387         }
 388         if (lp == NULL) {
 389                 error = ESRCH;
 390         } else {
 391                 /* Take a snapshot for copyout, which may block. */
 392                 LWPHOLD(lp);
 393                 lwkt_gettoken(&lp->lwp_token);
 394                 mask = lp->lwp_cpumask;
 395                 CPUMASK_ANDMASK(mask, smp_active_mask);
 396                 lwkt_reltoken(&lp->lwp_token);
 397                 LWPRELE(lp);
 398         }
 399
 400         lwkt_reltoken(&p->p_token);
 401         PRELE(p);
 402
 403         if (error == 0)
 404                 error = copyout(&mask, uap->mask, sizeof(cpumask_t));
 405
 406         return (error);
 407 }
 408
 409 int
 410 sys_lwp_setaffinity(struct lwp_setaffinity_args *uap)
 411 {
 412         struct proc *p;
 413         cpumask_t mask;
 414         struct lwp *lp;
 415         int error;
 416
 417         /*
 418          * NOTE:
 419          * Always allow change self CPU affinity.
 420          */
 421         if ((error = priv_check(curthread, PRIV_SCHED_CPUSET)) != 0 &&
 422             uap->pid != 0)
 423                 return (error);
 424
 425         error = copyin(uap->mask, &mask, sizeof(mask));
 426         if (error)
 427                 return (error);
 428
 429         CPUMASK_ANDMASK(mask, smp_active_mask);
 430         if (CPUMASK_TESTZERO(mask))
 431                 return (EPERM);
 432         if (uap->pid < 0)
 433                 return (EINVAL);
 434
 435         /*
 436          * Locate the process
 437          */
 438         if (uap->pid == 0) {
 439                 p = curproc;
 440                 PHOLD(p);
 441         } else {
 442                 p = pfind(uap->pid);    /* pfind() holds (p) */
 443                 if (p == NULL)
 444                         return (ESRCH);
 445         }
 446         lwkt_gettoken(&p->p_token);
 447
 448         if (uap->tid < 0) {
 449                 FOREACH_LWP_IN_PROC(lp, p) {
 450                         error = setaffinity_lp(lp, &mask);
 451                 }
 452                 /* not an error if no LPs left in process */
 453         } else {
 454                 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, uap->tid);
 455                 error = setaffinity_lp(lp, &mask);
 456         }
 457         lwkt_reltoken(&p->p_token);
 458         PRELE(p);
 459
 460         return (error);
 461 }
 462
 463 static int
 464 setaffinity_lp(struct lwp *lp, cpumask_t *mask)
 465 {
 466         if (lp == NULL)
 467                 return ESRCH;
 468
 469         LWPHOLD(lp);
 470         lwkt_gettoken(&lp->lwp_token);
 471         lp->lwp_cpumask = *mask;
 472
 473         /*
 474          * NOTE: When adjusting a thread that is not our own the migration
 475          *       will occur at the next reschedule.
 476          */
 477         if (lp == curthread->td_lwp) {
 478                 /*
 479                  * Self migration can be done immediately,
 480                  * if necessary.
 481                  */
 482                 if (CPUMASK_TESTBIT(lp->lwp_cpumask,
 483                     mycpu->gd_cpuid) == 0) {
 484                         lwkt_migratecpu(BSFCPUMASK(lp->lwp_cpumask));
 485                         lp->lwp_proc->p_usched->changedcpu(lp);
 486                 }
 487         }
 488         lwkt_reltoken(&lp->lwp_token);
 489         LWPRELE(lp);
 490
 491         return 0;
 492 }