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/caps.h>
  41 #include <sys/sysmsg.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 the 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 sysmsg *sysmsg, const 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 = caps_priv_check_self(SYSCAP_NOSCHED)) != 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 = caps_priv_check_self(SYSCAP_NOSCHED_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 = caps_priv_check_self(SYSCAP_NOSCHED_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 = caps_priv_check_self(SYSCAP_NOSCHED_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 sysmsg *sysmsg,
 364                     const struct lwp_getaffinity_args *uap)
 365 {
 366         struct proc *p;
 367         cpumask_t mask;
 368         struct lwp *lp;
 369         int error = 0;
 370
 371         if (uap->pid < 0)
 372                 return (EINVAL);
 373
 374         if (uap->pid == 0) {
 375                 p = curproc;
 376                 PHOLD(p);
 377         } else {
 378                 p = pfind(uap->pid);    /* pfind() holds (p) */
 379                 if (p == NULL)
 380                         return (ESRCH);
 381         }
 382         lwkt_gettoken(&p->p_token);
 383
 384         if (uap->tid < 0) {
 385                 lp = RB_FIRST(lwp_rb_tree, &p->p_lwp_tree);
 386         } else {
 387                 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, uap->tid);
 388         }
 389         if (lp == NULL) {
 390                 error = ESRCH;
 391         } else {
 392                 /* Take a snapshot for copyout, which may block. */
 393                 LWPHOLD(lp);
 394                 lwkt_gettoken(&lp->lwp_token);
 395                 mask = lp->lwp_cpumask;
 396                 CPUMASK_ANDMASK(mask, smp_active_mask);
 397                 lwkt_reltoken(&lp->lwp_token);
 398                 LWPRELE(lp);
 399         }
 400
 401         lwkt_reltoken(&p->p_token);
 402         PRELE(p);
 403
 404         if (error == 0)
 405                 error = copyout(&mask, uap->mask, sizeof(cpumask_t));
 406
 407         return (error);
 408 }
 409
 410 int
 411 sys_lwp_setaffinity(struct sysmsg *sysmsg,
 412                     const struct lwp_setaffinity_args *uap)
 413 {
 414         struct proc *p;
 415         cpumask_t mask;
 416         struct lwp *lp;
 417         int error;
 418
 419         /*
 420          * NOTE:
 421          * Always allow change self CPU affinity.
 422          */
 423         if ((error = caps_priv_check_self(SYSCAP_NOSCHED_CPUSET)) != 0 &&
 424             uap->pid != 0)
 425         {
 426                 return (error);
 427         }
 428
 429         error = copyin(uap->mask, &mask, sizeof(mask));
 430         if (error)
 431                 return (error);
 432
 433         CPUMASK_ANDMASK(mask, smp_active_mask);
 434         if (CPUMASK_TESTZERO(mask))
 435                 return (EPERM);
 436         if (uap->pid < 0)
 437                 return (EINVAL);
 438
 439         /*
 440          * Locate the process
 441          */
 442         if (uap->pid == 0) {
 443                 p = curproc;
 444                 PHOLD(p);
 445         } else {
 446                 p = pfind(uap->pid);    /* pfind() holds (p) */
 447                 if (p == NULL)
 448                         return (ESRCH);
 449         }
 450         lwkt_gettoken(&p->p_token);
 451
 452         if (uap->tid < 0) {
 453                 FOREACH_LWP_IN_PROC(lp, p) {
 454                         error = setaffinity_lp(lp, &mask);
 455                 }
 456                 /* not an error if no LPs left in process */
 457         } else {
 458                 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, uap->tid);
 459                 error = setaffinity_lp(lp, &mask);
 460         }
 461         lwkt_reltoken(&p->p_token);
 462         PRELE(p);
 463
 464         return (error);
 465 }
 466
 467 static int
 468 setaffinity_lp(struct lwp *lp, cpumask_t *mask)
 469 {
 470         if (lp == NULL)
 471                 return ESRCH;
 472
 473         LWPHOLD(lp);
 474         lwkt_gettoken(&lp->lwp_token);
 475         lp->lwp_cpumask = *mask;
 476
 477         /*
 478          * NOTE: When adjusting a thread that is not our own the migration
 479          *       will occur at the next reschedule.
 480          */
 481         if (lp == curthread->td_lwp) {
 482                 /*
 483                  * Self migration can be done immediately,
 484                  * if necessary.
 485                  */
 486                 if (CPUMASK_TESTBIT(lp->lwp_cpumask,
 487                     mycpu->gd_cpuid) == 0) {
 488                         lwkt_migratecpu(BSFCPUMASK(lp->lwp_cpumask));
 489                         lp->lwp_proc->p_usched->changedcpu(lp);
 490                 }
 491         }
 492         lwkt_reltoken(&lp->lwp_token);
 493         LWPRELE(lp);
 494
 495         return 0;
 496 }