kern_cpuset.c

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    1 /*-
    2  * Copyright (c) 2008,  Jeffrey Roberson <jeff@freebsd.org>
    3  * All rights reserved.
    4  * 
    5  * Copyright (c) 2008 Nokia Corporation
    6  * All rights reserved.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice unmodified, this list of conditions, and the following
   13  *    disclaimer.
   14  * 2. Redistributions in binary form must reproduce the above copyright
   15  *    notice, this list of conditions and the following disclaimer in the
   16  *    documentation and/or other materials provided with the distribution.
   17  *
   18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   28  *
   29  */
   30 
   31 #include <sys/cdefs.h>
   32 __FBSDID("$FreeBSD$");
   33 
   34 #include "opt_ddb.h"
   35 
   36 #include <sys/param.h>
   37 #include <sys/systm.h>
   38 #include <sys/sysproto.h>
   39 #include <sys/jail.h>
   40 #include <sys/kernel.h>
   41 #include <sys/lock.h>
   42 #include <sys/malloc.h>
   43 #include <sys/mutex.h>
   44 #include <sys/priv.h>
   45 #include <sys/proc.h>
   46 #include <sys/refcount.h>
   47 #include <sys/sched.h>
   48 #include <sys/smp.h>
   49 #include <sys/syscallsubr.h>
   50 #include <sys/cpuset.h>
   51 #include <sys/sx.h>
   52 #include <sys/queue.h>
   53 #include <sys/libkern.h>
   54 #include <sys/limits.h>
   55 #include <sys/bus.h>
   56 #include <sys/interrupt.h>
   57 
   58 #include <vm/uma.h>
   59 
   60 #ifdef DDB
   61 #include <ddb/ddb.h>
   62 #endif /* DDB */
   63 
   64 /*
   65  * cpusets provide a mechanism for creating and manipulating sets of
   66  * processors for the purpose of constraining the scheduling of threads to
   67  * specific processors.
   68  *
   69  * Each process belongs to an identified set, by default this is set 1.  Each
   70  * thread may further restrict the cpus it may run on to a subset of this
   71  * named set.  This creates an anonymous set which other threads and processes
   72  * may not join by number.
   73  *
   74  * The named set is referred to herein as the 'base' set to avoid ambiguity.
   75  * This set is usually a child of a 'root' set while the anonymous set may
   76  * simply be referred to as a mask.  In the syscall api these are referred to
   77  * as the ROOT, CPUSET, and MASK levels where CPUSET is called 'base' here.
   78  *
   79  * Threads inherit their set from their creator whether it be anonymous or
   80  * not.  This means that anonymous sets are immutable because they may be
   81  * shared.  To modify an anonymous set a new set is created with the desired
   82  * mask and the same parent as the existing anonymous set.  This gives the
   83  * illusion of each thread having a private mask.
   84  *
   85  * Via the syscall apis a user may ask to retrieve or modify the root, base,
   86  * or mask that is discovered via a pid, tid, or setid.  Modifying a set
   87  * modifies all numbered and anonymous child sets to comply with the new mask.
   88  * Modifying a pid or tid's mask applies only to that tid but must still
   89  * exist within the assigned parent set.
   90  *
   91  * A thread may not be assigned to a group separate from other threads in
   92  * the process.  This is to remove ambiguity when the setid is queried with
   93  * a pid argument.  There is no other technical limitation.
   94  *
   95  * This somewhat complex arrangement is intended to make it easy for
   96  * applications to query available processors and bind their threads to
   97  * specific processors while also allowing administrators to dynamically
   98  * reprovision by changing sets which apply to groups of processes.
   99  *
  100  * A simple application should not concern itself with sets at all and
  101  * rather apply masks to its own threads via CPU_WHICH_TID and a -1 id
  102  * meaning 'curthread'.  It may query available cpus for that tid with a
  103  * getaffinity call using (CPU_LEVEL_CPUSET, CPU_WHICH_PID, -1, ...).
  104  */
  105 static uma_zone_t cpuset_zone;
  106 static struct mtx cpuset_lock;
  107 static struct setlist cpuset_ids;
  108 static struct unrhdr *cpuset_unr;
  109 static struct cpuset *cpuset_zero;
  110 
  111 /* Return the size of cpuset_t at the kernel level */
  112 SYSCTL_INT(_kern_sched, OID_AUTO, cpusetsize, CTLFLAG_RD,
  113     SYSCTL_NULL_INT_PTR, sizeof(cpuset_t), "sizeof(cpuset_t)");
  114 
  115 cpuset_t *cpuset_root;
  116 
  117 /*
  118  * Acquire a reference to a cpuset, all pointers must be tracked with refs.
  119  */
  120 struct cpuset *
  121 cpuset_ref(struct cpuset *set)
  122 {
  123 
  124         refcount_acquire(&set->cs_ref);
  125         return (set);
  126 }
  127 
  128 /*
  129  * Walks up the tree from 'set' to find the root.  Returns the root
  130  * referenced.
  131  */
  132 static struct cpuset *
  133 cpuset_refroot(struct cpuset *set)
  134 {
  135 
  136         for (; set->cs_parent != NULL; set = set->cs_parent)
  137                 if (set->cs_flags & CPU_SET_ROOT)
  138                         break;
  139         cpuset_ref(set);
  140 
  141         return (set);
  142 }
  143 
  144 /*
  145  * Find the first non-anonymous set starting from 'set'.  Returns this set
  146  * referenced.  May return the passed in set with an extra ref if it is
  147  * not anonymous. 
  148  */
  149 static struct cpuset *
  150 cpuset_refbase(struct cpuset *set)
  151 {
  152 
  153         if (set->cs_id == CPUSET_INVALID)
  154                 set = set->cs_parent;
  155         cpuset_ref(set);
  156 
  157         return (set);
  158 }
  159 
  160 /*
  161  * Release a reference in a context where it is safe to allocate.
  162  */
  163 void
  164 cpuset_rel(struct cpuset *set)
  165 {
  166         cpusetid_t id;
  167 
  168         if (refcount_release(&set->cs_ref) == 0)
  169                 return;
  170         mtx_lock_spin(&cpuset_lock);
  171         LIST_REMOVE(set, cs_siblings);
  172         id = set->cs_id;
  173         if (id != CPUSET_INVALID)
  174                 LIST_REMOVE(set, cs_link);
  175         mtx_unlock_spin(&cpuset_lock);
  176         cpuset_rel(set->cs_parent);
  177         uma_zfree(cpuset_zone, set);
  178         if (id != CPUSET_INVALID)
  179                 free_unr(cpuset_unr, id);
  180 }
  181 
  182 /*
  183  * Deferred release must be used when in a context that is not safe to
  184  * allocate/free.  This places any unreferenced sets on the list 'head'.
  185  */
  186 static void
  187 cpuset_rel_defer(struct setlist *head, struct cpuset *set)
  188 {
  189 
  190         if (refcount_release(&set->cs_ref) == 0)
  191                 return;
  192         mtx_lock_spin(&cpuset_lock);
  193         LIST_REMOVE(set, cs_siblings);
  194         if (set->cs_id != CPUSET_INVALID)
  195                 LIST_REMOVE(set, cs_link);
  196         LIST_INSERT_HEAD(head, set, cs_link);
  197         mtx_unlock_spin(&cpuset_lock);
  198 }
  199 
  200 /*
  201  * Complete a deferred release.  Removes the set from the list provided to
  202  * cpuset_rel_defer.
  203  */
  204 static void
  205 cpuset_rel_complete(struct cpuset *set)
  206 {
  207         LIST_REMOVE(set, cs_link);
  208         cpuset_rel(set->cs_parent);
  209         uma_zfree(cpuset_zone, set);
  210 }
  211 
  212 /*
  213  * Find a set based on an id.  Returns it with a ref.
  214  */
  215 static struct cpuset *
  216 cpuset_lookup(cpusetid_t setid, struct thread *td)
  217 {
  218         struct cpuset *set;
  219 
  220         if (setid == CPUSET_INVALID)
  221                 return (NULL);
  222         mtx_lock_spin(&cpuset_lock);
  223         LIST_FOREACH(set, &cpuset_ids, cs_link)
  224                 if (set->cs_id == setid)
  225                         break;
  226         if (set)
  227                 cpuset_ref(set);
  228         mtx_unlock_spin(&cpuset_lock);
  229 
  230         KASSERT(td != NULL, ("[%s:%d] td is NULL", __func__, __LINE__));
  231         if (set != NULL && jailed(td->td_ucred)) {
  232                 struct cpuset *jset, *tset;
  233 
  234                 jset = td->td_ucred->cr_prison->pr_cpuset;
  235                 for (tset = set; tset != NULL; tset = tset->cs_parent)
  236                         if (tset == jset)
  237                                 break;
  238                 if (tset == NULL) {
  239                         cpuset_rel(set);
  240                         set = NULL;
  241                 }
  242         }
  243 
  244         return (set);
  245 }
  246 
  247 /*
  248  * Create a set in the space provided in 'set' with the provided parameters.
  249  * The set is returned with a single ref.  May return EDEADLK if the set
  250  * will have no valid cpu based on restrictions from the parent.
  251  */
  252 static int
  253 _cpuset_create(struct cpuset *set, struct cpuset *parent, const cpuset_t *mask,
  254     cpusetid_t id)
  255 {
  256 
  257         if (!CPU_OVERLAP(&parent->cs_mask, mask))
  258                 return (EDEADLK);
  259         CPU_COPY(mask, &set->cs_mask);
  260         LIST_INIT(&set->cs_children);
  261         refcount_init(&set->cs_ref, 1);
  262         set->cs_flags = 0;
  263         mtx_lock_spin(&cpuset_lock);
  264         CPU_AND(&set->cs_mask, &parent->cs_mask);
  265         set->cs_id = id;
  266         set->cs_parent = cpuset_ref(parent);
  267         LIST_INSERT_HEAD(&parent->cs_children, set, cs_siblings);
  268         if (set->cs_id != CPUSET_INVALID)
  269                 LIST_INSERT_HEAD(&cpuset_ids, set, cs_link);
  270         mtx_unlock_spin(&cpuset_lock);
  271 
  272         return (0);
  273 }
  274 
  275 /*
  276  * Create a new non-anonymous set with the requested parent and mask.  May
  277  * return failures if the mask is invalid or a new number can not be
  278  * allocated.
  279  */
  280 static int
  281 cpuset_create(struct cpuset **setp, struct cpuset *parent, const cpuset_t *mask)
  282 {
  283         struct cpuset *set;
  284         cpusetid_t id;
  285         int error;
  286 
  287         id = alloc_unr(cpuset_unr);
  288         if (id == -1)
  289                 return (ENFILE);
  290         *setp = set = uma_zalloc(cpuset_zone, M_WAITOK);
  291         error = _cpuset_create(set, parent, mask, id);
  292         if (error == 0)
  293                 return (0);
  294         free_unr(cpuset_unr, id);
  295         uma_zfree(cpuset_zone, set);
  296 
  297         return (error);
  298 }
  299 
  300 /*
  301  * Recursively check for errors that would occur from applying mask to
  302  * the tree of sets starting at 'set'.  Checks for sets that would become
  303  * empty as well as RDONLY flags.
  304  */
  305 static int
  306 cpuset_testupdate(struct cpuset *set, cpuset_t *mask, int check_mask)
  307 {
  308         struct cpuset *nset;
  309         cpuset_t newmask;
  310         int error;
  311 
  312         mtx_assert(&cpuset_lock, MA_OWNED);
  313         if (set->cs_flags & CPU_SET_RDONLY)
  314                 return (EPERM);
  315         if (check_mask) {
  316                 if (!CPU_OVERLAP(&set->cs_mask, mask))
  317                         return (EDEADLK);
  318                 CPU_COPY(&set->cs_mask, &newmask);
  319                 CPU_AND(&newmask, mask);
  320         } else
  321                 CPU_COPY(mask, &newmask);
  322         error = 0;
  323         LIST_FOREACH(nset, &set->cs_children, cs_siblings) 
  324                 if ((error = cpuset_testupdate(nset, &newmask, 1)) != 0)
  325                         break;
  326         return (error);
  327 }
  328 
  329 /*
  330  * Applies the mask 'mask' without checking for empty sets or permissions.
  331  */
  332 static void
  333 cpuset_update(struct cpuset *set, cpuset_t *mask)
  334 {
  335         struct cpuset *nset;
  336 
  337         mtx_assert(&cpuset_lock, MA_OWNED);
  338         CPU_AND(&set->cs_mask, mask);
  339         LIST_FOREACH(nset, &set->cs_children, cs_siblings) 
  340                 cpuset_update(nset, &set->cs_mask);
  341 
  342         return;
  343 }
  344 
  345 /*
  346  * Modify the set 'set' to use a copy of the mask provided.  Apply this new
  347  * mask to restrict all children in the tree.  Checks for validity before
  348  * applying the changes.
  349  */
  350 static int
  351 cpuset_modify(struct cpuset *set, cpuset_t *mask)
  352 {
  353         struct cpuset *root;
  354         int error;
  355 
  356         error = priv_check(curthread, PRIV_SCHED_CPUSET);
  357         if (error)
  358                 return (error);
  359         /*
  360          * In case we are called from within the jail
  361          * we do not allow modifying the dedicated root
  362          * cpuset of the jail but may still allow to
  363          * change child sets.
  364          */
  365         if (jailed(curthread->td_ucred) &&
  366             set->cs_flags & CPU_SET_ROOT)
  367                 return (EPERM);
  368         /*
  369          * Verify that we have access to this set of
  370          * cpus.
  371          */
  372         root = set->cs_parent;
  373         if (root && !CPU_SUBSET(&root->cs_mask, mask))
  374                 return (EINVAL);
  375         mtx_lock_spin(&cpuset_lock);
  376         error = cpuset_testupdate(set, mask, 0);
  377         if (error)
  378                 goto out;
  379         CPU_COPY(mask, &set->cs_mask);
  380         cpuset_update(set, mask);
  381 out:
  382         mtx_unlock_spin(&cpuset_lock);
  383 
  384         return (error);
  385 }
  386 
  387 /*
  388  * Resolve the 'which' parameter of several cpuset apis.
  389  *
  390  * For WHICH_PID and WHICH_TID return a locked proc and valid proc/tid.  Also
  391  * checks for permission via p_cansched().
  392  *
  393  * For WHICH_SET returns a valid set with a new reference.
  394  *
  395  * -1 may be supplied for any argument to mean the current proc/thread or
  396  * the base set of the current thread.  May fail with ESRCH/EPERM.
  397  */
  398 static int
  399 cpuset_which(cpuwhich_t which, id_t id, struct proc **pp, struct thread **tdp,
  400     struct cpuset **setp)
  401 {
  402         struct cpuset *set;
  403         struct thread *td;
  404         struct proc *p;
  405         int error;
  406 
  407         *pp = p = NULL;
  408         *tdp = td = NULL;
  409         *setp = set = NULL;
  410         switch (which) {
  411         case CPU_WHICH_PID:
  412                 if (id == -1) {
  413                         PROC_LOCK(curproc);
  414                         p = curproc;
  415                         break;
  416                 }
  417                 if ((p = pfind(id)) == NULL)
  418                         return (ESRCH);
  419                 break;
  420         case CPU_WHICH_TID:
  421                 if (id == -1) {
  422                         PROC_LOCK(curproc);
  423                         p = curproc;
  424                         td = curthread;
  425                         break;
  426                 }
  427                 td = tdfind(id, -1);
  428                 if (td == NULL)
  429                         return (ESRCH);
  430                 p = td->td_proc;
  431                 break;
  432         case CPU_WHICH_CPUSET:
  433                 if (id == -1) {
  434                         thread_lock(curthread);
  435                         set = cpuset_refbase(curthread->td_cpuset);
  436                         thread_unlock(curthread);
  437                 } else
  438                         set = cpuset_lookup(id, curthread);
  439                 if (set) {
  440                         *setp = set;
  441                         return (0);
  442                 }
  443                 return (ESRCH);
  444         case CPU_WHICH_JAIL:
  445         {
  446                 /* Find `set' for prison with given id. */
  447                 struct prison *pr;
  448 
  449                 sx_slock(&allprison_lock);
  450                 pr = prison_find_child(curthread->td_ucred->cr_prison, id);
  451                 sx_sunlock(&allprison_lock);
  452                 if (pr == NULL)
  453                         return (ESRCH);
  454                 cpuset_ref(pr->pr_cpuset);
  455                 *setp = pr->pr_cpuset;
  456                 mtx_unlock(&pr->pr_mtx);
  457                 return (0);
  458         }
  459         case CPU_WHICH_IRQ:
  460                 return (0);
  461         default:
  462                 return (EINVAL);
  463         }
  464         error = p_cansched(curthread, p);
  465         if (error) {
  466                 PROC_UNLOCK(p);
  467                 return (error);
  468         }
  469         if (td == NULL)
  470                 td = FIRST_THREAD_IN_PROC(p);
  471         *pp = p;
  472         *tdp = td;
  473         return (0);
  474 }
  475 
  476 /*
  477  * Create an anonymous set with the provided mask in the space provided by
  478  * 'fset'.  If the passed in set is anonymous we use its parent otherwise
  479  * the new set is a child of 'set'.
  480  */
  481 static int
  482 cpuset_shadow(struct cpuset *set, struct cpuset *fset, const cpuset_t *mask)
  483 {
  484         struct cpuset *parent;
  485 
  486         if (set->cs_id == CPUSET_INVALID)
  487                 parent = set->cs_parent;
  488         else
  489                 parent = set;
  490         if (!CPU_SUBSET(&parent->cs_mask, mask))
  491                 return (EDEADLK);
  492         return (_cpuset_create(fset, parent, mask, CPUSET_INVALID));
  493 }
  494 
  495 /*
  496  * Handle two cases for replacing the base set or mask of an entire process.
  497  *
  498  * 1) Set is non-null and mask is null.  This reparents all anonymous sets
  499  *    to the provided set and replaces all non-anonymous td_cpusets with the
  500  *    provided set.
  501  * 2) Mask is non-null and set is null.  This replaces or creates anonymous
  502  *    sets for every thread with the existing base as a parent.
  503  *
  504  * This is overly complicated because we can't allocate while holding a 
  505  * spinlock and spinlocks must be held while changing and examining thread
  506  * state.
  507  */
  508 static int
  509 cpuset_setproc(pid_t pid, struct cpuset *set, cpuset_t *mask)
  510 {
  511         struct setlist freelist;
  512         struct setlist droplist;
  513         struct cpuset *tdset;
  514         struct cpuset *nset;
  515         struct thread *td;
  516         struct proc *p;
  517         int threads;
  518         int nfree;
  519         int error;
  520         /*
  521          * The algorithm requires two passes due to locking considerations.
  522          * 
  523          * 1) Lookup the process and acquire the locks in the required order.
  524          * 2) If enough cpusets have not been allocated release the locks and
  525          *    allocate them.  Loop.
  526          */
  527         LIST_INIT(&freelist);
  528         LIST_INIT(&droplist);
  529         nfree = 0;
  530         for (;;) {
  531                 error = cpuset_which(CPU_WHICH_PID, pid, &p, &td, &nset);
  532                 if (error)
  533                         goto out;
  534                 if (nfree >= p->p_numthreads)
  535                         break;
  536                 threads = p->p_numthreads;
  537                 PROC_UNLOCK(p);
  538                 for (; nfree < threads; nfree++) {
  539                         nset = uma_zalloc(cpuset_zone, M_WAITOK);
  540                         LIST_INSERT_HEAD(&freelist, nset, cs_link);
  541                 }
  542         }
  543         PROC_LOCK_ASSERT(p, MA_OWNED);
  544         /*
  545          * Now that the appropriate locks are held and we have enough cpusets,
  546          * make sure the operation will succeed before applying changes.  The
  547          * proc lock prevents td_cpuset from changing between calls.
  548          */
  549         error = 0;
  550         FOREACH_THREAD_IN_PROC(p, td) {
  551                 thread_lock(td);
  552                 tdset = td->td_cpuset;
  553                 /*
  554                  * Verify that a new mask doesn't specify cpus outside of
  555                  * the set the thread is a member of.
  556                  */
  557                 if (mask) {
  558                         if (tdset->cs_id == CPUSET_INVALID)
  559                                 tdset = tdset->cs_parent;
  560                         if (!CPU_SUBSET(&tdset->cs_mask, mask))
  561                                 error = EDEADLK;
  562                 /*
  563                  * Verify that a new set won't leave an existing thread
  564                  * mask without a cpu to run on.  It can, however, restrict
  565                  * the set.
  566                  */
  567                 } else if (tdset->cs_id == CPUSET_INVALID) {
  568                         if (!CPU_OVERLAP(&set->cs_mask, &tdset->cs_mask))
  569                                 error = EDEADLK;
  570                 }
  571                 thread_unlock(td);
  572                 if (error)
  573                         goto unlock_out;
  574         }
  575         /*
  576          * Replace each thread's cpuset while using deferred release.  We
  577          * must do this because the thread lock must be held while operating
  578          * on the thread and this limits the type of operations allowed.
  579          */
  580         FOREACH_THREAD_IN_PROC(p, td) {
  581                 thread_lock(td);
  582                 /*
  583                  * If we presently have an anonymous set or are applying a
  584                  * mask we must create an anonymous shadow set.  That is
  585                  * either parented to our existing base or the supplied set.
  586                  *
  587                  * If we have a base set with no anonymous shadow we simply
  588                  * replace it outright.
  589                  */
  590                 tdset = td->td_cpuset;
  591                 if (tdset->cs_id == CPUSET_INVALID || mask) {
  592                         nset = LIST_FIRST(&freelist);
  593                         LIST_REMOVE(nset, cs_link);
  594                         if (mask)
  595                                 error = cpuset_shadow(tdset, nset, mask);
  596                         else
  597                                 error = _cpuset_create(nset, set,
  598                                     &tdset->cs_mask, CPUSET_INVALID);
  599                         if (error) {
  600                                 LIST_INSERT_HEAD(&freelist, nset, cs_link);
  601                                 thread_unlock(td);
  602                                 break;
  603                         }
  604                 } else
  605                         nset = cpuset_ref(set);
  606                 cpuset_rel_defer(&droplist, tdset);
  607                 td->td_cpuset = nset;
  608                 sched_affinity(td);
  609                 thread_unlock(td);
  610         }
  611 unlock_out:
  612         PROC_UNLOCK(p);
  613 out:
  614         while ((nset = LIST_FIRST(&droplist)) != NULL)
  615                 cpuset_rel_complete(nset);
  616         while ((nset = LIST_FIRST(&freelist)) != NULL) {
  617                 LIST_REMOVE(nset, cs_link);
  618                 uma_zfree(cpuset_zone, nset);
  619         }
  620         return (error);
  621 }
  622 
  623 /*
  624  * Return a string representing a valid layout for a cpuset_t object.
  625  * It expects an incoming buffer at least sized as CPUSETBUFSIZ.
  626  */
  627 char *
  628 cpusetobj_strprint(char *buf, const cpuset_t *set)
  629 {
  630         char *tbuf;
  631         size_t i, bytesp, bufsiz;
  632 
  633         tbuf = buf;
  634         bytesp = 0;
  635         bufsiz = CPUSETBUFSIZ;
  636 
  637         for (i = 0; i < (_NCPUWORDS - 1); i++) {
  638                 bytesp = snprintf(tbuf, bufsiz, "%lx,", set->__bits[i]);
  639                 bufsiz -= bytesp;
  640                 tbuf += bytesp;
  641         }
  642         snprintf(tbuf, bufsiz, "%lx", set->__bits[_NCPUWORDS - 1]);
  643         return (buf);
  644 }
  645 
  646 /*
  647  * Build a valid cpuset_t object from a string representation.
  648  * It expects an incoming buffer at least sized as CPUSETBUFSIZ.
  649  */
  650 int
  651 cpusetobj_strscan(cpuset_t *set, const char *buf)
  652 {
  653         u_int nwords;
  654         int i, ret;
  655 
  656         if (strlen(buf) > CPUSETBUFSIZ - 1)
  657                 return (-1);
  658 
  659         /* Allow to pass a shorter version of the mask when necessary. */
  660         nwords = 1;
  661         for (i = 0; buf[i] != '\0'; i++)
  662                 if (buf[i] == ',')
  663                         nwords++;
  664         if (nwords > _NCPUWORDS)
  665                 return (-1);
  666 
  667         CPU_ZERO(set);
  668         for (i = 0; i < (nwords - 1); i++) {
  669                 ret = sscanf(buf, "%lx,", &set->__bits[i]);
  670                 if (ret == 0 || ret == -1)
  671                         return (-1);
  672                 buf = strstr(buf, ",");
  673                 if (buf == NULL)
  674                         return (-1);
  675                 buf++;
  676         }
  677         ret = sscanf(buf, "%lx", &set->__bits[nwords - 1]);
  678         if (ret == 0 || ret == -1)
  679                 return (-1);
  680         return (0);
  681 }
  682 
  683 /*
  684  * Apply an anonymous mask to a single thread.
  685  */
  686 int
  687 cpuset_setthread(lwpid_t id, cpuset_t *mask)
  688 {
  689         struct cpuset *nset;
  690         struct cpuset *set;
  691         struct thread *td;
  692         struct proc *p;
  693         int error;
  694 
  695         nset = uma_zalloc(cpuset_zone, M_WAITOK);
  696         error = cpuset_which(CPU_WHICH_TID, id, &p, &td, &set);
  697         if (error)
  698                 goto out;
  699         set = NULL;
  700         thread_lock(td);
  701         error = cpuset_shadow(td->td_cpuset, nset, mask);
  702         if (error == 0) {
  703                 set = td->td_cpuset;
  704                 td->td_cpuset = nset;
  705                 sched_affinity(td);
  706                 nset = NULL;
  707         }
  708         thread_unlock(td);
  709         PROC_UNLOCK(p);
  710         if (set)
  711                 cpuset_rel(set);
  712 out:
  713         if (nset)
  714                 uma_zfree(cpuset_zone, nset);
  715         return (error);
  716 }
  717 
  718 /*
  719  * Creates the cpuset for thread0.  We make two sets:
  720  * 
  721  * 0 - The root set which should represent all valid processors in the
  722  *     system.  It is initially created with a mask of all processors
  723  *     because we don't know what processors are valid until cpuset_init()
  724  *     runs.  This set is immutable.
  725  * 1 - The default set which all processes are a member of until changed.
  726  *     This allows an administrator to move all threads off of given cpus to
  727  *     dedicate them to high priority tasks or save power etc.
  728  */
  729 struct cpuset *
  730 cpuset_thread0(void)
  731 {
  732         struct cpuset *set;
  733         int error;
  734 
  735         cpuset_zone = uma_zcreate("cpuset", sizeof(struct cpuset), NULL, NULL,
  736             NULL, NULL, UMA_ALIGN_PTR, 0);
  737         mtx_init(&cpuset_lock, "cpuset", NULL, MTX_SPIN | MTX_RECURSE);
  738         /*
  739          * Create the root system set for the whole machine.  Doesn't use
  740          * cpuset_create() due to NULL parent.
  741          */
  742         set = uma_zalloc(cpuset_zone, M_WAITOK | M_ZERO);
  743         CPU_FILL(&set->cs_mask);
  744         LIST_INIT(&set->cs_children);
  745         LIST_INSERT_HEAD(&cpuset_ids, set, cs_link);
  746         set->cs_ref = 1;
  747         set->cs_flags = CPU_SET_ROOT;
  748         cpuset_zero = set;
  749         cpuset_root = &set->cs_mask;
  750         /*
  751          * Now derive a default, modifiable set from that to give out.
  752          */
  753         set = uma_zalloc(cpuset_zone, M_WAITOK);
  754         error = _cpuset_create(set, cpuset_zero, &cpuset_zero->cs_mask, 1);
  755         KASSERT(error == 0, ("Error creating default set: %d\n", error));
  756         /*
  757          * Initialize the unit allocator. 0 and 1 are allocated above.
  758          */
  759         cpuset_unr = new_unrhdr(2, INT_MAX, NULL);
  760 
  761         return (set);
  762 }
  763 
  764 /*
  765  * Create a cpuset, which would be cpuset_create() but
  766  * mark the new 'set' as root.
  767  *
  768  * We are not going to reparent the td to it.  Use cpuset_setproc_update_set()
  769  * for that.
  770  *
  771  * In case of no error, returns the set in *setp locked with a reference.
  772  */
  773 int
  774 cpuset_create_root(struct prison *pr, struct cpuset **setp)
  775 {
  776         struct cpuset *set;
  777         int error;
  778 
  779         KASSERT(pr != NULL, ("[%s:%d] invalid pr", __func__, __LINE__));
  780         KASSERT(setp != NULL, ("[%s:%d] invalid setp", __func__, __LINE__));
  781 
  782         error = cpuset_create(setp, pr->pr_cpuset, &pr->pr_cpuset->cs_mask);
  783         if (error)
  784                 return (error);
  785 
  786         KASSERT(*setp != NULL, ("[%s:%d] cpuset_create returned invalid data",
  787             __func__, __LINE__));
  788 
  789         /* Mark the set as root. */
  790         set = *setp;
  791         set->cs_flags |= CPU_SET_ROOT;
  792 
  793         return (0);
  794 }
  795 
  796 int
  797 cpuset_setproc_update_set(struct proc *p, struct cpuset *set)
  798 {
  799         int error;
  800 
  801         KASSERT(p != NULL, ("[%s:%d] invalid proc", __func__, __LINE__));
  802         KASSERT(set != NULL, ("[%s:%d] invalid set", __func__, __LINE__));
  803 
  804         cpuset_ref(set);
  805         error = cpuset_setproc(p->p_pid, set, NULL);
  806         if (error)
  807                 return (error);
  808         cpuset_rel(set);
  809         return (0);
  810 }
  811 
  812 /*
  813  * This is called once the final set of system cpus is known.  Modifies
  814  * the root set and all children and mark the root read-only.  
  815  */
  816 static void
  817 cpuset_init(void *arg)
  818 {
  819         cpuset_t mask;
  820 
  821         mask = all_cpus;
  822         if (cpuset_modify(cpuset_zero, &mask))
  823                 panic("Can't set initial cpuset mask.\n");
  824         cpuset_zero->cs_flags |= CPU_SET_RDONLY;
  825 }
  826 SYSINIT(cpuset, SI_SUB_SMP, SI_ORDER_ANY, cpuset_init, NULL);
  827 
  828 #ifndef _SYS_SYSPROTO_H_
  829 struct cpuset_args {
  830         cpusetid_t      *setid;
  831 };
  832 #endif
  833 int
  834 sys_cpuset(struct thread *td, struct cpuset_args *uap)
  835 {
  836         struct cpuset *root;
  837         struct cpuset *set;
  838         int error;
  839 
  840         thread_lock(td);
  841         root = cpuset_refroot(td->td_cpuset);
  842         thread_unlock(td);
  843         error = cpuset_create(&set, root, &root->cs_mask);
  844         cpuset_rel(root);
  845         if (error)
  846                 return (error);
  847         error = copyout(&set->cs_id, uap->setid, sizeof(set->cs_id));
  848         if (error == 0)
  849                 error = cpuset_setproc(-1, set, NULL);
  850         cpuset_rel(set);
  851         return (error);
  852 }
  853 
  854 #ifndef _SYS_SYSPROTO_H_
  855 struct cpuset_setid_args {
  856         cpuwhich_t      which;
  857         id_t            id;
  858         cpusetid_t      setid;
  859 };
  860 #endif
  861 int
  862 sys_cpuset_setid(struct thread *td, struct cpuset_setid_args *uap)
  863 {
  864         struct cpuset *set;
  865         int error;
  866 
  867         /*
  868          * Presently we only support per-process sets.
  869          */
  870         if (uap->which != CPU_WHICH_PID)
  871                 return (EINVAL);
  872         set = cpuset_lookup(uap->setid, td);
  873         if (set == NULL)
  874                 return (ESRCH);
  875         error = cpuset_setproc(uap->id, set, NULL);
  876         cpuset_rel(set);
  877         return (error);
  878 }
  879 
  880 #ifndef _SYS_SYSPROTO_H_
  881 struct cpuset_getid_args {
  882         cpulevel_t      level;
  883         cpuwhich_t      which;
  884         id_t            id;
  885         cpusetid_t      *setid;
  886 };
  887 #endif
  888 int
  889 sys_cpuset_getid(struct thread *td, struct cpuset_getid_args *uap)
  890 {
  891         struct cpuset *nset;
  892         struct cpuset *set;
  893         struct thread *ttd;
  894         struct proc *p;
  895         cpusetid_t id;
  896         int error;
  897 
  898         if (uap->level == CPU_LEVEL_WHICH && uap->which != CPU_WHICH_CPUSET)
  899                 return (EINVAL);
  900         error = cpuset_which(uap->which, uap->id, &p, &ttd, &set);
  901         if (error)
  902                 return (error);
  903         switch (uap->which) {
  904         case CPU_WHICH_TID:
  905         case CPU_WHICH_PID:
  906                 thread_lock(ttd);
  907                 set = cpuset_refbase(ttd->td_cpuset);
  908                 thread_unlock(ttd);
  909                 PROC_UNLOCK(p);
  910                 break;
  911         case CPU_WHICH_CPUSET:
  912         case CPU_WHICH_JAIL:
  913                 break;
  914         case CPU_WHICH_IRQ:
  915                 return (EINVAL);
  916         }
  917         switch (uap->level) {
  918         case CPU_LEVEL_ROOT:
  919                 nset = cpuset_refroot(set);
  920                 cpuset_rel(set);
  921                 set = nset;
  922                 break;
  923         case CPU_LEVEL_CPUSET:
  924                 break;
  925         case CPU_LEVEL_WHICH:
  926                 break;
  927         }
  928         id = set->cs_id;
  929         cpuset_rel(set);
  930         if (error == 0)
  931                 error = copyout(&id, uap->setid, sizeof(id));
  932 
  933         return (error);
  934 }
  935 
  936 #ifndef _SYS_SYSPROTO_H_
  937 struct cpuset_getaffinity_args {
  938         cpulevel_t      level;
  939         cpuwhich_t      which;
  940         id_t            id;
  941         size_t          cpusetsize;
  942         cpuset_t        *mask;
  943 };
  944 #endif
  945 int
  946 sys_cpuset_getaffinity(struct thread *td, struct cpuset_getaffinity_args *uap)
  947 {
  948         struct thread *ttd;
  949         struct cpuset *nset;
  950         struct cpuset *set;
  951         struct proc *p;
  952         cpuset_t *mask;
  953         int error;
  954         size_t size;
  955 
  956         if (uap->cpusetsize < sizeof(cpuset_t) ||
  957             uap->cpusetsize > CPU_MAXSIZE / NBBY)
  958                 return (ERANGE);
  959         size = uap->cpusetsize;
  960         mask = malloc(size, M_TEMP, M_WAITOK | M_ZERO);
  961         error = cpuset_which(uap->which, uap->id, &p, &ttd, &set);
  962         if (error)
  963                 goto out;
  964         switch (uap->level) {
  965         case CPU_LEVEL_ROOT:
  966         case CPU_LEVEL_CPUSET:
  967                 switch (uap->which) {
  968                 case CPU_WHICH_TID:
  969                 case CPU_WHICH_PID:
  970                         thread_lock(ttd);
  971                         set = cpuset_ref(ttd->td_cpuset);
  972                         thread_unlock(ttd);
  973                         break;
  974                 case CPU_WHICH_CPUSET:
  975                 case CPU_WHICH_JAIL:
  976                         break;
  977                 case CPU_WHICH_IRQ:
  978                         error = EINVAL;
  979                         goto out;
  980                 }
  981                 if (uap->level == CPU_LEVEL_ROOT)
  982                         nset = cpuset_refroot(set);
  983                 else
  984                         nset = cpuset_refbase(set);
  985                 CPU_COPY(&nset->cs_mask, mask);
  986                 cpuset_rel(nset);
  987                 break;
  988         case CPU_LEVEL_WHICH:
  989                 switch (uap->which) {
  990                 case CPU_WHICH_TID:
  991                         thread_lock(ttd);
  992                         CPU_COPY(&ttd->td_cpuset->cs_mask, mask);
  993                         thread_unlock(ttd);
  994                         break;
  995                 case CPU_WHICH_PID:
  996                         FOREACH_THREAD_IN_PROC(p, ttd) {
  997                                 thread_lock(ttd);
  998                                 CPU_OR(mask, &ttd->td_cpuset->cs_mask);
  999                                 thread_unlock(ttd);
 1000                         }
 1001                         break;
 1002                 case CPU_WHICH_CPUSET:
 1003                 case CPU_WHICH_JAIL:
 1004                         CPU_COPY(&set->cs_mask, mask);
 1005                         break;
 1006                 case CPU_WHICH_IRQ:
 1007                         error = intr_getaffinity(uap->id, mask);
 1008                         break;
 1009                 }
 1010                 break;
 1011         default:
 1012                 error = EINVAL;
 1013                 break;
 1014         }
 1015         if (set)
 1016                 cpuset_rel(set);
 1017         if (p)
 1018                 PROC_UNLOCK(p);
 1019         if (error == 0)
 1020                 error = copyout(mask, uap->mask, size);
 1021 out:
 1022         free(mask, M_TEMP);
 1023         return (error);
 1024 }
 1025 
 1026 #ifndef _SYS_SYSPROTO_H_
 1027 struct cpuset_setaffinity_args {
 1028         cpulevel_t      level;
 1029         cpuwhich_t      which;
 1030         id_t            id;
 1031         size_t          cpusetsize;
 1032         const cpuset_t  *mask;
 1033 };
 1034 #endif
 1035 int
 1036 sys_cpuset_setaffinity(struct thread *td, struct cpuset_setaffinity_args *uap)
 1037 {
 1038         struct cpuset *nset;
 1039         struct cpuset *set;
 1040         struct thread *ttd;
 1041         struct proc *p;
 1042         cpuset_t *mask;
 1043         int error;
 1044 
 1045         if (uap->cpusetsize < sizeof(cpuset_t) ||
 1046             uap->cpusetsize > CPU_MAXSIZE / NBBY)
 1047                 return (ERANGE);
 1048         mask = malloc(uap->cpusetsize, M_TEMP, M_WAITOK | M_ZERO);
 1049         error = copyin(uap->mask, mask, uap->cpusetsize);
 1050         if (error)
 1051                 goto out;
 1052         /*
 1053          * Verify that no high bits are set.
 1054          */
 1055         if (uap->cpusetsize > sizeof(cpuset_t)) {
 1056                 char *end;
 1057                 char *cp;
 1058 
 1059                 end = cp = (char *)&mask->__bits;
 1060                 end += uap->cpusetsize;
 1061                 cp += sizeof(cpuset_t);
 1062                 while (cp != end)
 1063                         if (*cp++ != 0) {
 1064                                 error = EINVAL;
 1065                                 goto out;
 1066                         }
 1067 
 1068         }
 1069         switch (uap->level) {
 1070         case CPU_LEVEL_ROOT:
 1071         case CPU_LEVEL_CPUSET:
 1072                 error = cpuset_which(uap->which, uap->id, &p, &ttd, &set);
 1073                 if (error)
 1074                         break;
 1075                 switch (uap->which) {
 1076                 case CPU_WHICH_TID:
 1077                 case CPU_WHICH_PID:
 1078                         thread_lock(ttd);
 1079                         set = cpuset_ref(ttd->td_cpuset);
 1080                         thread_unlock(ttd);
 1081                         PROC_UNLOCK(p);
 1082                         break;
 1083                 case CPU_WHICH_CPUSET:
 1084                 case CPU_WHICH_JAIL:
 1085                         break;
 1086                 case CPU_WHICH_IRQ:
 1087                         error = EINVAL;
 1088                         goto out;
 1089                 }
 1090                 if (uap->level == CPU_LEVEL_ROOT)
 1091                         nset = cpuset_refroot(set);
 1092                 else
 1093                         nset = cpuset_refbase(set);
 1094                 error = cpuset_modify(nset, mask);
 1095                 cpuset_rel(nset);
 1096                 cpuset_rel(set);
 1097                 break;
 1098         case CPU_LEVEL_WHICH:
 1099                 switch (uap->which) {
 1100                 case CPU_WHICH_TID:
 1101                         error = cpuset_setthread(uap->id, mask);
 1102                         break;
 1103                 case CPU_WHICH_PID:
 1104                         error = cpuset_setproc(uap->id, NULL, mask);
 1105                         break;
 1106                 case CPU_WHICH_CPUSET:
 1107                 case CPU_WHICH_JAIL:
 1108                         error = cpuset_which(uap->which, uap->id, &p,
 1109                             &ttd, &set);
 1110                         if (error == 0) {
 1111                                 error = cpuset_modify(set, mask);
 1112                                 cpuset_rel(set);
 1113                         }
 1114                         break;
 1115                 case CPU_WHICH_IRQ:
 1116                         error = intr_setaffinity(uap->id, mask);
 1117                         break;
 1118                 default:
 1119                         error = EINVAL;
 1120                         break;
 1121                 }
 1122                 break;
 1123         default:
 1124                 error = EINVAL;
 1125                 break;
 1126         }
 1127 out:
 1128         free(mask, M_TEMP);
 1129         return (error);
 1130 }
 1131 
 1132 #ifdef DDB
 1133 void
 1134 ddb_display_cpuset(const cpuset_t *set)
 1135 {
 1136         int cpu, once;
 1137 
 1138         for (once = 0, cpu = 0; cpu < CPU_SETSIZE; cpu++) {
 1139                 if (CPU_ISSET(cpu, set)) {
 1140                         if (once == 0) {
 1141                                 db_printf("%d", cpu);
 1142                                 once = 1;
 1143                         } else  
 1144                                 db_printf(",%d", cpu);
 1145                 }
 1146         }
 1147         if (once == 0)
 1148                 db_printf("<none>");
 1149 }
 1150 
 1151 DB_SHOW_COMMAND(cpusets, db_show_cpusets)
 1152 {
 1153         struct cpuset *set;
 1154 
 1155         LIST_FOREACH(set, &cpuset_ids, cs_link) {
 1156                 db_printf("set=%p id=%-6u ref=%-6d flags=0x%04x parent id=%d\n",
 1157                     set, set->cs_id, set->cs_ref, set->cs_flags,
 1158                     (set->cs_parent != NULL) ? set->cs_parent->cs_id : 0);
 1159                 db_printf("  mask=");
 1160                 ddb_display_cpuset(&set->cs_mask);
 1161                 db_printf("\n");
 1162                 if (db_pager_quit)
 1163                         break;
 1164         }
 1165 }
 1166 #endif /* DDB */
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FreeBSD/Linux Kernel Cross Reference sys/kern/kern_cpuset.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_cpuset.c
