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: releng/9.0/sys/kern/kern_cpuset.c 225617 2011-09-16 13:58:51Z kmacy $");
   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         0, 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)
  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 (!CPU_OVERLAP(&set->cs_mask, mask))
  316                 return (EDEADLK);
  317         CPU_COPY(&set->cs_mask, &newmask);
  318         CPU_AND(&newmask, mask);
  319         error = 0;
  320         LIST_FOREACH(nset, &set->cs_children, cs_siblings) 
  321                 if ((error = cpuset_testupdate(nset, &newmask)) != 0)
  322                         break;
  323         return (error);
  324 }
  325 
  326 /*
  327  * Applies the mask 'mask' without checking for empty sets or permissions.
  328  */
  329 static void
  330 cpuset_update(struct cpuset *set, cpuset_t *mask)
  331 {
  332         struct cpuset *nset;
  333 
  334         mtx_assert(&cpuset_lock, MA_OWNED);
  335         CPU_AND(&set->cs_mask, mask);
  336         LIST_FOREACH(nset, &set->cs_children, cs_siblings) 
  337                 cpuset_update(nset, &set->cs_mask);
  338 
  339         return;
  340 }
  341 
  342 /*
  343  * Modify the set 'set' to use a copy of the mask provided.  Apply this new
  344  * mask to restrict all children in the tree.  Checks for validity before
  345  * applying the changes.
  346  */
  347 static int
  348 cpuset_modify(struct cpuset *set, cpuset_t *mask)
  349 {
  350         struct cpuset *root;
  351         int error;
  352 
  353         error = priv_check(curthread, PRIV_SCHED_CPUSET);
  354         if (error)
  355                 return (error);
  356         /*
  357          * In case we are called from within the jail
  358          * we do not allow modifying the dedicated root
  359          * cpuset of the jail but may still allow to
  360          * change child sets.
  361          */
  362         if (jailed(curthread->td_ucred) &&
  363             set->cs_flags & CPU_SET_ROOT)
  364                 return (EPERM);
  365         /*
  366          * Verify that we have access to this set of
  367          * cpus.
  368          */
  369         root = set->cs_parent;
  370         if (root && !CPU_SUBSET(&root->cs_mask, mask))
  371                 return (EINVAL);
  372         mtx_lock_spin(&cpuset_lock);
  373         error = cpuset_testupdate(set, mask);
  374         if (error)
  375                 goto out;
  376         cpuset_update(set, mask);
  377         CPU_COPY(mask, &set->cs_mask);
  378 out:
  379         mtx_unlock_spin(&cpuset_lock);
  380 
  381         return (error);
  382 }
  383 
  384 /*
  385  * Resolve the 'which' parameter of several cpuset apis.
  386  *
  387  * For WHICH_PID and WHICH_TID return a locked proc and valid proc/tid.  Also
  388  * checks for permission via p_cansched().
  389  *
  390  * For WHICH_SET returns a valid set with a new reference.
  391  *
  392  * -1 may be supplied for any argument to mean the current proc/thread or
  393  * the base set of the current thread.  May fail with ESRCH/EPERM.
  394  */
  395 static int
  396 cpuset_which(cpuwhich_t which, id_t id, struct proc **pp, struct thread **tdp,
  397     struct cpuset **setp)
  398 {
  399         struct cpuset *set;
  400         struct thread *td;
  401         struct proc *p;
  402         int error;
  403 
  404         *pp = p = NULL;
  405         *tdp = td = NULL;
  406         *setp = set = NULL;
  407         switch (which) {
  408         case CPU_WHICH_PID:
  409                 if (id == -1) {
  410                         PROC_LOCK(curproc);
  411                         p = curproc;
  412                         break;
  413                 }
  414                 if ((p = pfind(id)) == NULL)
  415                         return (ESRCH);
  416                 break;
  417         case CPU_WHICH_TID:
  418                 if (id == -1) {
  419                         PROC_LOCK(curproc);
  420                         p = curproc;
  421                         td = curthread;
  422                         break;
  423                 }
  424                 td = tdfind(id, -1);
  425                 if (td == NULL)
  426                         return (ESRCH);
  427                 p = td->td_proc;
  428                 break;
  429         case CPU_WHICH_CPUSET:
  430                 if (id == -1) {
  431                         thread_lock(curthread);
  432                         set = cpuset_refbase(curthread->td_cpuset);
  433                         thread_unlock(curthread);
  434                 } else
  435                         set = cpuset_lookup(id, curthread);
  436                 if (set) {
  437                         *setp = set;
  438                         return (0);
  439                 }
  440                 return (ESRCH);
  441         case CPU_WHICH_JAIL:
  442         {
  443                 /* Find `set' for prison with given id. */
  444                 struct prison *pr;
  445 
  446                 sx_slock(&allprison_lock);
  447                 pr = prison_find_child(curthread->td_ucred->cr_prison, id);
  448                 sx_sunlock(&allprison_lock);
  449                 if (pr == NULL)
  450                         return (ESRCH);
  451                 cpuset_ref(pr->pr_cpuset);
  452                 *setp = pr->pr_cpuset;
  453                 mtx_unlock(&pr->pr_mtx);
  454                 return (0);
  455         }
  456         case CPU_WHICH_IRQ:
  457                 return (0);
  458         default:
  459                 return (EINVAL);
  460         }
  461         error = p_cansched(curthread, p);
  462         if (error) {
  463                 PROC_UNLOCK(p);
  464                 return (error);
  465         }
  466         if (td == NULL)
  467                 td = FIRST_THREAD_IN_PROC(p);
  468         *pp = p;
  469         *tdp = td;
  470         return (0);
  471 }
  472 
  473 /*
  474  * Create an anonymous set with the provided mask in the space provided by
  475  * 'fset'.  If the passed in set is anonymous we use its parent otherwise
  476  * the new set is a child of 'set'.
  477  */
  478 static int
  479 cpuset_shadow(struct cpuset *set, struct cpuset *fset, const cpuset_t *mask)
  480 {
  481         struct cpuset *parent;
  482 
  483         if (set->cs_id == CPUSET_INVALID)
  484                 parent = set->cs_parent;
  485         else
  486                 parent = set;
  487         if (!CPU_SUBSET(&parent->cs_mask, mask))
  488                 return (EDEADLK);
  489         return (_cpuset_create(fset, parent, mask, CPUSET_INVALID));
  490 }
  491 
  492 /*
  493  * Handle two cases for replacing the base set or mask of an entire process.
  494  *
  495  * 1) Set is non-null and mask is null.  This reparents all anonymous sets
  496  *    to the provided set and replaces all non-anonymous td_cpusets with the
  497  *    provided set.
  498  * 2) Mask is non-null and set is null.  This replaces or creates anonymous
  499  *    sets for every thread with the existing base as a parent.
  500  *
  501  * This is overly complicated because we can't allocate while holding a 
  502  * spinlock and spinlocks must be held while changing and examining thread
  503  * state.
  504  */
  505 static int
  506 cpuset_setproc(pid_t pid, struct cpuset *set, cpuset_t *mask)
  507 {
  508         struct setlist freelist;
  509         struct setlist droplist;
  510         struct cpuset *tdset;
  511         struct cpuset *nset;
  512         struct thread *td;
  513         struct proc *p;
  514         int threads;
  515         int nfree;
  516         int error;
  517         /*
  518          * The algorithm requires two passes due to locking considerations.
  519          * 
  520          * 1) Lookup the process and acquire the locks in the required order.
  521          * 2) If enough cpusets have not been allocated release the locks and
  522          *    allocate them.  Loop.
  523          */
  524         LIST_INIT(&freelist);
  525         LIST_INIT(&droplist);
  526         nfree = 0;
  527         for (;;) {
  528                 error = cpuset_which(CPU_WHICH_PID, pid, &p, &td, &nset);
  529                 if (error)
  530                         goto out;
  531                 if (nfree >= p->p_numthreads)
  532                         break;
  533                 threads = p->p_numthreads;
  534                 PROC_UNLOCK(p);
  535                 for (; nfree < threads; nfree++) {
  536                         nset = uma_zalloc(cpuset_zone, M_WAITOK);
  537                         LIST_INSERT_HEAD(&freelist, nset, cs_link);
  538                 }
  539         }
  540         PROC_LOCK_ASSERT(p, MA_OWNED);
  541         /*
  542          * Now that the appropriate locks are held and we have enough cpusets,
  543          * make sure the operation will succeed before applying changes.  The
  544          * proc lock prevents td_cpuset from changing between calls.
  545          */
  546         error = 0;
  547         FOREACH_THREAD_IN_PROC(p, td) {
  548                 thread_lock(td);
  549                 tdset = td->td_cpuset;
  550                 /*
  551                  * Verify that a new mask doesn't specify cpus outside of
  552                  * the set the thread is a member of.
  553                  */
  554                 if (mask) {
  555                         if (tdset->cs_id == CPUSET_INVALID)
  556                                 tdset = tdset->cs_parent;
  557                         if (!CPU_SUBSET(&tdset->cs_mask, mask))
  558                                 error = EDEADLK;
  559                 /*
  560                  * Verify that a new set won't leave an existing thread
  561                  * mask without a cpu to run on.  It can, however, restrict
  562                  * the set.
  563                  */
  564                 } else if (tdset->cs_id == CPUSET_INVALID) {
  565                         if (!CPU_OVERLAP(&set->cs_mask, &tdset->cs_mask))
  566                                 error = EDEADLK;
  567                 }
  568                 thread_unlock(td);
  569                 if (error)
  570                         goto unlock_out;
  571         }
  572         /*
  573          * Replace each thread's cpuset while using deferred release.  We
  574          * must do this because the thread lock must be held while operating
  575          * on the thread and this limits the type of operations allowed.
  576          */
  577         FOREACH_THREAD_IN_PROC(p, td) {
  578                 thread_lock(td);
  579                 /*
  580                  * If we presently have an anonymous set or are applying a
  581                  * mask we must create an anonymous shadow set.  That is
  582                  * either parented to our existing base or the supplied set.
  583                  *
  584                  * If we have a base set with no anonymous shadow we simply
  585                  * replace it outright.
  586                  */
  587                 tdset = td->td_cpuset;
  588                 if (tdset->cs_id == CPUSET_INVALID || mask) {
  589                         nset = LIST_FIRST(&freelist);
  590                         LIST_REMOVE(nset, cs_link);
  591                         if (mask)
  592                                 error = cpuset_shadow(tdset, nset, mask);
  593                         else
  594                                 error = _cpuset_create(nset, set,
  595                                     &tdset->cs_mask, CPUSET_INVALID);
  596                         if (error) {
  597                                 LIST_INSERT_HEAD(&freelist, nset, cs_link);
  598                                 thread_unlock(td);
  599                                 break;
  600                         }
  601                 } else
  602                         nset = cpuset_ref(set);
  603                 cpuset_rel_defer(&droplist, tdset);
  604                 td->td_cpuset = nset;
  605                 sched_affinity(td);
  606                 thread_unlock(td);
  607         }
  608 unlock_out:
  609         PROC_UNLOCK(p);
  610 out:
  611         while ((nset = LIST_FIRST(&droplist)) != NULL)
  612                 cpuset_rel_complete(nset);
  613         while ((nset = LIST_FIRST(&freelist)) != NULL) {
  614                 LIST_REMOVE(nset, cs_link);
  615                 uma_zfree(cpuset_zone, nset);
  616         }
  617         return (error);
  618 }
  619 
  620 /*
  621  * Calculate the ffs() of the cpuset.
  622  */
  623 int
  624 cpusetobj_ffs(const cpuset_t *set)
  625 {
  626         size_t i;
  627         int cbit;
  628 
  629         cbit = 0;
  630         for (i = 0; i < _NCPUWORDS; i++) {
  631                 if (set->__bits[i] != 0) {
  632                         cbit = ffsl(set->__bits[i]);
  633                         cbit += i * _NCPUBITS;
  634                         break;
  635                 }
  636         }
  637         return (cbit);
  638 }
  639 
  640 /*
  641  * Return a string representing a valid layout for a cpuset_t object.
  642  * It expects an incoming buffer at least sized as CPUSETBUFSIZ.
  643  */
  644 char *
  645 cpusetobj_strprint(char *buf, const cpuset_t *set)
  646 {
  647         char *tbuf;
  648         size_t i, bytesp, bufsiz;
  649 
  650         tbuf = buf;
  651         bytesp = 0;
  652         bufsiz = CPUSETBUFSIZ;
  653 
  654         for (i = _NCPUWORDS - 1; i > 0; i--) {
  655                 bytesp = snprintf(tbuf, bufsiz, "%lx, ", set->__bits[i]);
  656                 bufsiz -= bytesp;
  657                 tbuf += bytesp;
  658         }
  659         snprintf(tbuf, bufsiz, "%lx", set->__bits[0]);
  660         return (buf);
  661 }
  662 
  663 /*
  664  * Build a valid cpuset_t object from a string representation.
  665  * It expects an incoming buffer at least sized as CPUSETBUFSIZ.
  666  */
  667 int
  668 cpusetobj_strscan(cpuset_t *set, const char *buf)
  669 {
  670         u_int nwords;
  671         int i, ret;
  672 
  673         if (strlen(buf) > CPUSETBUFSIZ - 1)
  674                 return (-1);
  675 
  676         /* Allow to pass a shorter version of the mask when necessary. */
  677         nwords = 1;
  678         for (i = 0; buf[i] != '\0'; i++)
  679                 if (buf[i] == ',')
  680                         nwords++;
  681         if (nwords > _NCPUWORDS)
  682                 return (-1);
  683 
  684         CPU_ZERO(set);
  685         for (i = nwords - 1; i > 0; i--) {
  686                 ret = sscanf(buf, "%lx, ", &set->__bits[i]);
  687                 if (ret == 0 || ret == -1)
  688                         return (-1);
  689                 buf = strstr(buf, " ");
  690                 if (buf == NULL)
  691                         return (-1);
  692                 buf++;
  693         }
  694         ret = sscanf(buf, "%lx", &set->__bits[0]);
  695         if (ret == 0 || ret == -1)
  696                 return (-1);
  697         return (0);
  698 }
  699 
  700 /*
  701  * Apply an anonymous mask to a single thread.
  702  */
  703 int
  704 cpuset_setthread(lwpid_t id, cpuset_t *mask)
  705 {
  706         struct cpuset *nset;
  707         struct cpuset *set;
  708         struct thread *td;
  709         struct proc *p;
  710         int error;
  711 
  712         nset = uma_zalloc(cpuset_zone, M_WAITOK);
  713         error = cpuset_which(CPU_WHICH_TID, id, &p, &td, &set);
  714         if (error)
  715                 goto out;
  716         set = NULL;
  717         thread_lock(td);
  718         error = cpuset_shadow(td->td_cpuset, nset, mask);
  719         if (error == 0) {
  720                 set = td->td_cpuset;
  721                 td->td_cpuset = nset;
  722                 sched_affinity(td);
  723                 nset = NULL;
  724         }
  725         thread_unlock(td);
  726         PROC_UNLOCK(p);
  727         if (set)
  728                 cpuset_rel(set);
  729 out:
  730         if (nset)
  731                 uma_zfree(cpuset_zone, nset);
  732         return (error);
  733 }
  734 
  735 /*
  736  * Creates the cpuset for thread0.  We make two sets:
  737  * 
  738  * 0 - The root set which should represent all valid processors in the
  739  *     system.  It is initially created with a mask of all processors
  740  *     because we don't know what processors are valid until cpuset_init()
  741  *     runs.  This set is immutable.
  742  * 1 - The default set which all processes are a member of until changed.
  743  *     This allows an administrator to move all threads off of given cpus to
  744  *     dedicate them to high priority tasks or save power etc.
  745  */
  746 struct cpuset *
  747 cpuset_thread0(void)
  748 {
  749         struct cpuset *set;
  750         int error;
  751 
  752         cpuset_zone = uma_zcreate("cpuset", sizeof(struct cpuset), NULL, NULL,
  753             NULL, NULL, UMA_ALIGN_PTR, 0);
  754         mtx_init(&cpuset_lock, "cpuset", NULL, MTX_SPIN | MTX_RECURSE);
  755         /*
  756          * Create the root system set for the whole machine.  Doesn't use
  757          * cpuset_create() due to NULL parent.
  758          */
  759         set = uma_zalloc(cpuset_zone, M_WAITOK | M_ZERO);
  760         CPU_FILL(&set->cs_mask);
  761         LIST_INIT(&set->cs_children);
  762         LIST_INSERT_HEAD(&cpuset_ids, set, cs_link);
  763         set->cs_ref = 1;
  764         set->cs_flags = CPU_SET_ROOT;
  765         cpuset_zero = set;
  766         cpuset_root = &set->cs_mask;
  767         /*
  768          * Now derive a default, modifiable set from that to give out.
  769          */
  770         set = uma_zalloc(cpuset_zone, M_WAITOK);
  771         error = _cpuset_create(set, cpuset_zero, &cpuset_zero->cs_mask, 1);
  772         KASSERT(error == 0, ("Error creating default set: %d\n", error));
  773         /*
  774          * Initialize the unit allocator. 0 and 1 are allocated above.
  775          */
  776         cpuset_unr = new_unrhdr(2, INT_MAX, NULL);
  777 
  778         return (set);
  779 }
  780 
  781 /*
  782  * Create a cpuset, which would be cpuset_create() but
  783  * mark the new 'set' as root.
  784  *
  785  * We are not going to reparent the td to it.  Use cpuset_setproc_update_set()
  786  * for that.
  787  *
  788  * In case of no error, returns the set in *setp locked with a reference.
  789  */
  790 int
  791 cpuset_create_root(struct prison *pr, struct cpuset **setp)
  792 {
  793         struct cpuset *set;
  794         int error;
  795 
  796         KASSERT(pr != NULL, ("[%s:%d] invalid pr", __func__, __LINE__));
  797         KASSERT(setp != NULL, ("[%s:%d] invalid setp", __func__, __LINE__));
  798 
  799         error = cpuset_create(setp, pr->pr_cpuset, &pr->pr_cpuset->cs_mask);
  800         if (error)
  801                 return (error);
  802 
  803         KASSERT(*setp != NULL, ("[%s:%d] cpuset_create returned invalid data",
  804             __func__, __LINE__));
  805 
  806         /* Mark the set as root. */
  807         set = *setp;
  808         set->cs_flags |= CPU_SET_ROOT;
  809 
  810         return (0);
  811 }
  812 
  813 int
  814 cpuset_setproc_update_set(struct proc *p, struct cpuset *set)
  815 {
  816         int error;
  817 
  818         KASSERT(p != NULL, ("[%s:%d] invalid proc", __func__, __LINE__));
  819         KASSERT(set != NULL, ("[%s:%d] invalid set", __func__, __LINE__));
  820 
  821         cpuset_ref(set);
  822         error = cpuset_setproc(p->p_pid, set, NULL);
  823         if (error)
  824                 return (error);
  825         cpuset_rel(set);
  826         return (0);
  827 }
  828 
  829 /*
  830  * This is called once the final set of system cpus is known.  Modifies
  831  * the root set and all children and mark the root read-only.  
  832  */
  833 static void
  834 cpuset_init(void *arg)
  835 {
  836         cpuset_t mask;
  837 
  838         mask = all_cpus;
  839         if (cpuset_modify(cpuset_zero, &mask))
  840                 panic("Can't set initial cpuset mask.\n");
  841         cpuset_zero->cs_flags |= CPU_SET_RDONLY;
  842 }
  843 SYSINIT(cpuset, SI_SUB_SMP, SI_ORDER_ANY, cpuset_init, NULL);
  844 
  845 #ifndef _SYS_SYSPROTO_H_
  846 struct cpuset_args {
  847         cpusetid_t      *setid;
  848 };
  849 #endif
  850 int
  851 sys_cpuset(struct thread *td, struct cpuset_args *uap)
  852 {
  853         struct cpuset *root;
  854         struct cpuset *set;
  855         int error;
  856 
  857         thread_lock(td);
  858         root = cpuset_refroot(td->td_cpuset);
  859         thread_unlock(td);
  860         error = cpuset_create(&set, root, &root->cs_mask);
  861         cpuset_rel(root);
  862         if (error)
  863                 return (error);
  864         error = copyout(&set->cs_id, uap->setid, sizeof(set->cs_id));
  865         if (error == 0)
  866                 error = cpuset_setproc(-1, set, NULL);
  867         cpuset_rel(set);
  868         return (error);
  869 }
  870 
  871 #ifndef _SYS_SYSPROTO_H_
  872 struct cpuset_setid_args {
  873         cpuwhich_t      which;
  874         id_t            id;
  875         cpusetid_t      setid;
  876 };
  877 #endif
  878 int
  879 sys_cpuset_setid(struct thread *td, struct cpuset_setid_args *uap)
  880 {
  881         struct cpuset *set;
  882         int error;
  883 
  884         /*
  885          * Presently we only support per-process sets.
  886          */
  887         if (uap->which != CPU_WHICH_PID)
  888                 return (EINVAL);
  889         set = cpuset_lookup(uap->setid, td);
  890         if (set == NULL)
  891                 return (ESRCH);
  892         error = cpuset_setproc(uap->id, set, NULL);
  893         cpuset_rel(set);
  894         return (error);
  895 }
  896 
  897 #ifndef _SYS_SYSPROTO_H_
  898 struct cpuset_getid_args {
  899         cpulevel_t      level;
  900         cpuwhich_t      which;
  901         id_t            id;
  902         cpusetid_t      *setid;
  903 #endif
  904 int
  905 sys_cpuset_getid(struct thread *td, struct cpuset_getid_args *uap)
  906 {
  907         struct cpuset *nset;
  908         struct cpuset *set;
  909         struct thread *ttd;
  910         struct proc *p;
  911         cpusetid_t id;
  912         int error;
  913 
  914         if (uap->level == CPU_LEVEL_WHICH && uap->which != CPU_WHICH_CPUSET)
  915                 return (EINVAL);
  916         error = cpuset_which(uap->which, uap->id, &p, &ttd, &set);
  917         if (error)
  918                 return (error);
  919         switch (uap->which) {
  920         case CPU_WHICH_TID:
  921         case CPU_WHICH_PID:
  922                 thread_lock(ttd);
  923                 set = cpuset_refbase(ttd->td_cpuset);
  924                 thread_unlock(ttd);
  925                 PROC_UNLOCK(p);
  926                 break;
  927         case CPU_WHICH_CPUSET:
  928         case CPU_WHICH_JAIL:
  929                 break;
  930         case CPU_WHICH_IRQ:
  931                 return (EINVAL);
  932         }
  933         switch (uap->level) {
  934         case CPU_LEVEL_ROOT:
  935                 nset = cpuset_refroot(set);
  936                 cpuset_rel(set);
  937                 set = nset;
  938                 break;
  939         case CPU_LEVEL_CPUSET:
  940                 break;
  941         case CPU_LEVEL_WHICH:
  942                 break;
  943         }
  944         id = set->cs_id;
  945         cpuset_rel(set);
  946         if (error == 0)
  947                 error = copyout(&id, uap->setid, sizeof(id));
  948 
  949         return (error);
  950 }
  951 
  952 #ifndef _SYS_SYSPROTO_H_
  953 struct cpuset_getaffinity_args {
  954         cpulevel_t      level;
  955         cpuwhich_t      which;
  956         id_t            id;
  957         size_t          cpusetsize;
  958         cpuset_t        *mask;
  959 };
  960 #endif
  961 int
  962 sys_cpuset_getaffinity(struct thread *td, struct cpuset_getaffinity_args *uap)
  963 {
  964         struct thread *ttd;
  965         struct cpuset *nset;
  966         struct cpuset *set;
  967         struct proc *p;
  968         cpuset_t *mask;
  969         int error;
  970         size_t size;
  971 
  972         if (uap->cpusetsize < sizeof(cpuset_t) ||
  973             uap->cpusetsize > CPU_MAXSIZE / NBBY)
  974                 return (ERANGE);
  975         size = uap->cpusetsize;
  976         mask = malloc(size, M_TEMP, M_WAITOK | M_ZERO);
  977         error = cpuset_which(uap->which, uap->id, &p, &ttd, &set);
  978         if (error)
  979                 goto out;
  980         switch (uap->level) {
  981         case CPU_LEVEL_ROOT:
  982         case CPU_LEVEL_CPUSET:
  983                 switch (uap->which) {
  984                 case CPU_WHICH_TID:
  985                 case CPU_WHICH_PID:
  986                         thread_lock(ttd);
  987                         set = cpuset_ref(ttd->td_cpuset);
  988                         thread_unlock(ttd);
  989                         break;
  990                 case CPU_WHICH_CPUSET:
  991                 case CPU_WHICH_JAIL:
  992                         break;
  993                 case CPU_WHICH_IRQ:
  994                         error = EINVAL;
  995                         goto out;
  996                 }
  997                 if (uap->level == CPU_LEVEL_ROOT)
  998                         nset = cpuset_refroot(set);
  999                 else
 1000                         nset = cpuset_refbase(set);
 1001                 CPU_COPY(&nset->cs_mask, mask);
 1002                 cpuset_rel(nset);
 1003                 break;
 1004         case CPU_LEVEL_WHICH:
 1005                 switch (uap->which) {
 1006                 case CPU_WHICH_TID:
 1007                         thread_lock(ttd);
 1008                         CPU_COPY(&ttd->td_cpuset->cs_mask, mask);
 1009                         thread_unlock(ttd);
 1010                         break;
 1011                 case CPU_WHICH_PID:
 1012                         FOREACH_THREAD_IN_PROC(p, ttd) {
 1013                                 thread_lock(ttd);
 1014                                 CPU_OR(mask, &ttd->td_cpuset->cs_mask);
 1015                                 thread_unlock(ttd);
 1016                         }
 1017                         break;
 1018                 case CPU_WHICH_CPUSET:
 1019                 case CPU_WHICH_JAIL:
 1020                         CPU_COPY(&set->cs_mask, mask);
 1021                         break;
 1022                 case CPU_WHICH_IRQ:
 1023                         error = intr_getaffinity(uap->id, mask);
 1024                         break;
 1025                 }
 1026                 break;
 1027         default:
 1028                 error = EINVAL;
 1029                 break;
 1030         }
 1031         if (set)
 1032                 cpuset_rel(set);
 1033         if (p)
 1034                 PROC_UNLOCK(p);
 1035         if (error == 0)
 1036                 error = copyout(mask, uap->mask, size);
 1037 out:
 1038         free(mask, M_TEMP);
 1039         return (error);
 1040 }
 1041 
 1042 #ifndef _SYS_SYSPROTO_H_
 1043 struct cpuset_setaffinity_args {
 1044         cpulevel_t      level;
 1045         cpuwhich_t      which;
 1046         id_t            id;
 1047         size_t          cpusetsize;
 1048         const cpuset_t  *mask;
 1049 };
 1050 #endif
 1051 int
 1052 sys_cpuset_setaffinity(struct thread *td, struct cpuset_setaffinity_args *uap)
 1053 {
 1054         struct cpuset *nset;
 1055         struct cpuset *set;
 1056         struct thread *ttd;
 1057         struct proc *p;
 1058         cpuset_t *mask;
 1059         int error;
 1060 
 1061         if (uap->cpusetsize < sizeof(cpuset_t) ||
 1062             uap->cpusetsize > CPU_MAXSIZE / NBBY)
 1063                 return (ERANGE);
 1064         mask = malloc(uap->cpusetsize, M_TEMP, M_WAITOK | M_ZERO);
 1065         error = copyin(uap->mask, mask, uap->cpusetsize);
 1066         if (error)
 1067                 goto out;
 1068         /*
 1069          * Verify that no high bits are set.
 1070          */
 1071         if (uap->cpusetsize > sizeof(cpuset_t)) {
 1072                 char *end;
 1073                 char *cp;
 1074 
 1075                 end = cp = (char *)&mask->__bits;
 1076                 end += uap->cpusetsize;
 1077                 cp += sizeof(cpuset_t);
 1078                 while (cp != end)
 1079                         if (*cp++ != 0) {
 1080                                 error = EINVAL;
 1081                                 goto out;
 1082                         }
 1083 
 1084         }
 1085         switch (uap->level) {
 1086         case CPU_LEVEL_ROOT:
 1087         case CPU_LEVEL_CPUSET:
 1088                 error = cpuset_which(uap->which, uap->id, &p, &ttd, &set);
 1089                 if (error)
 1090                         break;
 1091                 switch (uap->which) {
 1092                 case CPU_WHICH_TID:
 1093                 case CPU_WHICH_PID:
 1094                         thread_lock(ttd);
 1095                         set = cpuset_ref(ttd->td_cpuset);
 1096                         thread_unlock(ttd);
 1097                         PROC_UNLOCK(p);
 1098                         break;
 1099                 case CPU_WHICH_CPUSET:
 1100                 case CPU_WHICH_JAIL:
 1101                         break;
 1102                 case CPU_WHICH_IRQ:
 1103                         error = EINVAL;
 1104                         goto out;
 1105                 }
 1106                 if (uap->level == CPU_LEVEL_ROOT)
 1107                         nset = cpuset_refroot(set);
 1108                 else
 1109                         nset = cpuset_refbase(set);
 1110                 error = cpuset_modify(nset, mask);
 1111                 cpuset_rel(nset);
 1112                 cpuset_rel(set);
 1113                 break;
 1114         case CPU_LEVEL_WHICH:
 1115                 switch (uap->which) {
 1116                 case CPU_WHICH_TID:
 1117                         error = cpuset_setthread(uap->id, mask);
 1118                         break;
 1119                 case CPU_WHICH_PID:
 1120                         error = cpuset_setproc(uap->id, NULL, mask);
 1121                         break;
 1122                 case CPU_WHICH_CPUSET:
 1123                 case CPU_WHICH_JAIL:
 1124                         error = cpuset_which(uap->which, uap->id, &p,
 1125                             &ttd, &set);
 1126                         if (error == 0) {
 1127                                 error = cpuset_modify(set, mask);
 1128                                 cpuset_rel(set);
 1129                         }
 1130                         break;
 1131                 case CPU_WHICH_IRQ:
 1132                         error = intr_setaffinity(uap->id, mask);
 1133                         break;
 1134                 default:
 1135                         error = EINVAL;
 1136                         break;
 1137                 }
 1138                 break;
 1139         default:
 1140                 error = EINVAL;
 1141                 break;
 1142         }
 1143 out:
 1144         free(mask, M_TEMP);
 1145         return (error);
 1146 }
 1147 
 1148 #ifdef DDB
 1149 DB_SHOW_COMMAND(cpusets, db_show_cpusets)
 1150 {
 1151         struct cpuset *set;
 1152         int cpu, once;
 1153 
 1154         LIST_FOREACH(set, &cpuset_ids, cs_link) {
 1155                 db_printf("set=%p id=%-6u ref=%-6d flags=0x%04x parent id=%d\n",
 1156                     set, set->cs_id, set->cs_ref, set->cs_flags,
 1157                     (set->cs_parent != NULL) ? set->cs_parent->cs_id : 0);
 1158                 db_printf("  mask=");
 1159                 for (once = 0, cpu = 0; cpu < CPU_SETSIZE; cpu++) {
 1160                         if (CPU_ISSET(cpu, &set->cs_mask)) {
 1161                                 if (once == 0) {
 1162                                         db_printf("%d", cpu);
 1163                                         once = 1;
 1164                                 } else  
 1165                                         db_printf(",%d", cpu);
 1166                         }
 1167                 }
 1168                 db_printf("\n");
 1169                 if (db_pager_quit)
 1170                         break;
 1171         }
 1172 }
 1173 #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
