subr_pcpu.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-3-Clause
    3  *
    4  * Copyright (c) 2001 Wind River Systems, Inc.
    5  * All rights reserved.
    6  * Written by: John Baldwin <jhb@FreeBSD.org>
    7  *
    8  * Copyright (c) 2009 Jeffrey Roberson <jeff@freebsd.org>
    9  * All rights reserved.
   10  *
   11  * Redistribution and use in source and binary forms, with or without
   12  * modification, are permitted provided that the following conditions
   13  * are met:
   14  * 1. Redistributions of source code must retain the above copyright
   15  *    notice, this list of conditions and the following disclaimer.
   16  * 2. Redistributions in binary form must reproduce the above copyright
   17  *    notice, this list of conditions and the following disclaimer in the
   18  *    documentation and/or other materials provided with the distribution.
   19  * 3. Neither the name of the author nor the names of any co-contributors
   20  *    may be used to endorse or promote products derived from this software
   21  *    without specific prior written permission.
   22  *
   23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   33  * SUCH DAMAGE.
   34  */
   35 
   36 /*
   37  * This module provides MI support for per-cpu data.
   38  *
   39  * Each architecture determines the mapping of logical CPU IDs to physical
   40  * CPUs.  The requirements of this mapping are as follows:
   41  *  - Logical CPU IDs must reside in the range 0 ... MAXCPU - 1.
   42  *  - The mapping is not required to be dense.  That is, there may be
   43  *    gaps in the mappings.
   44  *  - The platform sets the value of MAXCPU in <machine/param.h>.
   45  *  - It is suggested, but not required, that in the non-SMP case, the
   46  *    platform define MAXCPU to be 1 and define the logical ID of the
   47  *    sole CPU as 0.
   48  */
   49 
   50 #include <sys/cdefs.h>
   51 __FBSDID("$FreeBSD$");
   52 
   53 #include "opt_ddb.h"
   54 
   55 #include <sys/param.h>
   56 #include <sys/systm.h>
   57 #include <sys/sysctl.h>
   58 #include <sys/lock.h>
   59 #include <sys/malloc.h>
   60 #include <sys/pcpu.h>
   61 #include <sys/proc.h>
   62 #include <sys/smp.h>
   63 #include <sys/sx.h>
   64 #include <vm/uma.h>
   65 #include <ddb/ddb.h>
   66 
   67 static MALLOC_DEFINE(M_PCPU, "Per-cpu", "Per-cpu resource accouting.");
   68 
   69 struct dpcpu_free {
   70         uintptr_t       df_start;
   71         int             df_len;
   72         TAILQ_ENTRY(dpcpu_free) df_link;
   73 };
   74 
   75 DPCPU_DEFINE_STATIC(char, modspace[DPCPU_MODMIN] __aligned(__alignof(void *)));
   76 static TAILQ_HEAD(, dpcpu_free) dpcpu_head = TAILQ_HEAD_INITIALIZER(dpcpu_head);
   77 static struct sx dpcpu_lock;
   78 uintptr_t dpcpu_off[MAXCPU];
   79 struct pcpu *cpuid_to_pcpu[MAXCPU];
   80 struct cpuhead cpuhead = STAILQ_HEAD_INITIALIZER(cpuhead);
   81 
   82 /*
   83  * Initialize the MI portions of a struct pcpu.
   84  */
   85 void
   86 pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
   87 {
   88 
   89         bzero(pcpu, size);
   90         KASSERT(cpuid >= 0 && cpuid < MAXCPU,
   91             ("pcpu_init: invalid cpuid %d", cpuid));
   92         pcpu->pc_cpuid = cpuid;
   93         cpuid_to_pcpu[cpuid] = pcpu;
   94         STAILQ_INSERT_TAIL(&cpuhead, pcpu, pc_allcpu);
   95         cpu_pcpu_init(pcpu, cpuid, size);
   96         pcpu->pc_rm_queue.rmq_next = &pcpu->pc_rm_queue;
   97         pcpu->pc_rm_queue.rmq_prev = &pcpu->pc_rm_queue;
   98         pcpu->pc_zpcpu_offset = zpcpu_offset_cpu(cpuid);
   99 }
  100 
  101 void
  102 dpcpu_init(void *dpcpu, int cpuid)
  103 {
  104         struct pcpu *pcpu;
  105 
  106         pcpu = pcpu_find(cpuid);
  107         pcpu->pc_dynamic = (uintptr_t)dpcpu - DPCPU_START;
  108 
  109         /*
  110          * Initialize defaults from our linker section.
  111          */
  112         memcpy(dpcpu, (void *)DPCPU_START, DPCPU_BYTES);
  113 
  114         /*
  115          * Place it in the global pcpu offset array.
  116          */
  117         dpcpu_off[cpuid] = pcpu->pc_dynamic;
  118 }
  119 
  120 static void
  121 dpcpu_startup(void *dummy __unused)
  122 {
  123         struct dpcpu_free *df;
  124 
  125         df = malloc(sizeof(*df), M_PCPU, M_WAITOK | M_ZERO);
  126         df->df_start = (uintptr_t)&DPCPU_NAME(modspace);
  127         df->df_len = DPCPU_MODMIN;
  128         TAILQ_INSERT_HEAD(&dpcpu_head, df, df_link);
  129         sx_init(&dpcpu_lock, "dpcpu alloc lock");
  130 }
  131 SYSINIT(dpcpu, SI_SUB_KLD, SI_ORDER_FIRST, dpcpu_startup, NULL);
  132 
  133 /*
  134  * UMA_ZONE_PCPU zones for general kernel use.
  135  */
  136 uma_zone_t pcpu_zone_4;
  137 uma_zone_t pcpu_zone_8;
  138 uma_zone_t pcpu_zone_16;
  139 uma_zone_t pcpu_zone_32;
  140 uma_zone_t pcpu_zone_64;
  141 
  142 static void
  143 pcpu_zones_startup(void)
  144 {
  145 
  146         pcpu_zone_4 = uma_zcreate("pcpu-4", 4,
  147             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_PCPU);
  148         pcpu_zone_8 = uma_zcreate("pcpu-8", 8,
  149             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_PCPU);
  150         pcpu_zone_16 = uma_zcreate("pcpu-16", 16,
  151             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_PCPU);
  152         pcpu_zone_32 = uma_zcreate("pcpu-32", 32,
  153             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_PCPU);
  154         pcpu_zone_64 = uma_zcreate("pcpu-64", 64,
  155             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_PCPU);
  156 }
  157 SYSINIT(pcpu_zones, SI_SUB_COUNTER, SI_ORDER_FIRST, pcpu_zones_startup, NULL);
  158 
  159 /*
  160  * First-fit extent based allocator for allocating space in the per-cpu
  161  * region reserved for modules.  This is only intended for use by the
  162  * kernel linkers to place module linker sets.
  163  */
  164 void *
  165 dpcpu_alloc(int size)
  166 {
  167         struct dpcpu_free *df;
  168         void *s;
  169 
  170         s = NULL;
  171         size = roundup2(size, sizeof(void *));
  172         sx_xlock(&dpcpu_lock);
  173         TAILQ_FOREACH(df, &dpcpu_head, df_link) {
  174                 if (df->df_len < size)
  175                         continue;
  176                 if (df->df_len == size) {
  177                         s = (void *)df->df_start;
  178                         TAILQ_REMOVE(&dpcpu_head, df, df_link);
  179                         free(df, M_PCPU);
  180                         break;
  181                 }
  182                 s = (void *)df->df_start;
  183                 df->df_len -= size;
  184                 df->df_start = df->df_start + size;
  185                 break;
  186         }
  187         sx_xunlock(&dpcpu_lock);
  188 
  189         return (s);
  190 }
  191 
  192 /*
  193  * Free dynamic per-cpu space at module unload time. 
  194  */
  195 void
  196 dpcpu_free(void *s, int size)
  197 {
  198         struct dpcpu_free *df;
  199         struct dpcpu_free *dn;
  200         uintptr_t start;
  201         uintptr_t end;
  202 
  203         size = roundup2(size, sizeof(void *));
  204         start = (uintptr_t)s;
  205         end = start + size;
  206         /*
  207          * Free a region of space and merge it with as many neighbors as
  208          * possible.  Keeping the list sorted simplifies this operation.
  209          */
  210         sx_xlock(&dpcpu_lock);
  211         TAILQ_FOREACH(df, &dpcpu_head, df_link) {
  212                 if (df->df_start > end)
  213                         break;
  214                 /*
  215                  * If we expand at the end of an entry we may have to
  216                  * merge it with the one following it as well.
  217                  */
  218                 if (df->df_start + df->df_len == start) {
  219                         df->df_len += size;
  220                         dn = TAILQ_NEXT(df, df_link);
  221                         if (df->df_start + df->df_len == dn->df_start) {
  222                                 df->df_len += dn->df_len;
  223                                 TAILQ_REMOVE(&dpcpu_head, dn, df_link);
  224                                 free(dn, M_PCPU);
  225                         }
  226                         sx_xunlock(&dpcpu_lock);
  227                         return;
  228                 }
  229                 if (df->df_start == end) {
  230                         df->df_start = start;
  231                         df->df_len += size;
  232                         sx_xunlock(&dpcpu_lock);
  233                         return;
  234                 }
  235         }
  236         dn = malloc(sizeof(*df), M_PCPU, M_WAITOK | M_ZERO);
  237         dn->df_start = start;
  238         dn->df_len = size;
  239         if (df)
  240                 TAILQ_INSERT_BEFORE(df, dn, df_link);
  241         else
  242                 TAILQ_INSERT_TAIL(&dpcpu_head, dn, df_link);
  243         sx_xunlock(&dpcpu_lock);
  244 }
  245 
  246 /*
  247  * Initialize the per-cpu storage from an updated linker-set region.
  248  */
  249 void
  250 dpcpu_copy(void *s, int size)
  251 {
  252 #ifdef SMP
  253         uintptr_t dpcpu;
  254         int i;
  255 
  256         CPU_FOREACH(i) {
  257                 dpcpu = dpcpu_off[i];
  258                 if (dpcpu == 0)
  259                         continue;
  260                 memcpy((void *)(dpcpu + (uintptr_t)s), s, size);
  261         }
  262 #else
  263         memcpy((void *)(dpcpu_off[0] + (uintptr_t)s), s, size);
  264 #endif
  265 }
  266 
  267 /*
  268  * Destroy a struct pcpu.
  269  */
  270 void
  271 pcpu_destroy(struct pcpu *pcpu)
  272 {
  273 
  274         STAILQ_REMOVE(&cpuhead, pcpu, pcpu, pc_allcpu);
  275         cpuid_to_pcpu[pcpu->pc_cpuid] = NULL;
  276         dpcpu_off[pcpu->pc_cpuid] = 0;
  277 }
  278 
  279 /*
  280  * Locate a struct pcpu by cpu id.
  281  */
  282 struct pcpu *
  283 pcpu_find(u_int cpuid)
  284 {
  285 
  286         return (cpuid_to_pcpu[cpuid]);
  287 }
  288 
  289 int
  290 sysctl_dpcpu_quad(SYSCTL_HANDLER_ARGS)
  291 {
  292         uintptr_t dpcpu;
  293         int64_t count;
  294         int i;
  295 
  296         count = 0;
  297         CPU_FOREACH(i) {
  298                 dpcpu = dpcpu_off[i];
  299                 if (dpcpu == 0)
  300                         continue;
  301                 count += *(int64_t *)(dpcpu + (uintptr_t)arg1);
  302         }
  303         return (SYSCTL_OUT(req, &count, sizeof(count)));
  304 }
  305 
  306 int
  307 sysctl_dpcpu_long(SYSCTL_HANDLER_ARGS)
  308 {
  309         uintptr_t dpcpu;
  310         long count;
  311         int i;
  312 
  313         count = 0;
  314         CPU_FOREACH(i) {
  315                 dpcpu = dpcpu_off[i];
  316                 if (dpcpu == 0)
  317                         continue;
  318                 count += *(long *)(dpcpu + (uintptr_t)arg1);
  319         }
  320         return (SYSCTL_OUT(req, &count, sizeof(count)));
  321 }
  322 
  323 int
  324 sysctl_dpcpu_int(SYSCTL_HANDLER_ARGS)
  325 {
  326         uintptr_t dpcpu;
  327         int count;
  328         int i;
  329 
  330         count = 0;
  331         CPU_FOREACH(i) {
  332                 dpcpu = dpcpu_off[i];
  333                 if (dpcpu == 0)
  334                         continue;
  335                 count += *(int *)(dpcpu + (uintptr_t)arg1);
  336         }
  337         return (SYSCTL_OUT(req, &count, sizeof(count)));
  338 }
  339 
  340 #ifdef DDB
  341 DB_SHOW_COMMAND(dpcpu_off, db_show_dpcpu_off)
  342 {
  343         int id;
  344 
  345         CPU_FOREACH(id) {
  346                 db_printf("dpcpu_off[%2d] = 0x%jx (+ DPCPU_START = %p)\n",
  347                     id, (uintmax_t)dpcpu_off[id],
  348                     (void *)(uintptr_t)(dpcpu_off[id] + DPCPU_START));
  349         }
  350 }
  351 
  352 static void
  353 show_pcpu(struct pcpu *pc)
  354 {
  355         struct thread *td;
  356 
  357         db_printf("cpuid        = %d\n", pc->pc_cpuid);
  358         db_printf("dynamic pcpu = %p\n", (void *)pc->pc_dynamic);
  359         db_printf("curthread    = ");
  360         td = pc->pc_curthread;
  361         if (td != NULL)
  362                 db_printf("%p: pid %d tid %d critnest %d \"%s\"\n", td,
  363                     td->td_proc->p_pid, td->td_tid, td->td_critnest,
  364                     td->td_name);
  365         else
  366                 db_printf("none\n");
  367         db_printf("curpcb       = %p\n", pc->pc_curpcb);
  368         db_printf("fpcurthread  = ");
  369         td = pc->pc_fpcurthread;
  370         if (td != NULL)
  371                 db_printf("%p: pid %d \"%s\"\n", td, td->td_proc->p_pid,
  372                     td->td_name);
  373         else
  374                 db_printf("none\n");
  375         db_printf("idlethread   = ");
  376         td = pc->pc_idlethread;
  377         if (td != NULL)
  378                 db_printf("%p: tid %d \"%s\"\n", td, td->td_tid, td->td_name);
  379         else
  380                 db_printf("none\n");
  381         db_show_mdpcpu(pc);
  382 
  383 #ifdef VIMAGE
  384         db_printf("curvnet      = %p\n", pc->pc_curthread->td_vnet);
  385 #endif
  386 
  387 #ifdef WITNESS
  388         db_printf("spin locks held:\n");
  389         witness_list_locks(&pc->pc_spinlocks, db_printf);
  390 #endif
  391 }
  392 
  393 DB_SHOW_COMMAND(pcpu, db_show_pcpu)
  394 {
  395         struct pcpu *pc;
  396         int id;
  397 
  398         if (have_addr)
  399                 id = ((addr >> 4) % 16) * 10 + (addr % 16);
  400         else
  401                 id = PCPU_GET(cpuid);
  402         pc = pcpu_find(id);
  403         if (pc == NULL) {
  404                 db_printf("CPU %d not found\n", id);
  405                 return;
  406         }
  407         show_pcpu(pc);
  408 }
  409 
  410 DB_SHOW_ALL_COMMAND(pcpu, db_show_cpu_all)
  411 {
  412         struct pcpu *pc;
  413         int id;
  414 
  415         db_printf("Current CPU: %d\n\n", PCPU_GET(cpuid));
  416         CPU_FOREACH(id) {
  417                 pc = pcpu_find(id);
  418                 if (pc != NULL) {
  419                         show_pcpu(pc);
  420                         db_printf("\n");
  421                 }
  422         }
  423 }
  424 DB_SHOW_ALIAS(allpcpu, db_show_cpu_all);
  425 #endif
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FreeBSD/Linux Kernel Cross Reference sys/kern/subr_pcpu.c

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