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

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    1 /*-
    2  * Copyright (c) 2004
    3  *      Bosko Milekic <bmilekic@FreeBSD.org>.
    4  *      All rights reserved.
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice unmodified, this list of conditions and the following
   11  *    disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  * 3. Neither the name of the author nor the names of contributors may be
   16  *    used to endorse or promote products derived from this software
   17  *    without specific prior written permission.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   29  * SUCH DAMAGE.
   30  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD: src/sys/kern/kern_mbuf.c,v 1.3 2004/08/02 00:18:35 green Exp $");
   34 
   35 #include "opt_mac.h"
   36 #include "opt_param.h"
   37 
   38 #include <sys/param.h>
   39 #include <sys/mac.h>
   40 #include <sys/malloc.h>
   41 #include <sys/systm.h>
   42 #include <sys/mbuf.h>
   43 #include <sys/domain.h>
   44 #include <sys/eventhandler.h>
   45 #include <sys/kernel.h>
   46 #include <sys/protosw.h>
   47 #include <sys/smp.h>
   48 #include <sys/sysctl.h>
   49 
   50 #include <vm/vm.h>
   51 #include <vm/vm_page.h>
   52 #include <vm/uma.h>
   53 
   54 /*
   55  * In FreeBSD, Mbufs and Mbuf Clusters are allocated from UMA
   56  * Zones.
   57  *
   58  * Mbuf Clusters (2K, contiguous) are allocated from the Cluster
   59  * Zone.  The Zone can be capped at kern.ipc.nmbclusters, if the
   60  * administrator so desires.
   61  *
   62  * Mbufs are allocated from a UMA Master Zone called the Mbuf
   63  * Zone.
   64  *
   65  * Additionally, FreeBSD provides a Packet Zone, which it
   66  * configures as a Secondary Zone to the Mbuf Master Zone,
   67  * thus sharing backend Slab kegs with the Mbuf Master Zone.
   68  *
   69  * Thus common-case allocations and locking are simplified:
   70  *
   71  *  m_clget()                m_getcl()
   72  *    |                         |
   73  *    |   .------------>[(Packet Cache)]    m_get(), m_gethdr()
   74  *    |   |             [     Packet   ]            |
   75  *  [(Cluster Cache)]   [    Secondary ]   [ (Mbuf Cache)     ]
   76  *  [ Cluster Zone  ]   [     Zone     ]   [ Mbuf Master Zone ]
   77  *        |                       \________         |
   78  *  [ Cluster Keg   ]                      \       /
   79  *        |                              [ Mbuf Keg   ] 
   80  *  [ Cluster Slabs ]                         |
   81  *        |                              [ Mbuf Slabs ]
   82  *         \____________(VM)_________________/
   83  */
   84 
   85 int nmbclusters;
   86 struct mbstat mbstat;
   87 
   88 static void
   89 tunable_mbinit(void *dummy)
   90 {
   91 
   92         /* This has to be done before VM init. */
   93         nmbclusters = 1024 + maxusers * 64;
   94         TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters);
   95 }
   96 SYSINIT(tunable_mbinit, SI_SUB_TUNABLES, SI_ORDER_ANY, tunable_mbinit, NULL);
   97 
   98 SYSCTL_DECL(_kern_ipc);
   99 SYSCTL_INT(_kern_ipc, OID_AUTO, nmbclusters, CTLFLAG_RW, &nmbclusters, 0,
  100     "Maximum number of mbuf clusters allowed");
  101 SYSCTL_STRUCT(_kern_ipc, OID_AUTO, mbstat, CTLFLAG_RD, &mbstat, mbstat,
  102     "Mbuf general information and statistics");
  103 
  104 /*
  105  * Zones from which we allocate.
  106  */
  107 uma_zone_t      zone_mbuf;
  108 uma_zone_t      zone_clust;
  109 uma_zone_t      zone_pack;
  110 
  111 /*
  112  * Local prototypes.
  113  */
  114 static int      mb_ctor_mbuf(void *, int, void *, int);
  115 static int      mb_ctor_clust(void *, int, void *, int);
  116 static int      mb_ctor_pack(void *, int, void *, int);
  117 static void     mb_dtor_mbuf(void *, int, void *);
  118 static void     mb_dtor_clust(void *, int, void *);     /* XXX */
  119 static void     mb_dtor_pack(void *, int, void *);      /* XXX */
  120 static int      mb_init_pack(void *, int, int);
  121 static void     mb_fini_pack(void *, int);
  122 
  123 static void     mb_reclaim(void *);
  124 static void     mbuf_init(void *);
  125 
  126 /*
  127  * Initialize FreeBSD Network buffer allocation.
  128  */
  129 SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbuf_init, NULL)
  130 static void
  131 mbuf_init(void *dummy)
  132 {
  133 
  134         /*
  135          * Configure UMA zones for Mbufs, Clusters, and Packets.
  136          */
  137         zone_mbuf = uma_zcreate("Mbuf", MSIZE, mb_ctor_mbuf, mb_dtor_mbuf,
  138             NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_MAXBUCKET);
  139         zone_clust = uma_zcreate("MbufClust", MCLBYTES, mb_ctor_clust,
  140             mb_dtor_clust, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
  141         if (nmbclusters > 0)
  142                 uma_zone_set_max(zone_clust, nmbclusters);
  143         zone_pack = uma_zsecond_create("Packet", mb_ctor_pack, mb_dtor_pack,
  144             mb_init_pack, mb_fini_pack, zone_mbuf);
  145 
  146         /* uma_prealloc() goes here */
  147 
  148         /*
  149          * Hook event handler for low-memory situation, used to
  150          * drain protocols and push data back to the caches (UMA
  151          * later pushes it back to VM).
  152          */
  153         EVENTHANDLER_REGISTER(vm_lowmem, mb_reclaim, NULL,
  154             EVENTHANDLER_PRI_FIRST);
  155 
  156         /*
  157          * [Re]set counters and local statistics knobs.
  158          * XXX Some of these should go and be replaced, but UMA stat
  159          * gathering needs to be revised.
  160          */
  161         mbstat.m_mbufs = 0;
  162         mbstat.m_mclusts = 0;
  163         mbstat.m_drain = 0;
  164         mbstat.m_msize = MSIZE;
  165         mbstat.m_mclbytes = MCLBYTES;
  166         mbstat.m_minclsize = MINCLSIZE;
  167         mbstat.m_mlen = MLEN;
  168         mbstat.m_mhlen = MHLEN;
  169         mbstat.m_numtypes = MT_NTYPES;
  170 
  171         mbstat.m_mcfail = mbstat.m_mpfail = 0;
  172         mbstat.sf_iocnt = 0;
  173         mbstat.sf_allocwait = mbstat.sf_allocfail = 0;
  174 }
  175 
  176 /*
  177  * Constructor for Mbuf master zone.
  178  *
  179  * The 'arg' pointer points to a mb_args structure which
  180  * contains call-specific information required to support the
  181  * mbuf allocation API.
  182  */
  183 static int
  184 mb_ctor_mbuf(void *mem, int size, void *arg, int how)
  185 {
  186         struct mbuf *m;
  187         struct mb_args *args;
  188 #ifdef MAC
  189         int error;
  190 #endif
  191         int flags;
  192         short type;
  193 
  194         m = (struct mbuf *)mem;
  195         args = (struct mb_args *)arg;
  196         flags = args->flags;
  197         type = args->type;
  198 
  199         m->m_type = type;
  200         m->m_next = NULL;
  201         m->m_nextpkt = NULL;
  202         m->m_flags = flags;
  203         if (flags & M_PKTHDR) {
  204                 m->m_data = m->m_pktdat;
  205                 m->m_pkthdr.rcvif = NULL;
  206                 m->m_pkthdr.csum_flags = 0;
  207                 SLIST_INIT(&m->m_pkthdr.tags);
  208 #ifdef MAC
  209                 /* If the label init fails, fail the alloc */
  210                 error = mac_init_mbuf(m, how);
  211                 if (error)
  212                         return (error);
  213 #endif
  214         } else
  215                 m->m_data = m->m_dat;
  216         mbstat.m_mbufs += 1;    /* XXX */
  217         return (0);
  218 }
  219 
  220 /*
  221  * The Mbuf master zone and Packet secondary zone destructor.
  222  */
  223 static void
  224 mb_dtor_mbuf(void *mem, int size, void *arg)
  225 {
  226         struct mbuf *m;
  227 
  228         m = (struct mbuf *)mem;
  229         if ((m->m_flags & M_PKTHDR) != 0)
  230                 m_tag_delete_chain(m, NULL);
  231         mbstat.m_mbufs -= 1;    /* XXX */
  232 }
  233 
  234 /* XXX Only because of stats */
  235 static void
  236 mb_dtor_pack(void *mem, int size, void *arg)
  237 {
  238         struct mbuf *m;
  239 
  240         m = (struct mbuf *)mem;
  241         if ((m->m_flags & M_PKTHDR) != 0)
  242                 m_tag_delete_chain(m, NULL);
  243         mbstat.m_mbufs -= 1;    /* XXX */
  244         mbstat.m_mclusts -= 1;  /* XXX */
  245 }
  246 
  247 /*
  248  * The Cluster zone constructor.
  249  *
  250  * Here the 'arg' pointer points to the Mbuf which we
  251  * are configuring cluster storage for.
  252  */
  253 static int
  254 mb_ctor_clust(void *mem, int size, void *arg, int how)
  255 {
  256         struct mbuf *m;
  257 
  258         m = (struct mbuf *)arg;
  259         m->m_ext.ext_buf = (caddr_t)mem;
  260         m->m_data = m->m_ext.ext_buf;
  261         m->m_flags |= M_EXT;
  262         m->m_ext.ext_free = NULL;
  263         m->m_ext.ext_args = NULL;
  264         m->m_ext.ext_size = MCLBYTES;
  265         m->m_ext.ext_type = EXT_CLUSTER;
  266         m->m_ext.ref_cnt = (u_int *)uma_find_refcnt(zone_clust,
  267             m->m_ext.ext_buf);
  268         *(m->m_ext.ref_cnt) = 1;
  269         mbstat.m_mclusts += 1;  /* XXX */
  270         return (0);
  271 }
  272 
  273 /* XXX */
  274 static void
  275 mb_dtor_clust(void *mem, int size, void *arg)
  276 {
  277         mbstat.m_mclusts -= 1;  /* XXX */
  278 }
  279 
  280 /*
  281  * The Packet secondary zone's init routine, executed on the
  282  * object's transition from keg slab to zone cache.
  283  */
  284 static int
  285 mb_init_pack(void *mem, int size, int how)
  286 {
  287         struct mbuf *m;
  288 
  289         m = (struct mbuf *)mem;
  290         m->m_ext.ext_buf = NULL;
  291         uma_zalloc_arg(zone_clust, m, how);
  292         if (m->m_ext.ext_buf == NULL)
  293                 return (ENOMEM);
  294         mbstat.m_mclusts -= 1;  /* XXX */
  295         return (0);
  296 }
  297 
  298 /*
  299  * The Packet secondary zone's fini routine, executed on the
  300  * object's transition from zone cache to keg slab.
  301  */
  302 static void
  303 mb_fini_pack(void *mem, int size)
  304 {
  305         struct mbuf *m;
  306 
  307         m = (struct mbuf *)mem;
  308         uma_zfree_arg(zone_clust, m->m_ext.ext_buf, NULL);
  309         m->m_ext.ext_buf = NULL;
  310         mbstat.m_mclusts += 1;  /* XXX */
  311 }
  312 
  313 /*
  314  * The "packet" keg constructor.
  315  */
  316 static int
  317 mb_ctor_pack(void *mem, int size, void *arg, int how)
  318 {
  319         struct mbuf *m;
  320         struct mb_args *args;
  321 #ifdef MAC
  322         int error;
  323 #endif
  324         int flags;
  325         short type;
  326 
  327         m = (struct mbuf *)mem;
  328         args = (struct mb_args *)arg;
  329         flags = args->flags;
  330         type = args->type;
  331 
  332         m->m_type = type;
  333         m->m_next = NULL;
  334         m->m_nextpkt = NULL;
  335         m->m_data = m->m_ext.ext_buf;
  336         m->m_flags = flags|M_EXT;
  337         m->m_ext.ext_free = NULL;
  338         m->m_ext.ext_args = NULL;
  339         m->m_ext.ext_size = MCLBYTES;
  340         m->m_ext.ext_type = EXT_PACKET;
  341         *(m->m_ext.ref_cnt) = 1;
  342 
  343         if (flags & M_PKTHDR) {
  344                 m->m_pkthdr.rcvif = NULL;
  345                 m->m_pkthdr.csum_flags = 0;
  346                 SLIST_INIT(&m->m_pkthdr.tags);
  347 #ifdef MAC
  348                 /* If the label init fails, fail the alloc */
  349                 error = mac_init_mbuf(m, how);
  350                 if (error)
  351                         return (error);
  352 #endif
  353         }
  354         mbstat.m_mbufs += 1;    /* XXX */
  355         mbstat.m_mclusts += 1;  /* XXX */
  356         return (0);
  357 }
  358 
  359 /*
  360  * This is the protocol drain routine.
  361  *
  362  * No locks should be held when this is called.  The drain routines have to
  363  * presently acquire some locks which raises the possibility of lock order
  364  * reversal.
  365  */
  366 static void
  367 mb_reclaim(void *junk)
  368 {
  369         struct domain *dp;
  370         struct protosw *pr;
  371 
  372         WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK | WARN_PANIC, NULL,
  373             "mb_reclaim()");
  374 
  375         mbstat.m_drain++;
  376         for (dp = domains; dp != NULL; dp = dp->dom_next)
  377                 for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
  378                         if (pr->pr_drain != NULL)
  379                                 (*pr->pr_drain)();
  380 }

Cache object: 3a2d25c131a2221de185348d43b60f3c


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