kern_mbuf.c

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/*-
 * Copyright (c) 2004, 2005,
 *      Bosko Milekic <bmilekic@FreeBSD.org>.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$BSDSUniX$");

#include "opt_param.h"

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/protosw.h>
#include <sys/smp.h>
#include <sys/sysctl.h>

#include <security/mac/mac_framework.h>

#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/uma.h>
#include <vm/uma_int.h>
#include <vm/uma_dbg.h>

/*
 * In FreeBSD, Mbufs and Mbuf Clusters are allocated from UMA
 * Zones.
 *
 * Mbuf Clusters (2K, contiguous) are allocated from the Cluster
 * Zone.  The Zone can be capped at kern.ipc.nmbclusters, if the
 * administrator so desires.
 *
 * Mbufs are allocated from a UMA Master Zone called the Mbuf
 * Zone.
 *
 * Additionally, FreeBSD provides a Packet Zone, which it
 * configures as a Secondary Zone to the Mbuf Master Zone,
 * thus sharing backend Slab kegs with the Mbuf Master Zone.
 *
 * Thus common-case allocations and locking are simplified:
 *
 *  m_clget()                m_getcl()
 *    |                         |
 *    |   .------------>[(Packet Cache)]    m_get(), m_gethdr()
 *    |   |             [     Packet   ]            |
 *  [(Cluster Cache)]   [    Secondary ]   [ (Mbuf Cache)     ]
 *  [ Cluster Zone  ]   [     Zone     ]   [ Mbuf Master Zone ]
 *        |                       \________         |
 *  [ Cluster Keg   ]                      \       /
 *        |                              [ Mbuf Keg   ]
 *  [ Cluster Slabs ]                         |
 *        |                              [ Mbuf Slabs ]
 *         \____________(VM)_________________/
 *
 *
 * Whenever an object is allocated with uma_zalloc() out of
 * one of the Zones its _ctor_ function is executed.  The same
 * for any deallocation through uma_zfree() the _dtor_ function
 * is executed.
 *
 * Caches are per-CPU and are filled from the Master Zone.
 *
 * Whenever an object is allocated from the underlying global
 * memory pool it gets pre-initialized with the _zinit_ functions.
 * When the Keg's are overfull objects get decomissioned with
 * _zfini_ functions and free'd back to the global memory pool.
 *
 */

int nmbufs;                     /* limits number of mbufs */
int nmbclusters;                /* limits number of mbuf clusters */
int nmbjumbop;                  /* limits number of page size jumbo clusters */
int nmbjumbo9;                  /* limits number of 9k jumbo clusters */
int nmbjumbo16;                 /* limits number of 16k jumbo clusters */
struct mbstat mbstat;

static quad_t maxmbufmem;       /* overall real memory limit for all mbufs */

SYSCTL_QUAD(_kern_ipc, OID_AUTO, maxmbufmem, CTLFLAG_RDTUN, &maxmbufmem, 0,
    "Maximum real memory allocateable to various mbuf types");

/*
 * tunable_mbinit() has to be run before any mbuf allocations are done.
 */
static void
tunable_mbinit(void *dummy)
{
        quad_t realmem;

        /*
         * The default limit for all mbuf related memory is 1/2 of all
         * available kernel memory (physical or kmem).
         * At most it can be 3/4 of available kernel memory.
         */
        realmem = qmin((quad_t)physmem * PAGE_SIZE,
            vm_map_max(kmem_map) - vm_map_min(kmem_map));
        maxmbufmem = realmem / 2;
        TUNABLE_QUAD_FETCH("kern.ipc.maxmbufmem", &maxmbufmem);
        if (maxmbufmem > realmem / 4 * 3)
                maxmbufmem = realmem / 4 * 3;

        TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters);
        if (nmbclusters == 0)
                nmbclusters = maxmbufmem / MCLBYTES / 4;

        TUNABLE_INT_FETCH("kern.ipc.nmbjumbop", &nmbjumbop);
        if (nmbjumbop == 0)
                nmbjumbop = maxmbufmem / MJUMPAGESIZE / 4;

        TUNABLE_INT_FETCH("kern.ipc.nmbjumbo9", &nmbjumbo9);
        if (nmbjumbo9 == 0)
                nmbjumbo9 = maxmbufmem / MJUM9BYTES / 6;

        TUNABLE_INT_FETCH("kern.ipc.nmbjumbo16", &nmbjumbo16);
        if (nmbjumbo16 == 0)
                nmbjumbo16 = maxmbufmem / MJUM16BYTES / 6;

        /*
         * We need at least as many mbufs as we have clusters of
         * the various types added together.
         */
        TUNABLE_INT_FETCH("kern.ipc.nmbufs", &nmbufs);
        if (nmbufs < nmbclusters + nmbjumbop + nmbjumbo9 + nmbjumbo16)
                nmbufs = lmax(maxmbufmem / MSIZE / 5,
                    nmbclusters + nmbjumbop + nmbjumbo9 + nmbjumbo16);
}
SYSINIT(tunable_mbinit, SI_SUB_KMEM, SI_ORDER_MIDDLE, tunable_mbinit, NULL);

static int
sysctl_nmbclusters(SYSCTL_HANDLER_ARGS)
{
        int error, newnmbclusters;

        newnmbclusters = nmbclusters;
        error = sysctl_handle_int(oidp, &newnmbclusters, 0, req);
        if (error == 0 && req->newptr && newnmbclusters != nmbclusters) {
                if (newnmbclusters > nmbclusters &&
                    nmbufs >= nmbclusters + nmbjumbop + nmbjumbo9 + nmbjumbo16) {
                        nmbclusters = newnmbclusters;
                        nmbclusters = uma_zone_set_max(zone_clust, nmbclusters);
                        EVENTHANDLER_INVOKE(nmbclusters_change);
                } else
                        error = EINVAL;
        }
        return (error);
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbclusters, CTLTYPE_INT|CTLFLAG_RW,
&nmbclusters, 0, sysctl_nmbclusters, "IU",
    "Maximum number of mbuf clusters allowed");

static int
sysctl_nmbjumbop(SYSCTL_HANDLER_ARGS)
{
        int error, newnmbjumbop;

        newnmbjumbop = nmbjumbop;
        error = sysctl_handle_int(oidp, &newnmbjumbop, 0, req);
        if (error == 0 && req->newptr && newnmbjumbop != nmbjumbop) {
                if (newnmbjumbop > nmbjumbop &&
                    nmbufs >= nmbclusters + nmbjumbop + nmbjumbo9 + nmbjumbo16) {
                        nmbjumbop = newnmbjumbop;
                        nmbjumbop = uma_zone_set_max(zone_jumbop, nmbjumbop);
                } else
                        error = EINVAL;
        }
        return (error);
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbop, CTLTYPE_INT|CTLFLAG_RW,
&nmbjumbop, 0, sysctl_nmbjumbop, "IU",
    "Maximum number of mbuf page size jumbo clusters allowed");

static int
sysctl_nmbjumbo9(SYSCTL_HANDLER_ARGS)
{
        int error, newnmbjumbo9;

        newnmbjumbo9 = nmbjumbo9;
        error = sysctl_handle_int(oidp, &newnmbjumbo9, 0, req);
        if (error == 0 && req->newptr && newnmbjumbo9 != nmbjumbo9) {
                if (newnmbjumbo9 > nmbjumbo9 &&
                    nmbufs >= nmbclusters + nmbjumbop + nmbjumbo9 + nmbjumbo16) {
                        nmbjumbo9 = newnmbjumbo9;
                        nmbjumbo9 = uma_zone_set_max(zone_jumbo9, nmbjumbo9);
                } else
                        error = EINVAL;
        }
        return (error);
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbo9, CTLTYPE_INT|CTLFLAG_RW,
&nmbjumbo9, 0, sysctl_nmbjumbo9, "IU",
    "Maximum number of mbuf 9k jumbo clusters allowed");

static int
sysctl_nmbjumbo16(SYSCTL_HANDLER_ARGS)
{
        int error, newnmbjumbo16;

        newnmbjumbo16 = nmbjumbo16;
        error = sysctl_handle_int(oidp, &newnmbjumbo16, 0, req);
        if (error == 0 && req->newptr && newnmbjumbo16 != nmbjumbo16) {
                if (newnmbjumbo16 > nmbjumbo16 &&
                    nmbufs >= nmbclusters + nmbjumbop + nmbjumbo9 + nmbjumbo16) {
                        nmbjumbo16 = newnmbjumbo16;
                        nmbjumbo16 = uma_zone_set_max(zone_jumbo16, nmbjumbo16);
                } else
                        error = EINVAL;
        }
        return (error);
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbo16, CTLTYPE_INT|CTLFLAG_RW,
&nmbjumbo16, 0, sysctl_nmbjumbo16, "IU",
    "Maximum number of mbuf 16k jumbo clusters allowed");

static int
sysctl_nmbufs(SYSCTL_HANDLER_ARGS)
{
        int error, newnmbufs;

        newnmbufs = nmbufs;
        error = sysctl_handle_int(oidp, &newnmbufs, 0, req);
        if (error == 0 && req->newptr && newnmbufs != nmbufs) {
                if (newnmbufs > nmbufs) {
                        nmbufs = newnmbufs;
                        nmbufs = uma_zone_set_max(zone_mbuf, nmbufs);
                        EVENTHANDLER_INVOKE(nmbufs_change);
                } else
                        error = EINVAL;
        }
        return (error);
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbufs, CTLTYPE_INT|CTLFLAG_RW,
&nmbufs, 0, sysctl_nmbufs, "IU",
    "Maximum number of mbufs allowed");

SYSCTL_STRUCT(_kern_ipc, OID_AUTO, mbstat, CTLFLAG_RD, &mbstat, mbstat,
    "Mbuf general information and statistics");

/*
 * Zones from which we allocate.
 */
uma_zone_t      zone_mbuf;
uma_zone_t      zone_clust;
uma_zone_t      zone_pack;
uma_zone_t      zone_jumbop;
uma_zone_t      zone_jumbo9;
uma_zone_t      zone_jumbo16;
uma_zone_t      zone_ext_refcnt;

/*
 * Local prototypes.
 */
static int      mb_ctor_mbuf(void *, int, void *, int);
static int      mb_ctor_clust(void *, int, void *, int);
static int      mb_ctor_pack(void *, int, void *, int);
static void     mb_dtor_mbuf(void *, int, void *);
static void     mb_dtor_clust(void *, int, void *);
static void     mb_dtor_pack(void *, int, void *);
static int      mb_zinit_pack(void *, int, int);
static void     mb_zfini_pack(void *, int);

static void     mb_reclaim(void *);
static void    *mbuf_jumbo_alloc(uma_zone_t, int, uint8_t *, int);

/* Ensure that MSIZE doesn't break dtom() - it must be a power of 2 */
CTASSERT((((MSIZE - 1) ^ MSIZE) + 1) >> 1 == MSIZE);

/*
 * Initialize FreeBSD Network buffer allocation.
 */
static void
mbuf_init(void *dummy)
{

        /*
         * Configure UMA zones for Mbufs, Clusters, and Packets.
         */
        zone_mbuf = uma_zcreate(MBUF_MEM_NAME, MSIZE,
            mb_ctor_mbuf, mb_dtor_mbuf,
#ifdef INVARIANTS
            trash_init, trash_fini,
#else
            NULL, NULL,
#endif
            MSIZE - 1, UMA_ZONE_MAXBUCKET);
        if (nmbufs > 0)
                nmbufs = uma_zone_set_max(zone_mbuf, nmbufs);

        zone_clust = uma_zcreate(MBUF_CLUSTER_MEM_NAME, MCLBYTES,
            mb_ctor_clust, mb_dtor_clust,
#ifdef INVARIANTS
            trash_init, trash_fini,
#else
            NULL, NULL,
#endif
            UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
        if (nmbclusters > 0)
                nmbclusters = uma_zone_set_max(zone_clust, nmbclusters);

        zone_pack = uma_zsecond_create(MBUF_PACKET_MEM_NAME, mb_ctor_pack,
            mb_dtor_pack, mb_zinit_pack, mb_zfini_pack, zone_mbuf);

        /* Make jumbo frame zone too. Page size, 9k and 16k. */
        zone_jumbop = uma_zcreate(MBUF_JUMBOP_MEM_NAME, MJUMPAGESIZE,
            mb_ctor_clust, mb_dtor_clust,
#ifdef INVARIANTS
            trash_init, trash_fini,
#else
            NULL, NULL,
#endif
            UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
        if (nmbjumbop > 0)
                nmbjumbop = uma_zone_set_max(zone_jumbop, nmbjumbop);

        zone_jumbo9 = uma_zcreate(MBUF_JUMBO9_MEM_NAME, MJUM9BYTES,
            mb_ctor_clust, mb_dtor_clust,
#ifdef INVARIANTS
            trash_init, trash_fini,
#else
            NULL, NULL,
#endif
            UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
        uma_zone_set_allocf(zone_jumbo9, mbuf_jumbo_alloc);
        if (nmbjumbo9 > 0)
                nmbjumbo9 = uma_zone_set_max(zone_jumbo9, nmbjumbo9);

        zone_jumbo16 = uma_zcreate(MBUF_JUMBO16_MEM_NAME, MJUM16BYTES,
            mb_ctor_clust, mb_dtor_clust,
#ifdef INVARIANTS
            trash_init, trash_fini,
#else
            NULL, NULL,
#endif
            UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
        uma_zone_set_allocf(zone_jumbo16, mbuf_jumbo_alloc);
        if (nmbjumbo16 > 0)
                nmbjumbo16 = uma_zone_set_max(zone_jumbo16, nmbjumbo16);

        zone_ext_refcnt = uma_zcreate(MBUF_EXTREFCNT_MEM_NAME, sizeof(u_int),
            NULL, NULL,
            NULL, NULL,
            UMA_ALIGN_PTR, UMA_ZONE_ZINIT);

        /* uma_prealloc() goes here... */

        /*
         * Hook event handler for low-memory situation, used to
         * drain protocols and push data back to the caches (UMA
         * later pushes it back to VM).
         */
        EVENTHANDLER_REGISTER(vm_lowmem, mb_reclaim, NULL,
            EVENTHANDLER_PRI_FIRST);

        /*
         * [Re]set counters and local statistics knobs.
         * XXX Some of these should go and be replaced, but UMA stat
         * gathering needs to be revised.
         */
        mbstat.m_mbufs = 0;
        mbstat.m_mclusts = 0;
        mbstat.m_drain = 0;
        mbstat.m_msize = MSIZE;
        mbstat.m_mclbytes = MCLBYTES;
        mbstat.m_minclsize = MINCLSIZE;
        mbstat.m_mlen = MLEN;
        mbstat.m_mhlen = MHLEN;
        mbstat.m_numtypes = MT_NTYPES;

        mbstat.m_mcfail = mbstat.m_mpfail = 0;
        mbstat.sf_iocnt = 0;
        mbstat.sf_allocwait = mbstat.sf_allocfail = 0;
}
SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbuf_init, NULL);

/*
 * UMA backend page allocator for the jumbo frame zones.
 *
 * Allocates kernel virtual memory that is backed by contiguous physical
 * pages.
 */
static void *
mbuf_jumbo_alloc(uma_zone_t zone, int bytes, uint8_t *flags, int wait)
{

        /* Inform UMA that this allocator uses kernel_map/object. */
        *flags = UMA_SLAB_KERNEL;
        return ((void *)kmem_alloc_contig(kernel_map, bytes, wait,
            (vm_paddr_t)0, ~(vm_paddr_t)0, 1, 0, VM_MEMATTR_DEFAULT));
}

/*
 * Constructor for Mbuf master zone.
 *
 * The 'arg' pointer points to a mb_args structure which
 * contains call-specific information required to support the
 * mbuf allocation API.  See mbuf.h.
 */
static int
mb_ctor_mbuf(void *mem, int size, void *arg, int how)
{
        struct mbuf *m;
        struct mb_args *args;
#ifdef MAC
        int error;
#endif
        int flags;
        short type;

#ifdef INVARIANTS
        trash_ctor(mem, size, arg, how);
#endif
        m = (struct mbuf *)mem;
        args = (struct mb_args *)arg;
        flags = args->flags;
        type = args->type;

        /*
         * The mbuf is initialized later.  The caller has the
         * responsibility to set up any MAC labels too.
         */
        if (type == MT_NOINIT)
                return (0);

        m->m_next = NULL;
        m->m_nextpkt = NULL;
        m->m_len = 0;
        m->m_flags = flags;
        m->m_type = type;
        if (flags & M_PKTHDR) {
                m->m_data = m->m_pktdat;
                m->m_pkthdr.rcvif = NULL;
                m->m_pkthdr.header = NULL;
                m->m_pkthdr.len = 0;
                m->m_pkthdr.csum_flags = 0;
                m->m_pkthdr.csum_data = 0;
                m->m_pkthdr.tso_segsz = 0;
                m->m_pkthdr.ether_vtag = 0;
                m->m_pkthdr.flowid = 0;
                SLIST_INIT(&m->m_pkthdr.tags);
#ifdef MAC
                /* If the label init fails, fail the alloc */
                error = mac_mbuf_init(m, how);
                if (error)
                        return (error);
#endif
        } else
                m->m_data = m->m_dat;
        return (0);
}

/*
 * The Mbuf master zone destructor.
 */
static void
mb_dtor_mbuf(void *mem, int size, void *arg)
{
        struct mbuf *m;
        unsigned long flags;

        m = (struct mbuf *)mem;
        flags = (unsigned long)arg;

        if ((flags & MB_NOTAGS) == 0 && (m->m_flags & M_PKTHDR) != 0)
                m_tag_delete_chain(m, NULL);
        KASSERT((m->m_flags & M_EXT) == 0, ("%s: M_EXT set", __func__));
        KASSERT((m->m_flags & M_NOFREE) == 0, ("%s: M_NOFREE set", __func__));
#ifdef INVARIANTS
        trash_dtor(mem, size, arg);
#endif
}

/*
 * The Mbuf Packet zone destructor.
 */
static void
mb_dtor_pack(void *mem, int size, void *arg)
{
        struct mbuf *m;

        m = (struct mbuf *)mem;
        if ((m->m_flags & M_PKTHDR) != 0)
                m_tag_delete_chain(m, NULL);

        /* Make sure we've got a clean cluster back. */
        KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
        KASSERT(m->m_ext.ext_buf != NULL, ("%s: ext_buf == NULL", __func__));
        KASSERT(m->m_ext.ext_free == NULL, ("%s: ext_free != NULL", __func__));
        KASSERT(m->m_ext.ext_arg1 == NULL, ("%s: ext_arg1 != NULL", __func__));
        KASSERT(m->m_ext.ext_arg2 == NULL, ("%s: ext_arg2 != NULL", __func__));
        KASSERT(m->m_ext.ext_size == MCLBYTES, ("%s: ext_size != MCLBYTES", __func__));
        KASSERT(m->m_ext.ext_type == EXT_PACKET, ("%s: ext_type != EXT_PACKET", __func__));
        KASSERT(*m->m_ext.ref_cnt == 1, ("%s: ref_cnt != 1", __func__));
#ifdef INVARIANTS
        trash_dtor(m->m_ext.ext_buf, MCLBYTES, arg);
#endif
        /*
         * If there are processes blocked on zone_clust, waiting for pages
         * to be freed up, * cause them to be woken up by draining the
         * packet zone.  We are exposed to a race here * (in the check for
         * the UMA_ZFLAG_FULL) where we might miss the flag set, but that
         * is deliberate. We don't want to acquire the zone lock for every
         * mbuf free.
         */
        if (uma_zone_exhausted_nolock(zone_clust))
                zone_drain(zone_pack);
}

/*
 * The Cluster and Jumbo[PAGESIZE|9|16] zone constructor.
 *
 * Here the 'arg' pointer points to the Mbuf which we
 * are configuring cluster storage for.  If 'arg' is
 * empty we allocate just the cluster without setting
 * the mbuf to it.  See mbuf.h.
 */
static int
mb_ctor_clust(void *mem, int size, void *arg, int how)
{
        struct mbuf *m;
        u_int *refcnt;
        int type;
        uma_zone_t zone;

#ifdef INVARIANTS
        trash_ctor(mem, size, arg, how);
#endif
        switch (size) {
        case MCLBYTES:
                type = EXT_CLUSTER;
                zone = zone_clust;
                break;
#if MJUMPAGESIZE != MCLBYTES
        case MJUMPAGESIZE:
                type = EXT_JUMBOP;
                zone = zone_jumbop;
                break;
#endif
        case MJUM9BYTES:
                type = EXT_JUMBO9;
                zone = zone_jumbo9;
                break;
        case MJUM16BYTES:
                type = EXT_JUMBO16;
                zone = zone_jumbo16;
                break;
        default:
                panic("unknown cluster size");
                break;
        }

        m = (struct mbuf *)arg;
        refcnt = uma_find_refcnt(zone, mem);
        *refcnt = 1;
        if (m != NULL) {
                m->m_ext.ext_buf = (caddr_t)mem;
                m->m_data = m->m_ext.ext_buf;
                m->m_flags |= M_EXT;
                m->m_ext.ext_free = NULL;
                m->m_ext.ext_arg1 = NULL;
                m->m_ext.ext_arg2 = NULL;
                m->m_ext.ext_size = size;
                m->m_ext.ext_type = type;
                m->m_ext.ref_cnt = refcnt;
        }

        return (0);
}

/*
 * The Mbuf Cluster zone destructor.
 */
static void
mb_dtor_clust(void *mem, int size, void *arg)
{
#ifdef INVARIANTS
        uma_zone_t zone;

        zone = m_getzone(size);
        KASSERT(*(uma_find_refcnt(zone, mem)) <= 1,
                ("%s: refcnt incorrect %u", __func__,
                 *(uma_find_refcnt(zone, mem))) );

        trash_dtor(mem, size, arg);
#endif
}

/*
 * The Packet secondary zone's init routine, executed on the
 * object's transition from mbuf keg slab to zone cache.
 */
static int
mb_zinit_pack(void *mem, int size, int how)
{
        struct mbuf *m;

        m = (struct mbuf *)mem;         /* m is virgin. */
        if (uma_zalloc_arg(zone_clust, m, how) == NULL ||
            m->m_ext.ext_buf == NULL)
                return (ENOMEM);
        m->m_ext.ext_type = EXT_PACKET; /* Override. */
#ifdef INVARIANTS
        trash_init(m->m_ext.ext_buf, MCLBYTES, how);
#endif
        return (0);
}

/*
 * The Packet secondary zone's fini routine, executed on the
 * object's transition from zone cache to keg slab.
 */
static void
mb_zfini_pack(void *mem, int size)
{
        struct mbuf *m;

        m = (struct mbuf *)mem;
#ifdef INVARIANTS
        trash_fini(m->m_ext.ext_buf, MCLBYTES);
#endif
        uma_zfree_arg(zone_clust, m->m_ext.ext_buf, NULL);
#ifdef INVARIANTS
        trash_dtor(mem, size, NULL);
#endif
}

/*
 * The "packet" keg constructor.
 */
static int
mb_ctor_pack(void *mem, int size, void *arg, int how)
{
        struct mbuf *m;
        struct mb_args *args;
#ifdef MAC
        int error;
#endif
        int flags;
        short type;

        m = (struct mbuf *)mem;
        args = (struct mb_args *)arg;
        flags = args->flags;
        type = args->type;

#ifdef INVARIANTS
        trash_ctor(m->m_ext.ext_buf, MCLBYTES, arg, how);
#endif
        m->m_next = NULL;
        m->m_nextpkt = NULL;
        m->m_data = m->m_ext.ext_buf;
        m->m_len = 0;
        m->m_flags = (flags | M_EXT);
        m->m_type = type;

        if (flags & M_PKTHDR) {
                m->m_pkthdr.rcvif = NULL;
                m->m_pkthdr.len = 0;
                m->m_pkthdr.header = NULL;
                m->m_pkthdr.csum_flags = 0;
                m->m_pkthdr.csum_data = 0;
                m->m_pkthdr.tso_segsz = 0;
                m->m_pkthdr.ether_vtag = 0;
                m->m_pkthdr.flowid = 0;
                SLIST_INIT(&m->m_pkthdr.tags);
#ifdef MAC
                /* If the label init fails, fail the alloc */
                error = mac_mbuf_init(m, how);
                if (error)
                        return (error);
#endif
        }
        /* m_ext is already initialized. */

        return (0);
}

int
m_pkthdr_init(struct mbuf *m, int how)
{
#ifdef MAC
        int error;
#endif
        m->m_data = m->m_pktdat;
        SLIST_INIT(&m->m_pkthdr.tags);
        m->m_pkthdr.rcvif = NULL;
        m->m_pkthdr.header = NULL;
        m->m_pkthdr.len = 0;
        m->m_pkthdr.flowid = 0;
        m->m_pkthdr.csum_flags = 0;
        m->m_pkthdr.csum_data = 0;
        m->m_pkthdr.tso_segsz = 0;
        m->m_pkthdr.ether_vtag = 0;
#ifdef MAC
        /* If the label init fails, fail the alloc */
        error = mac_mbuf_init(m, how);
        if (error)
                return (error);
#endif

        return (0);
}

/*
 * This is the protocol drain routine.
 *
 * No locks should be held when this is called.  The drain routines have to
 * presently acquire some locks which raises the possibility of lock order
 * reversal.
 */
static void
mb_reclaim(void *junk)
{
        struct domain *dp;
        struct protosw *pr;

        WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK | WARN_PANIC, NULL,
            "mb_reclaim()");

        for (dp = domains; dp != NULL; dp = dp->dom_next)
                for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
                        if (pr->pr_drain != NULL)
                                (*pr->pr_drain)();
}