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freebsd-dev/sys/kern/kern_mbuf.c
Alan Cox 3153e878dd Add support to the virtual memory system for configuring machine- 
dependent memory attributes:

Rename vm_cache_mode_t to vm_memattr_t.  The new name reflects the
fact that there are machine-dependent memory attributes that have
nothing to do with controlling the cache's behavior.

Introduce vm_object_set_memattr() for setting the default memory
attributes that will be given to an object's pages.

Introduce and use pmap_page_{get,set}_memattr() for getting and
setting a page's machine-dependent memory attributes.  Add full
support for these functions on amd64 and i386 and stubs for them on
the other architectures.  The function pmap_page_set_memattr() is also
responsible for any other machine-dependent aspects of changing a
page's memory attributes, such as flushing the cache or updating the
direct map.  The uses include kmem_alloc_contig(), vm_page_alloc(),
and the device pager:

  kmem_alloc_contig() can now be used to allocate kernel memory with
  non-default memory attributes on amd64 and i386.

  vm_page_alloc() and the device pager will set the memory attributes
  for the real or fictitious page according to the object's default
  memory attributes.

Update the various pmap functions on amd64 and i386 that map pages to
incorporate each page's memory attributes in the mapping.

Notes: (1) Inherent to this design are safety features that prevent
the specification of inconsistent memory attributes by different
mappings on amd64 and i386.  In addition, the device pager provides a
warning when a device driver creates a fictitious page with memory
attributes that are inconsistent with the real page that the
fictitious page is an alias for. (2) Storing the machine-dependent
memory attributes for amd64 and i386 as a dedicated "int" in "struct
md_page" represents a compromise between space efficiency and the ease
of MFCing these changes to RELENG_7.

In collaboration with: jhb

Approved by:	re (kib)
2009-07-12 23:31:20 +00:00

695 lines
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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("$FreeBSD$");
#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/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 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;
/*
* tunable_mbinit() has to be run before init_maxsockets() thus
* the SYSINIT order below is SI_ORDER_MIDDLE while init_maxsockets()
* runs at SI_ORDER_ANY.
*/
static void
tunable_mbinit(void *dummy)
{
TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters);
/* This has to be done before VM init. */
if (nmbclusters == 0)
nmbclusters = 1024 + maxusers * 64;
nmbjumbop = nmbclusters / 2;
nmbjumbo9 = nmbjumbop / 2;
nmbjumbo16 = nmbjumbo9 / 2;
}
SYSINIT(tunable_mbinit, SI_SUB_TUNABLES, 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) {
if (newnmbclusters > nmbclusters) {
nmbclusters = newnmbclusters;
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) {
if (newnmbjumbop> nmbjumbop) {
nmbjumbop = newnmbjumbop;
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) {
if (newnmbjumbo9> nmbjumbo9) {
nmbjumbo9 = newnmbjumbo9;
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) {
if (newnmbjumbo16> nmbjumbo16) {
nmbjumbo16 = newnmbjumbo16;
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");
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_init(void *);
static void *mbuf_jumbo_alloc(uma_zone_t, int, u_int8_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.
*/
SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbuf_init, NULL);
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);
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)
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)
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);
if (nmbjumbo9 > 0)
uma_zone_set_max(zone_jumbo9, nmbjumbo9);
uma_zone_set_allocf(zone_jumbo9, mbuf_jumbo_alloc);
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);
if (nmbjumbo16 > 0)
uma_zone_set_max(zone_jumbo16, nmbjumbo16);
uma_zone_set_allocf(zone_jumbo16, mbuf_jumbo_alloc);
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;
}
/*
* 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, u_int8_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)();
}
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