/
kern_mbuf.c
1659 lines (1473 loc) · 43.2 KB
/
kern_mbuf.c
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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* 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 "opt_kern_tls.h"
#include <sys/param.h>
#include <sys/conf.h>
#include <sys/domainset.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/ktls.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/protosw.h>
#include <sys/refcount.h>
#include <sys/sf_buf.h>
#include <sys/smp.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_var.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_map.h>
#include <vm/uma.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 Primary Zone called the Mbuf
* Zone.
*
* Additionally, FreeBSD provides a Packet Zone, which it
* configures as a Secondary Zone to the Mbuf Primary Zone,
* thus sharing backend Slab kegs with the Mbuf Primary 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 Primary 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 Primary 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 decommissioned 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 */
bool mb_use_ext_pgs; /* use M_EXTPG mbufs for sendfile & TLS */
SYSCTL_BOOL(_kern_ipc, OID_AUTO, mb_use_ext_pgs, CTLFLAG_RWTUN,
&mb_use_ext_pgs, 0,
"Use unmapped mbufs for sendfile(2) and TLS offload");
static quad_t maxmbufmem; /* overall real memory limit for all mbufs */
SYSCTL_QUAD(_kern_ipc, OID_AUTO, maxmbufmem, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &maxmbufmem, 0,
"Maximum real memory allocatable to various mbuf types");
static counter_u64_t snd_tag_count;
SYSCTL_COUNTER_U64(_kern_ipc, OID_AUTO, num_snd_tags, CTLFLAG_RW,
&snd_tag_count, "# of active mbuf send tags");
/*
* 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_kmem_size);
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 | CTLFLAG_NEEDGIANT, &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 | CTLFLAG_NEEDGIANT, &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 | CTLFLAG_NEEDGIANT, &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 | CTLFLAG_NEEDGIANT, &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 | CTLFLAG_NEEDGIANT,
&nmbufs, 0, sysctl_nmbufs, "IU",
"Maximum number of mbufs allowed");
/*
* 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;
/*
* 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_pack(void *, int, void *);
static int mb_zinit_pack(void *, int, int);
static void mb_zfini_pack(void *, int);
static void mb_reclaim(uma_zone_t, int);
/* Ensure that MSIZE is a power of 2. */
CTASSERT((((MSIZE - 1) ^ MSIZE) + 1) >> 1 == MSIZE);
_Static_assert(sizeof(struct mbuf) <= MSIZE,
"size of mbuf exceeds 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, NULL, NULL,
MSIZE - 1, UMA_ZONE_CONTIG | UMA_ZONE_MAXBUCKET);
if (nmbufs > 0)
nmbufs = uma_zone_set_max(zone_mbuf, nmbufs);
uma_zone_set_warning(zone_mbuf, "kern.ipc.nmbufs limit reached");
uma_zone_set_maxaction(zone_mbuf, mb_reclaim);
zone_clust = uma_zcreate(MBUF_CLUSTER_MEM_NAME, MCLBYTES,
mb_ctor_clust, NULL, NULL, NULL,
UMA_ALIGN_PTR, UMA_ZONE_CONTIG);
if (nmbclusters > 0)
nmbclusters = uma_zone_set_max(zone_clust, nmbclusters);
uma_zone_set_warning(zone_clust, "kern.ipc.nmbclusters limit reached");
uma_zone_set_maxaction(zone_clust, mb_reclaim);
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, NULL, NULL, NULL,
UMA_ALIGN_PTR, UMA_ZONE_CONTIG);
if (nmbjumbop > 0)
nmbjumbop = uma_zone_set_max(zone_jumbop, nmbjumbop);
uma_zone_set_warning(zone_jumbop, "kern.ipc.nmbjumbop limit reached");
uma_zone_set_maxaction(zone_jumbop, mb_reclaim);
zone_jumbo9 = uma_zcreate(MBUF_JUMBO9_MEM_NAME, MJUM9BYTES,
mb_ctor_clust, NULL, NULL, NULL,
UMA_ALIGN_PTR, UMA_ZONE_CONTIG);
if (nmbjumbo9 > 0)
nmbjumbo9 = uma_zone_set_max(zone_jumbo9, nmbjumbo9);
uma_zone_set_warning(zone_jumbo9, "kern.ipc.nmbjumbo9 limit reached");
uma_zone_set_maxaction(zone_jumbo9, mb_reclaim);
zone_jumbo16 = uma_zcreate(MBUF_JUMBO16_MEM_NAME, MJUM16BYTES,
mb_ctor_clust, NULL, NULL, NULL,
UMA_ALIGN_PTR, UMA_ZONE_CONTIG);
if (nmbjumbo16 > 0)
nmbjumbo16 = uma_zone_set_max(zone_jumbo16, nmbjumbo16);
uma_zone_set_warning(zone_jumbo16, "kern.ipc.nmbjumbo16 limit reached");
uma_zone_set_maxaction(zone_jumbo16, mb_reclaim);
/*
* 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);
snd_tag_count = counter_u64_alloc(M_WAITOK);
}
SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbuf_init, NULL);
#ifdef DEBUGNET
/*
* debugnet makes use of a pre-allocated pool of mbufs and clusters. When
* debugnet is configured, we initialize a set of UMA cache zones which return
* items from this pool. At panic-time, the regular UMA zone pointers are
* overwritten with those of the cache zones so that drivers may allocate and
* free mbufs and clusters without attempting to allocate physical memory.
*
* We keep mbufs and clusters in a pair of mbuf queues. In particular, for
* the purpose of caching clusters, we treat them as mbufs.
*/
static struct mbufq dn_mbufq =
{ STAILQ_HEAD_INITIALIZER(dn_mbufq.mq_head), 0, INT_MAX };
static struct mbufq dn_clustq =
{ STAILQ_HEAD_INITIALIZER(dn_clustq.mq_head), 0, INT_MAX };
static int dn_clsize;
static uma_zone_t dn_zone_mbuf;
static uma_zone_t dn_zone_clust;
static uma_zone_t dn_zone_pack;
static struct debugnet_saved_zones {
uma_zone_t dsz_mbuf;
uma_zone_t dsz_clust;
uma_zone_t dsz_pack;
uma_zone_t dsz_jumbop;
uma_zone_t dsz_jumbo9;
uma_zone_t dsz_jumbo16;
bool dsz_debugnet_zones_enabled;
} dn_saved_zones;
static int
dn_buf_import(void *arg, void **store, int count, int domain __unused,
int flags)
{
struct mbufq *q;
struct mbuf *m;
int i;
q = arg;
for (i = 0; i < count; i++) {
m = mbufq_dequeue(q);
if (m == NULL)
break;
trash_init(m, q == &dn_mbufq ? MSIZE : dn_clsize, flags);
store[i] = m;
}
KASSERT((flags & M_WAITOK) == 0 || i == count,
("%s: ran out of pre-allocated mbufs", __func__));
return (i);
}
static void
dn_buf_release(void *arg, void **store, int count)
{
struct mbufq *q;
struct mbuf *m;
int i;
q = arg;
for (i = 0; i < count; i++) {
m = store[i];
(void)mbufq_enqueue(q, m);
}
}
static int
dn_pack_import(void *arg __unused, void **store, int count, int domain __unused,
int flags __unused)
{
struct mbuf *m;
void *clust;
int i;
for (i = 0; i < count; i++) {
m = m_get(MT_DATA, M_NOWAIT);
if (m == NULL)
break;
clust = uma_zalloc(dn_zone_clust, M_NOWAIT);
if (clust == NULL) {
m_free(m);
break;
}
mb_ctor_clust(clust, dn_clsize, m, 0);
store[i] = m;
}
KASSERT((flags & M_WAITOK) == 0 || i == count,
("%s: ran out of pre-allocated mbufs", __func__));
return (i);
}
static void
dn_pack_release(void *arg __unused, void **store, int count)
{
struct mbuf *m;
void *clust;
int i;
for (i = 0; i < count; i++) {
m = store[i];
clust = m->m_ext.ext_buf;
uma_zfree(dn_zone_clust, clust);
uma_zfree(dn_zone_mbuf, m);
}
}
/*
* Free the pre-allocated mbufs and clusters reserved for debugnet, and destroy
* the corresponding UMA cache zones.
*/
void
debugnet_mbuf_drain(void)
{
struct mbuf *m;
void *item;
if (dn_zone_mbuf != NULL) {
uma_zdestroy(dn_zone_mbuf);
dn_zone_mbuf = NULL;
}
if (dn_zone_clust != NULL) {
uma_zdestroy(dn_zone_clust);
dn_zone_clust = NULL;
}
if (dn_zone_pack != NULL) {
uma_zdestroy(dn_zone_pack);
dn_zone_pack = NULL;
}
while ((m = mbufq_dequeue(&dn_mbufq)) != NULL)
m_free(m);
while ((item = mbufq_dequeue(&dn_clustq)) != NULL)
uma_zfree(m_getzone(dn_clsize), item);
}
/*
* Callback invoked immediately prior to starting a debugnet connection.
*/
void
debugnet_mbuf_start(void)
{
MPASS(!dn_saved_zones.dsz_debugnet_zones_enabled);
/* Save the old zone pointers to restore when debugnet is closed. */
dn_saved_zones = (struct debugnet_saved_zones) {
.dsz_debugnet_zones_enabled = true,
.dsz_mbuf = zone_mbuf,
.dsz_clust = zone_clust,
.dsz_pack = zone_pack,
.dsz_jumbop = zone_jumbop,
.dsz_jumbo9 = zone_jumbo9,
.dsz_jumbo16 = zone_jumbo16,
};
/*
* All cluster zones return buffers of the size requested by the
* drivers. It's up to the driver to reinitialize the zones if the
* MTU of a debugnet-enabled interface changes.
*/
printf("debugnet: overwriting mbuf zone pointers\n");
zone_mbuf = dn_zone_mbuf;
zone_clust = dn_zone_clust;
zone_pack = dn_zone_pack;
zone_jumbop = dn_zone_clust;
zone_jumbo9 = dn_zone_clust;
zone_jumbo16 = dn_zone_clust;
}
/*
* Callback invoked when a debugnet connection is closed/finished.
*/
void
debugnet_mbuf_finish(void)
{
MPASS(dn_saved_zones.dsz_debugnet_zones_enabled);
printf("debugnet: restoring mbuf zone pointers\n");
zone_mbuf = dn_saved_zones.dsz_mbuf;
zone_clust = dn_saved_zones.dsz_clust;
zone_pack = dn_saved_zones.dsz_pack;
zone_jumbop = dn_saved_zones.dsz_jumbop;
zone_jumbo9 = dn_saved_zones.dsz_jumbo9;
zone_jumbo16 = dn_saved_zones.dsz_jumbo16;
memset(&dn_saved_zones, 0, sizeof(dn_saved_zones));
}
/*
* Reinitialize the debugnet mbuf+cluster pool and cache zones.
*/
void
debugnet_mbuf_reinit(int nmbuf, int nclust, int clsize)
{
struct mbuf *m;
void *item;
debugnet_mbuf_drain();
dn_clsize = clsize;
dn_zone_mbuf = uma_zcache_create("debugnet_" MBUF_MEM_NAME,
MSIZE, mb_ctor_mbuf, mb_dtor_mbuf, NULL, NULL,
dn_buf_import, dn_buf_release,
&dn_mbufq, UMA_ZONE_NOBUCKET);
dn_zone_clust = uma_zcache_create("debugnet_" MBUF_CLUSTER_MEM_NAME,
clsize, mb_ctor_clust, NULL, NULL, NULL,
dn_buf_import, dn_buf_release,
&dn_clustq, UMA_ZONE_NOBUCKET);
dn_zone_pack = uma_zcache_create("debugnet_" MBUF_PACKET_MEM_NAME,
MCLBYTES, mb_ctor_pack, mb_dtor_pack, NULL, NULL,
dn_pack_import, dn_pack_release,
NULL, UMA_ZONE_NOBUCKET);
while (nmbuf-- > 0) {
m = m_get(MT_DATA, M_WAITOK);
uma_zfree(dn_zone_mbuf, m);
}
while (nclust-- > 0) {
item = uma_zalloc(m_getzone(dn_clsize), M_WAITOK);
uma_zfree(dn_zone_clust, item);
}
}
#endif /* DEBUGNET */
/*
* Constructor for Mbuf primary 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;
int error;
int flags;
short type;
args = (struct mb_args *)arg;
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 = (struct mbuf *)mem;
flags = args->flags;
MPASS((flags & M_NOFREE) == 0);
error = m_init(m, how, type, flags);
return (error);
}
/*
* The Mbuf primary 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;
KASSERT((m->m_flags & M_NOFREE) == 0, ("%s: M_NOFREE set", __func__));
if (!(flags & MB_DTOR_SKIP) && (m->m_flags & M_PKTHDR) && !SLIST_EMPTY(&m->m_pkthdr.tags))
m_tag_delete_chain(m, NULL);
}
/*
* 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__));
#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(zone_clust))
uma_zone_reclaim(zone_pack, UMA_RECLAIM_DRAIN);
}
/*
* 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;
m = (struct mbuf *)arg;
if (m != NULL) {
m->m_ext.ext_buf = (char *)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 = m_gettype(size);
m->m_ext.ext_flags = EXT_FLAG_EMBREF;
m->m_ext.ext_count = 1;
}
return (0);
}
/*
* 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;
int error, flags;
short type;
m = (struct mbuf *)mem;
args = (struct mb_args *)arg;
flags = args->flags;
type = args->type;
MPASS((flags & M_NOFREE) == 0);
#ifdef INVARIANTS
trash_ctor(m->m_ext.ext_buf, MCLBYTES, arg, how);
#endif
error = m_init(m, how, type, flags);
/* m_ext is already initialized. */
m->m_data = m->m_ext.ext_buf;
m->m_flags = (flags | M_EXT);
return (error);
}
/*
* This is the protocol drain routine. Called by UMA whenever any of the
* mbuf zones is closed to its limit.
*
* 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(uma_zone_t zone __unused, int pending __unused)
{
struct epoch_tracker et;
struct domain *dp;
struct protosw *pr;
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK | WARN_PANIC, NULL, __func__);
NET_EPOCH_ENTER(et);
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)();
NET_EPOCH_EXIT(et);
}
/*
* Free "count" units of I/O from an mbuf chain. They could be held
* in M_EXTPG or just as a normal mbuf. This code is intended to be
* called in an error path (I/O error, closed connection, etc).
*/
void
mb_free_notready(struct mbuf *m, int count)
{
int i;
for (i = 0; i < count && m != NULL; i++) {
if ((m->m_flags & M_EXTPG) != 0) {
m->m_epg_nrdy--;
if (m->m_epg_nrdy != 0)
continue;
}
m = m_free(m);
}
KASSERT(i == count, ("Removed only %d items from %p", i, m));
}
/*
* Compress an unmapped mbuf into a simple mbuf when it holds a small
* amount of data. This is used as a DOS defense to avoid having
* small packets tie up wired pages, an ext_pgs structure, and an
* mbuf. Since this converts the existing mbuf in place, it can only
* be used if there are no other references to 'm'.
*/
int
mb_unmapped_compress(struct mbuf *m)
{
volatile u_int *refcnt;
char buf[MLEN];
/*
* Assert that 'm' does not have a packet header. If 'm' had
* a packet header, it would only be able to hold MHLEN bytes
* and m_data would have to be initialized differently.
*/
KASSERT((m->m_flags & M_PKTHDR) == 0 && (m->m_flags & M_EXTPG),
("%s: m %p !M_EXTPG or M_PKTHDR", __func__, m));
KASSERT(m->m_len <= MLEN, ("m_len too large %p", m));
if (m->m_ext.ext_flags & EXT_FLAG_EMBREF) {
refcnt = &m->m_ext.ext_count;
} else {
KASSERT(m->m_ext.ext_cnt != NULL,
("%s: no refcounting pointer on %p", __func__, m));
refcnt = m->m_ext.ext_cnt;
}
if (*refcnt != 1)
return (EBUSY);
m_copydata(m, 0, m->m_len, buf);
/* Free the backing pages. */
m->m_ext.ext_free(m);
/* Turn 'm' into a "normal" mbuf. */
m->m_flags &= ~(M_EXT | M_RDONLY | M_EXTPG);
m->m_data = m->m_dat;
/* Copy data back into m. */
bcopy(buf, mtod(m, char *), m->m_len);
return (0);
}
/*
* These next few routines are used to permit downgrading an unmapped
* mbuf to a chain of mapped mbufs. This is used when an interface
* doesn't supported unmapped mbufs or if checksums need to be
* computed in software.
*
* Each unmapped mbuf is converted to a chain of mbufs. First, any
* TLS header data is stored in a regular mbuf. Second, each page of
* unmapped data is stored in an mbuf with an EXT_SFBUF external
* cluster. These mbufs use an sf_buf to provide a valid KVA for the
* associated physical page. They also hold a reference on the
* original M_EXTPG mbuf to ensure the physical page doesn't go away.
* Finally, any TLS trailer data is stored in a regular mbuf.
*
* mb_unmapped_free_mext() is the ext_free handler for the EXT_SFBUF
* mbufs. It frees the associated sf_buf and releases its reference
* on the original M_EXTPG mbuf.
*
* _mb_unmapped_to_ext() is a helper function that converts a single
* unmapped mbuf into a chain of mbufs.
*
* mb_unmapped_to_ext() is the public function that walks an mbuf
* chain converting any unmapped mbufs to mapped mbufs. It returns
* the new chain of unmapped mbufs on success. On failure it frees
* the original mbuf chain and returns NULL.
*/
static void
mb_unmapped_free_mext(struct mbuf *m)
{
struct sf_buf *sf;
struct mbuf *old_m;
sf = m->m_ext.ext_arg1;
sf_buf_free(sf);
/* Drop the reference on the backing M_EXTPG mbuf. */
old_m = m->m_ext.ext_arg2;
mb_free_extpg(old_m);
}
static struct mbuf *
_mb_unmapped_to_ext(struct mbuf *m)
{
struct mbuf *m_new, *top, *prev, *mref;
struct sf_buf *sf;
vm_page_t pg;
int i, len, off, pglen, pgoff, seglen, segoff;
volatile u_int *refcnt;
u_int ref_inc = 0;
M_ASSERTEXTPG(m);
len = m->m_len;
KASSERT(m->m_epg_tls == NULL, ("%s: can't convert TLS mbuf %p",
__func__, m));
/* See if this is the mbuf that holds the embedded refcount. */
if (m->m_ext.ext_flags & EXT_FLAG_EMBREF) {
refcnt = &m->m_ext.ext_count;
mref = m;
} else {
KASSERT(m->m_ext.ext_cnt != NULL,
("%s: no refcounting pointer on %p", __func__, m));
refcnt = m->m_ext.ext_cnt;
mref = __containerof(refcnt, struct mbuf, m_ext.ext_count);
}
/* Skip over any data removed from the front. */
off = mtod(m, vm_offset_t);
top = NULL;
if (m->m_epg_hdrlen != 0) {
if (off >= m->m_epg_hdrlen) {
off -= m->m_epg_hdrlen;
} else {
seglen = m->m_epg_hdrlen - off;
segoff = off;
seglen = min(seglen, len);
off = 0;
len -= seglen;
m_new = m_get(M_NOWAIT, MT_DATA);
if (m_new == NULL)
goto fail;
m_new->m_len = seglen;
prev = top = m_new;
memcpy(mtod(m_new, void *), &m->m_epg_hdr[segoff],
seglen);
}
}
pgoff = m->m_epg_1st_off;
for (i = 0; i < m->m_epg_npgs && len > 0; i++) {
pglen = m_epg_pagelen(m, i, pgoff);
if (off >= pglen) {
off -= pglen;
pgoff = 0;
continue;
}
seglen = pglen - off;
segoff = pgoff + off;
off = 0;
seglen = min(seglen, len);
len -= seglen;
pg = PHYS_TO_VM_PAGE(m->m_epg_pa[i]);
m_new = m_get(M_NOWAIT, MT_DATA);
if (m_new == NULL)
goto fail;
if (top == NULL) {
top = prev = m_new;