freebsd-dev/sys/kern/kern_mbuf.c
Mark Johnston 5475ca5aca Add an mbuf allocator for netdump.
The aim is to permit mbuf allocations after a panic without calling into
the page allocator, without imposing any runtime overhead during regular
operation of the system, and without modifying driver code. The approach
taken is to preallocate a number of mbufs and clusters, storing them
in linked lists, and using the lists to back some UMA cache zones. At
panic time, the mbuf and cluster zone pointers are overwritten with
those of the cache zones so that the mbuf allocator returns
preallocated items.

Using this scheme, drivers which cache mbuf zone pointers from
m_getzone() require special handling when implementing netdump support.

Reviewed by:	cem (earlier version), julian, sbruno
MFC after:	1 month
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D15251
2018-05-06 00:19:48 +00:00

1142 lines
30 KiB
C

/*-
* 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 <sys/param.h>
#include <sys/malloc.h>
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/protosw.h>
#include <sys/smp.h>
#include <sys/sysctl.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_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 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 */
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");
/*
* 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,
&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");
/*
* 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);
static void *mbuf_jumbo_alloc(uma_zone_t, vm_size_t, int, uint8_t *, int);
/* Ensure that MSIZE is 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);
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,
#ifdef INVARIANTS
trash_dtor, trash_init, trash_fini,
#else
NULL, NULL, NULL,
#endif
UMA_ALIGN_PTR, 0);
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,
#ifdef INVARIANTS
trash_dtor, trash_init, trash_fini,
#else
NULL, NULL, NULL,
#endif
UMA_ALIGN_PTR, 0);
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,
#ifdef INVARIANTS
trash_dtor, trash_init, trash_fini,
#else
NULL, NULL, NULL,
#endif
UMA_ALIGN_PTR, 0);
uma_zone_set_allocf(zone_jumbo9, mbuf_jumbo_alloc);
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,
#ifdef INVARIANTS
trash_dtor, trash_init, trash_fini,
#else
NULL, NULL, NULL,
#endif
UMA_ALIGN_PTR, 0);
uma_zone_set_allocf(zone_jumbo16, mbuf_jumbo_alloc);
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);
}
SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbuf_init, NULL);
#ifdef NETDUMP
/*
* netdump makes use of a pre-allocated pool of mbufs and clusters. When
* netdump 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 nd_mbufq =
{ STAILQ_HEAD_INITIALIZER(nd_mbufq.mq_head), 0, INT_MAX };
static struct mbufq nd_clustq =
{ STAILQ_HEAD_INITIALIZER(nd_clustq.mq_head), 0, INT_MAX };
static int nd_clsize;
static uma_zone_t nd_zone_mbuf;
static uma_zone_t nd_zone_clust;
static uma_zone_t nd_zone_pack;
static int
nd_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 == &nd_mbufq ? MSIZE : nd_clsize, flags);
store[i] = m;
}
return (i);
}
static void
nd_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
nd_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(nd_zone_clust, M_NOWAIT);
if (clust == NULL) {
m_free(m);
break;
}
mb_ctor_clust(clust, nd_clsize, m, 0);
store[i] = m;
}
return (i);
}
static void
nd_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(nd_zone_clust, clust);
uma_zfree(nd_zone_mbuf, m);
}
}
/*
* Free the pre-allocated mbufs and clusters reserved for netdump, and destroy
* the corresponding UMA cache zones.
*/
void
netdump_mbuf_drain(void)
{
struct mbuf *m;
void *item;
if (nd_zone_mbuf != NULL) {
uma_zdestroy(nd_zone_mbuf);
nd_zone_mbuf = NULL;
}
if (nd_zone_clust != NULL) {
uma_zdestroy(nd_zone_clust);
nd_zone_clust = NULL;
}
if (nd_zone_pack != NULL) {
uma_zdestroy(nd_zone_pack);
nd_zone_pack = NULL;
}
while ((m = mbufq_dequeue(&nd_mbufq)) != NULL)
m_free(m);
while ((item = mbufq_dequeue(&nd_clustq)) != NULL)
uma_zfree(m_getzone(nd_clsize), item);
}
/*
* Callback invoked immediately prior to starting a netdump.
*/
void
netdump_mbuf_dump(void)
{
/*
* 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 netdump-enabled interface changes.
*/
printf("netdump: overwriting mbuf zone pointers\n");
zone_mbuf = nd_zone_mbuf;
zone_clust = nd_zone_clust;
zone_pack = nd_zone_pack;
zone_jumbop = nd_zone_clust;
zone_jumbo9 = nd_zone_clust;
zone_jumbo16 = nd_zone_clust;
}
/*
* Reinitialize the netdump mbuf+cluster pool and cache zones.
*/
void
netdump_mbuf_reinit(int nmbuf, int nclust, int clsize)
{
struct mbuf *m;
void *item;
netdump_mbuf_drain();
nd_clsize = clsize;
nd_zone_mbuf = uma_zcache_create("netdump_" MBUF_MEM_NAME,
MSIZE, mb_ctor_mbuf, mb_dtor_mbuf,
#ifdef INVARIANTS
trash_init, trash_fini,
#else
NULL, NULL,
#endif
nd_buf_import, nd_buf_release,
&nd_mbufq, UMA_ZONE_NOBUCKET);
nd_zone_clust = uma_zcache_create("netdump_" MBUF_CLUSTER_MEM_NAME,
clsize, mb_ctor_clust,
#ifdef INVARIANTS
trash_dtor, trash_init, trash_fini,
#else
NULL, NULL, NULL,
#endif
nd_buf_import, nd_buf_release,
&nd_clustq, UMA_ZONE_NOBUCKET);
nd_zone_pack = uma_zcache_create("netdump_" MBUF_PACKET_MEM_NAME,
MCLBYTES, mb_ctor_pack, mb_dtor_pack, NULL, NULL,
nd_pack_import, nd_pack_release,
NULL, UMA_ZONE_NOBUCKET);
while (nmbuf-- > 0) {
m = m_get(MT_DATA, M_WAITOK);
uma_zfree(nd_zone_mbuf, m);
}
while (nclust-- > 0) {
item = uma_zalloc(m_getzone(nd_clsize), M_WAITOK);
uma_zfree(nd_zone_clust, item);
}
}
#endif /* NETDUMP */
/*
* 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, vm_size_t bytes, int domain, uint8_t *flags,
int wait)
{
/* Inform UMA that this allocator uses kernel_map/object. */
*flags = UMA_SLAB_KERNEL;
return ((void *)kmem_alloc_contig_domain(domain, 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;
int error;
int flags;
short type;
#ifdef INVARIANTS
trash_ctor(mem, size, arg, how);
#endif
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 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;
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);
#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__));
#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;
#ifdef INVARIANTS
trash_ctor(mem, size, arg, how);
#endif
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 domain *dp;
struct protosw *pr;
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK | WARN_PANIC, NULL, __func__);
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)();
}
/*
* Clean up after mbufs with M_EXT storage attached to them if the
* reference count hits 1.
*/
void
mb_free_ext(struct mbuf *m)
{
volatile u_int *refcnt;
struct mbuf *mref;
int freembuf;
KASSERT(m->m_flags & M_EXT, ("%s: M_EXT not set on %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);
}
/*
* Check if the header is embedded in the cluster. It is
* important that we can't touch any of the mbuf fields
* after we have freed the external storage, since mbuf
* could have been embedded in it. For now, the mbufs
* embedded into the cluster are always of type EXT_EXTREF,
* and for this type we won't free the mref.
*/
if (m->m_flags & M_NOFREE) {
freembuf = 0;
KASSERT(m->m_ext.ext_type == EXT_EXTREF,
("%s: no-free mbuf %p has wrong type", __func__, m));
} else
freembuf = 1;
/* Free attached storage if this mbuf is the only reference to it. */
if (*refcnt == 1 || atomic_fetchadd_int(refcnt, -1) == 1) {
switch (m->m_ext.ext_type) {
case EXT_PACKET:
/* The packet zone is special. */
if (*refcnt == 0)
*refcnt = 1;
uma_zfree(zone_pack, mref);
break;
case EXT_CLUSTER:
uma_zfree(zone_clust, m->m_ext.ext_buf);
uma_zfree(zone_mbuf, mref);
break;
case EXT_JUMBOP:
uma_zfree(zone_jumbop, m->m_ext.ext_buf);
uma_zfree(zone_mbuf, mref);
break;
case EXT_JUMBO9:
uma_zfree(zone_jumbo9, m->m_ext.ext_buf);
uma_zfree(zone_mbuf, mref);
break;
case EXT_JUMBO16:
uma_zfree(zone_jumbo16, m->m_ext.ext_buf);
uma_zfree(zone_mbuf, mref);
break;
case EXT_SFBUF:
case EXT_NET_DRV:
case EXT_MOD_TYPE:
case EXT_DISPOSABLE:
KASSERT(mref->m_ext.ext_free != NULL,
("%s: ext_free not set", __func__));
mref->m_ext.ext_free(mref);
uma_zfree(zone_mbuf, mref);
break;
case EXT_EXTREF:
KASSERT(m->m_ext.ext_free != NULL,
("%s: ext_free not set", __func__));
m->m_ext.ext_free(m);
break;
default:
KASSERT(m->m_ext.ext_type == 0,
("%s: unknown ext_type", __func__));
}
}
if (freembuf && m != mref)
uma_zfree(zone_mbuf, m);
}
/*
* Official mbuf(9) allocation KPI for stack and drivers:
*
* m_get() - a single mbuf without any attachments, sys/mbuf.h.
* m_gethdr() - a single mbuf initialized as M_PKTHDR, sys/mbuf.h.
* m_getcl() - an mbuf + 2k cluster, sys/mbuf.h.
* m_clget() - attach cluster to already allocated mbuf.
* m_cljget() - attach jumbo cluster to already allocated mbuf.
* m_get2() - allocate minimum mbuf that would fit size argument.
* m_getm2() - allocate a chain of mbufs/clusters.
* m_extadd() - attach external cluster to mbuf.
*
* m_free() - free single mbuf with its tags and ext, sys/mbuf.h.
* m_freem() - free chain of mbufs.
*/
int
m_clget(struct mbuf *m, int how)
{
KASSERT((m->m_flags & M_EXT) == 0, ("%s: mbuf %p has M_EXT",
__func__, m));
m->m_ext.ext_buf = (char *)NULL;
uma_zalloc_arg(zone_clust, m, how);
/*
* On a cluster allocation failure, drain the packet zone and retry,
* we might be able to loosen a few clusters up on the drain.
*/
if ((how & M_NOWAIT) && (m->m_ext.ext_buf == NULL)) {
zone_drain(zone_pack);
uma_zalloc_arg(zone_clust, m, how);
}
MBUF_PROBE2(m__clget, m, how);
return (m->m_flags & M_EXT);
}
/*
* m_cljget() is different from m_clget() as it can allocate clusters without
* attaching them to an mbuf. In that case the return value is the pointer
* to the cluster of the requested size. If an mbuf was specified, it gets
* the cluster attached to it and the return value can be safely ignored.
* For size it takes MCLBYTES, MJUMPAGESIZE, MJUM9BYTES, MJUM16BYTES.
*/
void *
m_cljget(struct mbuf *m, int how, int size)
{
uma_zone_t zone;
void *retval;
if (m != NULL) {
KASSERT((m->m_flags & M_EXT) == 0, ("%s: mbuf %p has M_EXT",
__func__, m));
m->m_ext.ext_buf = NULL;
}
zone = m_getzone(size);
retval = uma_zalloc_arg(zone, m, how);
MBUF_PROBE4(m__cljget, m, how, size, retval);
return (retval);
}
/*
* m_get2() allocates minimum mbuf that would fit "size" argument.
*/
struct mbuf *
m_get2(int size, int how, short type, int flags)
{
struct mb_args args;
struct mbuf *m, *n;
args.flags = flags;
args.type = type;
if (size <= MHLEN || (size <= MLEN && (flags & M_PKTHDR) == 0))
return (uma_zalloc_arg(zone_mbuf, &args, how));
if (size <= MCLBYTES)
return (uma_zalloc_arg(zone_pack, &args, how));
if (size > MJUMPAGESIZE)
return (NULL);
m = uma_zalloc_arg(zone_mbuf, &args, how);
if (m == NULL)
return (NULL);
n = uma_zalloc_arg(zone_jumbop, m, how);
if (n == NULL) {
uma_zfree(zone_mbuf, m);
return (NULL);
}
return (m);
}
/*
* m_getjcl() returns an mbuf with a cluster of the specified size attached.
* For size it takes MCLBYTES, MJUMPAGESIZE, MJUM9BYTES, MJUM16BYTES.
*/
struct mbuf *
m_getjcl(int how, short type, int flags, int size)
{
struct mb_args args;
struct mbuf *m, *n;
uma_zone_t zone;
if (size == MCLBYTES)
return m_getcl(how, type, flags);
args.flags = flags;
args.type = type;
m = uma_zalloc_arg(zone_mbuf, &args, how);
if (m == NULL)
return (NULL);
zone = m_getzone(size);
n = uma_zalloc_arg(zone, m, how);
if (n == NULL) {
uma_zfree(zone_mbuf, m);
return (NULL);
}
return (m);
}
/*
* Allocate a given length worth of mbufs and/or clusters (whatever fits
* best) and return a pointer to the top of the allocated chain. If an
* existing mbuf chain is provided, then we will append the new chain
* to the existing one but still return the top of the newly allocated
* chain.
*/
struct mbuf *
m_getm2(struct mbuf *m, int len, int how, short type, int flags)
{
struct mbuf *mb, *nm = NULL, *mtail = NULL;
KASSERT(len >= 0, ("%s: len is < 0", __func__));
/* Validate flags. */
flags &= (M_PKTHDR | M_EOR);
/* Packet header mbuf must be first in chain. */
if ((flags & M_PKTHDR) && m != NULL)
flags &= ~M_PKTHDR;
/* Loop and append maximum sized mbufs to the chain tail. */
while (len > 0) {
if (len > MCLBYTES)
mb = m_getjcl(how, type, (flags & M_PKTHDR),
MJUMPAGESIZE);
else if (len >= MINCLSIZE)
mb = m_getcl(how, type, (flags & M_PKTHDR));
else if (flags & M_PKTHDR)
mb = m_gethdr(how, type);
else
mb = m_get(how, type);
/* Fail the whole operation if one mbuf can't be allocated. */
if (mb == NULL) {
if (nm != NULL)
m_freem(nm);
return (NULL);
}
/* Book keeping. */
len -= M_SIZE(mb);
if (mtail != NULL)
mtail->m_next = mb;
else
nm = mb;
mtail = mb;
flags &= ~M_PKTHDR; /* Only valid on the first mbuf. */
}
if (flags & M_EOR)
mtail->m_flags |= M_EOR; /* Only valid on the last mbuf. */
/* If mbuf was supplied, append new chain to the end of it. */
if (m != NULL) {
for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next)
;
mtail->m_next = nm;
mtail->m_flags &= ~M_EOR;
} else
m = nm;
return (m);
}
/*-
* Configure a provided mbuf to refer to the provided external storage
* buffer and setup a reference count for said buffer.
*
* Arguments:
* mb The existing mbuf to which to attach the provided buffer.
* buf The address of the provided external storage buffer.
* size The size of the provided buffer.
* freef A pointer to a routine that is responsible for freeing the
* provided external storage buffer.
* args A pointer to an argument structure (of any type) to be passed
* to the provided freef routine (may be NULL).
* flags Any other flags to be passed to the provided mbuf.
* type The type that the external storage buffer should be
* labeled with.
*
* Returns:
* Nothing.
*/
void
m_extadd(struct mbuf *mb, char *buf, u_int size, m_ext_free_t freef,
void *arg1, void *arg2, int flags, int type)
{
KASSERT(type != EXT_CLUSTER, ("%s: EXT_CLUSTER not allowed", __func__));
mb->m_flags |= (M_EXT | flags);
mb->m_ext.ext_buf = buf;
mb->m_data = mb->m_ext.ext_buf;
mb->m_ext.ext_size = size;
mb->m_ext.ext_free = freef;
mb->m_ext.ext_arg1 = arg1;
mb->m_ext.ext_arg2 = arg2;
mb->m_ext.ext_type = type;
if (type != EXT_EXTREF) {
mb->m_ext.ext_count = 1;
mb->m_ext.ext_flags = EXT_FLAG_EMBREF;
} else
mb->m_ext.ext_flags = 0;
}
/*
* Free an entire chain of mbufs and associated external buffers, if
* applicable.
*/
void
m_freem(struct mbuf *mb)
{
MBUF_PROBE1(m__freem, mb);
while (mb != NULL)
mb = m_free(mb);
}