xref: /freebsd/sys/kern/kern_mbuf.c (revision 01ded8b942effbbb4d9225c4227f264e499e9698)
1 /*-
2  * Copyright (c) 2004, 2005,
3  * 	Bosko Milekic <bmilekic@FreeBSD.org>.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice unmodified, this list of conditions and the following
10  *    disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 
31 #include "opt_param.h"
32 
33 #include <sys/param.h>
34 #include <sys/malloc.h>
35 #include <sys/systm.h>
36 #include <sys/mbuf.h>
37 #include <sys/domain.h>
38 #include <sys/eventhandler.h>
39 #include <sys/kernel.h>
40 #include <sys/protosw.h>
41 #include <sys/smp.h>
42 #include <sys/sysctl.h>
43 
44 #include <security/mac/mac_framework.h>
45 
46 #include <vm/vm.h>
47 #include <vm/vm_extern.h>
48 #include <vm/vm_kern.h>
49 #include <vm/vm_page.h>
50 #include <vm/uma.h>
51 #include <vm/uma_int.h>
52 #include <vm/uma_dbg.h>
53 
54 /*
55  * In FreeBSD, Mbufs and Mbuf Clusters are allocated from UMA
56  * Zones.
57  *
58  * Mbuf Clusters (2K, contiguous) are allocated from the Cluster
59  * Zone.  The Zone can be capped at kern.ipc.nmbclusters, if the
60  * administrator so desires.
61  *
62  * Mbufs are allocated from a UMA Master Zone called the Mbuf
63  * Zone.
64  *
65  * Additionally, FreeBSD provides a Packet Zone, which it
66  * configures as a Secondary Zone to the Mbuf Master Zone,
67  * thus sharing backend Slab kegs with the Mbuf Master Zone.
68  *
69  * Thus common-case allocations and locking are simplified:
70  *
71  *  m_clget()                m_getcl()
72  *    |                         |
73  *    |   .------------>[(Packet Cache)]    m_get(), m_gethdr()
74  *    |   |             [     Packet   ]            |
75  *  [(Cluster Cache)]   [    Secondary ]   [ (Mbuf Cache)     ]
76  *  [ Cluster Zone  ]   [     Zone     ]   [ Mbuf Master Zone ]
77  *        |                       \________         |
78  *  [ Cluster Keg   ]                      \       /
79  *        |    	                         [ Mbuf Keg   ]
80  *  [ Cluster Slabs ]                         |
81  *        |                              [ Mbuf Slabs ]
82  *         \____________(VM)_________________/
83  *
84  *
85  * Whenever an object is allocated with uma_zalloc() out of
86  * one of the Zones its _ctor_ function is executed.  The same
87  * for any deallocation through uma_zfree() the _dtor_ function
88  * is executed.
89  *
90  * Caches are per-CPU and are filled from the Master Zone.
91  *
92  * Whenever an object is allocated from the underlying global
93  * memory pool it gets pre-initialized with the _zinit_ functions.
94  * When the Keg's are overfull objects get decomissioned with
95  * _zfini_ functions and free'd back to the global memory pool.
96  *
97  */
98 
99 int nmbclusters;		/* limits number of mbuf clusters */
100 int nmbjumbop;			/* limits number of page size jumbo clusters */
101 int nmbjumbo9;			/* limits number of 9k jumbo clusters */
102 int nmbjumbo16;			/* limits number of 16k jumbo clusters */
103 struct mbstat mbstat;
104 
105 /*
106  * tunable_mbinit() has to be run before init_maxsockets() thus
107  * the SYSINIT order below is SI_ORDER_MIDDLE while init_maxsockets()
108  * runs at SI_ORDER_ANY.
109  */
110 static void
111 tunable_mbinit(void *dummy)
112 {
113 	TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters);
114 
115 	/* This has to be done before VM init. */
116 	if (nmbclusters == 0)
117 		nmbclusters = 1024 + maxusers * 64;
118 	nmbjumbop = nmbclusters / 2;
119 	nmbjumbo9 = nmbjumbop / 2;
120 	nmbjumbo16 = nmbjumbo9 / 2;
121 }
122 SYSINIT(tunable_mbinit, SI_SUB_TUNABLES, SI_ORDER_MIDDLE, tunable_mbinit, NULL);
123 
124 static int
125 sysctl_nmbclusters(SYSCTL_HANDLER_ARGS)
126 {
127 	int error, newnmbclusters;
128 
129 	newnmbclusters = nmbclusters;
130 	error = sysctl_handle_int(oidp, &newnmbclusters, 0, req);
131 	if (error == 0 && req->newptr) {
132 		if (newnmbclusters > nmbclusters) {
133 			nmbclusters = newnmbclusters;
134 			uma_zone_set_max(zone_clust, nmbclusters);
135 			EVENTHANDLER_INVOKE(nmbclusters_change);
136 		} else
137 			error = EINVAL;
138 	}
139 	return (error);
140 }
141 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbclusters, CTLTYPE_INT|CTLFLAG_RW,
142 &nmbclusters, 0, sysctl_nmbclusters, "IU",
143     "Maximum number of mbuf clusters allowed");
144 
145 static int
146 sysctl_nmbjumbop(SYSCTL_HANDLER_ARGS)
147 {
148 	int error, newnmbjumbop;
149 
150 	newnmbjumbop = nmbjumbop;
151 	error = sysctl_handle_int(oidp, &newnmbjumbop, 0, req);
152 	if (error == 0 && req->newptr) {
153 		if (newnmbjumbop> nmbjumbop) {
154 			nmbjumbop = newnmbjumbop;
155 			uma_zone_set_max(zone_jumbop, nmbjumbop);
156 		} else
157 			error = EINVAL;
158 	}
159 	return (error);
160 }
161 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbop, CTLTYPE_INT|CTLFLAG_RW,
162 &nmbjumbop, 0, sysctl_nmbjumbop, "IU",
163 	 "Maximum number of mbuf page size jumbo clusters allowed");
164 
165 
166 static int
167 sysctl_nmbjumbo9(SYSCTL_HANDLER_ARGS)
168 {
169 	int error, newnmbjumbo9;
170 
171 	newnmbjumbo9 = nmbjumbo9;
172 	error = sysctl_handle_int(oidp, &newnmbjumbo9, 0, req);
173 	if (error == 0 && req->newptr) {
174 		if (newnmbjumbo9> nmbjumbo9) {
175 			nmbjumbo9 = newnmbjumbo9;
176 			uma_zone_set_max(zone_jumbo9, nmbjumbo9);
177 		} else
178 			error = EINVAL;
179 	}
180 	return (error);
181 }
182 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbo9, CTLTYPE_INT|CTLFLAG_RW,
183 &nmbjumbo9, 0, sysctl_nmbjumbo9, "IU",
184 	"Maximum number of mbuf 9k jumbo clusters allowed");
185 
186 static int
187 sysctl_nmbjumbo16(SYSCTL_HANDLER_ARGS)
188 {
189 	int error, newnmbjumbo16;
190 
191 	newnmbjumbo16 = nmbjumbo16;
192 	error = sysctl_handle_int(oidp, &newnmbjumbo16, 0, req);
193 	if (error == 0 && req->newptr) {
194 		if (newnmbjumbo16> nmbjumbo16) {
195 			nmbjumbo16 = newnmbjumbo16;
196 			uma_zone_set_max(zone_jumbo16, nmbjumbo16);
197 		} else
198 			error = EINVAL;
199 	}
200 	return (error);
201 }
202 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbo16, CTLTYPE_INT|CTLFLAG_RW,
203 &nmbjumbo16, 0, sysctl_nmbjumbo16, "IU",
204     "Maximum number of mbuf 16k jumbo clusters allowed");
205 
206 
207 
208 SYSCTL_STRUCT(_kern_ipc, OID_AUTO, mbstat, CTLFLAG_RD, &mbstat, mbstat,
209     "Mbuf general information and statistics");
210 
211 /*
212  * Zones from which we allocate.
213  */
214 uma_zone_t	zone_mbuf;
215 uma_zone_t	zone_clust;
216 uma_zone_t	zone_pack;
217 uma_zone_t	zone_jumbop;
218 uma_zone_t	zone_jumbo9;
219 uma_zone_t	zone_jumbo16;
220 uma_zone_t	zone_ext_refcnt;
221 
222 /*
223  * Local prototypes.
224  */
225 static int	mb_ctor_mbuf(void *, int, void *, int);
226 static int	mb_ctor_clust(void *, int, void *, int);
227 static int	mb_ctor_pack(void *, int, void *, int);
228 static void	mb_dtor_mbuf(void *, int, void *);
229 static void	mb_dtor_clust(void *, int, void *);
230 static void	mb_dtor_pack(void *, int, void *);
231 static int	mb_zinit_pack(void *, int, int);
232 static void	mb_zfini_pack(void *, int);
233 
234 static void	mb_reclaim(void *);
235 static void	mbuf_init(void *);
236 static void    *mbuf_jumbo_alloc(uma_zone_t, int, uint8_t *, int);
237 
238 /* Ensure that MSIZE doesn't break dtom() - it must be a power of 2 */
239 CTASSERT((((MSIZE - 1) ^ MSIZE) + 1) >> 1 == MSIZE);
240 
241 /*
242  * Initialize FreeBSD Network buffer allocation.
243  */
244 SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbuf_init, NULL);
245 static void
246 mbuf_init(void *dummy)
247 {
248 
249 	/*
250 	 * Configure UMA zones for Mbufs, Clusters, and Packets.
251 	 */
252 	zone_mbuf = uma_zcreate(MBUF_MEM_NAME, MSIZE,
253 	    mb_ctor_mbuf, mb_dtor_mbuf,
254 #ifdef INVARIANTS
255 	    trash_init, trash_fini,
256 #else
257 	    NULL, NULL,
258 #endif
259 	    MSIZE - 1, UMA_ZONE_MAXBUCKET);
260 
261 	zone_clust = uma_zcreate(MBUF_CLUSTER_MEM_NAME, MCLBYTES,
262 	    mb_ctor_clust, mb_dtor_clust,
263 #ifdef INVARIANTS
264 	    trash_init, trash_fini,
265 #else
266 	    NULL, NULL,
267 #endif
268 	    UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
269 	if (nmbclusters > 0)
270 		uma_zone_set_max(zone_clust, nmbclusters);
271 
272 	zone_pack = uma_zsecond_create(MBUF_PACKET_MEM_NAME, mb_ctor_pack,
273 	    mb_dtor_pack, mb_zinit_pack, mb_zfini_pack, zone_mbuf);
274 
275 	/* Make jumbo frame zone too. Page size, 9k and 16k. */
276 	zone_jumbop = uma_zcreate(MBUF_JUMBOP_MEM_NAME, MJUMPAGESIZE,
277 	    mb_ctor_clust, mb_dtor_clust,
278 #ifdef INVARIANTS
279 	    trash_init, trash_fini,
280 #else
281 	    NULL, NULL,
282 #endif
283 	    UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
284 	if (nmbjumbop > 0)
285 		uma_zone_set_max(zone_jumbop, nmbjumbop);
286 
287 	zone_jumbo9 = uma_zcreate(MBUF_JUMBO9_MEM_NAME, MJUM9BYTES,
288 	    mb_ctor_clust, mb_dtor_clust,
289 #ifdef INVARIANTS
290 	    trash_init, trash_fini,
291 #else
292 	    NULL, NULL,
293 #endif
294 	    UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
295 	if (nmbjumbo9 > 0)
296 		uma_zone_set_max(zone_jumbo9, nmbjumbo9);
297 	uma_zone_set_allocf(zone_jumbo9, mbuf_jumbo_alloc);
298 
299 	zone_jumbo16 = uma_zcreate(MBUF_JUMBO16_MEM_NAME, MJUM16BYTES,
300 	    mb_ctor_clust, mb_dtor_clust,
301 #ifdef INVARIANTS
302 	    trash_init, trash_fini,
303 #else
304 	    NULL, NULL,
305 #endif
306 	    UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
307 	if (nmbjumbo16 > 0)
308 		uma_zone_set_max(zone_jumbo16, nmbjumbo16);
309 	uma_zone_set_allocf(zone_jumbo16, mbuf_jumbo_alloc);
310 
311 	zone_ext_refcnt = uma_zcreate(MBUF_EXTREFCNT_MEM_NAME, sizeof(u_int),
312 	    NULL, NULL,
313 	    NULL, NULL,
314 	    UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
315 
316 	/* uma_prealloc() goes here... */
317 
318 	/*
319 	 * Hook event handler for low-memory situation, used to
320 	 * drain protocols and push data back to the caches (UMA
321 	 * later pushes it back to VM).
322 	 */
323 	EVENTHANDLER_REGISTER(vm_lowmem, mb_reclaim, NULL,
324 	    EVENTHANDLER_PRI_FIRST);
325 
326 	/*
327 	 * [Re]set counters and local statistics knobs.
328 	 * XXX Some of these should go and be replaced, but UMA stat
329 	 * gathering needs to be revised.
330 	 */
331 	mbstat.m_mbufs = 0;
332 	mbstat.m_mclusts = 0;
333 	mbstat.m_drain = 0;
334 	mbstat.m_msize = MSIZE;
335 	mbstat.m_mclbytes = MCLBYTES;
336 	mbstat.m_minclsize = MINCLSIZE;
337 	mbstat.m_mlen = MLEN;
338 	mbstat.m_mhlen = MHLEN;
339 	mbstat.m_numtypes = MT_NTYPES;
340 
341 	mbstat.m_mcfail = mbstat.m_mpfail = 0;
342 	mbstat.sf_iocnt = 0;
343 	mbstat.sf_allocwait = mbstat.sf_allocfail = 0;
344 }
345 
346 /*
347  * UMA backend page allocator for the jumbo frame zones.
348  *
349  * Allocates kernel virtual memory that is backed by contiguous physical
350  * pages.
351  */
352 static void *
353 mbuf_jumbo_alloc(uma_zone_t zone, int bytes, uint8_t *flags, int wait)
354 {
355 
356 	/* Inform UMA that this allocator uses kernel_map/object. */
357 	*flags = UMA_SLAB_KERNEL;
358 	return ((void *)kmem_alloc_contig(kernel_map, bytes, wait,
359 	    (vm_paddr_t)0, ~(vm_paddr_t)0, 1, 0, VM_MEMATTR_DEFAULT));
360 }
361 
362 /*
363  * Constructor for Mbuf master zone.
364  *
365  * The 'arg' pointer points to a mb_args structure which
366  * contains call-specific information required to support the
367  * mbuf allocation API.  See mbuf.h.
368  */
369 static int
370 mb_ctor_mbuf(void *mem, int size, void *arg, int how)
371 {
372 	struct mbuf *m;
373 	struct mb_args *args;
374 #ifdef MAC
375 	int error;
376 #endif
377 	int flags;
378 	short type;
379 
380 #ifdef INVARIANTS
381 	trash_ctor(mem, size, arg, how);
382 #endif
383 	m = (struct mbuf *)mem;
384 	args = (struct mb_args *)arg;
385 	flags = args->flags;
386 	type = args->type;
387 
388 	/*
389 	 * The mbuf is initialized later.  The caller has the
390 	 * responsibility to set up any MAC labels too.
391 	 */
392 	if (type == MT_NOINIT)
393 		return (0);
394 
395 	m->m_next = NULL;
396 	m->m_nextpkt = NULL;
397 	m->m_len = 0;
398 	m->m_flags = flags;
399 	m->m_type = type;
400 	if (flags & M_PKTHDR) {
401 		m->m_data = m->m_pktdat;
402 		m->m_pkthdr.rcvif = NULL;
403 		m->m_pkthdr.header = NULL;
404 		m->m_pkthdr.len = 0;
405 		m->m_pkthdr.csum_flags = 0;
406 		m->m_pkthdr.csum_data = 0;
407 		m->m_pkthdr.tso_segsz = 0;
408 		m->m_pkthdr.ether_vtag = 0;
409 		m->m_pkthdr.flowid = 0;
410 		SLIST_INIT(&m->m_pkthdr.tags);
411 #ifdef MAC
412 		/* If the label init fails, fail the alloc */
413 		error = mac_mbuf_init(m, how);
414 		if (error)
415 			return (error);
416 #endif
417 	} else
418 		m->m_data = m->m_dat;
419 	return (0);
420 }
421 
422 /*
423  * The Mbuf master zone destructor.
424  */
425 static void
426 mb_dtor_mbuf(void *mem, int size, void *arg)
427 {
428 	struct mbuf *m;
429 	unsigned long flags;
430 
431 	m = (struct mbuf *)mem;
432 	flags = (unsigned long)arg;
433 
434 	if ((flags & MB_NOTAGS) == 0 && (m->m_flags & M_PKTHDR) != 0)
435 		m_tag_delete_chain(m, NULL);
436 	KASSERT((m->m_flags & M_EXT) == 0, ("%s: M_EXT set", __func__));
437 	KASSERT((m->m_flags & M_NOFREE) == 0, ("%s: M_NOFREE set", __func__));
438 #ifdef INVARIANTS
439 	trash_dtor(mem, size, arg);
440 #endif
441 }
442 
443 /*
444  * The Mbuf Packet zone destructor.
445  */
446 static void
447 mb_dtor_pack(void *mem, int size, void *arg)
448 {
449 	struct mbuf *m;
450 
451 	m = (struct mbuf *)mem;
452 	if ((m->m_flags & M_PKTHDR) != 0)
453 		m_tag_delete_chain(m, NULL);
454 
455 	/* Make sure we've got a clean cluster back. */
456 	KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
457 	KASSERT(m->m_ext.ext_buf != NULL, ("%s: ext_buf == NULL", __func__));
458 	KASSERT(m->m_ext.ext_free == NULL, ("%s: ext_free != NULL", __func__));
459 	KASSERT(m->m_ext.ext_arg1 == NULL, ("%s: ext_arg1 != NULL", __func__));
460 	KASSERT(m->m_ext.ext_arg2 == NULL, ("%s: ext_arg2 != NULL", __func__));
461 	KASSERT(m->m_ext.ext_size == MCLBYTES, ("%s: ext_size != MCLBYTES", __func__));
462 	KASSERT(m->m_ext.ext_type == EXT_PACKET, ("%s: ext_type != EXT_PACKET", __func__));
463 	KASSERT(*m->m_ext.ref_cnt == 1, ("%s: ref_cnt != 1", __func__));
464 #ifdef INVARIANTS
465 	trash_dtor(m->m_ext.ext_buf, MCLBYTES, arg);
466 #endif
467 	/*
468 	 * If there are processes blocked on zone_clust, waiting for pages
469 	 * to be freed up, * cause them to be woken up by draining the
470 	 * packet zone.  We are exposed to a race here * (in the check for
471 	 * the UMA_ZFLAG_FULL) where we might miss the flag set, but that
472 	 * is deliberate. We don't want to acquire the zone lock for every
473 	 * mbuf free.
474 	 */
475 	if (uma_zone_exhausted_nolock(zone_clust))
476 		zone_drain(zone_pack);
477 }
478 
479 /*
480  * The Cluster and Jumbo[PAGESIZE|9|16] zone constructor.
481  *
482  * Here the 'arg' pointer points to the Mbuf which we
483  * are configuring cluster storage for.  If 'arg' is
484  * empty we allocate just the cluster without setting
485  * the mbuf to it.  See mbuf.h.
486  */
487 static int
488 mb_ctor_clust(void *mem, int size, void *arg, int how)
489 {
490 	struct mbuf *m;
491 	u_int *refcnt;
492 	int type;
493 	uma_zone_t zone;
494 
495 #ifdef INVARIANTS
496 	trash_ctor(mem, size, arg, how);
497 #endif
498 	switch (size) {
499 	case MCLBYTES:
500 		type = EXT_CLUSTER;
501 		zone = zone_clust;
502 		break;
503 #if MJUMPAGESIZE != MCLBYTES
504 	case MJUMPAGESIZE:
505 		type = EXT_JUMBOP;
506 		zone = zone_jumbop;
507 		break;
508 #endif
509 	case MJUM9BYTES:
510 		type = EXT_JUMBO9;
511 		zone = zone_jumbo9;
512 		break;
513 	case MJUM16BYTES:
514 		type = EXT_JUMBO16;
515 		zone = zone_jumbo16;
516 		break;
517 	default:
518 		panic("unknown cluster size");
519 		break;
520 	}
521 
522 	m = (struct mbuf *)arg;
523 	refcnt = uma_find_refcnt(zone, mem);
524 	*refcnt = 1;
525 	if (m != NULL) {
526 		m->m_ext.ext_buf = (caddr_t)mem;
527 		m->m_data = m->m_ext.ext_buf;
528 		m->m_flags |= M_EXT;
529 		m->m_ext.ext_free = NULL;
530 		m->m_ext.ext_arg1 = NULL;
531 		m->m_ext.ext_arg2 = NULL;
532 		m->m_ext.ext_size = size;
533 		m->m_ext.ext_type = type;
534 		m->m_ext.ref_cnt = refcnt;
535 	}
536 
537 	return (0);
538 }
539 
540 /*
541  * The Mbuf Cluster zone destructor.
542  */
543 static void
544 mb_dtor_clust(void *mem, int size, void *arg)
545 {
546 #ifdef INVARIANTS
547 	uma_zone_t zone;
548 
549 	zone = m_getzone(size);
550 	KASSERT(*(uma_find_refcnt(zone, mem)) <= 1,
551 		("%s: refcnt incorrect %u", __func__,
552 		 *(uma_find_refcnt(zone, mem))) );
553 
554 	trash_dtor(mem, size, arg);
555 #endif
556 }
557 
558 /*
559  * The Packet secondary zone's init routine, executed on the
560  * object's transition from mbuf keg slab to zone cache.
561  */
562 static int
563 mb_zinit_pack(void *mem, int size, int how)
564 {
565 	struct mbuf *m;
566 
567 	m = (struct mbuf *)mem;		/* m is virgin. */
568 	if (uma_zalloc_arg(zone_clust, m, how) == NULL ||
569 	    m->m_ext.ext_buf == NULL)
570 		return (ENOMEM);
571 	m->m_ext.ext_type = EXT_PACKET;	/* Override. */
572 #ifdef INVARIANTS
573 	trash_init(m->m_ext.ext_buf, MCLBYTES, how);
574 #endif
575 	return (0);
576 }
577 
578 /*
579  * The Packet secondary zone's fini routine, executed on the
580  * object's transition from zone cache to keg slab.
581  */
582 static void
583 mb_zfini_pack(void *mem, int size)
584 {
585 	struct mbuf *m;
586 
587 	m = (struct mbuf *)mem;
588 #ifdef INVARIANTS
589 	trash_fini(m->m_ext.ext_buf, MCLBYTES);
590 #endif
591 	uma_zfree_arg(zone_clust, m->m_ext.ext_buf, NULL);
592 #ifdef INVARIANTS
593 	trash_dtor(mem, size, NULL);
594 #endif
595 }
596 
597 /*
598  * The "packet" keg constructor.
599  */
600 static int
601 mb_ctor_pack(void *mem, int size, void *arg, int how)
602 {
603 	struct mbuf *m;
604 	struct mb_args *args;
605 #ifdef MAC
606 	int error;
607 #endif
608 	int flags;
609 	short type;
610 
611 	m = (struct mbuf *)mem;
612 	args = (struct mb_args *)arg;
613 	flags = args->flags;
614 	type = args->type;
615 
616 #ifdef INVARIANTS
617 	trash_ctor(m->m_ext.ext_buf, MCLBYTES, arg, how);
618 #endif
619 	m->m_next = NULL;
620 	m->m_nextpkt = NULL;
621 	m->m_data = m->m_ext.ext_buf;
622 	m->m_len = 0;
623 	m->m_flags = (flags | M_EXT);
624 	m->m_type = type;
625 
626 	if (flags & M_PKTHDR) {
627 		m->m_pkthdr.rcvif = NULL;
628 		m->m_pkthdr.len = 0;
629 		m->m_pkthdr.header = NULL;
630 		m->m_pkthdr.csum_flags = 0;
631 		m->m_pkthdr.csum_data = 0;
632 		m->m_pkthdr.tso_segsz = 0;
633 		m->m_pkthdr.ether_vtag = 0;
634 		m->m_pkthdr.flowid = 0;
635 		SLIST_INIT(&m->m_pkthdr.tags);
636 #ifdef MAC
637 		/* If the label init fails, fail the alloc */
638 		error = mac_mbuf_init(m, how);
639 		if (error)
640 			return (error);
641 #endif
642 	}
643 	/* m_ext is already initialized. */
644 
645 	return (0);
646 }
647 
648 int
649 m_pkthdr_init(struct mbuf *m, int how)
650 {
651 #ifdef MAC
652 	int error;
653 #endif
654 	m->m_data = m->m_pktdat;
655 	SLIST_INIT(&m->m_pkthdr.tags);
656 	m->m_pkthdr.rcvif = NULL;
657 	m->m_pkthdr.header = NULL;
658 	m->m_pkthdr.len = 0;
659 	m->m_pkthdr.flowid = 0;
660 	m->m_pkthdr.csum_flags = 0;
661 	m->m_pkthdr.csum_data = 0;
662 	m->m_pkthdr.tso_segsz = 0;
663 	m->m_pkthdr.ether_vtag = 0;
664 #ifdef MAC
665 	/* If the label init fails, fail the alloc */
666 	error = mac_mbuf_init(m, how);
667 	if (error)
668 		return (error);
669 #endif
670 
671 	return (0);
672 }
673 
674 /*
675  * This is the protocol drain routine.
676  *
677  * No locks should be held when this is called.  The drain routines have to
678  * presently acquire some locks which raises the possibility of lock order
679  * reversal.
680  */
681 static void
682 mb_reclaim(void *junk)
683 {
684 	struct domain *dp;
685 	struct protosw *pr;
686 
687 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK | WARN_PANIC, NULL,
688 	    "mb_reclaim()");
689 
690 	for (dp = domains; dp != NULL; dp = dp->dom_next)
691 		for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
692 			if (pr->pr_drain != NULL)
693 				(*pr->pr_drain)();
694 }
695