xref: /freebsd/sys/kern/kern_mbuf.c (revision 7dfd9569a2f0637fb9a48157b1c1bfe5709faee3)
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_mac.h"
32 #include "opt_param.h"
33 
34 #include <sys/param.h>
35 #include <sys/mac.h>
36 #include <sys/malloc.h>
37 #include <sys/systm.h>
38 #include <sys/mbuf.h>
39 #include <sys/domain.h>
40 #include <sys/eventhandler.h>
41 #include <sys/kernel.h>
42 #include <sys/protosw.h>
43 #include <sys/smp.h>
44 #include <sys/sysctl.h>
45 
46 #include <vm/vm.h>
47 #include <vm/vm_page.h>
48 #include <vm/uma.h>
49 #include <vm/uma_int.h>
50 #include <vm/uma_dbg.h>
51 
52 /*
53  * In FreeBSD, Mbufs and Mbuf Clusters are allocated from UMA
54  * Zones.
55  *
56  * Mbuf Clusters (2K, contiguous) are allocated from the Cluster
57  * Zone.  The Zone can be capped at kern.ipc.nmbclusters, if the
58  * administrator so desires.
59  *
60  * Mbufs are allocated from a UMA Master Zone called the Mbuf
61  * Zone.
62  *
63  * Additionally, FreeBSD provides a Packet Zone, which it
64  * configures as a Secondary Zone to the Mbuf Master Zone,
65  * thus sharing backend Slab kegs with the Mbuf Master Zone.
66  *
67  * Thus common-case allocations and locking are simplified:
68  *
69  *  m_clget()                m_getcl()
70  *    |                         |
71  *    |   .------------>[(Packet Cache)]    m_get(), m_gethdr()
72  *    |   |             [     Packet   ]            |
73  *  [(Cluster Cache)]   [    Secondary ]   [ (Mbuf Cache)     ]
74  *  [ Cluster Zone  ]   [     Zone     ]   [ Mbuf Master Zone ]
75  *        |                       \________         |
76  *  [ Cluster Keg   ]                      \       /
77  *        |    	                         [ Mbuf Keg   ]
78  *  [ Cluster Slabs ]                         |
79  *        |                              [ Mbuf Slabs ]
80  *         \____________(VM)_________________/
81  *
82  *
83  * Whenever an object is allocated with uma_zalloc() out of
84  * one of the Zones its _ctor_ function is executed.  The same
85  * for any deallocation through uma_zfree() the _dtor_ function
86  * is executed.
87  *
88  * Caches are per-CPU and are filled from the Master Zone.
89  *
90  * Whenever an object is allocated from the underlying global
91  * memory pool it gets pre-initialized with the _zinit_ functions.
92  * When the Keg's are overfull objects get decomissioned with
93  * _zfini_ functions and free'd back to the global memory pool.
94  *
95  */
96 
97 int nmbclusters;		/* limits number of mbuf clusters */
98 int nmbjumbop;			/* limits number of page size jumbo clusters */
99 int nmbjumbo9;			/* limits number of 9k jumbo clusters */
100 int nmbjumbo16;			/* limits number of 16k jumbo clusters */
101 struct mbstat mbstat;
102 
103 static void
104 tunable_mbinit(void *dummy)
105 {
106 
107 	/* This has to be done before VM init. */
108 	nmbclusters = 1024 + maxusers * 64;
109 	TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters);
110 }
111 SYSINIT(tunable_mbinit, SI_SUB_TUNABLES, SI_ORDER_ANY, tunable_mbinit, NULL);
112 
113 SYSCTL_DECL(_kern_ipc);
114 /* XXX: These should be tuneables. Can't change UMA limits on the fly. */
115 static int
116 sysctl_nmbclusters(SYSCTL_HANDLER_ARGS)
117 {
118 	int error, newnmbclusters;
119 
120 	newnmbclusters = nmbclusters;
121 	error = sysctl_handle_int(oidp, &newnmbclusters, sizeof(int), req);
122 	if (error == 0 && req->newptr) {
123 		if (newnmbclusters > nmbclusters) {
124 			nmbclusters = newnmbclusters;
125 			uma_zone_set_max(zone_clust, nmbclusters);
126 			EVENTHANDLER_INVOKE(nmbclusters_change);
127 		} else
128 			error = EINVAL;
129 	}
130 	return (error);
131 }
132 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbclusters, CTLTYPE_INT|CTLFLAG_RW,
133 &nmbclusters, 0, sysctl_nmbclusters, "IU",
134     "Maximum number of mbuf clusters allowed");
135 SYSCTL_INT(_kern_ipc, OID_AUTO, nmbjumbop, CTLFLAG_RW, &nmbjumbop, 0,
136     "Maximum number of mbuf page size jumbo clusters allowed");
137 SYSCTL_INT(_kern_ipc, OID_AUTO, nmbjumbo9, CTLFLAG_RW, &nmbjumbo9, 0,
138     "Maximum number of mbuf 9k jumbo clusters allowed");
139 SYSCTL_INT(_kern_ipc, OID_AUTO, nmbjumbo16, CTLFLAG_RW, &nmbjumbo16, 0,
140     "Maximum number of mbuf 16k jumbo clusters allowed");
141 SYSCTL_STRUCT(_kern_ipc, OID_AUTO, mbstat, CTLFLAG_RD, &mbstat, mbstat,
142     "Mbuf general information and statistics");
143 
144 /*
145  * Zones from which we allocate.
146  */
147 uma_zone_t	zone_mbuf;
148 uma_zone_t	zone_clust;
149 uma_zone_t	zone_pack;
150 uma_zone_t	zone_jumbop;
151 uma_zone_t	zone_jumbo9;
152 uma_zone_t	zone_jumbo16;
153 uma_zone_t	zone_ext_refcnt;
154 uma_zone_t	zone_mtag_vlan;
155 
156 /*
157  * Local prototypes.
158  */
159 static int	mb_ctor_mbuf(void *, int, void *, int);
160 static int	mb_ctor_clust(void *, int, void *, int);
161 static int	mb_ctor_pack(void *, int, void *, int);
162 static void	mb_dtor_mbuf(void *, int, void *);
163 static void	mb_dtor_clust(void *, int, void *);
164 static void	mb_dtor_pack(void *, int, void *);
165 static int	mb_zinit_pack(void *, int, int);
166 static void	mb_zfini_pack(void *, int);
167 static int	mt_zinit_vlan(void *, int, int);
168 
169 static void	mb_reclaim(void *);
170 static void	mbuf_init(void *);
171 
172 /* Ensure that MSIZE doesn't break dtom() - it must be a power of 2 */
173 CTASSERT((((MSIZE - 1) ^ MSIZE) + 1) >> 1 == MSIZE);
174 
175 /*
176  * Initialize FreeBSD Network buffer allocation.
177  */
178 SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbuf_init, NULL)
179 static void
180 mbuf_init(void *dummy)
181 {
182 
183 	/*
184 	 * Configure UMA zones for Mbufs, Clusters, and Packets.
185 	 */
186 	zone_mbuf = uma_zcreate(MBUF_MEM_NAME, MSIZE,
187 	    mb_ctor_mbuf, mb_dtor_mbuf,
188 #ifdef INVARIANTS
189 	    trash_init, trash_fini,
190 #else
191 	    NULL, NULL,
192 #endif
193 	    MSIZE - 1, UMA_ZONE_MAXBUCKET);
194 
195 	zone_clust = uma_zcreate(MBUF_CLUSTER_MEM_NAME, MCLBYTES,
196 	    mb_ctor_clust, mb_dtor_clust,
197 #ifdef INVARIANTS
198 	    trash_init, trash_fini,
199 #else
200 	    NULL, NULL,
201 #endif
202 	    UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
203 	if (nmbclusters > 0)
204 		uma_zone_set_max(zone_clust, nmbclusters);
205 
206 	zone_pack = uma_zsecond_create(MBUF_PACKET_MEM_NAME, mb_ctor_pack,
207 	    mb_dtor_pack, mb_zinit_pack, mb_zfini_pack, zone_mbuf);
208 
209 	/* Make jumbo frame zone too. Page size, 9k and 16k. */
210 	zone_jumbop = uma_zcreate(MBUF_JUMBOP_MEM_NAME, MJUMPAGESIZE,
211 	    mb_ctor_clust, mb_dtor_clust,
212 #ifdef INVARIANTS
213 	    trash_init, trash_fini,
214 #else
215 	    NULL, NULL,
216 #endif
217 	    UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
218 	if (nmbjumbop > 0)
219 		uma_zone_set_max(zone_jumbop, nmbjumbop);
220 
221 	zone_jumbo9 = uma_zcreate(MBUF_JUMBO9_MEM_NAME, MJUM9BYTES,
222 	    mb_ctor_clust, mb_dtor_clust,
223 #ifdef INVARIANTS
224 	    trash_init, trash_fini,
225 #else
226 	    NULL, NULL,
227 #endif
228 	    UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
229 	if (nmbjumbo9 > 0)
230 		uma_zone_set_max(zone_jumbo9, nmbjumbo9);
231 
232 	zone_jumbo16 = uma_zcreate(MBUF_JUMBO16_MEM_NAME, MJUM16BYTES,
233 	    mb_ctor_clust, mb_dtor_clust,
234 #ifdef INVARIANTS
235 	    trash_init, trash_fini,
236 #else
237 	    NULL, NULL,
238 #endif
239 	    UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
240 	if (nmbjumbo16 > 0)
241 		uma_zone_set_max(zone_jumbo16, nmbjumbo16);
242 
243 	zone_ext_refcnt = uma_zcreate(MBUF_EXTREFCNT_MEM_NAME, sizeof(u_int),
244 	    NULL, NULL,
245 	    NULL, NULL,
246 	    UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
247 
248 	zone_mtag_vlan = uma_zcreate("mtag_vlan",
249 	    sizeof(struct m_tag) + sizeof(u_int),
250 	    NULL, NULL,
251 	    mt_zinit_vlan, NULL,
252 	    UMA_ALIGN_INT, 0);
253 
254 	/* uma_prealloc() goes here... */
255 
256 	/*
257 	 * Hook event handler for low-memory situation, used to
258 	 * drain protocols and push data back to the caches (UMA
259 	 * later pushes it back to VM).
260 	 */
261 	EVENTHANDLER_REGISTER(vm_lowmem, mb_reclaim, NULL,
262 	    EVENTHANDLER_PRI_FIRST);
263 
264 	/*
265 	 * [Re]set counters and local statistics knobs.
266 	 * XXX Some of these should go and be replaced, but UMA stat
267 	 * gathering needs to be revised.
268 	 */
269 	mbstat.m_mbufs = 0;
270 	mbstat.m_mclusts = 0;
271 	mbstat.m_drain = 0;
272 	mbstat.m_msize = MSIZE;
273 	mbstat.m_mclbytes = MCLBYTES;
274 	mbstat.m_minclsize = MINCLSIZE;
275 	mbstat.m_mlen = MLEN;
276 	mbstat.m_mhlen = MHLEN;
277 	mbstat.m_numtypes = MT_NTYPES;
278 
279 	mbstat.m_mcfail = mbstat.m_mpfail = 0;
280 	mbstat.sf_iocnt = 0;
281 	mbstat.sf_allocwait = mbstat.sf_allocfail = 0;
282 }
283 
284 /*
285  * Constructor for Mbuf master zone.
286  *
287  * The 'arg' pointer points to a mb_args structure which
288  * contains call-specific information required to support the
289  * mbuf allocation API.  See mbuf.h.
290  */
291 static int
292 mb_ctor_mbuf(void *mem, int size, void *arg, int how)
293 {
294 	struct mbuf *m;
295 	struct mb_args *args;
296 #ifdef MAC
297 	int error;
298 #endif
299 	int flags;
300 	short type;
301 
302 #ifdef INVARIANTS
303 	trash_ctor(mem, size, arg, how);
304 #endif
305 	m = (struct mbuf *)mem;
306 	args = (struct mb_args *)arg;
307 	flags = args->flags;
308 	type = args->type;
309 
310 	/*
311 	 * The mbuf is initialized later.  The caller has the
312 	 * responsibility to set up any MAC labels too.
313 	 */
314 	if (type == MT_NOINIT)
315 		return (0);
316 
317 	m->m_next = NULL;
318 	m->m_nextpkt = NULL;
319 	m->m_len = 0;
320 	m->m_flags = flags;
321 	m->m_type = type;
322 	if (flags & M_PKTHDR) {
323 		m->m_data = m->m_pktdat;
324 		m->m_pkthdr.rcvif = NULL;
325 		m->m_pkthdr.len = 0;
326 		m->m_pkthdr.header = NULL;
327 		m->m_pkthdr.csum_flags = 0;
328 		m->m_pkthdr.csum_data = 0;
329 		SLIST_INIT(&m->m_pkthdr.tags);
330 #ifdef MAC
331 		/* If the label init fails, fail the alloc */
332 		error = mac_init_mbuf(m, how);
333 		if (error)
334 			return (error);
335 #endif
336 	} else
337 		m->m_data = m->m_dat;
338 	return (0);
339 }
340 
341 /*
342  * The Mbuf master zone destructor.
343  */
344 static void
345 mb_dtor_mbuf(void *mem, int size, void *arg)
346 {
347 	struct mbuf *m;
348 
349 	m = (struct mbuf *)mem;
350 	if ((m->m_flags & M_PKTHDR) != 0)
351 		m_tag_delete_chain(m, NULL);
352 	KASSERT((m->m_flags & M_EXT) == 0, ("%s: M_EXT set", __func__));
353 #ifdef INVARIANTS
354 	trash_dtor(mem, size, arg);
355 #endif
356 }
357 
358 /*
359  * The Mbuf Packet zone destructor.
360  */
361 static void
362 mb_dtor_pack(void *mem, int size, void *arg)
363 {
364 	struct mbuf *m;
365 
366 	m = (struct mbuf *)mem;
367 	if ((m->m_flags & M_PKTHDR) != 0)
368 		m_tag_delete_chain(m, NULL);
369 
370 	/* Make sure we've got a clean cluster back. */
371 	KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
372 	KASSERT(m->m_ext.ext_buf != NULL, ("%s: ext_buf == NULL", __func__));
373 	KASSERT(m->m_ext.ext_free == NULL, ("%s: ext_free != NULL", __func__));
374 	KASSERT(m->m_ext.ext_args == NULL, ("%s: ext_args != NULL", __func__));
375 	KASSERT(m->m_ext.ext_size == MCLBYTES, ("%s: ext_size != MCLBYTES", __func__));
376 	KASSERT(m->m_ext.ext_type == EXT_PACKET, ("%s: ext_type != EXT_PACKET", __func__));
377 	KASSERT(*m->m_ext.ref_cnt == 1, ("%s: ref_cnt != 1", __func__));
378 #ifdef INVARIANTS
379 	trash_dtor(m->m_ext.ext_buf, MCLBYTES, arg);
380 #endif
381 }
382 
383 /*
384  * The Cluster and Jumbo[PAGESIZE|9|16] zone constructor.
385  *
386  * Here the 'arg' pointer points to the Mbuf which we
387  * are configuring cluster storage for.  If 'arg' is
388  * empty we allocate just the cluster without setting
389  * the mbuf to it.  See mbuf.h.
390  */
391 static int
392 mb_ctor_clust(void *mem, int size, void *arg, int how)
393 {
394 	struct mbuf *m;
395 	u_int *refcnt;
396 	int type = 0;
397 
398 #ifdef INVARIANTS
399 	trash_ctor(mem, size, arg, how);
400 #endif
401 	m = (struct mbuf *)arg;
402 	if (m != NULL) {
403 		switch (size) {
404 		case MCLBYTES:
405 			type = EXT_CLUSTER;
406 			break;
407 #if MJUMPAGESIZE != MCLBYTES
408 		case MJUMPAGESIZE:
409 			type = EXT_JUMBOP;
410 			break;
411 #endif
412 		case MJUM9BYTES:
413 			type = EXT_JUMBO9;
414 			break;
415 		case MJUM16BYTES:
416 			type = EXT_JUMBO16;
417 			break;
418 		default:
419 			panic("unknown cluster size");
420 			break;
421 		}
422 		m->m_ext.ext_buf = (caddr_t)mem;
423 		m->m_data = m->m_ext.ext_buf;
424 		m->m_flags |= M_EXT;
425 		m->m_ext.ext_free = NULL;
426 		m->m_ext.ext_args = NULL;
427 		m->m_ext.ext_size = size;
428 		m->m_ext.ext_type = type;
429 		m->m_ext.ref_cnt = uma_find_refcnt(zone_clust, mem);
430 		*m->m_ext.ref_cnt = 1;
431 	} else {
432 		refcnt =  uma_find_refcnt(zone_clust, mem);
433 		*refcnt = 1;
434 	}
435 	return (0);
436 }
437 
438 /*
439  * The Mbuf Cluster zone destructor.
440  */
441 static void
442 mb_dtor_clust(void *mem, int size, void *arg)
443 {
444 
445 	KASSERT(*(uma_find_refcnt(zone_clust, mem)) <= 1,
446 		("%s: refcnt incorrect %u", __func__,
447 		 *(uma_find_refcnt(zone_clust, mem))) );
448 #ifdef INVARIANTS
449 	trash_dtor(mem, size, arg);
450 #endif
451 }
452 
453 /*
454  * The Packet secondary zone's init routine, executed on the
455  * object's transition from mbuf keg slab to zone cache.
456  */
457 static int
458 mb_zinit_pack(void *mem, int size, int how)
459 {
460 	struct mbuf *m;
461 
462 	m = (struct mbuf *)mem;		/* m is virgin. */
463 	if (uma_zalloc_arg(zone_clust, m, how) == NULL ||
464 	    m->m_ext.ext_buf == NULL)
465 		return (ENOMEM);
466 	m->m_ext.ext_type = EXT_PACKET;	/* Override. */
467 #ifdef INVARIANTS
468 	trash_init(m->m_ext.ext_buf, MCLBYTES, how);
469 #endif
470 	return (0);
471 }
472 
473 /*
474  * The Packet secondary zone's fini routine, executed on the
475  * object's transition from zone cache to keg slab.
476  */
477 static void
478 mb_zfini_pack(void *mem, int size)
479 {
480 	struct mbuf *m;
481 
482 	m = (struct mbuf *)mem;
483 #ifdef INVARIANTS
484 	trash_fini(m->m_ext.ext_buf, MCLBYTES);
485 #endif
486 	uma_zfree_arg(zone_clust, m->m_ext.ext_buf, NULL);
487 #ifdef INVARIANTS
488 	trash_dtor(mem, size, NULL);
489 #endif
490 }
491 
492 /*
493  * The "packet" keg constructor.
494  */
495 static int
496 mb_ctor_pack(void *mem, int size, void *arg, int how)
497 {
498 	struct mbuf *m;
499 	struct mb_args *args;
500 #ifdef MAC
501 	int error;
502 #endif
503 	int flags;
504 	short type;
505 
506 	m = (struct mbuf *)mem;
507 	args = (struct mb_args *)arg;
508 	flags = args->flags;
509 	type = args->type;
510 
511 #ifdef INVARIANTS
512 	trash_ctor(m->m_ext.ext_buf, MCLBYTES, arg, how);
513 #endif
514 	m->m_next = NULL;
515 	m->m_nextpkt = NULL;
516 	m->m_data = m->m_ext.ext_buf;
517 	m->m_len = 0;
518 	m->m_flags = (flags | M_EXT);
519 	m->m_type = type;
520 
521 	if (flags & M_PKTHDR) {
522 		m->m_pkthdr.rcvif = NULL;
523 		m->m_pkthdr.len = 0;
524 		m->m_pkthdr.header = NULL;
525 		m->m_pkthdr.csum_flags = 0;
526 		m->m_pkthdr.csum_data = 0;
527 		SLIST_INIT(&m->m_pkthdr.tags);
528 #ifdef MAC
529 		/* If the label init fails, fail the alloc */
530 		error = mac_init_mbuf(m, how);
531 		if (error)
532 			return (error);
533 #endif
534 	}
535 	/* m_ext is already initialized. */
536 
537 	return (0);
538 }
539 
540 static void
541 mt_vlan_free(struct m_tag *mtag)
542 {
543 	uma_zfree(zone_mtag_vlan, mtag);
544 }
545 
546 static int
547 mt_zinit_vlan(void *mem, int size, int how)
548 {
549 	struct m_tag *mtag = (struct m_tag *)mem;
550 
551 	m_tag_setup(mtag, MTAG_VLAN, MTAG_VLAN_TAG, sizeof(u_int));
552 	mtag->m_tag_free = mt_vlan_free;
553 
554 	return (0);
555 }
556 
557 /*
558  * This is the protocol drain routine.
559  *
560  * No locks should be held when this is called.  The drain routines have to
561  * presently acquire some locks which raises the possibility of lock order
562  * reversal.
563  */
564 static void
565 mb_reclaim(void *junk)
566 {
567 	struct domain *dp;
568 	struct protosw *pr;
569 
570 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK | WARN_PANIC, NULL,
571 	    "mb_reclaim()");
572 
573 	for (dp = domains; dp != NULL; dp = dp->dom_next)
574 		for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
575 			if (pr->pr_drain != NULL)
576 				(*pr->pr_drain)();
577 }
578