xref: /freebsd/sys/kern/kern_mbuf.c (revision 3fe92528afe8313fecf48822dde74bad5e380f48)
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 /* XXX: These should be tuneables. Can't change UMA limits on the fly. */
114 static int
115 sysctl_nmbclusters(SYSCTL_HANDLER_ARGS)
116 {
117 	int error, newnmbclusters;
118 
119 	newnmbclusters = nmbclusters;
120 	error = sysctl_handle_int(oidp, &newnmbclusters, sizeof(int), req);
121 	if (error == 0 && req->newptr) {
122 		if (newnmbclusters > nmbclusters) {
123 			nmbclusters = newnmbclusters;
124 			uma_zone_set_max(zone_clust, nmbclusters);
125 			EVENTHANDLER_INVOKE(nmbclusters_change);
126 		} else
127 			error = EINVAL;
128 	}
129 	return (error);
130 }
131 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbclusters, CTLTYPE_INT|CTLFLAG_RW,
132 &nmbclusters, 0, sysctl_nmbclusters, "IU",
133     "Maximum number of mbuf clusters allowed");
134 SYSCTL_INT(_kern_ipc, OID_AUTO, nmbjumbop, CTLFLAG_RW, &nmbjumbop, 0,
135     "Maximum number of mbuf page size jumbo clusters allowed");
136 SYSCTL_INT(_kern_ipc, OID_AUTO, nmbjumbo9, CTLFLAG_RW, &nmbjumbo9, 0,
137     "Maximum number of mbuf 9k jumbo clusters allowed");
138 SYSCTL_INT(_kern_ipc, OID_AUTO, nmbjumbo16, CTLFLAG_RW, &nmbjumbo16, 0,
139     "Maximum number of mbuf 16k jumbo clusters allowed");
140 SYSCTL_STRUCT(_kern_ipc, OID_AUTO, mbstat, CTLFLAG_RD, &mbstat, mbstat,
141     "Mbuf general information and statistics");
142 
143 /*
144  * Zones from which we allocate.
145  */
146 uma_zone_t	zone_mbuf;
147 uma_zone_t	zone_clust;
148 uma_zone_t	zone_pack;
149 uma_zone_t	zone_jumbop;
150 uma_zone_t	zone_jumbo9;
151 uma_zone_t	zone_jumbo16;
152 uma_zone_t	zone_ext_refcnt;
153 
154 /*
155  * Local prototypes.
156  */
157 static int	mb_ctor_mbuf(void *, int, void *, int);
158 static int	mb_ctor_clust(void *, int, void *, int);
159 static int	mb_ctor_pack(void *, int, void *, int);
160 static void	mb_dtor_mbuf(void *, int, void *);
161 static void	mb_dtor_clust(void *, int, void *);
162 static void	mb_dtor_pack(void *, int, void *);
163 static int	mb_zinit_pack(void *, int, int);
164 static void	mb_zfini_pack(void *, int);
165 
166 static void	mb_reclaim(void *);
167 static void	mbuf_init(void *);
168 
169 /* Ensure that MSIZE doesn't break dtom() - it must be a power of 2 */
170 CTASSERT((((MSIZE - 1) ^ MSIZE) + 1) >> 1 == MSIZE);
171 
172 /*
173  * Initialize FreeBSD Network buffer allocation.
174  */
175 SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbuf_init, NULL)
176 static void
177 mbuf_init(void *dummy)
178 {
179 
180 	/*
181 	 * Configure UMA zones for Mbufs, Clusters, and Packets.
182 	 */
183 	zone_mbuf = uma_zcreate(MBUF_MEM_NAME, MSIZE,
184 	    mb_ctor_mbuf, mb_dtor_mbuf,
185 #ifdef INVARIANTS
186 	    trash_init, trash_fini,
187 #else
188 	    NULL, NULL,
189 #endif
190 	    MSIZE - 1, UMA_ZONE_MAXBUCKET);
191 
192 	zone_clust = uma_zcreate(MBUF_CLUSTER_MEM_NAME, MCLBYTES,
193 	    mb_ctor_clust, mb_dtor_clust,
194 #ifdef INVARIANTS
195 	    trash_init, trash_fini,
196 #else
197 	    NULL, NULL,
198 #endif
199 	    UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
200 	if (nmbclusters > 0)
201 		uma_zone_set_max(zone_clust, nmbclusters);
202 
203 	zone_pack = uma_zsecond_create(MBUF_PACKET_MEM_NAME, mb_ctor_pack,
204 	    mb_dtor_pack, mb_zinit_pack, mb_zfini_pack, zone_mbuf);
205 
206 	/* Make jumbo frame zone too. Page size, 9k and 16k. */
207 	zone_jumbop = uma_zcreate(MBUF_JUMBOP_MEM_NAME, MJUMPAGESIZE,
208 	    mb_ctor_clust, mb_dtor_clust,
209 #ifdef INVARIANTS
210 	    trash_init, trash_fini,
211 #else
212 	    NULL, NULL,
213 #endif
214 	    UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
215 	if (nmbjumbop > 0)
216 		uma_zone_set_max(zone_jumbop, nmbjumbop);
217 
218 	zone_jumbo9 = uma_zcreate(MBUF_JUMBO9_MEM_NAME, MJUM9BYTES,
219 	    mb_ctor_clust, mb_dtor_clust,
220 #ifdef INVARIANTS
221 	    trash_init, trash_fini,
222 #else
223 	    NULL, NULL,
224 #endif
225 	    UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
226 	if (nmbjumbo9 > 0)
227 		uma_zone_set_max(zone_jumbo9, nmbjumbo9);
228 
229 	zone_jumbo16 = uma_zcreate(MBUF_JUMBO16_MEM_NAME, MJUM16BYTES,
230 	    mb_ctor_clust, mb_dtor_clust,
231 #ifdef INVARIANTS
232 	    trash_init, trash_fini,
233 #else
234 	    NULL, NULL,
235 #endif
236 	    UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
237 	if (nmbjumbo16 > 0)
238 		uma_zone_set_max(zone_jumbo16, nmbjumbo16);
239 
240 	zone_ext_refcnt = uma_zcreate(MBUF_EXTREFCNT_MEM_NAME, sizeof(u_int),
241 	    NULL, NULL,
242 	    NULL, NULL,
243 	    UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
244 
245 	/* uma_prealloc() goes here... */
246 
247 	/*
248 	 * Hook event handler for low-memory situation, used to
249 	 * drain protocols and push data back to the caches (UMA
250 	 * later pushes it back to VM).
251 	 */
252 	EVENTHANDLER_REGISTER(vm_lowmem, mb_reclaim, NULL,
253 	    EVENTHANDLER_PRI_FIRST);
254 
255 	/*
256 	 * [Re]set counters and local statistics knobs.
257 	 * XXX Some of these should go and be replaced, but UMA stat
258 	 * gathering needs to be revised.
259 	 */
260 	mbstat.m_mbufs = 0;
261 	mbstat.m_mclusts = 0;
262 	mbstat.m_drain = 0;
263 	mbstat.m_msize = MSIZE;
264 	mbstat.m_mclbytes = MCLBYTES;
265 	mbstat.m_minclsize = MINCLSIZE;
266 	mbstat.m_mlen = MLEN;
267 	mbstat.m_mhlen = MHLEN;
268 	mbstat.m_numtypes = MT_NTYPES;
269 
270 	mbstat.m_mcfail = mbstat.m_mpfail = 0;
271 	mbstat.sf_iocnt = 0;
272 	mbstat.sf_allocwait = mbstat.sf_allocfail = 0;
273 }
274 
275 /*
276  * Constructor for Mbuf master zone.
277  *
278  * The 'arg' pointer points to a mb_args structure which
279  * contains call-specific information required to support the
280  * mbuf allocation API.  See mbuf.h.
281  */
282 static int
283 mb_ctor_mbuf(void *mem, int size, void *arg, int how)
284 {
285 	struct mbuf *m;
286 	struct mb_args *args;
287 #ifdef MAC
288 	int error;
289 #endif
290 	int flags;
291 	short type;
292 
293 #ifdef INVARIANTS
294 	trash_ctor(mem, size, arg, how);
295 #endif
296 	m = (struct mbuf *)mem;
297 	args = (struct mb_args *)arg;
298 	flags = args->flags;
299 	type = args->type;
300 
301 	/*
302 	 * The mbuf is initialized later.  The caller has the
303 	 * responsibility to set up any MAC labels too.
304 	 */
305 	if (type == MT_NOINIT)
306 		return (0);
307 
308 	m->m_next = NULL;
309 	m->m_nextpkt = NULL;
310 	m->m_len = 0;
311 	m->m_flags = flags;
312 	m->m_type = type;
313 	if (flags & M_PKTHDR) {
314 		m->m_data = m->m_pktdat;
315 		m->m_pkthdr.rcvif = NULL;
316 		m->m_pkthdr.len = 0;
317 		m->m_pkthdr.header = NULL;
318 		m->m_pkthdr.csum_flags = 0;
319 		m->m_pkthdr.csum_data = 0;
320 		m->m_pkthdr.tso_segsz = 0;
321 		m->m_pkthdr.ether_vtag = 0;
322 		SLIST_INIT(&m->m_pkthdr.tags);
323 #ifdef MAC
324 		/* If the label init fails, fail the alloc */
325 		error = mac_init_mbuf(m, how);
326 		if (error)
327 			return (error);
328 #endif
329 	} else
330 		m->m_data = m->m_dat;
331 	return (0);
332 }
333 
334 /*
335  * The Mbuf master zone destructor.
336  */
337 static void
338 mb_dtor_mbuf(void *mem, int size, void *arg)
339 {
340 	struct mbuf *m;
341 
342 	m = (struct mbuf *)mem;
343 	if ((m->m_flags & M_PKTHDR) != 0)
344 		m_tag_delete_chain(m, NULL);
345 	KASSERT((m->m_flags & M_EXT) == 0, ("%s: M_EXT set", __func__));
346 #ifdef INVARIANTS
347 	trash_dtor(mem, size, arg);
348 #endif
349 }
350 
351 /*
352  * The Mbuf Packet zone destructor.
353  */
354 static void
355 mb_dtor_pack(void *mem, int size, void *arg)
356 {
357 	struct mbuf *m;
358 
359 	m = (struct mbuf *)mem;
360 	if ((m->m_flags & M_PKTHDR) != 0)
361 		m_tag_delete_chain(m, NULL);
362 
363 	/* Make sure we've got a clean cluster back. */
364 	KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
365 	KASSERT(m->m_ext.ext_buf != NULL, ("%s: ext_buf == NULL", __func__));
366 	KASSERT(m->m_ext.ext_free == NULL, ("%s: ext_free != NULL", __func__));
367 	KASSERT(m->m_ext.ext_args == NULL, ("%s: ext_args != NULL", __func__));
368 	KASSERT(m->m_ext.ext_size == MCLBYTES, ("%s: ext_size != MCLBYTES", __func__));
369 	KASSERT(m->m_ext.ext_type == EXT_PACKET, ("%s: ext_type != EXT_PACKET", __func__));
370 	KASSERT(*m->m_ext.ref_cnt == 1, ("%s: ref_cnt != 1", __func__));
371 #ifdef INVARIANTS
372 	trash_dtor(m->m_ext.ext_buf, MCLBYTES, arg);
373 #endif
374 }
375 
376 /*
377  * The Cluster and Jumbo[PAGESIZE|9|16] zone constructor.
378  *
379  * Here the 'arg' pointer points to the Mbuf which we
380  * are configuring cluster storage for.  If 'arg' is
381  * empty we allocate just the cluster without setting
382  * the mbuf to it.  See mbuf.h.
383  */
384 static int
385 mb_ctor_clust(void *mem, int size, void *arg, int how)
386 {
387 	struct mbuf *m;
388 	u_int *refcnt;
389 	int type = 0;
390 
391 #ifdef INVARIANTS
392 	trash_ctor(mem, size, arg, how);
393 #endif
394 	m = (struct mbuf *)arg;
395 	if (m != NULL) {
396 		switch (size) {
397 		case MCLBYTES:
398 			type = EXT_CLUSTER;
399 			break;
400 #if MJUMPAGESIZE != MCLBYTES
401 		case MJUMPAGESIZE:
402 			type = EXT_JUMBOP;
403 			break;
404 #endif
405 		case MJUM9BYTES:
406 			type = EXT_JUMBO9;
407 			break;
408 		case MJUM16BYTES:
409 			type = EXT_JUMBO16;
410 			break;
411 		default:
412 			panic("unknown cluster size");
413 			break;
414 		}
415 		m->m_ext.ext_buf = (caddr_t)mem;
416 		m->m_data = m->m_ext.ext_buf;
417 		m->m_flags |= M_EXT;
418 		m->m_ext.ext_free = NULL;
419 		m->m_ext.ext_args = NULL;
420 		m->m_ext.ext_size = size;
421 		m->m_ext.ext_type = type;
422 		m->m_ext.ref_cnt = uma_find_refcnt(zone_clust, mem);
423 		*m->m_ext.ref_cnt = 1;
424 	} else {
425 		refcnt =  uma_find_refcnt(zone_clust, mem);
426 		*refcnt = 1;
427 	}
428 	return (0);
429 }
430 
431 /*
432  * The Mbuf Cluster zone destructor.
433  */
434 static void
435 mb_dtor_clust(void *mem, int size, void *arg)
436 {
437 
438 	KASSERT(*(uma_find_refcnt(zone_clust, mem)) <= 1,
439 		("%s: refcnt incorrect %u", __func__,
440 		 *(uma_find_refcnt(zone_clust, mem))) );
441 #ifdef INVARIANTS
442 	trash_dtor(mem, size, arg);
443 #endif
444 }
445 
446 /*
447  * The Packet secondary zone's init routine, executed on the
448  * object's transition from mbuf keg slab to zone cache.
449  */
450 static int
451 mb_zinit_pack(void *mem, int size, int how)
452 {
453 	struct mbuf *m;
454 
455 	m = (struct mbuf *)mem;		/* m is virgin. */
456 	if (uma_zalloc_arg(zone_clust, m, how) == NULL ||
457 	    m->m_ext.ext_buf == NULL)
458 		return (ENOMEM);
459 	m->m_ext.ext_type = EXT_PACKET;	/* Override. */
460 #ifdef INVARIANTS
461 	trash_init(m->m_ext.ext_buf, MCLBYTES, how);
462 #endif
463 	return (0);
464 }
465 
466 /*
467  * The Packet secondary zone's fini routine, executed on the
468  * object's transition from zone cache to keg slab.
469  */
470 static void
471 mb_zfini_pack(void *mem, int size)
472 {
473 	struct mbuf *m;
474 
475 	m = (struct mbuf *)mem;
476 #ifdef INVARIANTS
477 	trash_fini(m->m_ext.ext_buf, MCLBYTES);
478 #endif
479 	uma_zfree_arg(zone_clust, m->m_ext.ext_buf, NULL);
480 #ifdef INVARIANTS
481 	trash_dtor(mem, size, NULL);
482 #endif
483 }
484 
485 /*
486  * The "packet" keg constructor.
487  */
488 static int
489 mb_ctor_pack(void *mem, int size, void *arg, int how)
490 {
491 	struct mbuf *m;
492 	struct mb_args *args;
493 #ifdef MAC
494 	int error;
495 #endif
496 	int flags;
497 	short type;
498 
499 	m = (struct mbuf *)mem;
500 	args = (struct mb_args *)arg;
501 	flags = args->flags;
502 	type = args->type;
503 
504 #ifdef INVARIANTS
505 	trash_ctor(m->m_ext.ext_buf, MCLBYTES, arg, how);
506 #endif
507 	m->m_next = NULL;
508 	m->m_nextpkt = NULL;
509 	m->m_data = m->m_ext.ext_buf;
510 	m->m_len = 0;
511 	m->m_flags = (flags | M_EXT);
512 	m->m_type = type;
513 
514 	if (flags & M_PKTHDR) {
515 		m->m_pkthdr.rcvif = NULL;
516 		m->m_pkthdr.len = 0;
517 		m->m_pkthdr.header = NULL;
518 		m->m_pkthdr.csum_flags = 0;
519 		m->m_pkthdr.csum_data = 0;
520 		m->m_pkthdr.tso_segsz = 0;
521 		m->m_pkthdr.ether_vtag = 0;
522 		SLIST_INIT(&m->m_pkthdr.tags);
523 #ifdef MAC
524 		/* If the label init fails, fail the alloc */
525 		error = mac_init_mbuf(m, how);
526 		if (error)
527 			return (error);
528 #endif
529 	}
530 	/* m_ext is already initialized. */
531 
532 	return (0);
533 }
534 
535 /*
536  * This is the protocol drain routine.
537  *
538  * No locks should be held when this is called.  The drain routines have to
539  * presently acquire some locks which raises the possibility of lock order
540  * reversal.
541  */
542 static void
543 mb_reclaim(void *junk)
544 {
545 	struct domain *dp;
546 	struct protosw *pr;
547 
548 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK | WARN_PANIC, NULL,
549 	    "mb_reclaim()");
550 
551 	for (dp = domains; dp != NULL; dp = dp->dom_next)
552 		for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
553 			if (pr->pr_drain != NULL)
554 				(*pr->pr_drain)();
555 }
556