FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_mbuf.c
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: releng/11.0/sys/kern/kern_mbuf.c 300113 2016-05-18 04:35:58Z scottl $");
30
31 #include "opt_param.h"
32
33 #include <sys/param.h>
34 #include <sys/malloc.h>
35 #include <sys/types.h>
36 #include <sys/systm.h>
37 #include <sys/mbuf.h>
38 #include <sys/domain.h>
39 #include <sys/eventhandler.h>
40 #include <sys/kernel.h>
41 #include <sys/lock.h>
42 #include <sys/mutex.h>
43 #include <sys/protosw.h>
44 #include <sys/smp.h>
45 #include <sys/sysctl.h>
46
47 #include <vm/vm.h>
48 #include <vm/vm_extern.h>
49 #include <vm/vm_kern.h>
50 #include <vm/vm_page.h>
51 #include <vm/vm_map.h>
52 #include <vm/uma.h>
53 #include <vm/uma_dbg.h>
54
55 /*
56 * In FreeBSD, Mbufs and Mbuf Clusters are allocated from UMA
57 * Zones.
58 *
59 * Mbuf Clusters (2K, contiguous) are allocated from the Cluster
60 * Zone. The Zone can be capped at kern.ipc.nmbclusters, if the
61 * administrator so desires.
62 *
63 * Mbufs are allocated from a UMA Master Zone called the Mbuf
64 * Zone.
65 *
66 * Additionally, FreeBSD provides a Packet Zone, which it
67 * configures as a Secondary Zone to the Mbuf Master Zone,
68 * thus sharing backend Slab kegs with the Mbuf Master Zone.
69 *
70 * Thus common-case allocations and locking are simplified:
71 *
72 * m_clget() m_getcl()
73 * | |
74 * | .------------>[(Packet Cache)] m_get(), m_gethdr()
75 * | | [ Packet ] |
76 * [(Cluster Cache)] [ Secondary ] [ (Mbuf Cache) ]
77 * [ Cluster Zone ] [ Zone ] [ Mbuf Master Zone ]
78 * | \________ |
79 * [ Cluster Keg ] \ /
80 * | [ Mbuf Keg ]
81 * [ Cluster Slabs ] |
82 * | [ Mbuf Slabs ]
83 * \____________(VM)_________________/
84 *
85 *
86 * Whenever an object is allocated with uma_zalloc() out of
87 * one of the Zones its _ctor_ function is executed. The same
88 * for any deallocation through uma_zfree() the _dtor_ function
89 * is executed.
90 *
91 * Caches are per-CPU and are filled from the Master Zone.
92 *
93 * Whenever an object is allocated from the underlying global
94 * memory pool it gets pre-initialized with the _zinit_ functions.
95 * When the Keg's are overfull objects get decommissioned with
96 * _zfini_ functions and free'd back to the global memory pool.
97 *
98 */
99
100 int nmbufs; /* limits number of mbufs */
101 int nmbclusters; /* limits number of mbuf clusters */
102 int nmbjumbop; /* limits number of page size jumbo clusters */
103 int nmbjumbo9; /* limits number of 9k jumbo clusters */
104 int nmbjumbo16; /* limits number of 16k jumbo clusters */
105
106 static quad_t maxmbufmem; /* overall real memory limit for all mbufs */
107
108 SYSCTL_QUAD(_kern_ipc, OID_AUTO, maxmbufmem, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &maxmbufmem, 0,
109 "Maximum real memory allocatable to various mbuf types");
110
111 /*
112 * tunable_mbinit() has to be run before any mbuf allocations are done.
113 */
114 static void
115 tunable_mbinit(void *dummy)
116 {
117 quad_t realmem;
118
119 /*
120 * The default limit for all mbuf related memory is 1/2 of all
121 * available kernel memory (physical or kmem).
122 * At most it can be 3/4 of available kernel memory.
123 */
124 realmem = qmin((quad_t)physmem * PAGE_SIZE, vm_kmem_size);
125 maxmbufmem = realmem / 2;
126 TUNABLE_QUAD_FETCH("kern.ipc.maxmbufmem", &maxmbufmem);
127 if (maxmbufmem > realmem / 4 * 3)
128 maxmbufmem = realmem / 4 * 3;
129
130 TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters);
131 if (nmbclusters == 0)
132 nmbclusters = maxmbufmem / MCLBYTES / 4;
133
134 TUNABLE_INT_FETCH("kern.ipc.nmbjumbop", &nmbjumbop);
135 if (nmbjumbop == 0)
136 nmbjumbop = maxmbufmem / MJUMPAGESIZE / 4;
137
138 TUNABLE_INT_FETCH("kern.ipc.nmbjumbo9", &nmbjumbo9);
139 if (nmbjumbo9 == 0)
140 nmbjumbo9 = maxmbufmem / MJUM9BYTES / 6;
141
142 TUNABLE_INT_FETCH("kern.ipc.nmbjumbo16", &nmbjumbo16);
143 if (nmbjumbo16 == 0)
144 nmbjumbo16 = maxmbufmem / MJUM16BYTES / 6;
145
146 /*
147 * We need at least as many mbufs as we have clusters of
148 * the various types added together.
149 */
150 TUNABLE_INT_FETCH("kern.ipc.nmbufs", &nmbufs);
151 if (nmbufs < nmbclusters + nmbjumbop + nmbjumbo9 + nmbjumbo16)
152 nmbufs = lmax(maxmbufmem / MSIZE / 5,
153 nmbclusters + nmbjumbop + nmbjumbo9 + nmbjumbo16);
154 }
155 SYSINIT(tunable_mbinit, SI_SUB_KMEM, SI_ORDER_MIDDLE, tunable_mbinit, NULL);
156
157 static int
158 sysctl_nmbclusters(SYSCTL_HANDLER_ARGS)
159 {
160 int error, newnmbclusters;
161
162 newnmbclusters = nmbclusters;
163 error = sysctl_handle_int(oidp, &newnmbclusters, 0, req);
164 if (error == 0 && req->newptr && newnmbclusters != nmbclusters) {
165 if (newnmbclusters > nmbclusters &&
166 nmbufs >= nmbclusters + nmbjumbop + nmbjumbo9 + nmbjumbo16) {
167 nmbclusters = newnmbclusters;
168 nmbclusters = uma_zone_set_max(zone_clust, nmbclusters);
169 EVENTHANDLER_INVOKE(nmbclusters_change);
170 } else
171 error = EINVAL;
172 }
173 return (error);
174 }
175 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbclusters, CTLTYPE_INT|CTLFLAG_RW,
176 &nmbclusters, 0, sysctl_nmbclusters, "IU",
177 "Maximum number of mbuf clusters allowed");
178
179 static int
180 sysctl_nmbjumbop(SYSCTL_HANDLER_ARGS)
181 {
182 int error, newnmbjumbop;
183
184 newnmbjumbop = nmbjumbop;
185 error = sysctl_handle_int(oidp, &newnmbjumbop, 0, req);
186 if (error == 0 && req->newptr && newnmbjumbop != nmbjumbop) {
187 if (newnmbjumbop > nmbjumbop &&
188 nmbufs >= nmbclusters + nmbjumbop + nmbjumbo9 + nmbjumbo16) {
189 nmbjumbop = newnmbjumbop;
190 nmbjumbop = uma_zone_set_max(zone_jumbop, nmbjumbop);
191 } else
192 error = EINVAL;
193 }
194 return (error);
195 }
196 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbop, CTLTYPE_INT|CTLFLAG_RW,
197 &nmbjumbop, 0, sysctl_nmbjumbop, "IU",
198 "Maximum number of mbuf page size jumbo clusters allowed");
199
200 static int
201 sysctl_nmbjumbo9(SYSCTL_HANDLER_ARGS)
202 {
203 int error, newnmbjumbo9;
204
205 newnmbjumbo9 = nmbjumbo9;
206 error = sysctl_handle_int(oidp, &newnmbjumbo9, 0, req);
207 if (error == 0 && req->newptr && newnmbjumbo9 != nmbjumbo9) {
208 if (newnmbjumbo9 > nmbjumbo9 &&
209 nmbufs >= nmbclusters + nmbjumbop + nmbjumbo9 + nmbjumbo16) {
210 nmbjumbo9 = newnmbjumbo9;
211 nmbjumbo9 = uma_zone_set_max(zone_jumbo9, nmbjumbo9);
212 } else
213 error = EINVAL;
214 }
215 return (error);
216 }
217 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbo9, CTLTYPE_INT|CTLFLAG_RW,
218 &nmbjumbo9, 0, sysctl_nmbjumbo9, "IU",
219 "Maximum number of mbuf 9k jumbo clusters allowed");
220
221 static int
222 sysctl_nmbjumbo16(SYSCTL_HANDLER_ARGS)
223 {
224 int error, newnmbjumbo16;
225
226 newnmbjumbo16 = nmbjumbo16;
227 error = sysctl_handle_int(oidp, &newnmbjumbo16, 0, req);
228 if (error == 0 && req->newptr && newnmbjumbo16 != nmbjumbo16) {
229 if (newnmbjumbo16 > nmbjumbo16 &&
230 nmbufs >= nmbclusters + nmbjumbop + nmbjumbo9 + nmbjumbo16) {
231 nmbjumbo16 = newnmbjumbo16;
232 nmbjumbo16 = uma_zone_set_max(zone_jumbo16, nmbjumbo16);
233 } else
234 error = EINVAL;
235 }
236 return (error);
237 }
238 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbo16, CTLTYPE_INT|CTLFLAG_RW,
239 &nmbjumbo16, 0, sysctl_nmbjumbo16, "IU",
240 "Maximum number of mbuf 16k jumbo clusters allowed");
241
242 static int
243 sysctl_nmbufs(SYSCTL_HANDLER_ARGS)
244 {
245 int error, newnmbufs;
246
247 newnmbufs = nmbufs;
248 error = sysctl_handle_int(oidp, &newnmbufs, 0, req);
249 if (error == 0 && req->newptr && newnmbufs != nmbufs) {
250 if (newnmbufs > nmbufs) {
251 nmbufs = newnmbufs;
252 nmbufs = uma_zone_set_max(zone_mbuf, nmbufs);
253 EVENTHANDLER_INVOKE(nmbufs_change);
254 } else
255 error = EINVAL;
256 }
257 return (error);
258 }
259 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbufs, CTLTYPE_INT|CTLFLAG_RW,
260 &nmbufs, 0, sysctl_nmbufs, "IU",
261 "Maximum number of mbufs allowed");
262
263 /*
264 * Zones from which we allocate.
265 */
266 uma_zone_t zone_mbuf;
267 uma_zone_t zone_clust;
268 uma_zone_t zone_pack;
269 uma_zone_t zone_jumbop;
270 uma_zone_t zone_jumbo9;
271 uma_zone_t zone_jumbo16;
272
273 /*
274 * Local prototypes.
275 */
276 static int mb_ctor_mbuf(void *, int, void *, int);
277 static int mb_ctor_clust(void *, int, void *, int);
278 static int mb_ctor_pack(void *, int, void *, int);
279 static void mb_dtor_mbuf(void *, int, void *);
280 static void mb_dtor_pack(void *, int, void *);
281 static int mb_zinit_pack(void *, int, int);
282 static void mb_zfini_pack(void *, int);
283 static void mb_reclaim(uma_zone_t, int);
284 static void *mbuf_jumbo_alloc(uma_zone_t, vm_size_t, uint8_t *, int);
285
286 /* Ensure that MSIZE is a power of 2. */
287 CTASSERT((((MSIZE - 1) ^ MSIZE) + 1) >> 1 == MSIZE);
288
289 /*
290 * Initialize FreeBSD Network buffer allocation.
291 */
292 static void
293 mbuf_init(void *dummy)
294 {
295
296 /*
297 * Configure UMA zones for Mbufs, Clusters, and Packets.
298 */
299 zone_mbuf = uma_zcreate(MBUF_MEM_NAME, MSIZE,
300 mb_ctor_mbuf, mb_dtor_mbuf,
301 #ifdef INVARIANTS
302 trash_init, trash_fini,
303 #else
304 NULL, NULL,
305 #endif
306 MSIZE - 1, UMA_ZONE_MAXBUCKET);
307 if (nmbufs > 0)
308 nmbufs = uma_zone_set_max(zone_mbuf, nmbufs);
309 uma_zone_set_warning(zone_mbuf, "kern.ipc.nmbufs limit reached");
310 uma_zone_set_maxaction(zone_mbuf, mb_reclaim);
311
312 zone_clust = uma_zcreate(MBUF_CLUSTER_MEM_NAME, MCLBYTES,
313 mb_ctor_clust,
314 #ifdef INVARIANTS
315 trash_dtor, trash_init, trash_fini,
316 #else
317 NULL, NULL, NULL,
318 #endif
319 UMA_ALIGN_PTR, 0);
320 if (nmbclusters > 0)
321 nmbclusters = uma_zone_set_max(zone_clust, nmbclusters);
322 uma_zone_set_warning(zone_clust, "kern.ipc.nmbclusters limit reached");
323 uma_zone_set_maxaction(zone_clust, mb_reclaim);
324
325 zone_pack = uma_zsecond_create(MBUF_PACKET_MEM_NAME, mb_ctor_pack,
326 mb_dtor_pack, mb_zinit_pack, mb_zfini_pack, zone_mbuf);
327
328 /* Make jumbo frame zone too. Page size, 9k and 16k. */
329 zone_jumbop = uma_zcreate(MBUF_JUMBOP_MEM_NAME, MJUMPAGESIZE,
330 mb_ctor_clust,
331 #ifdef INVARIANTS
332 trash_dtor, trash_init, trash_fini,
333 #else
334 NULL, NULL, NULL,
335 #endif
336 UMA_ALIGN_PTR, 0);
337 if (nmbjumbop > 0)
338 nmbjumbop = uma_zone_set_max(zone_jumbop, nmbjumbop);
339 uma_zone_set_warning(zone_jumbop, "kern.ipc.nmbjumbop limit reached");
340 uma_zone_set_maxaction(zone_jumbop, mb_reclaim);
341
342 zone_jumbo9 = uma_zcreate(MBUF_JUMBO9_MEM_NAME, MJUM9BYTES,
343 mb_ctor_clust,
344 #ifdef INVARIANTS
345 trash_dtor, trash_init, trash_fini,
346 #else
347 NULL, NULL, NULL,
348 #endif
349 UMA_ALIGN_PTR, 0);
350 uma_zone_set_allocf(zone_jumbo9, mbuf_jumbo_alloc);
351 if (nmbjumbo9 > 0)
352 nmbjumbo9 = uma_zone_set_max(zone_jumbo9, nmbjumbo9);
353 uma_zone_set_warning(zone_jumbo9, "kern.ipc.nmbjumbo9 limit reached");
354 uma_zone_set_maxaction(zone_jumbo9, mb_reclaim);
355
356 zone_jumbo16 = uma_zcreate(MBUF_JUMBO16_MEM_NAME, MJUM16BYTES,
357 mb_ctor_clust,
358 #ifdef INVARIANTS
359 trash_dtor, trash_init, trash_fini,
360 #else
361 NULL, NULL, NULL,
362 #endif
363 UMA_ALIGN_PTR, 0);
364 uma_zone_set_allocf(zone_jumbo16, mbuf_jumbo_alloc);
365 if (nmbjumbo16 > 0)
366 nmbjumbo16 = uma_zone_set_max(zone_jumbo16, nmbjumbo16);
367 uma_zone_set_warning(zone_jumbo16, "kern.ipc.nmbjumbo16 limit reached");
368 uma_zone_set_maxaction(zone_jumbo16, mb_reclaim);
369
370 /*
371 * Hook event handler for low-memory situation, used to
372 * drain protocols and push data back to the caches (UMA
373 * later pushes it back to VM).
374 */
375 EVENTHANDLER_REGISTER(vm_lowmem, mb_reclaim, NULL,
376 EVENTHANDLER_PRI_FIRST);
377 }
378 SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbuf_init, NULL);
379
380 /*
381 * UMA backend page allocator for the jumbo frame zones.
382 *
383 * Allocates kernel virtual memory that is backed by contiguous physical
384 * pages.
385 */
386 static void *
387 mbuf_jumbo_alloc(uma_zone_t zone, vm_size_t bytes, uint8_t *flags, int wait)
388 {
389
390 /* Inform UMA that this allocator uses kernel_map/object. */
391 *flags = UMA_SLAB_KERNEL;
392 return ((void *)kmem_alloc_contig(kernel_arena, bytes, wait,
393 (vm_paddr_t)0, ~(vm_paddr_t)0, 1, 0, VM_MEMATTR_DEFAULT));
394 }
395
396 /*
397 * Constructor for Mbuf master zone.
398 *
399 * The 'arg' pointer points to a mb_args structure which
400 * contains call-specific information required to support the
401 * mbuf allocation API. See mbuf.h.
402 */
403 static int
404 mb_ctor_mbuf(void *mem, int size, void *arg, int how)
405 {
406 struct mbuf *m;
407 struct mb_args *args;
408 int error;
409 int flags;
410 short type;
411
412 #ifdef INVARIANTS
413 trash_ctor(mem, size, arg, how);
414 #endif
415 args = (struct mb_args *)arg;
416 type = args->type;
417
418 /*
419 * The mbuf is initialized later. The caller has the
420 * responsibility to set up any MAC labels too.
421 */
422 if (type == MT_NOINIT)
423 return (0);
424
425 m = (struct mbuf *)mem;
426 flags = args->flags;
427 MPASS((flags & M_NOFREE) == 0);
428
429 error = m_init(m, how, type, flags);
430
431 return (error);
432 }
433
434 /*
435 * The Mbuf master zone destructor.
436 */
437 static void
438 mb_dtor_mbuf(void *mem, int size, void *arg)
439 {
440 struct mbuf *m;
441 unsigned long flags;
442
443 m = (struct mbuf *)mem;
444 flags = (unsigned long)arg;
445
446 KASSERT((m->m_flags & M_NOFREE) == 0, ("%s: M_NOFREE set", __func__));
447 if (!(flags & MB_DTOR_SKIP) && (m->m_flags & M_PKTHDR) && !SLIST_EMPTY(&m->m_pkthdr.tags))
448 m_tag_delete_chain(m, NULL);
449 #ifdef INVARIANTS
450 trash_dtor(mem, size, arg);
451 #endif
452 }
453
454 /*
455 * The Mbuf Packet zone destructor.
456 */
457 static void
458 mb_dtor_pack(void *mem, int size, void *arg)
459 {
460 struct mbuf *m;
461
462 m = (struct mbuf *)mem;
463 if ((m->m_flags & M_PKTHDR) != 0)
464 m_tag_delete_chain(m, NULL);
465
466 /* Make sure we've got a clean cluster back. */
467 KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
468 KASSERT(m->m_ext.ext_buf != NULL, ("%s: ext_buf == NULL", __func__));
469 KASSERT(m->m_ext.ext_free == NULL, ("%s: ext_free != NULL", __func__));
470 KASSERT(m->m_ext.ext_arg1 == NULL, ("%s: ext_arg1 != NULL", __func__));
471 KASSERT(m->m_ext.ext_arg2 == NULL, ("%s: ext_arg2 != NULL", __func__));
472 KASSERT(m->m_ext.ext_size == MCLBYTES, ("%s: ext_size != MCLBYTES", __func__));
473 KASSERT(m->m_ext.ext_type == EXT_PACKET, ("%s: ext_type != EXT_PACKET", __func__));
474 #ifdef INVARIANTS
475 trash_dtor(m->m_ext.ext_buf, MCLBYTES, arg);
476 #endif
477 /*
478 * If there are processes blocked on zone_clust, waiting for pages
479 * to be freed up, * cause them to be woken up by draining the
480 * packet zone. We are exposed to a race here * (in the check for
481 * the UMA_ZFLAG_FULL) where we might miss the flag set, but that
482 * is deliberate. We don't want to acquire the zone lock for every
483 * mbuf free.
484 */
485 if (uma_zone_exhausted_nolock(zone_clust))
486 zone_drain(zone_pack);
487 }
488
489 /*
490 * The Cluster and Jumbo[PAGESIZE|9|16] zone constructor.
491 *
492 * Here the 'arg' pointer points to the Mbuf which we
493 * are configuring cluster storage for. If 'arg' is
494 * empty we allocate just the cluster without setting
495 * the mbuf to it. See mbuf.h.
496 */
497 static int
498 mb_ctor_clust(void *mem, int size, void *arg, int how)
499 {
500 struct mbuf *m;
501
502 #ifdef INVARIANTS
503 trash_ctor(mem, size, arg, how);
504 #endif
505 m = (struct mbuf *)arg;
506 if (m != NULL) {
507 m->m_ext.ext_buf = (caddr_t)mem;
508 m->m_data = m->m_ext.ext_buf;
509 m->m_flags |= M_EXT;
510 m->m_ext.ext_free = NULL;
511 m->m_ext.ext_arg1 = NULL;
512 m->m_ext.ext_arg2 = NULL;
513 m->m_ext.ext_size = size;
514 m->m_ext.ext_type = m_gettype(size);
515 m->m_ext.ext_flags = EXT_FLAG_EMBREF;
516 m->m_ext.ext_count = 1;
517 }
518
519 return (0);
520 }
521
522 /*
523 * The Packet secondary zone's init routine, executed on the
524 * object's transition from mbuf keg slab to zone cache.
525 */
526 static int
527 mb_zinit_pack(void *mem, int size, int how)
528 {
529 struct mbuf *m;
530
531 m = (struct mbuf *)mem; /* m is virgin. */
532 if (uma_zalloc_arg(zone_clust, m, how) == NULL ||
533 m->m_ext.ext_buf == NULL)
534 return (ENOMEM);
535 m->m_ext.ext_type = EXT_PACKET; /* Override. */
536 #ifdef INVARIANTS
537 trash_init(m->m_ext.ext_buf, MCLBYTES, how);
538 #endif
539 return (0);
540 }
541
542 /*
543 * The Packet secondary zone's fini routine, executed on the
544 * object's transition from zone cache to keg slab.
545 */
546 static void
547 mb_zfini_pack(void *mem, int size)
548 {
549 struct mbuf *m;
550
551 m = (struct mbuf *)mem;
552 #ifdef INVARIANTS
553 trash_fini(m->m_ext.ext_buf, MCLBYTES);
554 #endif
555 uma_zfree_arg(zone_clust, m->m_ext.ext_buf, NULL);
556 #ifdef INVARIANTS
557 trash_dtor(mem, size, NULL);
558 #endif
559 }
560
561 /*
562 * The "packet" keg constructor.
563 */
564 static int
565 mb_ctor_pack(void *mem, int size, void *arg, int how)
566 {
567 struct mbuf *m;
568 struct mb_args *args;
569 int error, flags;
570 short type;
571
572 m = (struct mbuf *)mem;
573 args = (struct mb_args *)arg;
574 flags = args->flags;
575 type = args->type;
576 MPASS((flags & M_NOFREE) == 0);
577
578 #ifdef INVARIANTS
579 trash_ctor(m->m_ext.ext_buf, MCLBYTES, arg, how);
580 #endif
581
582 error = m_init(m, how, type, flags);
583
584 /* m_ext is already initialized. */
585 m->m_data = m->m_ext.ext_buf;
586 m->m_flags = (flags | M_EXT);
587
588 return (error);
589 }
590
591 /*
592 * This is the protocol drain routine. Called by UMA whenever any of the
593 * mbuf zones is closed to its limit.
594 *
595 * No locks should be held when this is called. The drain routines have to
596 * presently acquire some locks which raises the possibility of lock order
597 * reversal.
598 */
599 static void
600 mb_reclaim(uma_zone_t zone __unused, int pending __unused)
601 {
602 struct domain *dp;
603 struct protosw *pr;
604
605 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK | WARN_PANIC, NULL, __func__);
606
607 for (dp = domains; dp != NULL; dp = dp->dom_next)
608 for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
609 if (pr->pr_drain != NULL)
610 (*pr->pr_drain)();
611 }
612
613 /*
614 * Clean up after mbufs with M_EXT storage attached to them if the
615 * reference count hits 1.
616 */
617 void
618 mb_free_ext(struct mbuf *m)
619 {
620 volatile u_int *refcnt;
621 struct mbuf *mref;
622 int freembuf;
623
624 KASSERT(m->m_flags & M_EXT, ("%s: M_EXT not set on %p", __func__, m));
625
626 /* See if this is the mbuf that holds the embedded refcount. */
627 if (m->m_ext.ext_flags & EXT_FLAG_EMBREF) {
628 refcnt = &m->m_ext.ext_count;
629 mref = m;
630 } else {
631 KASSERT(m->m_ext.ext_cnt != NULL,
632 ("%s: no refcounting pointer on %p", __func__, m));
633 refcnt = m->m_ext.ext_cnt;
634 mref = __containerof(refcnt, struct mbuf, m_ext.ext_count);
635 }
636
637 /*
638 * Check if the header is embedded in the cluster. It is
639 * important that we can't touch any of the mbuf fields
640 * after we have freed the external storage, since mbuf
641 * could have been embedded in it. For now, the mbufs
642 * embedded into the cluster are always of type EXT_EXTREF,
643 * and for this type we won't free the mref.
644 */
645 if (m->m_flags & M_NOFREE) {
646 freembuf = 0;
647 KASSERT(m->m_ext.ext_type == EXT_EXTREF,
648 ("%s: no-free mbuf %p has wrong type", __func__, m));
649 } else
650 freembuf = 1;
651
652 /* Free attached storage if this mbuf is the only reference to it. */
653 if (*refcnt == 1 || atomic_fetchadd_int(refcnt, -1) == 1) {
654 switch (m->m_ext.ext_type) {
655 case EXT_PACKET:
656 /* The packet zone is special. */
657 if (*refcnt == 0)
658 *refcnt = 1;
659 uma_zfree(zone_pack, mref);
660 break;
661 case EXT_CLUSTER:
662 uma_zfree(zone_clust, m->m_ext.ext_buf);
663 uma_zfree(zone_mbuf, mref);
664 break;
665 case EXT_JUMBOP:
666 uma_zfree(zone_jumbop, m->m_ext.ext_buf);
667 uma_zfree(zone_mbuf, mref);
668 break;
669 case EXT_JUMBO9:
670 uma_zfree(zone_jumbo9, m->m_ext.ext_buf);
671 uma_zfree(zone_mbuf, mref);
672 break;
673 case EXT_JUMBO16:
674 uma_zfree(zone_jumbo16, m->m_ext.ext_buf);
675 uma_zfree(zone_mbuf, mref);
676 break;
677 case EXT_SFBUF:
678 sf_ext_free(m->m_ext.ext_arg1, m->m_ext.ext_arg2);
679 uma_zfree(zone_mbuf, mref);
680 break;
681 case EXT_SFBUF_NOCACHE:
682 sf_ext_free_nocache(m->m_ext.ext_arg1,
683 m->m_ext.ext_arg2);
684 uma_zfree(zone_mbuf, mref);
685 break;
686 case EXT_NET_DRV:
687 case EXT_MOD_TYPE:
688 case EXT_DISPOSABLE:
689 KASSERT(m->m_ext.ext_free != NULL,
690 ("%s: ext_free not set", __func__));
691 (*(m->m_ext.ext_free))(m, m->m_ext.ext_arg1,
692 m->m_ext.ext_arg2);
693 uma_zfree(zone_mbuf, mref);
694 break;
695 case EXT_EXTREF:
696 KASSERT(m->m_ext.ext_free != NULL,
697 ("%s: ext_free not set", __func__));
698 (*(m->m_ext.ext_free))(m, m->m_ext.ext_arg1,
699 m->m_ext.ext_arg2);
700 break;
701 default:
702 KASSERT(m->m_ext.ext_type == 0,
703 ("%s: unknown ext_type", __func__));
704 }
705 }
706
707 if (freembuf && m != mref)
708 uma_zfree(zone_mbuf, m);
709 }
710
711 /*
712 * Official mbuf(9) allocation KPI for stack and drivers:
713 *
714 * m_get() - a single mbuf without any attachments, sys/mbuf.h.
715 * m_gethdr() - a single mbuf initialized as M_PKTHDR, sys/mbuf.h.
716 * m_getcl() - an mbuf + 2k cluster, sys/mbuf.h.
717 * m_clget() - attach cluster to already allocated mbuf.
718 * m_cljget() - attach jumbo cluster to already allocated mbuf.
719 * m_get2() - allocate minimum mbuf that would fit size argument.
720 * m_getm2() - allocate a chain of mbufs/clusters.
721 * m_extadd() - attach external cluster to mbuf.
722 *
723 * m_free() - free single mbuf with its tags and ext, sys/mbuf.h.
724 * m_freem() - free chain of mbufs.
725 */
726
727 int
728 m_clget(struct mbuf *m, int how)
729 {
730
731 KASSERT((m->m_flags & M_EXT) == 0, ("%s: mbuf %p has M_EXT",
732 __func__, m));
733 m->m_ext.ext_buf = (char *)NULL;
734 uma_zalloc_arg(zone_clust, m, how);
735 /*
736 * On a cluster allocation failure, drain the packet zone and retry,
737 * we might be able to loosen a few clusters up on the drain.
738 */
739 if ((how & M_NOWAIT) && (m->m_ext.ext_buf == NULL)) {
740 zone_drain(zone_pack);
741 uma_zalloc_arg(zone_clust, m, how);
742 }
743 MBUF_PROBE2(m__clget, m, how);
744 return (m->m_flags & M_EXT);
745 }
746
747 /*
748 * m_cljget() is different from m_clget() as it can allocate clusters without
749 * attaching them to an mbuf. In that case the return value is the pointer
750 * to the cluster of the requested size. If an mbuf was specified, it gets
751 * the cluster attached to it and the return value can be safely ignored.
752 * For size it takes MCLBYTES, MJUMPAGESIZE, MJUM9BYTES, MJUM16BYTES.
753 */
754 void *
755 m_cljget(struct mbuf *m, int how, int size)
756 {
757 uma_zone_t zone;
758 void *retval;
759
760 if (m != NULL) {
761 KASSERT((m->m_flags & M_EXT) == 0, ("%s: mbuf %p has M_EXT",
762 __func__, m));
763 m->m_ext.ext_buf = NULL;
764 }
765
766 zone = m_getzone(size);
767 retval = uma_zalloc_arg(zone, m, how);
768
769 MBUF_PROBE4(m__cljget, m, how, size, retval);
770
771 return (retval);
772 }
773
774 /*
775 * m_get2() allocates minimum mbuf that would fit "size" argument.
776 */
777 struct mbuf *
778 m_get2(int size, int how, short type, int flags)
779 {
780 struct mb_args args;
781 struct mbuf *m, *n;
782
783 args.flags = flags;
784 args.type = type;
785
786 if (size <= MHLEN || (size <= MLEN && (flags & M_PKTHDR) == 0))
787 return (uma_zalloc_arg(zone_mbuf, &args, how));
788 if (size <= MCLBYTES)
789 return (uma_zalloc_arg(zone_pack, &args, how));
790
791 if (size > MJUMPAGESIZE)
792 return (NULL);
793
794 m = uma_zalloc_arg(zone_mbuf, &args, how);
795 if (m == NULL)
796 return (NULL);
797
798 n = uma_zalloc_arg(zone_jumbop, m, how);
799 if (n == NULL) {
800 uma_zfree(zone_mbuf, m);
801 return (NULL);
802 }
803
804 return (m);
805 }
806
807 /*
808 * m_getjcl() returns an mbuf with a cluster of the specified size attached.
809 * For size it takes MCLBYTES, MJUMPAGESIZE, MJUM9BYTES, MJUM16BYTES.
810 */
811 struct mbuf *
812 m_getjcl(int how, short type, int flags, int size)
813 {
814 struct mb_args args;
815 struct mbuf *m, *n;
816 uma_zone_t zone;
817
818 if (size == MCLBYTES)
819 return m_getcl(how, type, flags);
820
821 args.flags = flags;
822 args.type = type;
823
824 m = uma_zalloc_arg(zone_mbuf, &args, how);
825 if (m == NULL)
826 return (NULL);
827
828 zone = m_getzone(size);
829 n = uma_zalloc_arg(zone, m, how);
830 if (n == NULL) {
831 uma_zfree(zone_mbuf, m);
832 return (NULL);
833 }
834 return (m);
835 }
836
837 /*
838 * Allocate a given length worth of mbufs and/or clusters (whatever fits
839 * best) and return a pointer to the top of the allocated chain. If an
840 * existing mbuf chain is provided, then we will append the new chain
841 * to the existing one but still return the top of the newly allocated
842 * chain.
843 */
844 struct mbuf *
845 m_getm2(struct mbuf *m, int len, int how, short type, int flags)
846 {
847 struct mbuf *mb, *nm = NULL, *mtail = NULL;
848
849 KASSERT(len >= 0, ("%s: len is < 0", __func__));
850
851 /* Validate flags. */
852 flags &= (M_PKTHDR | M_EOR);
853
854 /* Packet header mbuf must be first in chain. */
855 if ((flags & M_PKTHDR) && m != NULL)
856 flags &= ~M_PKTHDR;
857
858 /* Loop and append maximum sized mbufs to the chain tail. */
859 while (len > 0) {
860 if (len > MCLBYTES)
861 mb = m_getjcl(how, type, (flags & M_PKTHDR),
862 MJUMPAGESIZE);
863 else if (len >= MINCLSIZE)
864 mb = m_getcl(how, type, (flags & M_PKTHDR));
865 else if (flags & M_PKTHDR)
866 mb = m_gethdr(how, type);
867 else
868 mb = m_get(how, type);
869
870 /* Fail the whole operation if one mbuf can't be allocated. */
871 if (mb == NULL) {
872 if (nm != NULL)
873 m_freem(nm);
874 return (NULL);
875 }
876
877 /* Book keeping. */
878 len -= M_SIZE(mb);
879 if (mtail != NULL)
880 mtail->m_next = mb;
881 else
882 nm = mb;
883 mtail = mb;
884 flags &= ~M_PKTHDR; /* Only valid on the first mbuf. */
885 }
886 if (flags & M_EOR)
887 mtail->m_flags |= M_EOR; /* Only valid on the last mbuf. */
888
889 /* If mbuf was supplied, append new chain to the end of it. */
890 if (m != NULL) {
891 for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next)
892 ;
893 mtail->m_next = nm;
894 mtail->m_flags &= ~M_EOR;
895 } else
896 m = nm;
897
898 return (m);
899 }
900
901 /*-
902 * Configure a provided mbuf to refer to the provided external storage
903 * buffer and setup a reference count for said buffer.
904 *
905 * Arguments:
906 * mb The existing mbuf to which to attach the provided buffer.
907 * buf The address of the provided external storage buffer.
908 * size The size of the provided buffer.
909 * freef A pointer to a routine that is responsible for freeing the
910 * provided external storage buffer.
911 * args A pointer to an argument structure (of any type) to be passed
912 * to the provided freef routine (may be NULL).
913 * flags Any other flags to be passed to the provided mbuf.
914 * type The type that the external storage buffer should be
915 * labeled with.
916 *
917 * Returns:
918 * Nothing.
919 */
920 void
921 m_extadd(struct mbuf *mb, caddr_t buf, u_int size,
922 void (*freef)(struct mbuf *, void *, void *), void *arg1, void *arg2,
923 int flags, int type)
924 {
925
926 KASSERT(type != EXT_CLUSTER, ("%s: EXT_CLUSTER not allowed", __func__));
927
928 mb->m_flags |= (M_EXT | flags);
929 mb->m_ext.ext_buf = buf;
930 mb->m_data = mb->m_ext.ext_buf;
931 mb->m_ext.ext_size = size;
932 mb->m_ext.ext_free = freef;
933 mb->m_ext.ext_arg1 = arg1;
934 mb->m_ext.ext_arg2 = arg2;
935 mb->m_ext.ext_type = type;
936
937 if (type != EXT_EXTREF) {
938 mb->m_ext.ext_count = 1;
939 mb->m_ext.ext_flags = EXT_FLAG_EMBREF;
940 } else
941 mb->m_ext.ext_flags = 0;
942 }
943
944 /*
945 * Free an entire chain of mbufs and associated external buffers, if
946 * applicable.
947 */
948 void
949 m_freem(struct mbuf *mb)
950 {
951
952 MBUF_PROBE1(m__freem, mb);
953 while (mb != NULL)
954 mb = m_free(mb);
955 }
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