2 * Copyright (c) 2004 Jeffrey M. Hsu. All rights reserved.
3 * Copyright (c) 2004 The DragonFly Project. All rights reserved.
5 * This code is derived from software contributed to The DragonFly Project
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of The DragonFly Project nor the names of its
17 * contributors may be used to endorse or promote products derived
18 * from this software without specific, prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * Copyright (c) 2004 Jeffrey M. Hsu. All rights reserved.
37 * License terms: all terms for the DragonFly license above plus the following:
39 * 4. All advertising materials mentioning features or use of this software
40 * must display the following acknowledgement:
42 * This product includes software developed by Jeffrey M. Hsu
43 * for the DragonFly Project.
45 * This requirement may be waived with permission from Jeffrey Hsu.
46 * This requirement will sunset and may be removed on July 8 2005,
47 * after which the standard DragonFly license (as shown above) will
52 * Copyright (c) 1982, 1986, 1988, 1991, 1993
53 * The Regents of the University of California. All rights reserved.
55 * Redistribution and use in source and binary forms, with or without
56 * modification, are permitted provided that the following conditions
58 * 1. Redistributions of source code must retain the above copyright
59 * notice, this list of conditions and the following disclaimer.
60 * 2. Redistributions in binary form must reproduce the above copyright
61 * notice, this list of conditions and the following disclaimer in the
62 * documentation and/or other materials provided with the distribution.
63 * 3. All advertising materials mentioning features or use of this software
64 * must display the following acknowledgement:
65 * This product includes software developed by the University of
66 * California, Berkeley and its contributors.
67 * 4. Neither the name of the University nor the names of its contributors
68 * may be used to endorse or promote products derived from this software
69 * without specific prior written permission.
71 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
72 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
73 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
74 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
75 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
76 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
77 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
78 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
79 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
80 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
83 * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94
84 * $FreeBSD: src/sys/kern/uipc_mbuf.c,v 1.51.2.24 2003/04/15 06:59:29 silby Exp $
85 * $DragonFly: src/sys/kern/uipc_mbuf.c,v 1.35 2005/03/04 02:21:48 hsu Exp $
88 #include "opt_param.h"
89 #include "opt_mbuf_stress_test.h"
90 #include <sys/param.h>
91 #include <sys/systm.h>
92 #include <sys/malloc.h>
94 #include <sys/kernel.h>
95 #include <sys/sysctl.h>
96 #include <sys/domain.h>
97 #include <sys/protosw.h>
99 #include <sys/thread.h>
100 #include <sys/globaldata.h>
101 #include <sys/thread2.h>
104 #include <vm/vm_kern.h>
105 #include <vm/vm_extern.h>
108 #include <machine/cpu.h>
112 * mbuf cluster meta-data
114 typedef struct mbcluster {
115 struct mbcluster *mcl_next;
121 typedef struct mbuf *mbuf_t;
123 #define MCL_MAGIC 0x6d62636c
125 static void mbinit (void *);
126 SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbinit, NULL)
128 static u_long mbtypes[MT_NTYPES];
130 struct mbstat mbstat;
139 #ifdef MBUF_STRESS_TEST
140 int m_defragrandomfailures;
145 u_int m_mballoc_wid = 0;
146 u_int m_clalloc_wid = 0;
148 SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RW,
149 &max_linkhdr, 0, "");
150 SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RW,
151 &max_protohdr, 0, "");
152 SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RW, &max_hdr, 0, "");
153 SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW,
154 &max_datalen, 0, "");
155 SYSCTL_INT(_kern_ipc, OID_AUTO, mbuf_wait, CTLFLAG_RW,
157 SYSCTL_STRUCT(_kern_ipc, KIPC_MBSTAT, mbstat, CTLFLAG_RW, &mbstat, mbstat, "");
158 SYSCTL_OPAQUE(_kern_ipc, OID_AUTO, mbtypes, CTLFLAG_RD, mbtypes,
159 sizeof(mbtypes), "LU", "");
160 SYSCTL_INT(_kern_ipc, KIPC_NMBCLUSTERS, nmbclusters, CTLFLAG_RW,
161 &nmbclusters, 0, "Maximum number of mbuf clusters available");
162 SYSCTL_INT(_kern_ipc, OID_AUTO, nmbufs, CTLFLAG_RW, &nmbufs, 0,
163 "Maximum number of mbufs available");
164 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD,
165 &m_defragpackets, 0, "");
166 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD,
167 &m_defragbytes, 0, "");
168 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD,
169 &m_defraguseless, 0, "");
170 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD,
171 &m_defragfailure, 0, "");
172 #ifdef MBUF_STRESS_TEST
173 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW,
174 &m_defragrandomfailures, 0, "");
177 static int mcl_pool_count;
178 static int mcl_pool_max = 20;
179 static int mcl_free_max = 1000;
180 static int mbuf_free_max = 5000;
182 SYSCTL_INT(_kern_ipc, OID_AUTO, mcl_pool_max, CTLFLAG_RW, &mcl_pool_max, 0,
183 "Maximum number of mbufs+cluster in free list");
184 SYSCTL_INT(_kern_ipc, OID_AUTO, mcl_pool_count, CTLFLAG_RD, &mcl_pool_count, 0,
185 "Current number of mbufs+cluster in free list");
186 SYSCTL_INT(_kern_ipc, OID_AUTO, mcl_free_max, CTLFLAG_RW, &mcl_free_max, 0,
187 "Maximum number of clusters on the free list");
188 SYSCTL_INT(_kern_ipc, OID_AUTO, mbuf_free_max, CTLFLAG_RW, &mbuf_free_max, 0,
189 "Maximum number of mbufs on the free list");
191 static MALLOC_DEFINE(M_MBUF, "mbuf", "mbuf");
192 static MALLOC_DEFINE(M_MBUFCL, "mbufcl", "mbufcl");
194 static mbuf_t mmbfree;
195 static mbcluster_t mclfree;
196 static struct mbuf *mcl_pool;
198 static void m_reclaim (void);
199 static int m_mballoc(int nmb, int how);
200 static int m_clalloc(int ncl, int how);
201 static struct mbuf *m_mballoc_wait(int caller, int type);
202 static void m_mclref(void *arg);
203 static void m_mclfree(void *arg);
206 #define NMBCLUSTERS (512 + maxusers * 16)
209 #define NMBUFS (nmbclusters * 4)
213 * Perform sanity checks of tunables declared above.
216 tunable_mbinit(void *dummy)
220 * This has to be done before VM init.
222 nmbclusters = NMBCLUSTERS;
223 TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters);
225 TUNABLE_INT_FETCH("kern.ipc.nmbufs", &nmbufs);
227 if (nmbufs < nmbclusters * 2)
228 nmbufs = nmbclusters * 2;
232 SYSINIT(tunable_mbinit, SI_SUB_TUNABLES, SI_ORDER_ANY, tunable_mbinit, NULL);
234 /* "number of clusters of pages" */
245 mbstat.m_msize = MSIZE;
246 mbstat.m_mclbytes = MCLBYTES;
247 mbstat.m_minclsize = MINCLSIZE;
248 mbstat.m_mlen = MLEN;
249 mbstat.m_mhlen = MHLEN;
252 if (m_mballoc(NMB_INIT, MB_DONTWAIT) == 0)
254 #if MCLBYTES <= PAGE_SIZE
255 if (m_clalloc(NCL_INIT, MB_DONTWAIT) == 0)
258 /* It's OK to call contigmalloc in this context. */
259 if (m_clalloc(16, MB_WAIT) == 0)
270 * Allocate at least nmb mbufs and place on mbuf free list.
271 * Returns the number of mbufs successfully allocated, 0 if none.
273 * Must be called while in a critical section.
276 m_mballoc(int nmb, int how)
282 * If we've hit the mbuf limit, stop allocating (or trying to)
283 * in order to avoid exhausting kernel memory entirely.
285 if ((nmb + mbstat.m_mbufs) > nmbufs)
289 * Attempt to allocate the requested number of mbufs, terminate when
290 * the allocation fails but if blocking is allowed allocate at least
293 for (i = 0; i < nmb; ++i) {
294 m = malloc(MSIZE, M_MBUF, M_NOWAIT|M_NULLOK|M_ZERO);
296 if (how == MB_WAIT) {
298 m = malloc(MSIZE, M_MBUF,
299 M_WAITOK|M_NULLOK|M_ZERO);
314 * Once mbuf memory has been exhausted and if the call to the allocation macros
315 * (or, in some cases, functions) is with MB_WAIT, then it is necessary to rely
316 * solely on reclaimed mbufs. Here we wait for an mbuf to be freed for a
317 * designated (mbuf_wait) time.
320 m_mballoc_wait(int caller, int type)
326 if ((tsleep(&m_mballoc_wid, 0, "mballc", mbuf_wait)) == EWOULDBLOCK)
331 * Now that we (think) that we've got something, we will redo an
332 * MGET, but avoid getting into another instance of m_mballoc_wait()
333 * XXX: We retry to fetch _even_ if the sleep timed out. This is left
334 * this way, purposely, in the [unlikely] case that an mbuf was
335 * freed but the sleep was not awakened in time.
340 MGET(m, MB_DONTWAIT, type);
343 MGETHDR(m, MB_DONTWAIT, type);
346 panic("m_mballoc_wait: invalid caller (%d)", caller);
350 if (m != NULL) { /* We waited and got something... */
352 /* Wake up another if we have more free. */
360 #if MCLBYTES > PAGE_SIZE
361 static int i_want_my_mcl;
370 tsleep(&i_want_my_mcl, 0, "mclalloc", 0);
372 while (i_want_my_mcl > 0) {
373 if (m_clalloc(1, MB_WAIT) == 0)
374 printf("m_clalloc failed even in thread context!\n");
382 static struct thread *mclallocthread;
383 static struct kproc_desc mclalloc_kp = {
388 SYSINIT(mclallocthread, SI_SUB_KTHREAD_UPDATE, SI_ORDER_ANY, kproc_start,
393 * Allocate at least nmb mbuf clusters and place on mbuf free list.
394 * Returns the number of mbuf clusters successfully allocated, 0 if none.
396 * Must be called while in a critical section.
399 m_clalloc(int ncl, int how)
401 static int last_report;
407 * If we've hit the mbuf cluster limit, stop allocating (or trying to).
409 if ((ncl + mbstat.m_clusters) > nmbclusters)
413 * Attempt to allocate the requested number of mbuf clusters,
414 * terminate when the allocation fails but if blocking is allowed
415 * allocate at least one.
417 * We need to allocate two structures for each cluster... a
418 * ref counting / governing structure and the actual data. MCLBYTES
419 * should be a power of 2 which means that the slab allocator will
420 * return a buffer that does not cross a page boundary.
422 for (i = 0; i < ncl; ++i) {
426 mcl = malloc(sizeof(*mcl), M_MBUFCL, M_NOWAIT|M_NULLOK|M_ZERO);
428 if (how == MB_WAIT) {
430 mcl = malloc(sizeof(*mcl),
431 M_MBUFCL, M_WAITOK|M_NULLOK|M_ZERO);
438 * Physically contiguous data buffer.
440 #if MCLBYTES > PAGE_SIZE
441 if (how != MB_WAIT) {
442 i_want_my_mcl += ncl - i;
443 wakeup(&i_want_my_mcl);
447 data = contigmalloc_map(MCLBYTES, M_MBUFCL,
448 M_WAITOK, 0ul, ~0ul, PAGE_SIZE, 0, kernel_map);
451 data = malloc(MCLBYTES, M_MBUFCL, M_NOWAIT|M_NULLOK);
453 if (how == MB_WAIT) {
455 data = malloc(MCLBYTES, M_MBUFCL,
464 mcl->mcl_next = mclfree;
465 mcl->mcl_data = data;
466 mcl->mcl_magic = MCL_MAGIC;
475 * If we could not allocate any report failure no more often then
480 if (ticks < last_report || (ticks - last_report) >= hz) {
482 printf("All mbuf clusters exhausted, please see tuning(7).\n");
489 * Once cluster memory has been exhausted and the allocation is called with
490 * MB_WAIT, we rely on the mclfree pointers. If nothing is free, we will
491 * sleep for a designated amount of time (mbuf_wait) or until we're woken up
492 * due to sudden mcluster availability.
494 * Must be called while in a critical section.
499 /* If in interrupt context, and INVARIANTS, maintain sanity and die. */
500 KASSERT(mycpu->gd_intr_nesting_level == 0,
501 ("CLALLOC: CANNOT WAIT IN INTERRUPT"));
504 * Sleep until something's available or until we expire.
507 if ((tsleep(&m_clalloc_wid, 0, "mclalc", mbuf_wait)) == EWOULDBLOCK)
511 * Try the allocation once more, and if we see mor then two
512 * free entries wake up others as well.
514 m_clalloc(1, MB_WAIT);
515 if (mclfree && mclfree->mcl_next) {
521 * Return the number of references to this mbuf's data. 0 is returned
522 * if the mbuf is not M_EXT, a reference count is returned if it is
523 * M_EXT|M_EXT_CLUSTER, and 99 is returned if it is a special M_EXT.
526 m_sharecount(struct mbuf *m)
530 switch(m->m_flags & (M_EXT|M_EXT_CLUSTER)) {
537 case M_EXT|M_EXT_CLUSTER:
538 count = ((mbcluster_t)m->m_ext.ext_arg)->mcl_refs;
541 panic("bad mbuf flags: %p", m);
548 * change mbuf to new type
551 m_chtype(struct mbuf *m, int type)
554 --mbtypes[m->m_type];
561 * When MGET fails, ask protocols to free space when short of memory,
562 * then re-attempt to allocate an mbuf.
565 m_retry(int how, int t)
570 * Must only do the reclaim if not in an interrupt context.
572 if (how == MB_WAIT) {
573 KASSERT(mycpu->gd_intr_nesting_level == 0,
574 ("MBALLOC: CANNOT WAIT IN INTERRUPT"));
579 * Try to pull a new mbuf out of the cache, if the cache is empty
580 * try to allocate a new one and if that doesn't work we give up.
583 if ((m = mmbfree) == NULL) {
585 if ((m = mmbfree) == NULL) {
586 static int last_report;
590 if (ticks < last_report ||
591 (ticks - last_report) >= hz) {
593 printf("All mbufs exhausted, please see tuning(7).\n");
600 * Cache case, adjust globals before leaving the critical section
611 m->m_data = m->m_dat;
617 * As above; retry an MGETHDR.
620 m_retryhdr(int how, int t)
625 * Must only do the reclaim if not in an interrupt context.
627 if (how == MB_WAIT) {
628 KASSERT(mycpu->gd_intr_nesting_level == 0,
629 ("MBALLOC: CANNOT WAIT IN INTERRUPT"));
634 * Try to pull a new mbuf out of the cache, if the cache is empty
635 * try to allocate a new one and if that doesn't work we give up.
638 if ((m = mmbfree) == NULL) {
640 if ((m = mmbfree) == NULL) {
641 static int last_report;
645 if (ticks < last_report ||
646 (ticks - last_report) >= hz) {
648 printf("All mbufs exhausted, please see tuning(7).\n");
655 * Cache case, adjust globals before leaving the critical section
666 m->m_data = m->m_pktdat;
667 m->m_flags = M_PKTHDR;
668 m->m_pkthdr.rcvif = NULL;
669 SLIST_INIT(&m->m_pkthdr.tags);
670 m->m_pkthdr.csum_flags = 0;
681 SLIST_FOREACH(dp, &domains, dom_next) {
682 for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) {
692 * Allocate an mbuf. If no mbufs are immediately available try to
693 * bring a bunch more into our cache (mmbfree list). A critical
694 * section is required to protect the mmbfree list and counters
695 * against interrupts.
698 m_get(int how, int type)
703 * Try to pull a new mbuf out of the cache, if the cache is empty
704 * try to allocate a new one and if that doesn't work try even harder
705 * by calling m_retryhdr().
708 if ((m = mmbfree) == NULL) {
710 if ((m = mmbfree) == NULL) {
712 m = m_retry(how, type);
713 if (m == NULL && how == MB_WAIT)
714 m = m_mballoc_wait(MGET_C, type);
720 * Cache case, adjust globals before leaving the critical section
730 m->m_data = m->m_dat;
736 m_gethdr(int how, int type)
741 * Try to pull a new mbuf out of the cache, if the cache is empty
742 * try to allocate a new one and if that doesn't work try even harder
743 * by calling m_retryhdr().
746 if ((m = mmbfree) == NULL) {
748 if ((m = mmbfree) == NULL) {
750 m = m_retryhdr(how, type);
751 if (m == NULL && how == MB_WAIT)
752 m = m_mballoc_wait(MGETHDR_C, type);
758 * Cache case, adjust globals before leaving the critical section
768 m->m_data = m->m_pktdat;
769 m->m_flags = M_PKTHDR;
770 m->m_pkthdr.rcvif = NULL;
771 SLIST_INIT(&m->m_pkthdr.tags);
772 m->m_pkthdr.csum_flags = 0;
773 m->m_pkthdr.fw_flags = 0;
778 m_getclr(int how, int type)
782 if ((m = m_get(how, type)) != NULL) {
783 bzero(mtod(m, caddr_t), MLEN);
789 * m_getcl() returns an mbuf with an attached cluster.
790 * Because many network drivers use this kind of buffers a lot, it is
791 * convenient to keep a small pool of free buffers of this kind.
792 * Even a small size such as 10 gives about 10% improvement in the
793 * forwarding rate in a bridge or router.
794 * The size of this free list is controlled by the sysctl variable
795 * mcl_pool_max. The list is populated on m_freem(), and used in
796 * m_getcl() if elements are available.
799 m_getcl(int how, short type, int flags)
804 if (flags & M_PKTHDR) {
805 if (type == MT_DATA && mcl_pool) {
807 mcl_pool = mp->m_nextpkt;
810 mp->m_nextpkt = NULL;
811 mp->m_data = mp->m_ext.ext_buf;
812 mp->m_flags = M_PKTHDR|M_EXT|M_EXT_CLUSTER;
813 mp->m_pkthdr.rcvif = NULL;
814 mp->m_pkthdr.csum_flags = 0;
817 MGETHDR(mp, how, type);
823 if ((mp->m_flags & M_EXT) == 0) {
834 * m_getm(m, len, how, type)
836 * This will allocate len-worth of mbufs and/or mbuf clusters (whatever fits
837 * best) and return a pointer to the top of the allocated chain. If m is
838 * non-null, then we assume that it is a single mbuf or an mbuf chain to
839 * which we want len bytes worth of mbufs and/or clusters attached, and so
840 * if we succeed in allocating it, we will just return a pointer to m.
842 * If we happen to fail at any point during the allocation, we will free
843 * up everything we have already allocated and return NULL.
847 m_getm(struct mbuf *m, int len, int how, int type)
849 struct mbuf *top, *tail, *mp, *mtail = NULL;
851 KASSERT(len >= 0, ("len is < 0 in m_getm"));
853 mp = m_get(how, type);
856 } else if (len > MINCLSIZE) {
858 if ((mp->m_flags & M_EXT) == 0) {
864 len -= M_TRAILINGSPACE(mp);
867 for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next)
875 mp = m_get(how, type);
881 if (len > MINCLSIZE) {
883 if ((mp->m_flags & M_EXT) == 0)
888 len -= M_TRAILINGSPACE(mp);
900 * m_mclget() - Adds a cluster to a normal mbuf, M_EXT is set on success.
903 m_mclget(struct mbuf *m, int how)
907 KKASSERT((m->m_flags & M_EXT_OLD) == 0);
910 * Allocate a cluster, return if we can't get one.
913 if ((mcl = mclfree) == NULL) {
915 if ((mcl = mclfree) == NULL) {
916 if (how == MB_WAIT) {
928 * We have a cluster, unlink it from the free list and set the ref
931 KKASSERT(mcl->mcl_refs == 0);
932 mclfree = mcl->mcl_next;
938 * Add the cluster to the mbuf. The caller will detect that the
939 * mbuf now has an attached cluster.
941 m->m_ext.ext_arg = mcl;
942 m->m_ext.ext_buf = mcl->mcl_data;
943 m->m_ext.ext_nref.new = m_mclref;
944 m->m_ext.ext_nfree.new = m_mclfree;
945 m->m_ext.ext_size = MCLBYTES;
947 m->m_data = m->m_ext.ext_buf;
948 m->m_flags |= M_EXT | M_EXT_CLUSTER;
954 mbcluster_t mcl = arg;
956 KKASSERT(mcl->mcl_magic == MCL_MAGIC);
957 KKASSERT(mcl->mcl_refs > 0);
959 if (--mcl->mcl_refs == 0) {
960 if (mbstat.m_clfree < mcl_free_max) {
961 mcl->mcl_next = mclfree;
967 free(mcl->mcl_data, M_MBUFCL);
978 mbcluster_t mcl = arg;
980 KKASSERT(mcl->mcl_magic == MCL_MAGIC);
987 * Helper routines for M_EXT reference/free
990 m_extref(const struct mbuf *m)
992 KKASSERT(m->m_ext.ext_nfree.any != NULL);
994 if (m->m_flags & M_EXT_OLD)
995 m->m_ext.ext_nref.old(m->m_ext.ext_buf, m->m_ext.ext_size);
997 m->m_ext.ext_nref.new(m->m_ext.ext_arg);
1004 * Free a single mbuf and any associated external storage. The successor,
1005 * if any, is returned.
1007 * We do need to check non-first mbuf for m_aux, since some of existing
1008 * code does not call M_PREPEND properly.
1009 * (example: call to bpf_mtap from drivers)
1012 m_free(struct mbuf *m)
1017 KASSERT(m->m_type != MT_FREE, ("freeing free mbuf %p", m));
1020 * Adjust our type count and delete any attached chains if the
1021 * mbuf is a packet header.
1023 if ((m->m_flags & M_PKTHDR) != 0)
1024 m_tag_delete_chain(m, NULL);
1027 * Place the mbuf on the appropriate free list. Try to maintain a
1028 * small cache of mbuf+cluster pairs.
1032 if (m->m_flags & M_EXT) {
1033 KKASSERT(m->m_ext.ext_nfree.any != NULL);
1034 if (mcl_pool_count < mcl_pool_max && m && m->m_next == NULL &&
1035 (m->m_flags & (M_PKTHDR|M_EXT_CLUSTER)) == (M_PKTHDR|M_EXT_CLUSTER) &&
1036 m->m_type == MT_DATA && M_EXT_WRITABLE(m) ) {
1037 KKASSERT(((mbcluster_t)m->m_ext.ext_arg)->mcl_magic == MCL_MAGIC);
1038 m->m_nextpkt = mcl_pool;
1043 if (m->m_flags & M_EXT_OLD)
1044 m->m_ext.ext_nfree.old(m->m_ext.ext_buf, m->m_ext.ext_size);
1046 m->m_ext.ext_nfree.new(m->m_ext.ext_arg);
1048 m->m_ext.ext_arg = NULL;
1049 m->m_ext.ext_nref.new = NULL;
1050 m->m_ext.ext_nfree.new = NULL;
1054 --mbtypes[m->m_type];
1055 if (mbtypes[MT_FREE] < mbuf_free_max) {
1056 m->m_type = MT_FREE;
1058 m->m_next = mmbfree;
1071 m_freem(struct mbuf *m)
1080 * Mbuffer utility routines.
1084 * Lesser-used path for M_PREPEND:
1085 * allocate new mbuf to prepend to chain,
1089 m_prepend(struct mbuf *m, int len, int how)
1093 MGET(mn, how, m->m_type);
1094 if (mn == (struct mbuf *)NULL) {
1096 return ((struct mbuf *)NULL);
1098 if (m->m_flags & M_PKTHDR)
1099 M_MOVE_PKTHDR(mn, m);
1109 * Make a copy of an mbuf chain starting "off0" bytes from the beginning,
1110 * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf.
1111 * The wait parameter is a choice of MB_WAIT/MB_DONTWAIT from caller.
1112 * Note that the copy is read-only, because clusters are not copied,
1113 * only their reference counts are incremented.
1115 #define MCFail (mbstat.m_mcfail)
1118 m_copym(const struct mbuf *m, int off0, int len, int wait)
1120 struct mbuf *n, **np;
1125 KASSERT(off >= 0, ("m_copym, negative off %d", off));
1126 KASSERT(len >= 0, ("m_copym, negative len %d", len));
1127 if (off == 0 && m->m_flags & M_PKTHDR)
1130 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain"));
1140 KASSERT(len == M_COPYALL,
1141 ("m_copym, length > size of mbuf chain"));
1144 MGET(n, wait, m->m_type);
1149 if (!m_dup_pkthdr(n, m, wait))
1151 if (len == M_COPYALL)
1152 n->m_pkthdr.len -= off0;
1154 n->m_pkthdr.len = len;
1157 n->m_len = min(len, m->m_len - off);
1158 if (m->m_flags & M_EXT) {
1159 n->m_data = m->m_data + off;
1161 n->m_ext = m->m_ext;
1162 n->m_flags |= m->m_flags &
1163 (M_EXT | M_EXT_OLD | M_EXT_CLUSTER);
1165 bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
1166 (unsigned)n->m_len);
1168 if (len != M_COPYALL)
1184 * Copy an entire packet, including header (which must be present).
1185 * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'.
1186 * Note that the copy is read-only, because clusters are not copied,
1187 * only their reference counts are incremented.
1188 * Preserve alignment of the first mbuf so if the creator has left
1189 * some room at the beginning (e.g. for inserting protocol headers)
1190 * the copies also have the room available.
1193 m_copypacket(struct mbuf *m, int how)
1195 struct mbuf *top, *n, *o;
1197 MGET(n, how, m->m_type);
1202 if (!m_dup_pkthdr(n, m, how))
1204 n->m_len = m->m_len;
1205 if (m->m_flags & M_EXT) {
1206 n->m_data = m->m_data;
1208 n->m_ext = m->m_ext;
1209 n->m_flags |= m->m_flags & (M_EXT | M_EXT_OLD | M_EXT_CLUSTER);
1211 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat );
1212 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
1217 MGET(o, how, m->m_type);
1224 n->m_len = m->m_len;
1225 if (m->m_flags & M_EXT) {
1226 n->m_data = m->m_data;
1228 n->m_ext = m->m_ext;
1229 n->m_flags |= m->m_flags &
1230 (M_EXT | M_EXT_OLD | M_EXT_CLUSTER);
1232 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
1245 * Copy data from an mbuf chain starting "off" bytes from the beginning,
1246 * continuing for "len" bytes, into the indicated buffer.
1249 m_copydata(const struct mbuf *m, int off, int len, caddr_t cp)
1253 KASSERT(off >= 0, ("m_copydata, negative off %d", off));
1254 KASSERT(len >= 0, ("m_copydata, negative len %d", len));
1256 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain"));
1263 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain"));
1264 count = min(m->m_len - off, len);
1265 bcopy(mtod(m, caddr_t) + off, cp, count);
1274 * Copy a packet header mbuf chain into a completely new chain, including
1275 * copying any mbuf clusters. Use this instead of m_copypacket() when
1276 * you need a writable copy of an mbuf chain.
1279 m_dup(struct mbuf *m, int how)
1281 struct mbuf **p, *top = NULL;
1282 int remain, moff, nsize;
1287 KASSERT((m->m_flags & M_PKTHDR) != 0, ("%s: !PKTHDR", __func__));
1289 /* While there's more data, get a new mbuf, tack it on, and fill it */
1290 remain = m->m_pkthdr.len;
1293 while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */
1296 /* Get the next new mbuf */
1297 MGET(n, how, m->m_type);
1300 if (top == NULL) { /* first one, must be PKTHDR */
1301 if (!m_dup_pkthdr(n, m, how))
1304 } else /* not the first one */
1306 if (remain >= MINCLSIZE) {
1308 if ((n->m_flags & M_EXT) == 0) {
1316 /* Link it into the new chain */
1320 /* Copy data from original mbuf(s) into new mbuf */
1321 while (n->m_len < nsize && m != NULL) {
1322 int chunk = min(nsize - n->m_len, m->m_len - moff);
1324 bcopy(m->m_data + moff, n->m_data + n->m_len, chunk);
1328 if (moff == m->m_len) {
1334 /* Check correct total mbuf length */
1335 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL),
1336 ("%s: bogus m_pkthdr.len", __func__));
1347 * Concatenate mbuf chain n to m.
1348 * Both chains must be of the same type (e.g. MT_DATA).
1349 * Any m_pkthdr is not updated.
1352 m_cat(struct mbuf *m, struct mbuf *n)
1357 if (m->m_flags & M_EXT ||
1358 m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) {
1359 /* just join the two chains */
1363 /* splat the data from one into the other */
1364 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
1366 m->m_len += n->m_len;
1372 m_adj(struct mbuf *mp, int req_len)
1378 if ((m = mp) == NULL)
1384 while (m != NULL && len > 0) {
1385 if (m->m_len <= len) {
1396 if (mp->m_flags & M_PKTHDR)
1397 m->m_pkthdr.len -= (req_len - len);
1400 * Trim from tail. Scan the mbuf chain,
1401 * calculating its length and finding the last mbuf.
1402 * If the adjustment only affects this mbuf, then just
1403 * adjust and return. Otherwise, rescan and truncate
1404 * after the remaining size.
1410 if (m->m_next == (struct mbuf *)0)
1414 if (m->m_len >= len) {
1416 if (mp->m_flags & M_PKTHDR)
1417 mp->m_pkthdr.len -= len;
1424 * Correct length for chain is "count".
1425 * Find the mbuf with last data, adjust its length,
1426 * and toss data from remaining mbufs on chain.
1429 if (m->m_flags & M_PKTHDR)
1430 m->m_pkthdr.len = count;
1431 for (; m; m = m->m_next) {
1432 if (m->m_len >= count) {
1439 (m = m->m_next) ->m_len = 0;
1444 * Rearange an mbuf chain so that len bytes are contiguous
1445 * and in the data area of an mbuf (so that mtod will work for a structure
1446 * of size len). Returns the resulting mbuf chain on success, frees it and
1447 * returns null on failure. If there is room, it will add up to
1448 * max_protohdr-len extra bytes to the contiguous region in an attempt to
1449 * avoid being called next time.
1451 #define MPFail (mbstat.m_mpfail)
1454 m_pullup(struct mbuf *n, int len)
1461 * If first mbuf has no cluster, and has room for len bytes
1462 * without shifting current data, pullup into it,
1463 * otherwise allocate a new mbuf to prepend to the chain.
1465 if ((n->m_flags & M_EXT) == 0 &&
1466 n->m_data + len < &n->m_dat[MLEN] && n->m_next) {
1467 if (n->m_len >= len)
1475 MGET(m, MB_DONTWAIT, n->m_type);
1479 if (n->m_flags & M_PKTHDR)
1480 M_MOVE_PKTHDR(m, n);
1482 space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
1484 count = min(min(max(len, max_protohdr), space), n->m_len);
1485 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
1495 } while (len > 0 && n);
1509 * Partition an mbuf chain in two pieces, returning the tail --
1510 * all but the first len0 bytes. In case of failure, it returns NULL and
1511 * attempts to restore the chain to its original state.
1513 * Note that the resulting mbufs might be read-only, because the new
1514 * mbuf can end up sharing an mbuf cluster with the original mbuf if
1515 * the "breaking point" happens to lie within a cluster mbuf. Use the
1516 * M_WRITABLE() macro to check for this case.
1519 m_split(struct mbuf *m0, int len0, int wait)
1522 unsigned len = len0, remain;
1524 for (m = m0; m && len > m->m_len; m = m->m_next)
1528 remain = m->m_len - len;
1529 if (m0->m_flags & M_PKTHDR) {
1530 MGETHDR(n, wait, m0->m_type);
1533 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif;
1534 n->m_pkthdr.len = m0->m_pkthdr.len - len0;
1535 m0->m_pkthdr.len = len0;
1536 if (m->m_flags & M_EXT)
1538 if (remain > MHLEN) {
1539 /* m can't be the lead packet */
1541 n->m_next = m_split(m, len, wait);
1542 if (n->m_next == 0) {
1550 MH_ALIGN(n, remain);
1551 } else if (remain == 0) {
1556 MGET(n, wait, m->m_type);
1562 if (m->m_flags & M_EXT) {
1563 n->m_data = m->m_data + len;
1565 n->m_ext = m->m_ext;
1566 n->m_flags |= m->m_flags & (M_EXT | M_EXT_OLD | M_EXT_CLUSTER);
1568 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain);
1572 n->m_next = m->m_next;
1577 * Routine to copy from device local memory into mbufs.
1580 m_devget(char *buf, int totlen, int off0, struct ifnet *ifp,
1581 void (*copy) (char *from, caddr_t to, u_int len))
1584 struct mbuf *top = 0, **mp = ⊤
1585 int off = off0, len;
1592 cp += off + 2 * sizeof(u_short);
1593 totlen -= 2 * sizeof(u_short);
1595 MGETHDR(m, MB_DONTWAIT, MT_DATA);
1598 m->m_pkthdr.rcvif = ifp;
1599 m->m_pkthdr.len = totlen;
1602 while (totlen > 0) {
1604 MGET(m, MB_DONTWAIT, MT_DATA);
1611 len = min(totlen, epkt - cp);
1612 if (len >= MINCLSIZE) {
1613 MCLGET(m, MB_DONTWAIT);
1614 if (m->m_flags & M_EXT)
1615 m->m_len = len = min(len, MCLBYTES);
1620 * Place initial small packet/header at end of mbuf.
1622 if (len < m->m_len) {
1623 if (top == 0 && len + max_linkhdr <= m->m_len)
1624 m->m_data += max_linkhdr;
1630 copy(cp, mtod(m, caddr_t), (unsigned)len);
1632 bcopy(cp, mtod(m, caddr_t), (unsigned)len);
1644 * Copy data from a buffer back into the indicated mbuf chain,
1645 * starting "off" bytes from the beginning, extending the mbuf
1646 * chain if necessary.
1649 m_copyback(struct mbuf *m0, int off, int len, caddr_t cp)
1652 struct mbuf *m = m0, *n;
1657 while (off > (mlen = m->m_len)) {
1660 if (m->m_next == 0) {
1661 n = m_getclr(MB_DONTWAIT, m->m_type);
1664 n->m_len = min(MLEN, len + off);
1670 mlen = min (m->m_len - off, len);
1671 bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen);
1679 if (m->m_next == 0) {
1680 n = m_get(MB_DONTWAIT, m->m_type);
1683 n->m_len = min(MLEN, len);
1688 out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
1689 m->m_pkthdr.len = totlen;
1693 m_print(const struct mbuf *m)
1696 const struct mbuf *m2;
1698 len = m->m_pkthdr.len;
1701 printf("%p %*D\n", m2, m2->m_len, (u_char *)m2->m_data, "-");
1709 * "Move" mbuf pkthdr from "from" to "to".
1710 * "from" must have M_PKTHDR set, and "to" must be empty.
1713 m_move_pkthdr(struct mbuf *to, struct mbuf *from)
1715 KASSERT((to->m_flags & M_EXT) == 0, ("m_move_pkthdr: to has cluster"));
1717 to->m_flags = from->m_flags & M_COPYFLAGS;
1718 to->m_data = to->m_pktdat;
1719 to->m_pkthdr = from->m_pkthdr; /* especially tags */
1720 SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */
1721 from->m_flags &= ~M_PKTHDR;
1725 * Duplicate "from"'s mbuf pkthdr in "to".
1726 * "from" must have M_PKTHDR set, and "to" must be empty.
1727 * In particular, this does a deep copy of the packet tags.
1730 m_dup_pkthdr(struct mbuf *to, const struct mbuf *from, int how)
1732 to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT);
1733 if ((to->m_flags & M_EXT) == 0)
1734 to->m_data = to->m_pktdat;
1735 to->m_pkthdr = from->m_pkthdr;
1736 SLIST_INIT(&to->m_pkthdr.tags);
1737 return (m_tag_copy_chain(to, from, how));
1741 * Defragment a mbuf chain, returning the shortest possible
1742 * chain of mbufs and clusters. If allocation fails and
1743 * this cannot be completed, NULL will be returned, but
1744 * the passed in chain will be unchanged. Upon success,
1745 * the original chain will be freed, and the new chain
1748 * If a non-packet header is passed in, the original
1749 * mbuf (chain?) will be returned unharmed.
1751 * m_defrag_nofree doesn't free the passed in mbuf.
1754 m_defrag(struct mbuf *m0, int how)
1758 if ((m_new = m_defrag_nofree(m0, how)) == NULL)
1766 m_defrag_nofree(struct mbuf *m0, int how)
1768 struct mbuf *m_new = NULL, *m_final = NULL;
1769 int progress = 0, length;
1771 if (!(m0->m_flags & M_PKTHDR))
1774 #ifdef MBUF_STRESS_TEST
1775 if (m_defragrandomfailures) {
1776 int temp = arc4random() & 0xff;
1782 if (m0->m_pkthdr.len > MHLEN)
1783 m_final = m_getcl(how, MT_DATA, M_PKTHDR);
1785 m_final = m_gethdr(how, MT_DATA);
1787 if (m_final == NULL)
1790 if (m_dup_pkthdr(m_final, m0, how) == NULL)
1795 while (progress < m0->m_pkthdr.len) {
1796 length = m0->m_pkthdr.len - progress;
1797 if (length > MCLBYTES)
1800 if (m_new == NULL) {
1802 m_new = m_getcl(how, MT_DATA, 0);
1804 m_new = m_get(how, MT_DATA);
1809 m_copydata(m0, progress, length, mtod(m_new, caddr_t));
1811 m_new->m_len = length;
1812 if (m_new != m_final)
1813 m_cat(m_final, m_new);
1816 if (m0->m_next == NULL)
1819 m_defragbytes += m_final->m_pkthdr.len;
1831 * Move data from uio into mbufs.
1832 * A length of zero means copy the whole uio.
1835 m_uiomove(struct uio *uio, int wait, int len0)
1837 struct mbuf *head; /* result mbuf chain */
1838 struct mbuf *m; /* current working mbuf */
1840 int resid, datalen, error;
1842 resid = (len0 == 0) ? uio->uio_resid : min(len0, uio->uio_resid);
1847 if (resid > MHLEN) {
1848 m = m_getcl(wait, MT_DATA, head == NULL ? M_PKTHDR : 0);
1851 if (m->m_flags & M_PKTHDR)
1852 m->m_pkthdr.len = 0;
1855 MGETHDR(m, wait, MT_DATA);
1858 m->m_pkthdr.len = 0;
1859 /* Leave room for protocol headers. */
1863 MGET(m, wait, MT_DATA);
1868 datalen = min(MCLBYTES, resid);
1869 error = uiomove(mtod(m, caddr_t), datalen, uio);
1877 head->m_pkthdr.len += datalen;
1879 } while (resid > 0);