/*- * Copyright (c) 2001 * Bosko Milekic . All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD$ */ #include "opt_param.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Maximum number of PCPU containers. If you know what you're doing you could * explicitly define MBALLOC_NCPU to be exactly the number of CPUs on your * system during compilation, and thus prevent kernel structure bloat. * * SMP and non-SMP kernels clearly have a different number of possible CPUs, * but because we cannot assume a dense array of CPUs, we always allocate * and traverse PCPU containers up to NCPU amount and merely check for * CPU availability. */ #ifdef MBALLOC_NCPU #define NCPU MBALLOC_NCPU #else #define NCPU MAXCPU #endif /*- * The mbuf allocator is heavily based on Alfred Perlstein's * (alfred@FreeBSD.org) "memcache" allocator which is itself based * on concepts from several per-CPU memory allocators. The difference * between this allocator and memcache is that, among other things: * * (i) We don't free back to the map from the free() routine - we leave the * option of implementing lazy freeing (from a kproc) in the future. * * (ii) We allocate from separate sub-maps of kmem_map, thus limiting the * maximum number of allocatable objects of a given type. Further, * we handle blocking on a cv in the case that the map is starved and * we have to rely solely on cached (circulating) objects. * * The mbuf allocator keeps all objects that it allocates in mb_buckets. * The buckets keep a page worth of objects (an object can be an mbuf or an * mbuf cluster) and facilitate moving larger sets of contiguous objects * from the per-CPU lists to the main list for the given object. The buckets * also have an added advantage in that after several moves from a per-CPU * list to the main list and back to the per-CPU list, contiguous objects * are kept together, thus trying to put the TLB cache to good use. * * The buckets are kept on singly-linked lists called "containers." A container * is protected by a mutex lock in order to ensure consistency. The mutex lock * itself is allocated separately and attached to the container at boot time, * thus allowing for certain containers to share the same mutex lock. Per-CPU * containers for mbufs and mbuf clusters all share the same per-CPU * lock whereas the "general system" containers (i.e., the "main lists") for * these objects share one global lock. */ struct mb_bucket { SLIST_ENTRY(mb_bucket) mb_blist; int mb_owner; int mb_numfree; void *mb_free[0]; }; struct mb_container { SLIST_HEAD(mc_buckethd, mb_bucket) mc_bhead; struct mtx *mc_lock; int mc_numowner; u_int mc_starved; long *mc_types; u_long *mc_objcount; u_long *mc_numpgs; }; struct mb_gen_list { struct mb_container mb_cont; struct cv mgl_mstarved; }; struct mb_pcpu_list { struct mb_container mb_cont; }; /* * Boot-time configurable object counts that will determine the maximum * number of permitted objects in the mbuf and mcluster cases. In the * ext counter (nmbcnt) case, it's just an indicator serving to scale * kmem_map size properly - in other words, we may be allowed to allocate * more than nmbcnt counters, whereas we will never be allowed to allocate * more than nmbufs mbufs or nmbclusters mclusters. * As for nsfbufs, it is used to indicate how many sendfile(2) buffers will be * allocatable by the sfbuf allocator (found in uipc_syscalls.c) */ #ifndef NMBCLUSTERS #define NMBCLUSTERS (1024 + maxusers * 64) #endif #ifndef NMBUFS #define NMBUFS (nmbclusters * 2) #endif #ifndef NSFBUFS #define NSFBUFS (512 + maxusers * 16) #endif #ifndef NMBCNTS #define NMBCNTS (nmbclusters + nsfbufs) #endif int nmbufs; int nmbclusters; int nmbcnt; int nsfbufs; /* * Perform sanity checks of tunables declared above. */ static void tunable_mbinit(void *dummy) { /* * This has to be done before VM init. */ nmbclusters = NMBCLUSTERS; TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters); nmbufs = NMBUFS; TUNABLE_INT_FETCH("kern.ipc.nmbufs", &nmbufs); nsfbufs = NSFBUFS; TUNABLE_INT_FETCH("kern.ipc.nsfbufs", &nsfbufs); nmbcnt = NMBCNTS; TUNABLE_INT_FETCH("kern.ipc.nmbcnt", &nmbcnt); /* Sanity checks */ if (nmbufs < nmbclusters * 2) nmbufs = nmbclusters * 2; if (nmbcnt < nmbclusters + nsfbufs) nmbcnt = nmbclusters + nsfbufs; } SYSINIT(tunable_mbinit, SI_SUB_TUNABLES, SI_ORDER_ANY, tunable_mbinit, NULL); /* * The freelist structures and mutex locks. The number statically declared * here depends on the number of CPUs. * * We set up in such a way that all the objects (mbufs, clusters) * share the same mutex lock. It has been established that we do not benefit * from different locks for different objects, so we use the same lock, * regardless of object type. */ struct mb_lstmngr { struct mb_gen_list *ml_genlist; struct mb_pcpu_list *ml_cntlst[NCPU]; struct mb_bucket **ml_btable; vm_map_t ml_map; vm_offset_t ml_mapbase; vm_offset_t ml_maptop; int ml_mapfull; u_int ml_objsize; u_int *ml_wmhigh; }; static struct mb_lstmngr mb_list_mbuf, mb_list_clust; static struct mtx mbuf_gen, mbuf_pcpu[NCPU]; /* * Local macros for internal allocator structure manipulations. */ #ifdef SMP #define MB_GET_PCPU_LIST(mb_lst) (mb_lst)->ml_cntlst[PCPU_GET(cpuid)] #else #define MB_GET_PCPU_LIST(mb_lst) (mb_lst)->ml_cntlst[0] #endif #define MB_GET_GEN_LIST(mb_lst) (mb_lst)->ml_genlist #define MB_LOCK_CONT(mb_cnt) mtx_lock((mb_cnt)->mb_cont.mc_lock) #define MB_UNLOCK_CONT(mb_cnt) mtx_unlock((mb_cnt)->mb_cont.mc_lock) #define MB_GET_PCPU_LIST_NUM(mb_lst, num) \ (mb_lst)->ml_cntlst[(num)] #define MB_BUCKET_INDX(mb_obj, mb_lst) \ (int)(((caddr_t)(mb_obj) - (caddr_t)(mb_lst)->ml_mapbase) / PAGE_SIZE) #define MB_GET_OBJECT(mb_objp, mb_bckt, mb_lst) \ { \ struct mc_buckethd *_mchd = &((mb_lst)->mb_cont.mc_bhead); \ \ (mb_bckt)->mb_numfree--; \ (mb_objp) = (mb_bckt)->mb_free[((mb_bckt)->mb_numfree)]; \ (*((mb_lst)->mb_cont.mc_objcount))--; \ if ((mb_bckt)->mb_numfree == 0) { \ SLIST_REMOVE_HEAD(_mchd, mb_blist); \ SLIST_NEXT((mb_bckt), mb_blist) = NULL; \ (mb_bckt)->mb_owner |= MB_BUCKET_FREE; \ } \ } #define MB_PUT_OBJECT(mb_objp, mb_bckt, mb_lst) \ (mb_bckt)->mb_free[((mb_bckt)->mb_numfree)] = (mb_objp); \ (mb_bckt)->mb_numfree++; \ (*((mb_lst)->mb_cont.mc_objcount))++; #define MB_MBTYPES_INC(mb_cnt, mb_type, mb_num) \ if ((mb_type) != MT_NOTMBUF) \ (*((mb_cnt)->mb_cont.mc_types + (mb_type))) += (mb_num) #define MB_MBTYPES_DEC(mb_cnt, mb_type, mb_num) \ if ((mb_type) != MT_NOTMBUF) \ (*((mb_cnt)->mb_cont.mc_types + (mb_type))) -= (mb_num) /* * Ownership of buckets/containers is represented by integers. The PCPU * lists range from 0 to NCPU-1. We need a free numerical id for the general * list (we use NCPU). We also need a non-conflicting free bit to indicate * that the bucket is free and removed from a container, while not losing * the bucket's originating container id. We use the highest bit * for the free marker. */ #define MB_GENLIST_OWNER (NCPU) #define MB_BUCKET_FREE (1 << (sizeof(int) * 8 - 1)) /* Statistics structures for allocator (per-CPU and general). */ static struct mbpstat mb_statpcpu[NCPU + 1]; struct mbstat mbstat; /* Sleep time for wait code (in ticks). */ static int mbuf_wait = 64; static u_int mbuf_limit = 512; /* Upper limit on # of mbufs per CPU. */ static u_int clust_limit = 128; /* Upper limit on # of clusters per CPU. */ /* * Objects exported by sysctl(8). */ SYSCTL_DECL(_kern_ipc); SYSCTL_INT(_kern_ipc, OID_AUTO, nmbclusters, CTLFLAG_RD, &nmbclusters, 0, "Maximum number of mbuf clusters available"); SYSCTL_INT(_kern_ipc, OID_AUTO, nmbufs, CTLFLAG_RD, &nmbufs, 0, "Maximum number of mbufs available"); SYSCTL_INT(_kern_ipc, OID_AUTO, nmbcnt, CTLFLAG_RD, &nmbcnt, 0, "Number used to scale kmem_map to ensure sufficient space for counters"); SYSCTL_INT(_kern_ipc, OID_AUTO, nsfbufs, CTLFLAG_RD, &nsfbufs, 0, "Maximum number of sendfile(2) sf_bufs available"); SYSCTL_INT(_kern_ipc, OID_AUTO, mbuf_wait, CTLFLAG_RW, &mbuf_wait, 0, "Sleep time of mbuf subsystem wait allocations during exhaustion"); SYSCTL_UINT(_kern_ipc, OID_AUTO, mbuf_limit, CTLFLAG_RW, &mbuf_limit, 0, "Upper limit of number of mbufs allowed on each PCPU list"); SYSCTL_UINT(_kern_ipc, OID_AUTO, clust_limit, CTLFLAG_RW, &clust_limit, 0, "Upper limit of number of mbuf clusters allowed on each PCPU list"); SYSCTL_STRUCT(_kern_ipc, OID_AUTO, mbstat, CTLFLAG_RD, &mbstat, mbstat, "Mbuf general information and statistics"); SYSCTL_OPAQUE(_kern_ipc, OID_AUTO, mb_statpcpu, CTLFLAG_RD, mb_statpcpu, sizeof(mb_statpcpu), "S,", "Mbuf allocator per CPU statistics"); /* * Prototypes of local allocator routines. */ static void *mb_alloc_wait(struct mb_lstmngr *, short); static struct mb_bucket *mb_pop_cont(struct mb_lstmngr *, int, struct mb_pcpu_list *); static void mb_reclaim(void); static void mbuf_init(void *); /* * Initial allocation numbers. Each parameter represents the number of buckets * of each object that will be placed initially in each PCPU container for * said object. */ #define NMB_MBUF_INIT 4 #define NMB_CLUST_INIT 16 /* * Initialize the mbuf subsystem. * * We sub-divide the kmem_map into several submaps; this way, we don't have * to worry about artificially limiting the number of mbuf or mbuf cluster * allocations, due to fear of one type of allocation "stealing" address * space initially reserved for another. * * Set up both the general containers and all the PCPU containers. Populate * the PCPU containers with initial numbers. */ MALLOC_DEFINE(M_MBUF, "mbufmgr", "mbuf subsystem management structures"); SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbuf_init, NULL) void mbuf_init(void *dummy) { struct mb_pcpu_list *pcpu_cnt; vm_size_t mb_map_size; int i, j; /* * Set up all the submaps, for each type of object that we deal * with in this allocator. */ mb_map_size = (vm_size_t)(nmbufs * MSIZE); mb_map_size = rounddown(mb_map_size, PAGE_SIZE); mb_list_mbuf.ml_btable = malloc((unsigned long)mb_map_size / PAGE_SIZE * sizeof(struct mb_bucket *), M_MBUF, M_NOWAIT); if (mb_list_mbuf.ml_btable == NULL) goto bad; mb_list_mbuf.ml_map = kmem_suballoc(kmem_map,&(mb_list_mbuf.ml_mapbase), &(mb_list_mbuf.ml_maptop), mb_map_size); mb_list_mbuf.ml_map->system_map = 1; mb_list_mbuf.ml_mapfull = 0; mb_list_mbuf.ml_objsize = MSIZE; mb_list_mbuf.ml_wmhigh = &mbuf_limit; mb_map_size = (vm_size_t)(nmbclusters * MCLBYTES); mb_map_size = rounddown(mb_map_size, PAGE_SIZE); mb_list_clust.ml_btable = malloc((unsigned long)mb_map_size / PAGE_SIZE * sizeof(struct mb_bucket *), M_MBUF, M_NOWAIT); if (mb_list_clust.ml_btable == NULL) goto bad; mb_list_clust.ml_map = kmem_suballoc(kmem_map, &(mb_list_clust.ml_mapbase), &(mb_list_clust.ml_maptop), mb_map_size); mb_list_clust.ml_map->system_map = 1; mb_list_clust.ml_mapfull = 0; mb_list_clust.ml_objsize = MCLBYTES; mb_list_clust.ml_wmhigh = &clust_limit; /* * Allocate required general (global) containers for each object type. */ mb_list_mbuf.ml_genlist = malloc(sizeof(struct mb_gen_list), M_MBUF, M_NOWAIT); mb_list_clust.ml_genlist = malloc(sizeof(struct mb_gen_list), M_MBUF, M_NOWAIT); if ((mb_list_mbuf.ml_genlist == NULL) || (mb_list_clust.ml_genlist == NULL)) goto bad; /* * Initialize condition variables and general container mutex locks. */ mtx_init(&mbuf_gen, "mbuf subsystem general lists lock", NULL, 0); cv_init(&(mb_list_mbuf.ml_genlist->mgl_mstarved), "mbuf pool starved"); cv_init(&(mb_list_clust.ml_genlist->mgl_mstarved), "mcluster pool starved"); mb_list_mbuf.ml_genlist->mb_cont.mc_lock = mb_list_clust.ml_genlist->mb_cont.mc_lock = &mbuf_gen; /* * Set up the general containers for each object. */ mb_list_mbuf.ml_genlist->mb_cont.mc_numowner = mb_list_clust.ml_genlist->mb_cont.mc_numowner = MB_GENLIST_OWNER; mb_list_mbuf.ml_genlist->mb_cont.mc_starved = mb_list_clust.ml_genlist->mb_cont.mc_starved = 0; mb_list_mbuf.ml_genlist->mb_cont.mc_objcount = &(mb_statpcpu[MB_GENLIST_OWNER].mb_mbfree); mb_list_clust.ml_genlist->mb_cont.mc_objcount = &(mb_statpcpu[MB_GENLIST_OWNER].mb_clfree); mb_list_mbuf.ml_genlist->mb_cont.mc_numpgs = &(mb_statpcpu[MB_GENLIST_OWNER].mb_mbpgs); mb_list_clust.ml_genlist->mb_cont.mc_numpgs = &(mb_statpcpu[MB_GENLIST_OWNER].mb_clpgs); mb_list_mbuf.ml_genlist->mb_cont.mc_types = &(mb_statpcpu[MB_GENLIST_OWNER].mb_mbtypes[0]); mb_list_clust.ml_genlist->mb_cont.mc_types = NULL; SLIST_INIT(&(mb_list_mbuf.ml_genlist->mb_cont.mc_bhead)); SLIST_INIT(&(mb_list_clust.ml_genlist->mb_cont.mc_bhead)); /* * Initialize general mbuf statistics. */ mbstat.m_msize = MSIZE; mbstat.m_mclbytes = MCLBYTES; mbstat.m_minclsize = MINCLSIZE; mbstat.m_mlen = MLEN; mbstat.m_mhlen = MHLEN; mbstat.m_numtypes = MT_NTYPES; /* * Allocate and initialize PCPU containers. */ for (i = 0; i < NCPU; i++) { if (CPU_ABSENT(i)) continue; mb_list_mbuf.ml_cntlst[i] = malloc(sizeof(struct mb_pcpu_list), M_MBUF, M_NOWAIT); mb_list_clust.ml_cntlst[i] = malloc(sizeof(struct mb_pcpu_list), M_MBUF, M_NOWAIT); if ((mb_list_mbuf.ml_cntlst[i] == NULL) || (mb_list_clust.ml_cntlst[i] == NULL)) goto bad; mtx_init(&mbuf_pcpu[i], "mbuf PCPU list lock", NULL, 0); mb_list_mbuf.ml_cntlst[i]->mb_cont.mc_lock = mb_list_clust.ml_cntlst[i]->mb_cont.mc_lock = &mbuf_pcpu[i]; mb_statpcpu[i].mb_active = 1; mb_list_mbuf.ml_cntlst[i]->mb_cont.mc_numowner = mb_list_clust.ml_cntlst[i]->mb_cont.mc_numowner = i; mb_list_mbuf.ml_cntlst[i]->mb_cont.mc_starved = mb_list_clust.ml_cntlst[i]->mb_cont.mc_starved = 0; mb_list_mbuf.ml_cntlst[i]->mb_cont.mc_objcount = &(mb_statpcpu[i].mb_mbfree); mb_list_clust.ml_cntlst[i]->mb_cont.mc_objcount = &(mb_statpcpu[i].mb_clfree); mb_list_mbuf.ml_cntlst[i]->mb_cont.mc_numpgs = &(mb_statpcpu[i].mb_mbpgs); mb_list_clust.ml_cntlst[i]->mb_cont.mc_numpgs = &(mb_statpcpu[i].mb_clpgs); mb_list_mbuf.ml_cntlst[i]->mb_cont.mc_types = &(mb_statpcpu[i].mb_mbtypes[0]); mb_list_clust.ml_cntlst[i]->mb_cont.mc_types = NULL; SLIST_INIT(&(mb_list_mbuf.ml_cntlst[i]->mb_cont.mc_bhead)); SLIST_INIT(&(mb_list_clust.ml_cntlst[i]->mb_cont.mc_bhead)); /* * Perform initial allocations. */ pcpu_cnt = MB_GET_PCPU_LIST_NUM(&mb_list_mbuf, i); MB_LOCK_CONT(pcpu_cnt); for (j = 0; j < NMB_MBUF_INIT; j++) { if (mb_pop_cont(&mb_list_mbuf, M_DONTWAIT, pcpu_cnt) == NULL) goto bad; } MB_UNLOCK_CONT(pcpu_cnt); pcpu_cnt = MB_GET_PCPU_LIST_NUM(&mb_list_clust, i); MB_LOCK_CONT(pcpu_cnt); for (j = 0; j < NMB_CLUST_INIT; j++) { if (mb_pop_cont(&mb_list_clust, M_DONTWAIT, pcpu_cnt) == NULL) goto bad; } MB_UNLOCK_CONT(pcpu_cnt); } return; bad: panic("mbuf_init(): failed to initialize mbuf subsystem!"); } /* * Populate a given mbuf PCPU container with a bucket full of fresh new * buffers. Return a pointer to the new bucket (already in the container if * successful), or return NULL on failure. * * LOCKING NOTES: * PCPU container lock must be held when this is called. * The lock is dropped here so that we can cleanly call the underlying VM * code. If we fail, we return with no locks held. If we succeed (i.e., return * non-NULL), we return with the PCPU lock held, ready for allocation from * the returned bucket. */ static struct mb_bucket * mb_pop_cont(struct mb_lstmngr *mb_list, int how, struct mb_pcpu_list *cnt_lst) { struct mb_bucket *bucket; caddr_t p; int i; MB_UNLOCK_CONT(cnt_lst); /* * If our object's (finite) map is starved now (i.e., no more address * space), bail out now. */ if (mb_list->ml_mapfull) return (NULL); bucket = malloc(sizeof(struct mb_bucket) + PAGE_SIZE / mb_list->ml_objsize * sizeof(void *), M_MBUF, how == M_TRYWAIT ? M_WAITOK : M_NOWAIT); if (bucket == NULL) return (NULL); p = (caddr_t)kmem_malloc(mb_list->ml_map, PAGE_SIZE, how == M_TRYWAIT ? M_WAITOK : M_NOWAIT); if (p == NULL) { free(bucket, M_MBUF); if (how == M_TRYWAIT) mb_list->ml_mapfull = 1; return (NULL); } bucket->mb_numfree = 0; mb_list->ml_btable[MB_BUCKET_INDX(p, mb_list)] = bucket; for (i = 0; i < (PAGE_SIZE / mb_list->ml_objsize); i++) { bucket->mb_free[i] = p; bucket->mb_numfree++; p += mb_list->ml_objsize; } MB_LOCK_CONT(cnt_lst); bucket->mb_owner = cnt_lst->mb_cont.mc_numowner; SLIST_INSERT_HEAD(&(cnt_lst->mb_cont.mc_bhead), bucket, mb_blist); (*(cnt_lst->mb_cont.mc_numpgs))++; *(cnt_lst->mb_cont.mc_objcount) += bucket->mb_numfree; return (bucket); } /* * Allocate an mbuf-subsystem type object. * The general case is very easy. Complications only arise if our PCPU * container is empty. Things get worse if the PCPU container is empty, * the general container is empty, and we've run out of address space * in our map; then we try to block if we're willing to (M_TRYWAIT). */ static __inline void * mb_alloc(struct mb_lstmngr *mb_list, int how, short type) { static int last_report; struct mb_pcpu_list *cnt_lst; struct mb_bucket *bucket; void *m; m = NULL; cnt_lst = MB_GET_PCPU_LIST(mb_list); MB_LOCK_CONT(cnt_lst); if ((bucket = SLIST_FIRST(&(cnt_lst->mb_cont.mc_bhead))) != NULL) { /* * This is the easy allocation case. We just grab an object * from a bucket in the PCPU container. At worst, we * have just emptied the bucket and so we remove it * from the container. */ MB_GET_OBJECT(m, bucket, cnt_lst); MB_MBTYPES_INC(cnt_lst, type, 1); MB_UNLOCK_CONT(cnt_lst); } else { struct mb_gen_list *gen_list; /* * This is the less-common more difficult case. We must * first verify if the general list has anything for us * and if that also fails, we must allocate a page from * the map and create a new bucket to place in our PCPU * container (already locked). If the map is starved then * we're really in for trouble, as we have to wait on * the general container's condition variable. */ gen_list = MB_GET_GEN_LIST(mb_list); MB_LOCK_CONT(gen_list); if ((bucket = SLIST_FIRST(&(gen_list->mb_cont.mc_bhead))) != NULL) { /* * Give ownership of the bucket to our CPU's * container, but only actually put the bucket * in the container if it doesn't become free * upon removing an mbuf from it. */ SLIST_REMOVE_HEAD(&(gen_list->mb_cont.mc_bhead), mb_blist); bucket->mb_owner = cnt_lst->mb_cont.mc_numowner; (*(gen_list->mb_cont.mc_numpgs))--; (*(cnt_lst->mb_cont.mc_numpgs))++; *(gen_list->mb_cont.mc_objcount) -= bucket->mb_numfree; bucket->mb_numfree--; m = bucket->mb_free[(bucket->mb_numfree)]; if (bucket->mb_numfree == 0) { SLIST_NEXT(bucket, mb_blist) = NULL; bucket->mb_owner |= MB_BUCKET_FREE; } else { SLIST_INSERT_HEAD(&(cnt_lst->mb_cont.mc_bhead), bucket, mb_blist); *(cnt_lst->mb_cont.mc_objcount) += bucket->mb_numfree; } MB_UNLOCK_CONT(gen_list); MB_MBTYPES_INC(cnt_lst, type, 1); MB_UNLOCK_CONT(cnt_lst); } else { /* * We'll have to allocate a new page. */ MB_UNLOCK_CONT(gen_list); bucket = mb_pop_cont(mb_list, how, cnt_lst); if (bucket != NULL) { MB_GET_OBJECT(m, bucket, cnt_lst); MB_MBTYPES_INC(cnt_lst, type, 1); MB_UNLOCK_CONT(cnt_lst); } else { if (how == M_TRYWAIT) { /* * Absolute worst-case scenario. * We block if we're willing to, but * only after trying to steal from * other lists. */ m = mb_alloc_wait(mb_list, type); } else { /* XXX: No consistency. */ mbstat.m_drops++; if (ticks < last_report || (ticks - last_report) >= hz) { last_report = ticks; printf( "All mbufs exhausted, please see tuning(7).\n"); /* XXX: Actually could be clusters, but it gets the point across. */ } } } } } return (m); } /* * This is the worst-case scenario called only if we're allocating with * M_TRYWAIT. We first drain all the protocols, then try to find an mbuf * by looking in every PCPU container. If we're still unsuccesful, we * try the general container one last time and possibly block on our * starved cv. */ static void * mb_alloc_wait(struct mb_lstmngr *mb_list, short type) { struct mb_pcpu_list *cnt_lst; struct mb_gen_list *gen_list; struct mb_bucket *bucket; void *m; int i, cv_ret; /* * Try to reclaim mbuf-related objects (mbufs, clusters). */ mb_reclaim(); /* * Cycle all the PCPU containers. Increment starved counts if found * empty. */ for (i = 0; i < NCPU; i++) { if (CPU_ABSENT(i)) continue; cnt_lst = MB_GET_PCPU_LIST_NUM(mb_list, i); MB_LOCK_CONT(cnt_lst); /* * If container is non-empty, get a single object from it. * If empty, increment starved count. */ if ((bucket = SLIST_FIRST(&(cnt_lst->mb_cont.mc_bhead))) != NULL) { MB_GET_OBJECT(m, bucket, cnt_lst); MB_MBTYPES_INC(cnt_lst, type, 1); MB_UNLOCK_CONT(cnt_lst); mbstat.m_wait++; /* XXX: No consistency. */ return (m); } else cnt_lst->mb_cont.mc_starved++; MB_UNLOCK_CONT(cnt_lst); } /* * We're still here, so that means it's time to get the general * container lock, check it one more time (now that mb_reclaim() * has been called) and if we still get nothing, block on the cv. */ gen_list = MB_GET_GEN_LIST(mb_list); MB_LOCK_CONT(gen_list); if ((bucket = SLIST_FIRST(&(gen_list->mb_cont.mc_bhead))) != NULL) { MB_GET_OBJECT(m, bucket, gen_list); MB_MBTYPES_INC(gen_list, type, 1); MB_UNLOCK_CONT(gen_list); mbstat.m_wait++; /* XXX: No consistency. */ return (m); } gen_list->mb_cont.mc_starved++; cv_ret = cv_timedwait(&(gen_list->mgl_mstarved), gen_list->mb_cont.mc_lock, mbuf_wait); gen_list->mb_cont.mc_starved--; if ((cv_ret == 0) && ((bucket = SLIST_FIRST(&(gen_list->mb_cont.mc_bhead))) != NULL)) { MB_GET_OBJECT(m, bucket, gen_list); MB_MBTYPES_INC(gen_list, type, 1); mbstat.m_wait++; /* XXX: No consistency. */ } else { mbstat.m_drops++; /* XXX: No consistency. */ m = NULL; } MB_UNLOCK_CONT(gen_list); return (m); } /*- * Free an object to its rightful container. * In the very general case, this operation is really very easy. * Complications arise primarily if: * (a) We've hit the high limit on number of free objects allowed in * our PCPU container. * (b) We're in a critical situation where our container has been * marked 'starved' and we need to issue wakeups on the starved * condition variable. * (c) Minor (odd) cases: our bucket has migrated while we were * waiting for the lock; our bucket is in the general container; * our bucket is empty. */ static __inline void mb_free(struct mb_lstmngr *mb_list, void *m, short type) { struct mb_pcpu_list *cnt_lst; struct mb_gen_list *gen_list; struct mb_bucket *bucket; u_int owner; bucket = mb_list->ml_btable[MB_BUCKET_INDX(m, mb_list)]; /* * Make sure that if after we lock the bucket's present container the * bucket has migrated, that we drop the lock and get the new one. */ retry_lock: owner = bucket->mb_owner & ~MB_BUCKET_FREE; switch (owner) { case MB_GENLIST_OWNER: gen_list = MB_GET_GEN_LIST(mb_list); MB_LOCK_CONT(gen_list); if (owner != (bucket->mb_owner & ~MB_BUCKET_FREE)) { MB_UNLOCK_CONT(gen_list); goto retry_lock; } /* * If we're intended for the general container, this is * real easy: no migrating required. The only `bogon' * is that we're now contending with all the threads * dealing with the general list, but this is expected. */ MB_PUT_OBJECT(m, bucket, gen_list); MB_MBTYPES_DEC(gen_list, type, 1); if (gen_list->mb_cont.mc_starved > 0) cv_signal(&(gen_list->mgl_mstarved)); MB_UNLOCK_CONT(gen_list); break; default: cnt_lst = MB_GET_PCPU_LIST_NUM(mb_list, owner); MB_LOCK_CONT(cnt_lst); if (owner != (bucket->mb_owner & ~MB_BUCKET_FREE)) { MB_UNLOCK_CONT(cnt_lst); goto retry_lock; } MB_PUT_OBJECT(m, bucket, cnt_lst); MB_MBTYPES_DEC(cnt_lst, type, 1); if (cnt_lst->mb_cont.mc_starved > 0) { /* * This is a tough case. It means that we've * been flagged at least once to indicate that * we're empty, and that the system is in a critical * situation, so we ought to migrate at least one * bucket over to the general container. * There may or may not be a thread blocking on * the starved condition variable, but chances * are that one will eventually come up soon so * it's better to migrate now than never. */ gen_list = MB_GET_GEN_LIST(mb_list); MB_LOCK_CONT(gen_list); KASSERT((bucket->mb_owner & MB_BUCKET_FREE) != 0, ("mb_free: corrupt bucket %p\n", bucket)); SLIST_INSERT_HEAD(&(gen_list->mb_cont.mc_bhead), bucket, mb_blist); bucket->mb_owner = MB_GENLIST_OWNER; (*(cnt_lst->mb_cont.mc_objcount))--; (*(gen_list->mb_cont.mc_objcount))++; (*(cnt_lst->mb_cont.mc_numpgs))--; (*(gen_list->mb_cont.mc_numpgs))++; /* * Determine whether or not to keep transferring * buckets to the general list or whether we've * transferred enough already. * We realize that although we may flag another * bucket to be migrated to the general container * that in the meantime, the thread that was * blocked on the cv is already woken up and * long gone. But in that case, the worst * consequence is that we will end up migrating * one bucket too many, which is really not a big * deal, especially if we're close to a critical * situation. */ if (gen_list->mb_cont.mc_starved > 0) { cnt_lst->mb_cont.mc_starved--; cv_signal(&(gen_list->mgl_mstarved)); } else cnt_lst->mb_cont.mc_starved = 0; MB_UNLOCK_CONT(gen_list); MB_UNLOCK_CONT(cnt_lst); break; } if (*(cnt_lst->mb_cont.mc_objcount) > *(mb_list->ml_wmhigh)) { /* * We've hit the high limit of allowed numbers of mbufs * on this PCPU list. We must now migrate a bucket * over to the general container. */ gen_list = MB_GET_GEN_LIST(mb_list); MB_LOCK_CONT(gen_list); if ((bucket->mb_owner & MB_BUCKET_FREE) == 0) { bucket = SLIST_FIRST(&(cnt_lst->mb_cont.mc_bhead)); SLIST_REMOVE_HEAD(&(cnt_lst->mb_cont.mc_bhead), mb_blist); } SLIST_INSERT_HEAD(&(gen_list->mb_cont.mc_bhead), bucket, mb_blist); bucket->mb_owner = MB_GENLIST_OWNER; *(cnt_lst->mb_cont.mc_objcount) -= bucket->mb_numfree; *(gen_list->mb_cont.mc_objcount) += bucket->mb_numfree; (*(cnt_lst->mb_cont.mc_numpgs))--; (*(gen_list->mb_cont.mc_numpgs))++; /* * While we're at it, transfer some of the mbtypes * "count load" onto the general list's mbtypes * array, seeing as how we're moving the bucket * there now, meaning that the freeing of objects * there will now decrement the _general list's_ * mbtypes counters, and no longer our PCPU list's * mbtypes counters. We do this for the type presently * being freed in an effort to keep the mbtypes * counters approximately balanced across all lists. */ MB_MBTYPES_DEC(cnt_lst, type, (PAGE_SIZE / mb_list->ml_objsize) - bucket->mb_numfree); MB_MBTYPES_INC(gen_list, type, (PAGE_SIZE / mb_list->ml_objsize) - bucket->mb_numfree); MB_UNLOCK_CONT(gen_list); MB_UNLOCK_CONT(cnt_lst); break; } if (bucket->mb_owner & MB_BUCKET_FREE) { SLIST_INSERT_HEAD(&(cnt_lst->mb_cont.mc_bhead), bucket, mb_blist); bucket->mb_owner = cnt_lst->mb_cont.mc_numowner; } MB_UNLOCK_CONT(cnt_lst); break; } } /* * Drain protocols in hopes to free up some resources. * * LOCKING NOTES: * No locks should be held when this is called. The drain routines have to * presently acquire some locks which raises the possibility of lock order * violation if we're holding any mutex if that mutex is acquired in reverse * order relative to one of the locks in the drain routines. */ static void mb_reclaim(void) { struct domain *dp; struct protosw *pr; /* * XXX: Argh, we almost always trip here with witness turned on now-a-days * XXX: because we often come in with Giant held. For now, there's no way * XXX: to avoid this. */ #ifdef WITNESS KASSERT(witness_list(curthread) == 0, ("mb_reclaim() called with locks held")); #endif mbstat.m_drain++; /* XXX: No consistency. */ for (dp = domains; dp != NULL; dp = dp->dom_next) for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) if (pr->pr_drain != NULL) (*pr->pr_drain)(); } /* * Local mbuf & cluster alloc macros and routines. * Local macro and function names begin with an underscore ("_"). */ static void _mclfree(struct mbuf *); #define _m_get(m, how, type) do { \ (m) = (struct mbuf *)mb_alloc(&mb_list_mbuf, (how), (type)); \ if ((m) != NULL) { \ (m)->m_type = (type); \ (m)->m_next = NULL; \ (m)->m_nextpkt = NULL; \ (m)->m_data = (m)->m_dat; \ (m)->m_flags = 0; \ } \ } while (0) #define _m_gethdr(m, how, type) do { \ (m) = (struct mbuf *)mb_alloc(&mb_list_mbuf, (how), (type)); \ if ((m) != NULL) { \ (m)->m_type = (type); \ (m)->m_next = NULL; \ (m)->m_nextpkt = NULL; \ (m)->m_data = (m)->m_pktdat; \ (m)->m_flags = M_PKTHDR; \ (m)->m_pkthdr.rcvif = NULL; \ (m)->m_pkthdr.csum_flags = 0; \ (m)->m_pkthdr.aux = NULL; \ } \ } while (0) /* XXX: Check for M_PKTHDR && m_pkthdr.aux is bogus... please fix (see KAME). */ #define _m_free(m, n) do { \ (n) = (m)->m_next; \ if ((m)->m_flags & M_EXT) \ MEXTFREE((m)); \ if (((m)->m_flags & M_PKTHDR) != 0 && (m)->m_pkthdr.aux) { \ m_freem((m)->m_pkthdr.aux); \ (m)->m_pkthdr.aux = NULL; \ } \ mb_free(&mb_list_mbuf, (m), (m)->m_type); \ } while (0) #define _mext_init_ref(m) do { \ (m)->m_ext.ref_cnt = malloc(sizeof(u_int), M_MBUF, M_NOWAIT); \ if ((m)->m_ext.ref_cnt != NULL) { \ *((m)->m_ext.ref_cnt) = 0; \ MEXT_ADD_REF((m)); \ } \ } while (0) #define _mext_dealloc_ref(m) \ free((m)->m_ext.ref_cnt, M_MBUF) void _mext_free(struct mbuf *mb) { if (mb->m_ext.ext_type == EXT_CLUSTER) mb_free(&mb_list_clust, (caddr_t)mb->m_ext.ext_buf, MT_NOTMBUF); else (*(mb->m_ext.ext_free))(mb->m_ext.ext_buf, mb->m_ext.ext_args); _mext_dealloc_ref(mb); } /* * We only include this here to avoid making m_clget() excessively large * due to too much inlined code. */ static void _mclfree(struct mbuf *mb) { mb_free(&mb_list_clust, (caddr_t)mb->m_ext.ext_buf, MT_NOTMBUF); mb->m_ext.ext_buf = NULL; } /* * Exported space allocation and de-allocation routines. */ struct mbuf * m_get(int how, int type) { struct mbuf *mb; _m_get(mb, how, type); return (mb); } struct mbuf * m_gethdr(int how, int type) { struct mbuf *mb; _m_gethdr(mb, how, type); return (mb); } struct mbuf * m_get_clrd(int how, int type) { struct mbuf *mb; _m_get(mb, how, type); if (mb != NULL) bzero(mtod(mb, caddr_t), MLEN); return (mb); } struct mbuf * m_gethdr_clrd(int how, int type) { struct mbuf *mb; _m_gethdr(mb, how, type); if (mb != NULL) bzero(mtod(mb, caddr_t), MHLEN); return (mb); } struct mbuf * m_free(struct mbuf *mb) { struct mbuf *nb; _m_free(mb, nb); return (nb); } void m_clget(struct mbuf *mb, int how) { mb->m_ext.ext_buf = (caddr_t)mb_alloc(&mb_list_clust, how, MT_NOTMBUF); if (mb->m_ext.ext_buf != NULL) { _mext_init_ref(mb); if (mb->m_ext.ref_cnt == NULL) _mclfree(mb); else { mb->m_data = mb->m_ext.ext_buf; mb->m_flags |= M_EXT; mb->m_ext.ext_free = NULL; mb->m_ext.ext_args = NULL; mb->m_ext.ext_size = MCLBYTES; mb->m_ext.ext_type = EXT_CLUSTER; } } } void m_extadd(struct mbuf *mb, caddr_t buf, u_int size, void (*freef)(void *, void *), void *args, short flags, int type) { _mext_init_ref(mb); if (mb->m_ext.ref_cnt != NULL) { mb->m_flags |= (M_EXT | flags); mb->m_ext.ext_buf = buf; mb->m_data = mb->m_ext.ext_buf; mb->m_ext.ext_size = size; mb->m_ext.ext_free = freef; mb->m_ext.ext_args = args; mb->m_ext.ext_type = type; } } /* * Change type for mbuf `mb'; this is a relatively expensive operation and * should be avoided. */ void m_chtype(struct mbuf *mb, short new_type) { struct mb_gen_list *gen_list; gen_list = MB_GET_GEN_LIST(&mb_list_mbuf); MB_LOCK_CONT(gen_list); MB_MBTYPES_DEC(gen_list, mb->m_type, 1); MB_MBTYPES_INC(gen_list, new_type, 1); MB_UNLOCK_CONT(gen_list); mb->m_type = new_type; }