diff options
author | wollman <wollman@FreeBSD.org> | 1996-05-08 19:38:27 +0000 |
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committer | wollman <wollman@FreeBSD.org> | 1996-05-08 19:38:27 +0000 |
commit | 577771db625c04242662f7e9ceb22c54f78a77ee (patch) | |
tree | a64fbe1967604e074495985930a3c00e1bf4d695 /sys/kern | |
parent | 2d7d383bb75e7bb82763c67e05af41c00059465d (diff) | |
download | FreeBSD-src-577771db625c04242662f7e9ceb22c54f78a77ee.zip FreeBSD-src-577771db625c04242662f7e9ceb22c54f78a77ee.tar.gz |
Our new-old mbugf allocator. This is actually something of a blast from
the past, since it returns to the old system of allocating mbufs out of
a private area rather than using the kernel malloc(). While this may seem
like a backwards step to some, the new allocator is some 20% faster than
the old one and has much better caching properties.
Written by: John Wroclawski <jtw@lcs.mit.edu>
Diffstat (limited to 'sys/kern')
-rw-r--r-- | sys/kern/uipc_mbuf.c | 104 |
1 files changed, 103 insertions, 1 deletions
diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c index 744631a..9c2d315 100644 --- a/sys/kern/uipc_mbuf.c +++ b/sys/kern/uipc_mbuf.c @@ -31,7 +31,7 @@ * SUCH DAMAGE. * * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94 - * $Id: uipc_mbuf.c,v 1.18 1996/05/02 14:20:29 phk Exp $ + * $Id: uipc_mbuf.c,v 1.19 1996/05/06 17:18:12 phk Exp $ */ #include <sys/param.h> @@ -56,6 +56,7 @@ SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbinit, NULL) struct mbuf *mbutl; char *mclrefcnt; struct mbstat mbstat; +struct mbuf *mmbfree; union mcluster *mclfree; int max_linkhdr; int max_protohdr; @@ -71,12 +72,17 @@ mbinit(dummy) { int s; +#define NMB_INIT 16 #if MCLBYTES < 4096 #define NCL_INIT (4096/MCLBYTES) #else #define NCL_INIT 1 #endif + + mmbfree = NULL; mclfree = NULL; s = splimp(); + if (m_mballoc(NMB_INIT, M_DONTWAIT) == 0) + goto bad; if (m_clalloc(NCL_INIT, M_DONTWAIT) == 0) goto bad; splx(s); @@ -86,6 +92,47 @@ bad: } /* + * Allocate at least nmb mbufs and place on mbuf free list. + * Must be called at splimp. + */ +/* ARGSUSED */ +int +m_mballoc(nmb, nowait) + register int nmb; + int nowait; +{ + register caddr_t p; + register int i; + int nbytes; + + /* Once we run out of map space, it will be impossible to get + * any more (nothing is ever freed back to the map) (XXX which + * is dumb). (however you are not dead as m_reclaim might + * still be able to free a substantial amount of space). + */ + if (mb_map_full) + return (0); + + nbytes = round_page(nmb * MSIZE); + p = (caddr_t)kmem_malloc(mb_map, nbytes, nowait ? M_NOWAIT : M_WAITOK); + /* + * Either the map is now full, or this is nowait and there + * are no pages left. + */ + if (p == NULL) + return (0); + + nmb = nbytes / MSIZE; + for (i = 0; i < nmb; i++) { + ((struct mbuf *)p)->m_next = mmbfree; + mmbfree = (struct mbuf *)p; + p += MSIZE; + } + mbstat.m_mbufs += nmb; + return (1); +} + +/* * Allocate some number of mbuf clusters * and place on cluster free list. * Must be called at splimp. @@ -355,6 +402,61 @@ nospace: } /* + * Copy an entire packet, including header (which must be present). + * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'. + */ +struct mbuf * +m_copypacket(m, how) + struct mbuf *m; + int how; +{ + struct mbuf *top, *n, *o; + + MGET(n, how, m->m_type); + top = n; + if (!n) + goto nospace; + + M_COPY_PKTHDR(n, m); + n->m_len = m->m_len; + if (m->m_flags & M_EXT) { + n->m_data = m->m_data; + mclrefcnt[mtocl(m->m_ext.ext_buf)]++; + n->m_ext = m->m_ext; + n->m_flags |= M_EXT; + } else { + bcopy(mtod(m, char *), mtod(n, char *), n->m_len); + } + + m = m->m_next; + while (m) { + MGET(o, how, m->m_type); + if (!o) + goto nospace; + + n->m_next = o; + n = n->m_next; + + n->m_len = m->m_len; + if (m->m_flags & M_EXT) { + n->m_data = m->m_data; + mclrefcnt[mtocl(m->m_ext.ext_buf)]++; + n->m_ext = m->m_ext; + n->m_flags |= M_EXT; + } else { + bcopy(mtod(m, char *), mtod(n, char *), n->m_len); + } + + m = m->m_next; + } + return top; +nospace: + m_freem(top); + MCFail++; + return 0; +} + +/* * Copy data from an mbuf chain starting "off" bytes from the beginning, * continuing for "len" bytes, into the indicated buffer. */ |