Date: Mon, 15 Jul 2002 08:33:01 -0700 (PDT) From: Bosko Milekic <bmilekic@FreeBSD.org> To: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/kern subr_mbuf.c uipc_mbuf.c src/sys/sys mbuf.h Message-ID: <200207151533.g6FFX1Yo039597@freefall.freebsd.org>
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bmilekic 2002/07/15 08:33:00 PDT
Modified files:
sys/kern subr_mbuf.c uipc_mbuf.c
sys/sys mbuf.h
Log:
o Introduce new m_getcl() interface routine that allocates an mbuf
and a cluster in one shot.
o Introduce MBP_PERSIST and MBP_PERSISTENT control bits to mb_alloc();
MBP_PERSIST means "if you can allocate, then keep the cache lock
held on exit," and MBP_PERSISTENT means "a cache lock is alredy held
on entry, so allocate from the specified (already locked) cache."
They may be used in combination.
o m_getcl() uses the MBP_PERSIST/MBP_PERSISTENT interface so that it
doesn't drop the cache lock in between the mbuf and cluster allocations.
o m_getm(), which takes a size and allocates an mbuf + cluster "best fit"
chain, has been moved from uipc_mbuf.c to subr_mbuf.c and shown how to
use MBP_PERSIST/MBP_PERSISTENT to attempt to do a grouped allocation
without dropping the cache lock in between.
Why this is good: much less bus-locked lock acquires/drops when they're
not needed. Also, prototype for m_getcl():
struct mbuf * m_getcl(int how, short type, int flags);
"how" and "type" are self-explanatory. "flags" may be M_PKTHDR, in
which case m_getcl() will make the mbuf a pkthdr-mbuf.
While I'm in subr_mbuf.c:
o Every exported routine now has a nice comment with a description of
the expected arguments. Eventually, mbuf(9) needs to be re-vamped
but there's still more code to write/finalize before I get to that.
o internal macros have been changed a bit.
o consistently use 'short' for "type." This somehow slipped through
before (that 'type' was sometimes declared as int).
Alfred has been pushing for the MBP_PERSIST{,ENT} thing for almost a
year now. Luigi asked for m_getcl(), and will probably MFC that
part of this commit.
TODO [Related]: teach mb_free() about MBP_PERSIST{, ENT}.
Revision Changes Path
1.21 +394 -73 src/sys/kern/subr_mbuf.c
1.93 +0 -66 src/sys/kern/uipc_mbuf.c
1.96 +6 -5 src/sys/sys/mbuf.h
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