with a number of positive benefits:
- Start using UMA(9) statistics for mbufs and clusters, which avoids
using the mbuf allocator statistics which suffer from races under
load on SMP. This should eliminate "negative" mbuf counts in
netstat -mb.
- We are now able to track cached (free) mbufs and clusters and count
it towards memory allocated by the network stack.
- We are now also able to track memory allocated to mbuf tags since
libmemstat(3) can also query malloc(9). We don't print this except
as part of the total (for now - #if 0).
- We are now able to track mbuf/cluster/packet allocation failures,
although they are not currently printed (#if 0).
- Don't print out sfbuf statistics when running on a kernel core, as
currently that code is able only to query sysctl for statistics.
MFC after: 1 week
per-connection and globally. This eliminates potential DoS attacks
where SACK scoreboard elements tie up too much memory.
Submitted by: Raja Mukerji (raja at moselle dot com).
Reviewed by: Mohan Srinivasan (mohans at yahoo-inc dot com).
hosts to share an IP address, providing high availability and load
balancing.
Original work on CARP done by Michael Shalayeff, with many
additions by Marco Pfatschbacher and Ryan McBride.
FreeBSD port done solely by Max Laier.
Patch by: mlaier
Obtained from: OpenBSD (mickey, mcbride)
Without this change, when running netstat with a kernel without
INET6 built in, you will get a complain at the end of "netstat -s"
output.
X-MFC: NO_INET6 was called "NOINET6" on RELENG_5
netstat(1):
- Make previously unnecessarily global variables local.
- Use LIST_FOREACH() in preference to manual iteration.
- Restore a sanity check through slightly incestuous use of queue macro
knowledge.
Submitted by: rik
home-brew linked lists. Read in the ipxpcb_list structure first in
order to find the first pcb pointer. Then follow the chain as
before, only the termination condition is a NULL next pointer
rather than a next pointer equal to the original offset.
socket in LISTEN state happens to be bound to an interface, it will
show up in netstat(1) output even without the -a switch.
As the definition of "sockets used by server processes" is a
difficult one to qualify with regards to UDP, do not change the
output behaviour for UDP sockets.
PR: bin/26359
mbuma is an Mbuf & Cluster allocator built on top of a number of
extensions to the UMA framework, all included herein.
Extensions to UMA worth noting:
- Better layering between slab <-> zone caches; introduce
Keg structure which splits off slab cache away from the
zone structure and allows multiple zones to be stacked
on top of a single Keg (single type of slab cache);
perhaps we should look into defining a subset API on
top of the Keg for special use by malloc(9),
for example.
- UMA_ZONE_REFCNT zones can now be added, and reference
counters automagically allocated for them within the end
of the associated slab structures. uma_find_refcnt()
does a kextract to fetch the slab struct reference from
the underlying page, and lookup the corresponding refcnt.
mbuma things worth noting:
- integrates mbuf & cluster allocations with extended UMA
and provides caches for commonly-allocated items; defines
several zones (two primary, one secondary) and two kegs.
- change up certain code paths that always used to do:
m_get() + m_clget() to instead just use m_getcl() and
try to take advantage of the newly defined secondary
Packet zone.
- netstat(1) and systat(1) quickly hacked up to do basic
stat reporting but additional stats work needs to be
done once some other details within UMA have been taken
care of and it becomes clearer to how stats will work
within the modified framework.
From the user perspective, one implication is that the
NMBCLUSTERS compile-time option is no longer used. The
maximum number of clusters is still capped off according
to maxusers, but it can be made unlimited by setting
the kern.ipc.nmbclusters boot-time tunable to zero.
Work should be done to write an appropriate sysctl
handler allowing dynamic tuning of kern.ipc.nmbclusters
at runtime.
Additional things worth noting/known issues (READ):
- One report of 'ips' (ServeRAID) driver acting really
slow in conjunction with mbuma. Need more data.
Latest report is that ips is equally sucking with
and without mbuma.
- Giant leak in NFS code sometimes occurs, can't
reproduce but currently analyzing; brueffer is
able to reproduce but THIS IS NOT an mbuma-specific
problem and currently occurs even WITHOUT mbuma.
- Issues in network locking: there is at least one
code path in the rip code where one or more locks
are acquired and we end up in m_prepend() with
M_WAITOK, which causes WITNESS to whine from within
UMA. Current temporary solution: force all UMA
allocations to be M_NOWAIT from within UMA for now
to avoid deadlocks unless WITNESS is defined and we
can determine with certainty that we're not holding
any locks when we're M_WAITOK.
- I've seen at least one weird socketbuffer empty-but-
mbuf-still-attached panic. I don't believe this
to be related to mbuma but please keep your eyes
open, turn on debugging, and capture crash dumps.
This change removes more code than it adds.
A paper is available detailing the change and considering
various performance issues, it was presented at BSDCan2004:
http://www.unixdaemons.com/~bmilekic/netbuf_bmilekic.pdf
Please read the paper for Future Work and implementation
details, as well as credits.
Testing and Debugging:
rwatson,
brueffer,
Ketrien I. Saihr-Kesenchedra,
...
Reviewed by: Lots of people (for different parts)
- 0 should have been -1 in previous commit (just to stay consistent),
- Spell null pointers as NULL, not 0,
- Fixed the comment about pr_usesysctl to not confuse it with boolean.
Pointed by: bde
calculations. Long longs should never be used, since they break compiling
with C90 compilers and don't necessarily work any better than longs for
avoiding overflow.
Print percentages with another digit of precision since they can be small
and this is easy to do now that the format is floating point.
Restored some more of the old -m output:
Print the percentage of allocated memory that is in use. This is the
amount of memory in active mbufs and mbuf clusters relative to the
total amount of memory soft-allocated for mbufs and mbuf clusters.
Print the percentage of allocated memory that is wired (cached). The
old mbuf allocator never freed memory so printing this value wasn't
useful. A previous version of netstat for the new allocator printed
the in-use amount as a percentage of the wired amount.
Fixed some nearby style bugs (excessive parenthesization and a redundant
return).
Reviewed by: alfred
printf format warnings for inet6.c (pluralies() was implicit int, but
the context requires a "char *").
Added WARNS?=2 to the Makefile so that such errors don't come back.
Added NO_WERROR?= to the Makefile because I haven't checked that setting
WARNS doesn't uncover more bugs except on i386's.
