Commit Graph

11 Commits

Author SHA1 Message Date
Robert Watson
32a6bd9510 No longer maintain mbstat statistics for the mbuf allocator, UMA
statistics and libmemstat(3) are now used to track mbuf statistics.

MFC after:	1 month
2005-09-27 20:28:43 +00:00
Robert Watson
68352adfe7 Define four constants, MBUF_{,MEM,CLUSTER,PACKET,TAG}_MEM_NAME, which
are string names for their respective UMA zones and malloc types, and
are passed into uma_zcreate() and MALLOC_DEFINE().  Export them
outside of _KERNEL in mbuf.h so that netstat can reference them.

Change the names to improve consistency, with each zone/type
associated with the mbuf allocator being prefixed mbuf_.

MFC after:	1 week
2005-07-17 14:04:03 +00:00
Mike Silbersack
a7b844d2be Fix the false memory modified after free messages some users have been
reporting - in my previous change, I missed the case where a mbuf
from the packet zone was freed back to the mbuf/packet keg, where
it was subsequently put into the mbuf zone and found not to contain
the expected trash.  This change adds the necessary trash_dtor call inside
mb_fini_pack so that everything is correct.

Thanks for Bosko for finding the bug and showing me how secondary zones
work.

Approved by:	re (dwhite)
2005-06-29 08:18:26 +00:00
Mike Silbersack
121f050976 Change the mbuf, mbuf cluster, and mbuf packet allocation routines so that
the UMA "trash" allocator is used - this ensures that any writes to a freed
mbuf should provoke a panic.

Only enabled under INVARIANTS, of course.

Approved by:	re (scottl)
2005-06-23 04:33:39 +00:00
Bosko Milekic
8076cb5289 Well, it seems that I pre-maturely removed the "All rights reserved"
statement from some files, so re-add it for the moment, until the
related legalese is sorted out.  This change affects:

sys/kern/kern_mbuf.c
sys/vm/memguard.c
sys/vm/memguard.h
sys/vm/uma.h
sys/vm/uma_core.c
sys/vm/uma_dbg.c
sys/vm/uma_dbg.h
sys/vm/uma_int.h
2005-02-16 21:45:59 +00:00
Bosko Milekic
3d2a3ff25e Optimize the way reference counting is performed with Mbufs. We
do not need to perform an extra memory fetch in the Packet (Mbuf+Cluster)
constructor to initialize the reference counter anymore.  The reference
counts are located in a separate memory region (in the slab header,
because this zone is UMA_ZONE_REFCNT), so the memory fetch resulted very
often in a cache miss.  Additionally, and perhaps more significantly,
optimize the free mbuf+cluster (packet) case, which is very common, to
no longer require an atomic operation on free (to verify the reference
counter) if the reference on the cluster has never been increased (also
very common).  Reduces an atomic on mbuf free on average.

Original patch submitted by: Gerrit Nagelhout <gnagelhout@sandvine.com>
2005-02-10 22:23:02 +00:00
Bosko Milekic
737cd9525b Update copyright, remove "all rights reserved" (since they are not
all reserved, as the lisence makes clear), and strike the third clause
(now this is a 2-clause liberal BSDL as are the rest of files I hold
copyright over).
2005-02-01 03:17:52 +00:00
Brian Somers
a04946cf6e CTASSERT that MSZIE is a power of 2 (otherwise dtom() breaks)
Ask uma_zcreate() to align mbufs to MSIZE bytes (otherwise dtom() breaks)

As it happens, uma_zalloc_arg() always returned mbufs aligned to MSIZE
anyway, but that was an implementation side-effect....

KASSERT -> CTASSERT suggested by: dd@
Approved by:	silence on -net
2004-09-20 08:52:04 +00:00
Brian Feldman
b23f72e98a * Add a "how" argument to uma_zone constructors and initialization functions
so that they know whether the allocation is supposed to be able to sleep
  or not.
* Allow uma_zone constructors and initialation functions to return either
  success or error.  Almost all of the ones in the tree currently return
  success unconditionally, but mbuf is a notable exception: the packet
  zone constructor wants to be able to fail if it cannot suballocate an
  mbuf cluster, and the mbuf allocators want to be able to fail in general
  in a MAC kernel if the MAC mbuf initializer fails.  This fixes the
  panics people are seeing when they run out of memory for mbuf clusters.
* Allow debug.nosleepwithlocks on WITNESS to be disabled, without changing
  the default.

Both bmilekic and jeff have reviewed the changes made to make failable
zone allocations work.
2004-08-02 00:18:36 +00:00
Bosko Milekic
6bc72ab95a Fix a couple of bugs in the mbuf and packet ctors. In the latter case,
nextpkt within the m_hdr was not being initialized to NULL for
!M_PKTHDR cases.  *Maybe* this will fix weird socket buffer
inconsistency panics, but we'll see.
2004-06-01 16:17:10 +00:00
Bosko Milekic
099a0e588c Bring in mbuma to replace mballoc.
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)
2004-05-31 21:46:06 +00:00