had a 2.1 tag, thus sending these two changes into the 2.1 branch instead
of -current. Argh. I may bring these changes into the 2.1 anyway (they're
benign there) so I'm not going to admin them out of 2.1 for the time
being.
Claim the major numbers (before sombedoy else jumps in again and
claims the slots for his foocd driver :-), install all the hooks that
are required.
While i've been at this, i've cleaned up some of the routines at the
end of i386/conf.c; all the importers of the latest CDROM drivers
forgot to fill in the appropriate information. The `ata' driver
(vapourware?) does only occupy a slot in the bdevsw[] array, btw.
The actual import of the code does require a minor change in the SCSI
subsystem, and i want to have this reviewed by Peter first, so it will
be deferred for some days. The driver is already working for me
though.
Submitted by: akiyama@kme.mei.co.jp (Shunsuke Akiyama)
Submitted by: Andrew McRae <andrew@mega.com.au>
Some initial commits from the pcmcia stuff, to make life easier for the
testers.
We will use the name "pccard" since that is really the buzzword at present.
notebooks where a powerfail condition (external power drop; battery
state low) is signalled by an NMI. Makes it beep instead of panicing.
Reviewed by: davidg
what CSRG had, plus make things like, TYPE, REVISION, and BRANCH
easy to set, and derive RELEASE and VERSION from them.
Kill the JUST_TELL_ME hack, it is no longer needed.
Kill DISTNAME, I could find no reveference to it any place in the
source tree.
Now I just need to rework a few bits in release/Makefile, but want
to wait and talk to jkh about that.
Oh, and your now all running:
TYPE="FreeBSD"
REVISION="2.2"
BRANCH="CURRENT"
and the -BUILD-yymmdd is dead and gone. The date was already in the
version[] string, no need for it to be there in 2 formats!
proc or any VM system structure will have to be rebuilt!!!
Much needed overhaul of the VM system. Included in this first round of
changes:
1) Improved pager interfaces: init, alloc, dealloc, getpages, putpages,
haspage, and sync operations are supported. The haspage interface now
provides information about clusterability. All pager routines now take
struct vm_object's instead of "pagers".
2) Improved data structures. In the previous paradigm, there is constant
confusion caused by pagers being both a data structure ("allocate a
pager") and a collection of routines. The idea of a pager structure has
escentially been eliminated. Objects now have types, and this type is
used to index the appropriate pager. In most cases, items in the pager
structure were duplicated in the object data structure and thus were
unnecessary. In the few cases that remained, a un_pager structure union
was created in the object to contain these items.
3) Because of the cleanup of #1 & #2, a lot of unnecessary layering can now
be removed. For instance, vm_object_enter(), vm_object_lookup(),
vm_object_remove(), and the associated object hash list were some of the
things that were removed.
4) simple_lock's removed. Discussion with several people reveals that the
SMP locking primitives used in the VM system aren't likely the mechanism
that we'll be adopting. Even if it were, the locking that was in the code
was very inadequate and would have to be mostly re-done anyway. The
locking in a uni-processor kernel was a no-op but went a long way toward
making the code difficult to read and debug.
5) Places that attempted to kludge-up the fact that we don't have kernel
thread support have been fixed to reflect the reality that we are really
dealing with processes, not threads. The VM system didn't have complete
thread support, so the comments and mis-named routines were just wrong.
We now use tsleep and wakeup directly in the lock routines, for instance.
6) Where appropriate, the pagers have been improved, especially in the
pager_alloc routines. Most of the pager_allocs have been rewritten and
are now faster and easier to maintain.
7) The pagedaemon pageout clustering algorithm has been rewritten and
now tries harder to output an even number of pages before and after
the requested page. This is sort of the reverse of the ideal pagein
algorithm and should provide better overall performance.
8) Unnecessary (incorrect) casts to caddr_t in calls to tsleep & wakeup
have been removed. Some other unnecessary casts have also been removed.
9) Some almost useless debugging code removed.
10) Terminology of shadow objects vs. backing objects straightened out.
The fact that the vm_object data structure escentially had this
backwards really confused things. The use of "shadow" and "backing
object" throughout the code is now internally consistent and correct
in the Mach terminology.
11) Several minor bug fixes, including one in the vm daemon that caused
0 RSS objects to not get purged as intended.
12) A "default pager" has now been created which cleans up the transition
of objects to the "swap" type. The previous checks throughout the code
for swp->pg_data != NULL were really ugly. This change also provides
the rudiments for future backing of "anonymous" memory by something
other than the swap pager (via the vnode pager, for example), and it
allows the decision about which of these pagers to use to be made
dynamically (although will need some additional decision code to do
this, of course).
13) (dyson) MAP_COPY has been deprecated and the corresponding "copy
object" code has been removed. MAP_COPY was undocumented and non-
standard. It was furthermore broken in several ways which caused its
behavior to degrade to MAP_PRIVATE. Binaries that use MAP_COPY will
continue to work correctly, but via the slightly different semantics
of MAP_PRIVATE.
14) (dyson) Sharing maps have been removed. It's marginal usefulness in a
threads design can be worked around in other ways. Both #12 and #13
were done to simplify the code and improve readability and maintain-
ability. (As were most all of these changes)
TODO:
1) Rewrite most of the vnode pager to use VOP_GETPAGES/PUTPAGES. Doing
this will reduce the vnode pager to a mere fraction of its current size.
2) Rewrite vm_fault and the swap/vnode pagers to use the clustering
information provided by the new haspage pager interface. This will
substantially reduce the overhead by eliminating a large number of
VOP_BMAP() calls. The VOP_BMAP() filesystem interface should be
improved to provide both a "behind" and "ahead" indication of
contiguousness.
3) Implement the extended features of pager_haspage in swap_pager_haspage().
It currently just says 0 pages ahead/behind.
4) Re-implement the swap device (swstrategy) in a more elegant way, perhaps
via a much more general mechanism that could also be used for disk
striping of regular filesystems.
5) Do something to improve the architecture of vm_object_collapse(). The
fact that it makes calls into the swap pager and knows too much about
how the swap pager operates really bothers me. It also doesn't allow
for collapsing of non-swap pager objects ("unnamed" objects backed by
other pagers).
LINT talks about about 2.1. I changed that to 2.0.5,
and clarified why certain devices need "at scbus?".
There is still a crazy "PCVT=210" which shouldn't be there,
but corrected comment as it is needed for 2.0.5.
- option DODUMP no longer exists (remove all references to it).
- directive `swap on' is now a no-op (don't bother documenting it; remove
comment to match code).
- directive `dumps on' still works (restore code to match comment; deprecate
it in comment).
Reviewed by: Poul-Henning Kamp, and me
Submitted by: Bruce Evans
in machdep.c (it should use the global nmbclusters). Moved the calculation
of nmbclusters into conf/param.c (same place where nmbclusters has always
been assigned), and made the calculation include an extra amount based
on "maxusers". NMBCLUSTERS can still be overrided in the kernel config
file as always, but this change will make that generally unnecessary. This
fixes the "bug" reports from people who have misconfigured kernels seeing
the network "hang" when the mbuf cluster pool runs out.
Reviewed by: John Dyson
require specific partitions be mentioned in the kernel config
file ("swap on foo" is now obsolete).
From Poul-Henning:
The visible effect is this:
As default, unless
options "NSWAPDEV=23"
is in your config, you will have four swap-devices.
You can swapon(2) any block device you feel like, it doesn't have
to be in the kernel config.
There is a performance/resource win available by getting the NSWAPDEV right
(but only if you have just one swap-device ??), but using that as default
would be too restrictive.
The invisible effect is that:
Swap-handling disappears from the $arch part of the kernel.
It gets a lot simpler (-145 lines) and cleaner.
Reviewed by: John Dyson, David Greenman
Submitted by: Poul-Henning Kamp, with minor changes by me.
