Added some more of John's "anti-chatter" fixes - set the page activation
count to 0 after activating the page; the previous behavior biased the
pages too high in some cases.

Submitted by: John Dyson

Fixes from John Dyson to work around vnode lock hang. Basically, remove
the VOP_BMAP calls, and add one to bdwrite.

Submitted by: John Dyson

Various changes from John and myself that do the following:

New functions create - vm_object_pip_wakeup and pagedaemon_wakeup that
are used to reduce the actual number of wakeups.
New function vm_pa

Various changes from John and myself that do the following:

New functions create - vm_object_pip_wakeup and pagedaemon_wakeup that
are used to reduce the actual number of wakeups.
New function vm_page_protect which is used in conjuction with some new
page flags to reduce the number of calls to pmap_page_protect.
Minor changes to reduce unnecessary spl nesting.
Rewrote vm_page_alloc() to improve readability.
Various other mostly cosmetic changes.

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Fixed thrashing buffer problem.

Submitted by: John Dyson

Added some code to make sure that buffers associated with directories and
metadata aren't thrashed by regular file I/O.
Added mechanism to limit the amount of outstanding I/O on a given vnode.
Pageda

Added some code to make sure that buffers associated with directories and
metadata aren't thrashed by regular file I/O.
Added mechanism to limit the amount of outstanding I/O on a given vnode.
Pagedaemon wakeup policy changed to skew priority a little in favor of
file caching.
Slight code reorganization to improve clarity.
Added a few more comments.

Submitted by: John Dyson

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Only do object paging_in_progress wakeups if someone is waiting on this
condition.
Added some comments.

Submitted by: John Dyson

Only clear B_VMIO in brelse() - a bunch of special processing is required
whenever this happens, and that wasn't occurring in some cases.

Make B_NOCACHE and B_INVAL buffers work correctly - throw away the data in
the page cache.

Submitted by: John Dyson

Fix problem with freeing busy pages reported by Nick Sayer.

Submitted by: John Dyson

Fixed a variety of deadlock and panic bugs, removed the bypass code, and
implemented the ability to limit bufferspace by memory consumed. (vfs_bio.c)
Fixed recently introduced bugs that caused extra

Fixed a variety of deadlock and panic bugs, removed the bypass code, and
implemented the ability to limit bufferspace by memory consumed. (vfs_bio.c)
Fixed recently introduced bugs that caused extra I/O to happen in some
cases. (vfs_cluster.c)

Submitted by: John Dyson

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Restore original fix from ohki, not check m for NULL it is already done
in the code above.
Submitted by: ohki@gssm.otsuka.tsukuba.ac.jp

Change if (m->valid == 0) to if (m && m->valid == 0)

Submitted by: ohki@gssm.otsuka.tsukuba.ac.jp
When using cp to copy a file under the following circumstanes:

- original file in on an NFS filesystem
- destination file is on the same NFS filesystem
-

Submitted by: ohki@gssm.otsuka.tsukuba.ac.jp
When using cp to copy a file under the following circumstanes:

- original file in on an NFS filesystem
- destination file is on the same NFS filesystem
- the file is less than 8Mbytes in size
- the file is larger than 65536 bytes in size

the cp process can get frozen in device-wait and never wake up (cp uses
mmap() in this case).
A small change to allocbuf() fixes this.

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Attempt to close a hole using splhigh/splx. There still appears to be a
serious one in the same area that I don't have time to fix.

MFS doesn't bother to associate a struct mount with the vnode...so work
around this by not trying to cluster this type of I/O.

Submitted by: John Dyson

PG_FAKE is no longer used - so don't bother to clear it.

Fixed some formatting weirdness that I overlooked in the previous commit.

These changes embody the support of the fully coherent merged VM buffer cache,
much higher filesystem I/O performance, and much better paging performance. It
represents the culmination of over 6 mont

These changes embody the support of the fully coherent merged VM buffer cache,
much higher filesystem I/O performance, and much better paging performance. It
represents the culmination of over 6 months of R&D.

The majority of the merged VM/cache work is by John Dyson.

The following highlights the most significant changes. Additionally, there are
(mostly minor) changes to the various filesystem modules (nfs, msdosfs, etc) to
support the new VM/buffer scheme.

vfs_bio.c:
Significant rewrite of most of vfs_bio to support the merged VM buffer cache
scheme. The scheme is almost fully compatible with the old filesystem
interface. Significant improvement in the number of opportunities for write
clustering.

vfs_cluster.c, vfs_subr.c
Upgrade and performance enhancements in vfs layer code to support merged
VM/buffer cache. Fixup of vfs_cluster to eliminate the bogus pagemove stuff.

vm_object.c:
Yet more improvements in the collapse code. Elimination of some windows that
can cause list corruption.

vm_pageout.c:
Fixed it, it really works better now. Somehow in 2.0, some "enhancements"
broke the code. This code has been reworked from the ground-up.

vm_fault.c, vm_page.c, pmap.c, vm_object.c
Support for small-block filesystems with merged VM/buffer cache scheme.

pmap.c vm_map.c
Dynamic kernel VM size, now we dont have to pre-allocate excessive numbers of
kernel PTs.

vm_glue.c
Much simpler and more effective swapping code. No more gratuitous swapping.

proc.h
Fixed the problem that the p_lock flag was not being cleared on a fork.

swap_pager.c, vnode_pager.c
Removal of old vfs_bio cruft to support the past pseudo-coherency. Now the
code doesn't need it anymore.

machdep.c
Changes to better support the parameter values for the merged VM/buffer cache
scheme.

machdep.c, kern_exec.c, vm_glue.c
Implemented a seperate submap for temporary exec string space and another one
to contain process upages. This eliminates all map fragmentation problems
that previously existed.

ffs_inode.c, ufs_inode.c, ufs_readwrite.c
Changes for merged VM/buffer cache. Add "bypass" support for sneaking in on
busy buffers.

Submitted by: John Dyson and David Greenman

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Only VM_WAIT if curproc != pageproc. A deadlock can occur otherwise.

Submitted by: John Dyson

Removed references to bclnlist which we don't use/support/need.

Stuff object into v_vmdata rather than pager. Not important which at
the moment, but will be in the future. Other changes mostly cosmetic,
but are made for future VMIO considerations.

Submitted by:

Stuff object into v_vmdata rather than pager. Not important which at
the moment, but will be in the future. Other changes mostly cosmetic,
but are made for future VMIO considerations.

Submitted by: John Dyson

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Commented out anti-paging code as it was found to be the cause of a
buffer deadlock.

While in the real world, I had a bad case of being swapped out for a lot of
cycles. While waiting there I added a lot of the extra ()'s I have, (I have
never used LISP to any extent). So I compiled

While in the real world, I had a bad case of being swapped out for a lot of
cycles. While waiting there I added a lot of the extra ()'s I have, (I have
never used LISP to any extent). So I compiled the kernel with -Wall and
shut up a lot of "suggest you add ()'s", removed a bunch of unused var's
and added a couple of declarations here and there. Having a lap-top is
highly recommended. My kernel still runs, yell at me if you kernel breaks.

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Rather than exclude bounce buffers support with NOBOUNCE, include it
with BOUNCE_BUFFERS. This is more intuitive, and is better for future
multiplatform support. Added BOUNCE_BUFFERS option to the GE

Rather than exclude bounce buffers support with NOBOUNCE, include it
with BOUNCE_BUFFERS. This is more intuitive, and is better for future
multiplatform support. Added BOUNCE_BUFFERS option to the GENERIC and
LINT kernel config files.

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Changed to reclaim memory from other buffers to eliminate memory
thrashing.

Submitted by: John Dyson