1) Added protection against collapsing OBJ_DEAD objects.
2) bump reference counts by 2 instead of 1 so that an object deallocate
doesn't try to recursively collapse the object.
3) mark pages renam

1) Added protection against collapsing OBJ_DEAD objects.
2) bump reference counts by 2 instead of 1 so that an object deallocate
doesn't try to recursively collapse the object.
3) mark pages renamed during the collapse as dirty so that their contents
are preserved.

Submitted by: John and me.

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Carefully choose the value for vm_object_cache_max. The previous calculation
was rather bogus in most cases; the new value works very well for both
large and small memory machines.

swap_pager.c:
Fixed long standing bug in freeing swap space during object collapses.
Fixed 'out of space' messages from printing out too often.
Modified to use new kmem_malloc() calling convention.
I

swap_pager.c:
Fixed long standing bug in freeing swap space during object collapses.
Fixed 'out of space' messages from printing out too often.
Modified to use new kmem_malloc() calling convention.
Implemented an additional stat in the swap pager struct to count the
amount of space allocated to that pager. This may be removed at some
point in the future.
Minimized unnecessary wakeups.

vm_fault.c:
Don't try to collect fault stats on 'swapped' processes - there aren't
any upages to store the stats in.
Changed read-ahead policy (again!).

vm_glue.c:
Be sure to gain a reference to the process's map before swapping.
Be sure to lose it when done.

kern_malloc.c:
Added the ability to specify if allocations are at interrupt time or
are 'safe'; this affects what types of pages can be allocated.

vm_map.c:
Fixed a variety of map lock problems; there's still a lurking bug that
will eventually bite.

vm_object.c:
Explicitly initialize the object fields rather than bzeroing the struct.
Eliminated the 'rcollapse' code and folded it's functionality into the
"real" collapse routine.
Moved an object_unlock() so that the backing_object is protected in
the qcollapse routine.
Make sure nobody fools with the backing_object when we're destroying it.
Added some diagnostic code which can be called from the debugger that
looks through all the internal objects and makes certain that they
all belong to someone.

vm_page.c:
Fixed a rather serious logic bug that would result in random system
crashes. Changed pagedaemon wakeup policy (again!).

vm_pageout.c:
Removed unnecessary page rotations on the inactive queue.
Changed the number of pages to explicitly free to just free_reserved
level.

Submitted by: John Dyson

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Don't attempt to clean device_pager backed objects at terminate time.
There is similar bogusness in the pageout daemon that will be fixed soon.
This fixes a panic pointed out to me by Bruce Evans tha

Don't attempt to clean device_pager backed objects at terminate time.
There is similar bogusness in the pageout daemon that will be fixed soon.
This fixes a panic pointed out to me by Bruce Evans that occurs when
/dev/mem is used to map managed memory.

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Added ability to detect sequential faults and DTRT. (swap_pager.c)
Added hook for pmap_prefault() and use symbolic constant for new third
argument to vm_page_alloc() (vm_fault.c, various)
Changed the

Added ability to detect sequential faults and DTRT. (swap_pager.c)
Added hook for pmap_prefault() and use symbolic constant for new third
argument to vm_page_alloc() (vm_fault.c, various)
Changed the way that upages and page tables are held. (vm_glue.c)
Fixed architectural flaw in allocating pages at interrupt time that was
introduced with the merged cache changes. (vm_page.c, various)
Adjusted some algorithms to acheive better paging performance and to
accomodate the fix for the architectural flaw mentioned above. (vm_pageout.c)
Fixed pbuf handling problem, changed policy on handling read-behind page.
(vnode_pager.c)

Submitted by: John Dyson

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Protect a qcollapse call with an object lock before calling. The locks
need to be moved into the qcollapse and rcollapse routines, but I don't
have time at the moment to make all the required changes

Protect a qcollapse call with an object lock before calling. The locks
need to be moved into the qcollapse and rcollapse routines, but I don't
have time at the moment to make all the required changes...this will do
for now.

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Improve my previous change to use the same tests as are used in qcollapse.

Fixed a panic that Garrett reported to me...the OBJ_INTERNAL flag wasn't
being cleared in some cases for vnode backed objects; we now do this in
vnode_pager_alloc proper to guarantee it. Also be more

Fixed a panic that Garrett reported to me...the OBJ_INTERNAL flag wasn't
being cleared in some cases for vnode backed objects; we now do this in
vnode_pager_alloc proper to guarantee it. Also be more careful in the
rcollapse code about messing with busy/bmapped pages.

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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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Make sure that the object being collapsed doesn't go away on us...by
gaining extra references to it.

Submitted by: John Dyson
Obtained from:

Do vm_page_rename more conservatively in rcollapse and qcollapse, and
change list walk so that it doesn't get stuck in an infinite loop.

Submitted by: John Dyson

Don't put objects that have no parent on the reverse_shadow_list. Problem
identified and explained by Gene Stark (thanks Gene!).

Submitted by: John Dyson

These changes fix a couple of lingering VM problems:

1. The pageout daemon used to block under certain
circumstances, and we needed to add new functionality
that would cause the pageout daemon to

These changes fix a couple of lingering VM problems:

1. The pageout daemon used to block under certain
circumstances, and we needed to add new functionality
that would cause the pageout daemon to block more often.
Now, the pageout daemon mostly just gets rid of pages
and kills processes when the system is out of swap.
The swapping, rss limiting and object cache trimming
have been folded into a new daemon called "vmdaemon".
This new daemon does things that need to be done for
the VM system, but can block. For example, if the
vmdaemon blocks for memory, the pageout daemon
can take care of it. If the pageout daemon had
blocked for memory, it was difficult to handle
the situation correctly (and in some cases, was
impossible).

2. The collapse problem has now been entirely fixed.
It now appears to be impossible to accumulate unnecessary
vm objects. The object collapsing now occurs when ref counts
drop to one (where it is more likely to be more simple anyway
because less pages would be out on disk.) The original
fixes were incomplete in that pathological circumstances
could still be contrived to cause uncontrolled growth
of swap. Also, the old code still, under steady state
conditions, used more swap space than necessary. When
using the new code, users will generally notice a
significant decrease in swap space usage, and theoretically,
the system should be leaving fewer unused pages around
competing for memory.

Submitted by: John Dyson

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Added support for starting the experimental "vmdaemon" system process.
Enabled via REL2_1.

Added support for doing object collapses "on the fly". Enabled via REL2_1a.

Improved object collapses so t

Added support for starting the experimental "vmdaemon" system process.
Enabled via REL2_1.

Added support for doing object collapses "on the fly". Enabled via REL2_1a.

Improved object collapses so that they can happen in more cases. Improved
sensing of modified pages to fix an apparant race condition and improve
clustered pageout opportunities. Fixed an "oops" with not restarting page
scan after a potential block in vm_pageout_clean() (not doing this can result
in strange behavior in some cases).

Submitted by: John Dyson & David Greenman

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Properly count object lookups and hits.

Cosmetics: unused vars, ()'s, #include's &c &c to silence gcc.
Reviewed by: davidg

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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1) Changed ddb into a option rather than a pseudo-device (use options DDB
in your kernel config now).
2) Added ps ddb function from 1.1.5. Cleaned it up a bit and moved into its
own file.
3) Ad

1) Changed ddb into a option rather than a pseudo-device (use options DDB
in your kernel config now).
2) Added ps ddb function from 1.1.5. Cleaned it up a bit and moved into its
own file.
3) Added \r handing in db_printf.
4) Added missing memory usage stats to statclock().
5) Added dummy function to pseudo_set so it will be emitted if there
are no other pseudo declarations.

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Fix up some sloppy coding practices:

- Delete redundant declarations.
- Add -Wredundant-declarations to Makefile.i386 so they don't come back.
- Delete sloppy COMMON-style declarations of uninitiali

Fix up some sloppy coding practices:

- Delete redundant declarations.
- Add -Wredundant-declarations to Makefile.i386 so they don't come back.
- Delete sloppy COMMON-style declarations of uninitialized data in
header files.
- Add a few prototypes.
- Clean up warnings resulting from the above.

NB: ioconf.c will still generate a redundant-declaration warning, which
is unavoidable unless somebody volunteers to make `config' smarter.

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Provide support for upcoming merged VM/buffer cache, and fixed a few bugs
that haven't appeared to manifest themselves (yet).

Submitted by: John Dyson

Added $Id$

The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.

Reviewed by: Rodney W. Grimes
Submitted by: John Dyson and David Greenman

BSD 4.4 Lite Kernel Sources