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History log of /src/sys/uvm/uvm.h
RevisionDateAuthorComments
 1.78  17-Jul-2023  riastradh uvm(9): One rndsource for faults -- not one per CPU.

All relevant state is per-CPU anyway; the only substantive difference
this makes is how many entries appear in `rndctl -l' output and what
they are called -- formerly the somewhat confusing `cpuN', meaning
`page faults on cpuN', and now just `uvmfault'. I don't think
there's any real value in being able to enable or disable measurement
or counting of page faults on one CPU vs others, so although this
could be a minor compatibility change, it's hard to imagine it
matters much.

XXX kernel ABI change in struct cpu_info
 1.77  17-May-2020  ad - If the hardware provided NUMA info, then use it to decide how to set up
the allocator's buckets, instead of doing round robin distribution. There
are open questions here but this is better than doing nothing.

- Kernel reserve pages are for the kernel not realtime threads.
 1.76  14-Mar-2020  ad Make page waits (WANTED vs BUSY) interlocked by pg->interlock. Gets RW
locks out of the equation for sleep/wakeup, and allows observing+waiting
for busy pages when holding only a read lock. Proposed on tech-kern.
 1.75  23-Feb-2020  ad UVM locking changes, proposed on tech-kern:

- Change the lock on uvm_object, vm_amap and vm_anon to be a RW lock.
- Break v_interlock and vmobjlock apart. v_interlock remains a mutex.
- Do partial PV list locking in the x86 pmap. Others to follow later.
 1.74  18-Feb-2020  chs remove the aiodoned thread. I originally added this to provide a thread context
for doing page cache iodone work, but since then biodone() has changed to
hand off all iodone work to a softint thread, so we no longer need the
special-purpose aiodoned thread.
 1.73  31-Dec-2019  ad branches: 1.73.2;
- Add and use wrapper functions that take and acquire page interlocks, and pairs
of page interlocks. Require that the page interlock be held over calls to
uvm_pageactivate(), uvm_pagewire() and similar.

- Solve the concurrency problem with page replacement state. Rather than
updating the global state synchronously, set an intended state on
individual pages (active, inactive, enqueued, dequeued) while holding the
page interlock. After the interlock is released put the pages on a 128
entry per-CPU queue for their state changes to be made real in batch.
This results in in a ~400 fold decrease in contention on my test system.
Proposed on tech-kern but modified to use the page interlock rather than
atomics to synchronise as it's much easier to maintain that way, and
cheaper.
 1.72  27-Dec-2019  ad Nothing uses uvm.cpus any more, and we can do the same with cpu_lookup(),
so get rid of it.
 1.71  27-Dec-2019  ad Redo the page allocator to perform better, especially on multi-core and
multi-socket systems. Proposed on tech-kern. While here:

- add rudimentary NUMA support - needs more work.
- remove now unused "listq" from vm_page.
 1.70  13-Dec-2019  ad Break the global uvm_pageqlock into a per-page identity lock and a private
lock for use of the pagedaemon policy code. Discussed on tech-kern.

PR kern/54209: NetBSD 8 large memory performance extremely low
PR kern/54210: NetBSD-8 processes presumably not exiting
PR kern/54727: writing a large file causes unreasonable system behaviour
 1.69  01-Dec-2019  ad - Adjust uvmexp.swpgonly with atomics, and make uvm_swap_data_lock static.
- A bit more __cacheline_aligned on mutexes.
 1.68  02-Jan-2017  cherry branches: 1.68.16;
Move sys/uvm/uvm_physseg.h inclusion to within _KERNEL only.
 1.67  22-Dec-2016  cherry Use uvm_physseg.h:uvm_page_physload() instead of uvm_extern.h

For this, include uvm_physseg.h in the build and include tree, make a
cosmetic modification to the prototype for uvm_page_physload().
 1.66  13-Apr-2015  riastradh branches: 1.66.2;
Limit <sys/rndsource.h> include to kernel.
 1.65  13-Apr-2015  riastradh Convert remaining MI <sys/rnd.h> stragglers. Many MD ones left.
 1.64  10-Aug-2014  tls branches: 1.64.4;
Merge tls-earlyentropy branch into HEAD.
 1.63  02-Feb-2012  tls branches: 1.63.6; 1.63.20;
Entropy-pool implementation move and cleanup.

1) Move core entropy-pool code and source/sink/sample management code
to sys/kern from sys/dev.

2) Remove use of NRND as test for presence of entropy-pool code throughout
source tree.

3) Remove use of RND_ENABLED in device drivers as microoptimization to
avoid expensive operations on disabled entropy sources; make the
rnd_add calls do this directly so all callers benefit.

4) Fix bug in recent rnd_add_data()/rnd_add_uint32() changes that might
have lead to slight entropy overestimation for some sources.

5) Add new source types for environmental sensors, power sensors, VM
system events, and skew between clocks, with a sample implementation
for each.

ok releng to go in before the branch due to the difficulty of later
pullup (widespread #ifdef removal and moved files). Tested with release
builds on amd64 and evbarm and live testing on amd64.
 1.62  17-May-2011  mrg branches: 1.62.4; 1.62.8;
move and rename the uvm history code out of uvm_stat to "kernhist".

rename "UVMHIST" option to enable the uvm histories.

TODO:
- make UVMHIST properly depend upon KERNHIST
- enable dynamic registration of histories. this is mostly just
allocating something in a bitmap, and is only for viewing multiple
histories in a merged form.


tested on amd64 and sparc64.
 1.61  02-Feb-2011  chuck udpate license clauses on my code to match the new-style BSD licenses.
based on diff that rmind@ sent me.

no functional change with this commit.
 1.60  02-Feb-2011  chuck udpate license clauses on my code to match the new-style BSD licenses.
based on diff that rmind@ sent me.

no functional change with this commit.
 1.59  09-Dec-2010  uebayasi branches: 1.59.2; 1.59.4;
Make UVM_PAGE_TRKOWN a real flag.
 1.58  25-Apr-2010  ad Reduce memory spent on bookkeeping for large values of MAXCPUS.
 1.57  21-Oct-2009  rmind branches: 1.57.2; 1.57.4;
Remove uarea swap-out functionality:

- Addresses the issue described in PR/38828.
- Some simplification in threading and sleepq subsystems.
- Eliminates pmap_collect() and, as a side note, allows pmap optimisations.
- Eliminates XS_CTL_DATA_ONSTACK in scsipi code.
- Avoids few scans on LWP list and thus potentially long holds of proc_lock.
- Cuts ~1.5k lines of code. Reduces amd64 kernel size by ~4k.
- Removes __SWAP_BROKEN cases.

Tested on x86, mips, acorn32 (thanks <mpumford>) and partly tested on
acorn26 (thanks to <bjh21>).

Discussed on <tech-kern>, reviewed by <ad>.
 1.56  28-Jun-2009  rmind Ephemeral mapping (emap) implementation. Concept is based on the idea that
activity of other threads will perform the TLB flush for the processes using
emap as a side effect. To track that, global and per-CPU generation numbers
are used. This idea was suggested by Andrew Doran; various improvements to
it by me. Notes:

- For now, zero-copy on pipe is not yet enabled.
- TCP socket code would likely need more work.
- Additional UVM loaning improvements are needed.

Proposed on <tech-kern>, silence there.
Quickly reviewed by <ad>.
 1.55  04-Jun-2008  ad branches: 1.55.12; 1.55.16;
Replace the global vm_page hash with a per vm_object rbtree.
Proposed on tech-kern@.
 1.54  04-Jun-2008  ad - vm_page: put listq, pageq into a union alongside a LIST_ENTRY, so we can
use both types of list.

- Make page coloring and idle zero state per-CPU.

- Maintain per-CPU page freelists. When freeing, put pages onto the local
CPU's lists and the global lists. When allocating, prefer to take pages
from the local CPU. If none are available take from the global list as
done now. Proposed on tech-kern@.
 1.53  02-Jan-2008  ad branches: 1.53.6; 1.53.8; 1.53.10; 1.53.12;
Merge vmlocking2 to head.
 1.52  21-Jul-2007  ad branches: 1.52.6; 1.52.12; 1.52.14; 1.52.18; 1.52.22;
Merge unobtrusive locking changes from the vmlocking branch.
 1.51  09-Jul-2007  ad branches: 1.51.2;
Merge some of the less invasive changes from the vmlocking branch:

- kthread, callout, devsw API changes
- select()/poll() improvements
- miscellaneous MT safety improvements
 1.50  15-Jun-2007  ad Add a sysctl to disable swapout of kernel stacks. Discussed on tech-kern@.
 1.49  21-Feb-2007  thorpej branches: 1.49.4; 1.49.6;
Pick up some additional files that were missed before due to conflicts
with newlock2 merge:

Replace the Mach-derived boolean_t type with the C99 bool type. A
future commit will replace use of TRUE and FALSE with true and false.
 1.48  21-Feb-2007  thorpej Replace the Mach-derived boolean_t type with the C99 bool type. A
future commit will replace use of TRUE and FALSE with true and false.
 1.47  19-Feb-2007  ad uvm_kick_scheduler(): do nothing until the swap subsystem is initialized.
 1.46  15-Feb-2007  ad branches: 1.46.2;
Add uvm_kick_scheduler() (MP safe) to replace wakeup(&proc0).
 1.45  21-Dec-2006  yamt merge yamt-splraiseipl branch.

- finish implementing splraiseipl (and makeiplcookie).
http://mail-index.NetBSD.org/tech-kern/2006/07/01/0000.html
- complete workqueue(9) and fix its ipl problem, which is reported
to cause audio skipping.
- fix netbt (at least compilation problems) for some ports.
- fix PR/33218.
 1.44  15-Sep-2006  yamt branches: 1.44.2;
merge yamt-pdpolicy branch.
- separate page replacement policy from the rest of kernel
- implement an alternative replacement policy
 1.43  11-Feb-2006  yamt branches: 1.43.2; 1.43.14;
remove the following options. no objections on tech-kern@.

UVM_PAGER_INLINE
UVM_AMAP_INLINE
UVM_PAGE_INLINE
UVM_MAP_INLINE
 1.42  29-Nov-2005  yamt branches: 1.42.2; 1.42.4; 1.42.6;
read-ahead statistics.
 1.41  30-Oct-2005  yamt branches: 1.41.2;
don't include uvm_*_i.h unless needed,
to reduce bogus header dependencies.
 1.40  11-May-2005  yamt branches: 1.40.2; 1.40.4;
allocate anons on-demand, rather than reserving static amount of
them on boot/swapon.
 1.39  01-Jan-2005  yamt for in-kernel maps,
- allocate kva for vm_map_entry from the map itsself and
remove the static limit, MAX_KMAPENT.
- keep merged entries for later splitting to fix allocate-to-free problem.
PR/24039.
 1.38  23-Nov-2004  yamt introduce UVMHIST_LOANHIST and sprinkle UVMHIST_LOGs.
 1.37  10-Feb-2004  matt Back out the changes in
http://mail-index.netbsd.org/source-changes/2004/01/29/0027.html
since they don't really fix the problem.

Incorpate one fix: Mark uvm_map_entry's that were created with
UVM_FLAG_NOMERGE so that they will not be used as future merge
candidates.
 1.36  29-Jan-2004  yamt - split uvm_map() into two functions for the followings.
- for in-kernel maps, disable map entry merging so that
unmap operations won't block. (workaround for PR/24039)
- for in-kernel maps, allocate kva for vm_map_entry from
the map itsself and eliminate MAX_KMAPENT and
uvm_map_entry_kmem_pool.
 1.35  01-Dec-2002  matt branches: 1.35.6;
Reorder things so that with multiple inclusion protection that optional
definitions are outside the protection checks.
 1.34  02-Nov-2002  perry gah. reversed a test.
 1.33  02-Nov-2002  perry /*CONTCOND*/, and protect UVMHIST_DECL with #ifdef UVMHIST
 1.32  15-Sep-2002  thorpej Protect "struct uvm" with _KERNEL.
 1.31  15-Sep-2001  chs branches: 1.31.6; 1.31.12;
a whole bunch of changes to improve performance and robustness under load:

- remove special treatment of pager_map mappings in pmaps. this is
required now, since I've removed the globals that expose the address range.
pager_map now uses pmap_kenter_pa() instead of pmap_enter(), so there's
no longer any need to special-case it.
- eliminate struct uvm_vnode by moving its fields into struct vnode.
- rewrite the pageout path. the pager is now responsible for handling the
high-level requests instead of only getting control after a bunch of work
has already been done on its behalf. this will allow us to UBCify LFS,
which needs tighter control over its pages than other filesystems do.
writing a page to disk no longer requires making it read-only, which
allows us to write wired pages without causing all kinds of havoc.
- use a new PG_PAGEOUT flag to indicate that a page should be freed
on behalf of the pagedaemon when it's unlocked. this flag is very similar
to PG_RELEASED, but unlike PG_RELEASED, PG_PAGEOUT can be cleared if the
pageout fails due to eg. an indirect-block buffer being locked.
this allows us to remove the "version" field from struct vm_page,
and together with shrinking "loan_count" from 32 bits to 16,
struct vm_page is now 4 bytes smaller.
- no longer use PG_RELEASED for swap-backed pages. if the page is busy
because it's being paged out, we can't release the swap slot to be
reallocated until that write is complete, but unlike with vnodes we
don't keep a count of in-progress writes so there's no good way to
know when the write is done. instead, when we need to free a busy
swap-backed page, just sleep until we can get it busy ourselves.
- implement a fast-path for extending writes which allows us to avoid
zeroing new pages. this substantially reduces cpu usage.
- encapsulate the data used by the genfs code in a struct genfs_node,
which must be the first element of the filesystem-specific vnode data
for filesystems which use genfs_{get,put}pages().
- eliminate many of the UVM pagerops, since they aren't needed anymore
now that the pager "put" operation is a higher-level operation.
- enhance the genfs code to allow NFS to use the genfs_{get,put}pages
instead of a modified copy.
- clean up struct vnode by removing all the fields that used to be used by
the vfs_cluster.c code (which we don't use anymore with UBC).
- remove kmem_object and mb_object since they were useless.
instead of allocating pages to these objects, we now just allocate
pages with no object. such pages are mapped in the kernel until they
are freed, so we can use the mapping to find the page to free it.
this allows us to remove splvm() protection in several places.

The sum of all these changes improves write throughput on my
decstation 5000/200 to within 1% of the rate of NetBSD 1.5
and reduces the elapsed time for "make release" of a NetBSD 1.5
source tree on my 128MB pc to 10% less than a 1.5 kernel took.
 1.30  27-Jun-2001  thorpej branches: 1.30.2; 1.30.4;
Macro'ize the code that checks the free and inactive thresholds and
wakes the pagedaemon.
 1.29  02-Jun-2001  chs replace vm_map{,_entry}_t with struct vm_map{,_entry} *.
 1.28  30-May-2001  mrg use _KERNEL_OPT
 1.27  26-May-2001  chs replace {simple_,}lock{_data,}_t with struct {simple,}lock {,*}.
 1.26  22-May-2001  ross Merge the swap-backed and object-backed inactive lists.
 1.25  29-Apr-2001  thorpej Implement page coloring, using a round-robin bucket selection
algorithm (Solaris calls this "Bin Hopping").

This implementation currently relies on MD code to define a
constant defining the number of buckets. This will change
reasonably soon (MD code will be able to dynamically size
the bucket array).
 1.24  27-Nov-2000  chs branches: 1.24.2;
Initial integration of the Unified Buffer Cache project.
 1.23  26-Jun-2000  mrg remove/move more mach vm header files:

<vm/pglist.h> -> <uvm/uvm_pglist.h>
<vm/vm_inherit.h> -> <uvm/uvm_inherit.h>
<vm/vm_kern.h> -> into <uvm/uvm_extern.h>
<vm/vm_object.h> -> nothing
<vm/vm_pager.h> -> into <uvm/uvm_pager.h>

also includes a bunch of <vm/vm_page.h> include removals (due to redudancy
with <vm/vm.h>), and a scattering of other similar headers.
 1.22  08-Jun-2000  thorpej Change UVM_UNLOCK_AND_WAIT() to use ltsleep() (it is now atomic, as
advertised). Garbage-collect uvm_sleep().
 1.21  24-Apr-2000  thorpej branches: 1.21.2;
Changes necessary to implement pre-zero'ing of pages in the idle loop:
- Make page free lists have two actual queues: known-zero pages and
pages with unknown contents.
- Implement uvm_pageidlezero(). This function attempts to zero up to
the target number of pages until the target has been reached (currently
target is `all free pages') or until whichqs becomes non-zero (indicating
that a process is ready to run).
- Define a new hook for the pmap module for pre-zero'ing pages. This is
used to zero the pages using uncached access. This allows us to zero
as many pages as we want without polluting the cache.

In order to use this feature, each platform must add the appropropriate
glue in their idle loop.
 1.20  10-Apr-2000  chs tidy.
 1.19  02-Apr-2000  thorpej Instead of checking vm_physmem[<physseg>].pgs to determine if
uvm_page_init() has completed, add a boolean uvm.page_init_done,
and test against that. Use this same boolean (rather than
pmap_initialized) in pmap_growkernel() to determine if we are
being called via uvm_page_init() to grow the kernel address space.

This fixes a problem on some i386 configurations where pmap_init()
itself was needing to have the kernel page table grown, and since
pmap_initialized was not yet set to TRUE, pmap_growkernel() was
choosing the wrong code path.

Fix tested by Havard Eidnes.
 1.18  13-Nov-1999  thorpej Always pass all arguments to uvm_sleep().
 1.17  22-Jul-1999  thorpej branches: 1.17.2; 1.17.4; 1.17.8;
Garbage collect thread_sleep()/thread_wakeup() left over from the old
Mach VM code. Also nuke iprintf(), which was no longer used anywhere.

Add proclist locking where appropriate.
 1.16  21-Jun-1999  thorpej Protect prototypes, certain macros, and inlines from userland.
 1.15  26-Mar-1999  chs branches: 1.15.2; 1.15.4;
add uvmexp.swpgonly and use it to detect out-of-swap conditions.
 1.14  25-Mar-1999  mrg remove now >1 year old pre-release message.
 1.13  11-Oct-1998  chuck branches: 1.13.2;
remove unused share map code from UVM:
dump UVM_ET_MAP/UVM_ET_ISMAP. if you need to detect a submap use
UVM_ET_SUBMAP/UVM_ET_ISSUBMAP.
 1.12  24-Sep-1998  thorpej NCPU > 1 -> MULTIPROCESSOR
 1.11  13-Aug-1998  eeh Merge paddr_t changes into the main branch.
 1.10  08-Jul-1998  thorpej branches: 1.10.2;
Add support for multiple memory free lists. There is at least one
default free list, and 0 - N additional free list, in order of descending
priority.

A new page allocation function, uvm_pagealloc_strat(), has been added,
providing three page allocation strategies:

- normal: high -> low priority free list walk, taking the
page off the first free list that has one.

- only: attempt to allocate a page only from the specified free
list, failing if that free list has none available.

- fallback: if `only' fails, fall back on `normal'.

uvm_pagealloc(...) is provided for normal use (and is a synonym for
uvm_pagealloc_strat(..., UVM_PGA_STRAT_NORMAL, 0); the free list argument
is ignored for the `normal' case).

uvm_page_physload() now specified which free list the pages will be
loaded onto. This means that some platforms which have multiple physical
memory segments may define additional vm_physsegs if they wish to break
individual physical segments into differing priorities.

Machine-dependent code must define _at least_ the following constants
in <machine/vmparam.h>:

VM_NFREELIST: the number of free lists the system will have

VM_FREELIST_DEFAULT: the default freelist (should always be 0,
but is defined in machdep code so that it's with all of the
other free list-related constants).

Additional free list names may be defined by machine-dependent code, but
they will only be used by machine-dependent code (e.g. for loading the
vm_physsegs).
 1.9  04-Jul-1998  pk Shield `#include opt_*.h'.
 1.8  20-May-1998  thorpej defopt LOCKDEBUG
 1.7  18-May-1998  pk No dummy locks if LOCKDEBUG.
 1.6  01-Mar-1998  fvdl Merge with Lite2 + local changes
 1.5  10-Feb-1998  mrg - add defopt's for UVM, UVMHIST and PMAP_NEW.
- remove unnecessary UVMHIST_DECL's.
 1.4  10-Feb-1998  perry add/cleanup multiple inclusion protection.
 1.3  07-Feb-1998  mrg restore rcsids
 1.2  06-Feb-1998  thorpej RCS ID police.
 1.1  05-Feb-1998  mrg branches: 1.1.1;
Initial revision
 1.1.1.1  05-Feb-1998  mrg initial import of the new virtual memory system, UVM, into -current.

UVM was written by chuck cranor <chuck@maria.wustl.edu>, with some
minor portions derived from the old Mach code. i provided some help
getting swap and paging working, and other bug fixes/ideas. chuck
silvers <chuq@chuq.com> also provided some other fixes.

this is the UVM kernel code portion.


this will be KNF'd shortly. :-)
 1.10.2.1  30-Jul-1998  eeh Split vm_offset_t and vm_size_t into paddr_t, psize_t, vaddr_t, and vsize_t.
 1.13.2.3  09-Apr-1999  chs add globals for aiodone daemon.
 1.13.2.2  25-Feb-1999  chs declare ubchist here instead of in all the files that use it.
 1.13.2.1  09-Nov-1998  chs initial snapshot. lots left to do.
 1.15.4.6  02-Aug-1999  thorpej Update from trunk.
 1.15.4.5  31-Jul-1999  chs remove duplicate uvmhist decls.
 1.15.4.4  04-Jul-1999  chs uvm.aio_done is now a TAILQ of struct buf rather than struct uvm_aiodesc.
 1.15.4.3  02-Jul-1999  thorpej Fix merge botch.
 1.15.4.2  01-Jul-1999  thorpej Sync w/ -current.
 1.15.4.1  07-Jun-1999  chs merge everything from chs-ubc branch.
 1.15.2.1  26-Apr-2000  he Pull up revision 1.19 (requested by thorpej):
Use a more reliable method to determine if uvm_page_init() has
completed. This fixes a problem observed on some i386 configs
(typically with lots of memory) where the kernel page table needs
to grow during initialization.
 1.17.8.1  27-Dec-1999  wrstuden Pull up to last week's -current.
 1.17.4.1  15-Nov-1999  fvdl Sync with -current
 1.17.2.2  08-Dec-2000  bouyer Sync with HEAD.
 1.17.2.1  20-Nov-2000  bouyer Update thorpej_scsipi to -current as of a month ago
 1.21.2.1  22-Jun-2000  minoura Sync w/ netbsd-1-5-base.
 1.24.2.8  11-Dec-2002  thorpej Sync with HEAD.
 1.24.2.7  11-Nov-2002  nathanw Catch up to -current
 1.24.2.6  17-Sep-2002  nathanw Catch up to -current.
 1.24.2.5  16-Jul-2002  nathanw pagedaemon_proc really should be a proc, not a LWP.
 1.24.2.4  21-Sep-2001  nathanw Catch up to -current.
 1.24.2.3  24-Aug-2001  nathanw Catch up with -current.
 1.24.2.2  21-Jun-2001  nathanw Catch up to -current.
 1.24.2.1  05-Mar-2001  nathanw Initial commit of scheduler activations and lightweight process support.
 1.30.4.1  01-Oct-2001  fvdl Catch up with -current.
 1.30.2.2  10-Oct-2002  jdolecek sync kqueue with -current; this includes merge of gehenna-devsw branch,
merge of i386 MP branch, and part of autoconf rototil work
 1.30.2.1  10-Jan-2002  thorpej Sync kqueue branch with -current.
 1.31.12.1  15-Jun-2003  tron Pull up revision 1.32 (requested by cjep in ticket #1240):
Protect "struct uvm" with _KERNEL.
 1.31.6.6  12-Mar-2002  thorpej Make hashlock an adaptive mutex, and rename it to hash_mutex.
 1.31.6.5  12-Mar-2002  thorpej Make afreelock an adaptive mutex, and rename it to afree_mutex.
 1.31.6.4  12-Mar-2002  thorpej Make kentry_lock a spin mutex at IPL_VM, and rename it to kentry_mutex.
 1.31.6.3  12-Mar-2002  thorpej Make pageqlock an adaptive mutex, and rename it to pageq_mutex.
 1.31.6.2  12-Mar-2002  thorpej Convert the fpageqlock to a spin mutex at IPL_VM and rename it
to fpageq_mutex.
 1.31.6.1  11-Mar-2002  thorpej Convert swap_syscall_lock and uvm.swap_data_lock to adaptive mutexes,
and rename them apporpriately.
 1.35.6.7  11-Dec-2005  christos Sync with head.
 1.35.6.6  10-Nov-2005  skrll Sync with HEAD. Here we go again...
 1.35.6.5  17-Jan-2005  skrll Sync with HEAD.
 1.35.6.4  29-Nov-2004  skrll Sync with HEAD.
 1.35.6.3  21-Sep-2004  skrll Fix the sync with head I botched.
 1.35.6.2  18-Sep-2004  skrll Sync with HEAD.
 1.35.6.1  03-Aug-2004  skrll Sync with HEAD
 1.40.4.1  02-Nov-2005  yamt sync with head.
 1.40.2.5  21-Jan-2008  yamt sync with head
 1.40.2.4  03-Sep-2007  yamt sync with head.
 1.40.2.3  26-Feb-2007  yamt sync with head.
 1.40.2.2  30-Dec-2006  yamt sync with head.
 1.40.2.1  21-Jun-2006  yamt sync with head.
 1.41.2.1  29-Nov-2005  yamt sync with head.
 1.42.6.1  22-Apr-2006  simonb Sync with head.
 1.42.4.1  09-Sep-2006  rpaulo sync with head
 1.42.2.1  18-Feb-2006  yamt sync with head.
 1.43.14.2  12-Jan-2007  ad Sync with head.
 1.43.14.1  18-Nov-2006  ad Sync with head.
 1.43.2.2  15-Sep-2006  yamt make UVM_KICK_PDAEMON() a real function and stop including
uvm_pdpolicy.h from uvm.h. this also fixes build of pmap(1).
 1.43.2.1  05-Mar-2006  yamt separate page replacement policy from the rest of kernel.
 1.44.2.1  22-Oct-2006  yamt use workqueue for aiodoned.
 1.46.2.1  27-Feb-2007  yamt - sync with head.
- move sched_changepri back to kern_synch.c as it doesn't know PPQ anymore.
 1.49.6.1  11-Jul-2007  mjf Sync with head.
 1.49.4.5  21-Aug-2007  yamt fix some races around pagedaemon and uvm_wait. ok'ed by Andrew Doran.
 1.49.4.4  15-Jul-2007  ad Sync with head.
 1.49.4.3  28-Apr-2007  ad Split uvm_hashlock into an array of 32 locks.
 1.49.4.2  09-Apr-2007  ad - Add two new arguments to kthread_create1: pri_t pri, bool mpsafe.
- Fork kthreads off proc0 as new LWPs, not new processes.
 1.49.4.1  13-Mar-2007  ad Pull in the initial set of changes for the vmlocking branch.
 1.51.2.1  15-Aug-2007  skrll Sync with HEAD.
 1.52.22.2  21-Jul-2007  ad Merge unobtrusive locking changes from the vmlocking branch.
 1.52.22.1  21-Jul-2007  ad file uvm.h was added on branch matt-mips64 on 2007-07-21 19:21:54 +0000
 1.52.18.1  02-Jan-2008  bouyer Sync with HEAD
 1.52.14.1  04-Dec-2007  ad Pull the vmlocking changes into a new branch.
 1.52.12.1  18-Feb-2008  mjf Sync with HEAD.
 1.52.6.1  09-Jan-2008  matt sync with HEAD
 1.53.12.1  23-Jun-2008  wrstuden Sync w/ -current. 34 merge conflicts to follow.
 1.53.10.4  11-Aug-2010  yamt sync with head.
 1.53.10.3  11-Mar-2010  yamt sync with head
 1.53.10.2  18-Jul-2009  yamt sync with head.
 1.53.10.1  04-May-2009  yamt sync with head.
 1.53.8.1  17-Jun-2008  yamt sync with head.
 1.53.6.1  05-Jun-2008  mjf Sync with HEAD.

Also fix build.
 1.55.16.4  29-Feb-2012  matt Improve UVM_PAGE_TRKOWN.
Add more asserts to uvm_page.
 1.55.16.3  09-Feb-2012  matt Major changes to uvm.
Support multiple collections (groups) of free pages and run the page
reclaimation algorithm on each group independently.
 1.55.16.2  03-Jun-2011  matt Restore $NetBSD$
 1.55.16.1  03-Jun-2011  matt Rework page free lists to be sorted by color first rather than free_list.
Kept per color PGFL_* counter in each page free list.
Minor cleanups.
 1.55.12.1  23-Jul-2009  jym Sync with HEAD.
 1.57.4.3  31-May-2011  rmind sync with head
 1.57.4.2  05-Mar-2011  rmind sync with head
 1.57.4.1  30-May-2010  rmind sync with head
 1.57.2.1  30-Apr-2010  uebayasi Sync with HEAD.
 1.59.4.1  08-Feb-2011  bouyer Sync with HEAD
 1.59.2.1  06-Jun-2011  jruoho Sync with HEAD.
 1.62.8.1  18-Feb-2012  mrg merge to -current.
 1.62.4.5  17-Apr-2012  yamt sync with head
 1.62.4.4  26-Dec-2011  yamt - use O->A loan to serve read(2). based on a patch from Chuck Silvers
- associated O->A loan fixes.
 1.62.4.3  20-Nov-2011  yamt - fix page loaning XXX make O->A loaning further
- add some statistics
 1.62.4.2  12-Nov-2011  yamt redo the page clean/dirty/unknown accounting separately for file and
anonymous pages
 1.62.4.1  11-Nov-2011  yamt - track the number of clean/dirty/unknown pages in the system.
- g/c PG_MARKER
 1.63.20.1  07-Apr-2014  tls Be a little more clear and consistent about harvesting entropy from devices:

1) deprecate RND_FLAG_NO_ESTIMATE

2) define RND_FLAG_COLLECT_TIME, RND_FLAG_COLLECT_VALUE

3) define RND_FLAG_ESTIMATE_TIME, RND_FLAG_ESTIMATE_VALUE

4) define RND_FLAG_DEFAULT: RND_FLAG_COLLECT_TIME|
RND_FLAG_COLLECT_VALUE|RND_FLAG_ESTIMATE_TIME

5) Make entropy harvesting from environmental sensors a little more generic
and remove it from individual sensor drivers.

6) Remove individual open-coded delta-estimators for values from a few
places in the tree (uvm, environmental drivers).

7) 0 -> RND_FLAG_DEFAULT, actually gather entropy from various drivers
that had stubbed out code, other minor cleanups.
 1.63.6.2  03-Dec-2017  jdolecek update from HEAD
 1.63.6.1  20-Aug-2014  tls Rebase to HEAD as of a few days ago.
 1.64.4.2  05-Feb-2017  skrll Sync with HEAD
 1.64.4.1  06-Jun-2015  skrll Sync with HEAD
 1.66.2.1  07-Jan-2017  pgoyette Sync with HEAD. (Note that most of these changes are simply $NetBSD$
tag issues.)
 1.68.16.1  08-Apr-2020  martin Merge changes from current as of 20200406
 1.73.2.1  29-Feb-2020  ad Sync with head.

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