Commit Graph

257 Commits

Author SHA1 Message Date
dyson
d9d8bf6d30 Fix some vnode management problems, and better mgmt of vnode free list.
Fix the UIO optimization code.
Fix an assumption in vm_map_insert regarding allocation of swap pagers.
Fix an spl problem in the collapse handling in vm_object_deallocate.
When pages are freed from vnode objects, and the criteria for putting
the associated vnode onto the free list is reached, either put the
vnode onto the list, or put it onto an interrupt safe version of the
list, for further transfer onto the actual free list.
Some minor syntax changes changing pre-decs, pre-incs to post versions.
Remove a bogus timeout (that I added for debugging) from vn_lock.

PHK will likely still have problems with the vnode list management, and
so do I, but it is better than it was.
1998-01-12 01:46:33 +00:00
dyson
cb2800cd94 Make our v_usecount vnode reference count work identically to the
original BSD code.  The association between the vnode and the vm_object
no longer includes reference counts.  The major difference is that
vm_object's are no longer freed gratuitiously from the vnode, and so
once an object is created for the vnode, it will last as long as the
vnode does.

When a vnode object reference count is incremented, then the underlying
vnode reference count is incremented also.  The two "objects" are now
more intimately related, and so the interactions are now much less
complex.

When vnodes are now normally placed onto the free queue with an object still
attached.  The rundown of the object happens at vnode rundown time, and
happens with exactly the same filesystem semantics of the original VFS
code.  There is absolutely no need for vnode_pager_uncache and other
travesties like that anymore.

A side-effect of these changes is that SMP locking should be much simpler,
the I/O copyin/copyout optimizations work, NFS should be more ponderable,
and further work on layered filesystems should be less frustrating, because
of the totally coherent management of the vnode objects and vnodes.

Please be careful with your system while running this code, but I would
greatly appreciate feedback as soon a reasonably possible.
1998-01-06 05:26:17 +00:00
dyson
cd67bb82fe Lots of improvements, including restructring the caching and management
of vnodes and objects.  There are some metadata performance improvements
that come along with this.  There are also a few prototypes added when
the need is noticed.  Changes include:

1) Cleaning up vref, vget.
2) Removal of the object cache.
3) Nuke vnode_pager_uncache and friends, because they aren't needed anymore.
4) Correct some missing LK_RETRY's in vn_lock.
5) Correct the page range in the code for msync.

Be gentle, and please give me feedback asap.
1997-12-29 00:25:11 +00:00
dyson
d97fabbb53 Support running with inadequate swap space. Additionally, the code
will complain with a suggestion of increasing it.
1997-12-24 15:05:25 +00:00
dyson
9821c09585 Support an optional, sysctl enabled feature of idle process swapout. This
is apparently useful for large shell systems, or systems  with long running
idle processes.  To enable the feature:

	sysctl -w vm.swap_idle_enabled=1

Please note that some of the other vm sysctl variables have been renamed
to be more accurate.
Submitted by:	Much of it from Matt Dillon <dillon@best.net>
1997-12-06 02:23:36 +00:00
dyson
b1d65d1edc Add new (very useful) tunable for pageout daemon. The flag changes
the maximum pageout rate:

sysctl -w vm.vm_maxlaunder=n

 1 < n < inf.

If paging heavily on large systems, it is likely that a performance
improvement can be achieved by increasing the parameter.  On a large
system, the parm is 32, but numbers as large as 128 can make a big
difference.  If paging is expensive, you might try decreasing the
number to 1-8.
1997-12-05 05:41:06 +00:00
dyson
cd720ec73b Support applications that need to resist or deny use of swap space.
sysctl -w vm.defer_swap_pageouts=1
	Causes the system to resist the use of swap space.  In low memory
	conditions, performance will decrease.
sysctl -w vm.disable_swap_pageouts=1
	Causes the system to mostly disable the use of swap space.  In
	low memory conditions, the system will likely start killing
	processes.
1997-12-04 19:00:56 +00:00
dyson
56bd787cbb Support garbage collecting the pmap pv entries. The management doesn't
happen until the system would have nearly failed anyway, so no signficant
overhead is added.  This helps large systems with lots of processes.
1997-10-25 02:41:56 +00:00
dyson
9b2d1fdb85 Improve management of pages moving from the inactive to active queue. Additionally,
add some much needed comments.
1997-10-06 02:48:16 +00:00
bde
a08aff2d02 Removed unused #includes. 1997-09-01 03:17:34 +00:00
dyson
5e05983d33 Add the ability for the pageout daemon to measure stats on memory usage before
the system is out of memory.  The daemon does a minimal amount of work that
increases as the system becomes more likely to run out of memory and page in/out.

The default tuning is fairly low in background CPU usage, and sysctl variables
have been added to enable flexable operation.  This is an experimental feature
that will likely be changed and improved over time.
1997-07-27 04:49:19 +00:00
bde
61157dd0d7 Removed a wrong LK_INTERLOCK flag. 1997-02-27 15:38:41 +00:00
peter
94b6d72794 Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.
1997-02-22 09:48:43 +00:00
dyson
10f666af84 This is the kernel Lite/2 commit. There are some requisite userland
changes, so don't expect to be able to run the kernel as-is (very well)
without the appropriate Lite/2 userland changes.

The system boots and can mount UFS filesystems.

Untested: ext2fs, msdosfs, NFS
Known problems: Incorrect Berkeley ID strings in some files.
		Mount_std mounts will not work until the getfsent
		library routine is changed.

Reviewed by:	various people
Submitted by:	Jeffery Hsu <hsu@freebsd.org>
1997-02-10 02:22:35 +00:00
dyson
52f682b582 Change the map entry flags from bitfields to bitmasks. Allows
for some code simplification.
1997-01-16 04:16:22 +00:00
bde
dd18dffcc8 Removed redundant spl0()'s from kernel processes. They were work-arounds
for a bug in fork().
1997-01-15 19:05:08 +00:00
jkh
808a36ef65 Make the long-awaited change from $Id$ to $FreeBSD$
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore.  This update would have been
insane otherwise.
1997-01-14 07:20:47 +00:00
dyson
9215dc1c36 Slightly correct the code that moves pages from the active to the
inactive queue.  This is only a minor performance improvement, but will
not affect perf on machines that don't have ref bits.
1997-01-11 07:22:24 +00:00
dyson
b68b333a77 Undo the collapse breakage (swap space usage problem.) 1997-01-03 17:02:28 +00:00
dyson
3bb3295727 Guess what? We left alot of the old collapse code that is not needed
anymore with the "full" collapse fix that we added about 1yr ago!!!  The
code has been removed by optioning it out for now, so we can put it back
in ASAP if any problems are found.
1997-01-01 04:45:05 +00:00
dyson
f573ad0ab2 Make the kernel smaller with at worst a neutral effect on perf by
de-inlining some VM calls.  (Actually, I measured a small improvement.)
1996-11-28 23:15:07 +00:00
dyson
bf83250c76 Reviewed by:
Submitted by:
Obtained from:
1996-09-28 03:33:40 +00:00
dyson
62b009f8b1 Addition of page coloring support. Various levels of coloring are afforded.
The default level works with minimal overhead, but one can also enable
full, efficient use of a 512K cache.  (Parameters can be generated
to support arbitrary cache sizes also.)
1996-09-08 20:44:49 +00:00
dyson
01ce9d323a Backed out the recent changes/enhancements to the VM code. The
problem with the 'shell scripts' was found, but there was a 'strange'
problem found with a 486 laptop that we could not find.  This commit
backs the code back to 25-jul, and will be re-entered after the snapshot
in smaller (more easily tested) chunks.
1996-07-30 03:08:57 +00:00
dyson
293abd3564 This commit is meant to solve a couple of VM system problems or
performance issues.

	1) The pmap module has had too many inlines, and so the
	   object file is simply bigger than it needs to be.
	   Some common code is also merged into subroutines.
	2) Removal of some *evil* PHYS_TO_VM_PAGE macro calls.
	   Unfortunately, a few have needed to be added also.
	   The removal caused the need for more vm_page_lookups.
	   I added lookup hints to minimize the need for the
	   page table lookup operations.
	3) Removal of some bogus performance improvements, that
	   mostly made the code more complex (tracking individual
	   page table page updates unnecessarily).  Those improvements
	   actually hurt 386 processors perf (not that people who
	   worry about perf use 386 processors anymore :-)).
	4) Changed pv queue manipulations/structures to be TAILQ's.
	5) The pv queue code has had some performance problems since
	   day one.  Some significant scalability issues are resolved
	   by threading the pv entries from the pmap AND the physical
	   address instead of just the physical address.  This makes
	   certain pmap operations run much faster.  This does
	   not affect most micro-benchmarks, but should help loaded system
	   performance *significantly*.  DG helped and came up with most
	   of the solution for this one.
	6) Most if not all pmap bit operations follow the pattern:
		pmap_test_bit();
		pmap_clear_bit();
	   That made for twice the necessary pv list traversal.   The
	   pmap interface now supports only pmap_tc_bit type operations:
	   pmap_[test/clear]_modified, pmap_[test/clear]_referenced.
	   Additionally, the modified routine now takes a vm_page_t arg
	   instead of a phys address.  This eliminates a PHYS_TO_VM_PAGE
	   operation.
	7) Several rewrites of routines that contain redundant code to
	   use common routines, so that there is a greater likelihood of
	   keeping the cache footprint smaller.
1996-07-27 03:24:10 +00:00
dyson
824afef0c4 Back-off on the previous commit, specifically remove the look-ahead
optimization on the active queue scan.  I will do this correctly later.
1996-07-08 03:22:55 +00:00
dyson
f0e4f8d97a Fix a problem with the pageout daemon RSS limiting, where it degrades
performance to LRU or worse when RSS limiting takes effect.  Also,
make an end condition in the active queue scan more efficient in the
case where pages are removed from the active queue as a side effect
of a pmap operation.
1996-07-08 02:25:53 +00:00
dg
5b37bd13e0 Make sure we have an object in the map entry before trying to trim pages
from it.
1996-06-29 09:17:17 +00:00
dyson
9f0819bc54 This commit does a couple of things:
Re-enables the RSS limiting, and the routine is now tail-recursive,
	making it much more safe (eliminates the possiblity of kernel stack
	overflow.) Also, the RSS limiting is a little more intelligent about
	finding the likely objects that are pushing the process over the limit.

	Added some sysctls that help with VM system tuning.

New sysctl features:
	1)	Enable/disable lru pageout algorithm.
		vm.pageout_algorithm = 0, default algorithm that works
			well, especially using X windows and heavy
			memory loading.  Can have adverse effects,
			sometimes slowing down program loading.

		vm.pageout_algorithm = 1, close to true LRU.  Works much
			better than clock, etc.  Does not work as well as
			the default algorithm in general.  Certain memory
			"malloc" type benchmarks work a little better with
			this setting.

		Please give me feedback on the performance results
		associated with these.

	2)	Enable/disable swapping.
		vm.swapping_enabled = 1, default.

		vm.swapping_enabled = 0, useful for cases where swapping
			degrades performance.

		The config option "NO_SWAPPING" is still operative, and
		takes precedence over the sysctl.  If "NO_SWAPPING" is
		specified, the sysctl still exists, but "vm.swapping_enabled"
		is hard-wired to "0".

Each of these can be changed "on the fly."
1996-06-26 05:39:27 +00:00
dyson
aa5927cc6e Remove RSS limiting until I rewrite the code to be non-recursive. The
code can overrun the kernel stack under very stressful conditions.
1996-06-24 04:30:24 +00:00
dyson
5cd11c9038 Several bugfixes/improvements:
1) Make it much less likely to miss a wakeup in vm_page_free_wakeup
	2) Create a new entry point into pmap: pmap_ts_referenced, eliminates
	   the need to scan the pv lists twice in many cases.  Perhaps there
	   is alot more to do here to work on minimizing pv list manipulation
	3) Minor improvements to vm_pageout including the use of pmap_ts_ref.
	4) Major changes and code improvement to pmap.  This code has had
	   several serious bugs in page table page manipulation.  In order
	   to simplify the problem, and hopefully solve it for once and all,
	   page table pages are no longer "managed" with the pv list stuff.
	   Page table pages are only (mapped and held/wired) or
	   (free and unused) now.  Page table pages are never inactive,
	   active or cached.  These changes have probably fixed the
	   hold count problems, but if they haven't, then the code is
	   simpler anyway for future bugfixing.
	5) The pmap code has been sorely in need of re-organization, and I
	   have taken a first (of probably many) steps.  Please tell me
	   if you have any ideas.
1996-06-17 03:35:40 +00:00
dyson
65214cd0c8 This commit is dual-purpose, to fix more of the pageout daemon
queue corruption problems, and to apply Gary Palmer's code cleanups.
David Greenman helped with these problems also.  There is still
a hang problem using X in small memory machines.
1996-05-31 00:38:04 +00:00
dyson
c545522f30 Correct some unfortunately chosen constants, otherwise, not enough
pages are calculated for deferred allocation of swap pager data structures.
This is a follow-on to the previous commit to this file.
1996-05-29 06:33:30 +00:00
dyson
1f06055059 After careful review by David Greenman and myself, David had found a
case where blocking can occur, thereby giving other process's a chance
to modify the queue where a page resides.  This could cause numerous
process and system failures.
1996-05-29 05:15:33 +00:00
dyson
7aa7146d55 Fix a couple of problems in the pageout_scan routine. First, there is
a condition when blocking can occur, and the daemon did not check properly
for a page remaining on the expected queue.  Additionally, the inactive
target was being set much too large for small memory machines.  It is now
being calculated based upon the amount of user memory available on every
pageout daemon run.  Another problem was that if memory was very low, the
pageout daemon could fail repeatedly to traverse the inactive queue.
1996-05-26 07:52:09 +00:00
dyson
55bfe20284 Add apparently needed splvm protection to the active queue, and eliminate
an unnecessary test for dirty pages if it is already known to be dirty.
1996-05-24 05:19:15 +00:00
dyson
242e10df11 This set of commits to the VM system does the following, and contain
contributions or ideas from Stephen McKay <syssgm@devetir.qld.gov.au>,
Alan Cox <alc@cs.rice.edu>, David Greenman <davidg@freebsd.org> and me:

	More usage of the TAILQ macros.  Additional minor fix to queue.h.
	Performance enhancements to the pageout daemon.
		Addition of a wait in the case that the pageout daemon
		has to run immediately.
		Slightly modify the pageout algorithm.
	Significant revamp of the pmap/fork code:
		1) PTE's and UPAGES's are NO LONGER in the process's map.
		2) PTE's and UPAGES's reside in their own objects.
		3) TOTAL elimination of recursive page table pagefaults.
		4) The page directory now resides in the PTE object.
		5) Implemented pmap_copy, thereby speeding up fork time.
		6) Changed the pv entries so that the head is a pointer
		   and not an entire entry.
		7) Significant cleanup of pmap_protect, and pmap_remove.
		8) Removed significant amounts of machine dependent
		   fork code from vm_glue.  Pushed much of that code into
		   the machine dependent pmap module.
		9) Support more completely the reuse of already zeroed
		   pages (Page table pages and page directories) as being
		   already zeroed.
	Performance and code cleanups in vm_map:
		1) Improved and simplified allocation of map entries.
		2) Improved vm_map_copy code.
		3) Corrected some minor problems in the simplify code.
	Implemented splvm (combo of splbio and splimp.)  The VM code now
		seldom uses splhigh.
	Improved the speed of and simplified kmem_malloc.
	Minor mod to vm_fault to avoid using pre-zeroed pages in the case
		of objects with backing objects along with the already
		existant condition of having a vnode.  (If there is a backing
		object, there will likely be a COW...  With a COW, it isn't
		necessary to start with a pre-zeroed page.)
	Minor reorg of source to perhaps improve locality of ref.
1996-05-18 03:38:05 +00:00
bde
a680120460 Fixed a spl hog. The vmdaemon process ran entirely at splhigh. It
sometimes disabled clock interrupts for 60 msec or more on a P133.
Clock interrupts were lost ...

Reviewed by:	dyson
1996-04-11 21:05:25 +00:00
dyson
903a66b4af VM performance improvements, and reorder some operations in VM fault
in anticipation of a fix in pmap that will allow the mlock system call to work
without panicing the system.
1996-03-28 04:53:28 +00:00
hsu
0bb5cd954d For Lite2: proc LIST changes.
Reviewed by:	 davidg & bde
1996-03-11 06:11:43 +00:00
dyson
5abad5fc2d Fix a calculation for a paging parameter. 1996-03-09 06:53:27 +00:00
dg
f54e4705e6 Add a "NO_SWAPPING" option to disable swapping. This was originally done
to help diagnose a problem on wcarchive (where the kernel stack was
sometimes not present), but is useful in its own right since swapping
actually reduces performance on some systems (such as wcarchive).
Note: swapping in this context means making the U pages pageable and has
nothing to do with generic VM paging, which is unaffected by this option.

Reviewed by:	 <dyson>
1996-02-22 10:57:37 +00:00
dg
d31b06efba Improved killproc() log message and made it and the other similar message
tolerant of p_ucred being invalid. Starting using killproc() where
appropriate.
1996-01-31 12:44:33 +00:00
dyson
8fc8a772af Eliminated many redundant vm_map_lookup operations for vm_mmap.
Speed up for vfs_bio -- addition of a routine bqrelse to greatly diminish
	overhead for merged cache.
Efficiency improvement for vfs_cluster.  It used to do alot of redundant
	calls to cluster_rbuild.
Correct the ordering for vrele of .text and release of credentials.
Use the selective tlb update for 486/586/P6.
Numerous fixes to the size of objects allocated for files.  Additionally,
	fixes in the various pagers.
Fixes for proper positioning of vnode_pager_setsize in msdosfs and ext2fs.
Fixes in the swap pager for exhausted resources.  The pageout code
	will not as readily thrash.
Change the page queue flags (PG_ACTIVE, PG_INACTIVE, PG_FREE, PG_CACHE) into
	page queue indices (PQ_ACTIVE, PQ_INACTIVE, PQ_FREE, PQ_CACHE),
	thereby improving efficiency of several routines.
Eliminate even more unnecessary vm_page_protect operations.
Significantly speed up process forks.
Make vm_object_page_clean more efficient, thereby eliminating the pause
	that happens every 30seconds.
Make sequential clustered writes B_ASYNC instead of B_DELWRI even in the
	case of filesystems mounted async.
Fix a panic with busy pages when write clustering is done for non-VMIO
	buffers.
1996-01-19 04:00:31 +00:00
phk
9cb413a93c Another mega commit to staticize things. 1995-12-14 09:55:16 +00:00
dyson
601ed1a4c0 Changes to support 1Tb filesizes. Pages are now named by an
(object,index) pair instead of (object,offset) pair.
1995-12-11 04:58:34 +00:00
dg
c30f46c534 Untangled the vm.h include file spaghetti. 1995-12-07 12:48:31 +00:00
phk
07252df1ff Remove unused vars & funcs, make things static, protoize a little bit. 1995-11-20 12:20:02 +00:00
dyson
1b8e5404ee Greatly simplify the msync code. Eliminate complications in vm_pageout
for msyncing.  Remove a bug that manifests itself primarily on NFS
(the dirty range on the buffers is not set on msync.)
1995-11-05 20:46:03 +00:00
dyson
863d0ce972 Get rid of machine-dependent NBPG and replace with PAGE_SIZE. 1995-10-23 05:35:48 +00:00
dg
bf6129211c Fix argument passing to the "freeer" routine. Added some prototypes. (bde)
Moved extern declaration of swap_pager_full into swap_pager.h and out of
the various files that reference it. (davidg)

Submitted by:	bde & davidg
1995-10-07 19:02:56 +00:00
phk
3cbc1f1bb0 Avoid a 64bit divide. 1995-10-06 09:42:11 +00:00
dg
573c688a68 Fixed init functions argument type - caddr_t -> void *. Fixed a couple of
compiler warnings.
1995-09-09 18:10:37 +00:00
julian
ebb726ec45 Reviewed by: julian with quick glances by bruce and others
Submitted by:	terry (terry lambert)
This is  a composite of 3 patch sets submitted by terry.
they are:
New low-level init code that supports loadbal modules better
some cleanups in the namei code to help terry in 16-bit character support
some changes to the mount-root code to make it a little more
modular..

NOTE: mounting root off cdrom or NFS MIGHT be broken as I haven't been able
to test those cases..

certainly mounting root of disk still works just fine..
mfs should work but is untested. (tomorrows task)

The low level init stuff includes a total rewrite of init_main.c
to make it possible for new modules to have an init phase by simply
adding an entry to a TEXT_SET (or is it DATA_SET) list. thus a new module can
be added to the kernel without editing any other files other than the
'files' file.
1995-08-28 09:19:25 +00:00
dg
c8b0a7332c NOTE: libkvm, w, ps, 'top', and any other utility which depends on struct
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).
1995-07-13 08:48:48 +00:00
dg
d088fb31fa swapout_threads() -> swapout_procs(). 1995-07-10 08:53:22 +00:00
rgrimes
c86f0c7a71 Remove trailing whitespace. 1995-05-30 08:16:23 +00:00
dg
2045200a00 Changes to fix the following bugs:
1) Files weren't properly synced on filesystems other than UFS. In some
   cases, this lead to lost data. Most likely would be noticed on NFS.
   The fix is to make the VM page sync/object_clean general rather than
   in each filesystem.
2) Mixing regular and mmaped file I/O on NFS was very broken. It caused
   chunks of files to end up as zeroes rather than the intended contents.
   The fix was to fix several race conditions and to kludge up the
   "b_dirtyoff" and "b_dirtyend" that NFS relies upon - paying attention
   to page modifications that occurred via the mmapping.

Reviewed by:	David Greenman
Submitted by:	John Dyson
1995-05-21 21:39:31 +00:00
dg
a2a89cc5d7 Changed "handle" from type caddr_t to void *; "handle" is several different
types of pointers, and "char *" is a bad choice for the type.
1995-05-10 18:56:09 +00:00
dg
421cb9f144 Fixed a logic bug that caused the vmdaemon to not wake up when intended.
Submitted by:	John Dyson
1995-04-17 10:00:55 +00:00
dg
55264c56ce Removed obsolete/unused variable declarations. Killed externs and included
appropriate include files.
1995-04-16 14:12:15 +00:00
dg
a616136616 Moved some zero-initialized variables into .bss. Made code intended to be
called only from DDB #ifdef DDB. Removed some completely unused globals.
1995-04-16 12:56:22 +00:00
dg
b804a53282 Changes from John Dyson and myself:
Fixed remaining known bugs in the buffer IO and VM system.

vfs_bio.c:
Fixed some race conditions and locking bugs. Improved performance
by removing some (now) unnecessary code and fixing some broken
logic.
Fixed process accounting of # of FS outputs.
Properly handle NFS interrupts (B_EINTR).

(various)
Replaced calls to clrbuf() with calls to an optimized routine
called vfs_bio_clrbuf().

(various FS sync)
Sync out modified vnode_pager backed pages.

ffs_vnops.c:
Do two passes: Sync out file data first, then indirect blocks.

vm_fault.c:
Fixed deadly embrace caused by acquiring locks in the wrong order.

vnode_pager.c:
Changed to use buffer I/O system for writing out modified pages. This
should fix the problem with the modification date previous not getting
updated. Also dramatically simplifies the code. Note that this is
going to change in the future and be implemented via VOP_PUTPAGES().

vm_object.c:
Fixed a pile of bugs related to cleaning (vnode) objects. The performance
of vm_object_page_clean() is terrible when dealing with huge objects,
but this will change when we implement a binary tree to keep the object
pages sorted.

vm_pageout.c:
Fixed broken clustering of pageouts. Fixed race conditions and other
lockup style bugs in the scanning of pages. Improved performance.
1995-04-09 06:03:56 +00:00
dg
a2d4bff195 Fixed typo...using wrong variable in page_shortage calculation. 1995-03-28 05:58:35 +00:00
dg
3fb870b9c6 Fixed "pages freed by daemon" statistic (again). 1995-03-28 05:35:29 +00:00
bde
289f11acb4 Add and move declarations to fix all of the warnings from `gcc -Wimplicit'
(except in netccitt, netiso and netns) and most of the warnings from
`gcc -Wnested-externs'.  Fix all the bugs found.  There were no serious
ones.
1995-03-16 18:17:34 +00:00
dg
a013c3ca28 Deleted vm_object_setpager(). 1995-03-12 07:58:29 +00:00
dg
eb198debb8 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.
1995-03-01 23:30:04 +00:00
bde
0cde10efb4 Don't use __P(()) in a function definition. 1995-02-25 18:39:04 +00:00
dg
29a4bea1ce vm_page.c:
Use request==VM_ALLOC_NORMAL rather than object!=kmem_object in deciding
if the caller is "important" in vm_page_alloc(). Also established a new
low threshold for non-interrupt allocations via cnt.v_interrupt_free_min.

vm_pageout.c:
Various algorithmic cleanup. Some calculations simplified. Initialize
cnt.v_interrupt_free_min to 2 pages.

Submitted by:	John Dyson
1995-02-22 10:27:24 +00:00
dg
b523cbbaad Only do object paging_in_progress wakeups if someone is waiting on this
condition.

Submitted by:	John Dyson
1995-02-22 09:15:35 +00:00
dg
528492b434 Moved ACT_MAX, ACT_ADVANCE, and ACT_DECLINE to vm_page.h. 1995-02-20 23:35:45 +00:00
phk
49f19f3584 YF fix. 1995-02-14 06:14:28 +00:00
dg
2bd1a20fe1 Minor algorithmic adjustments that reduce the CPU consumption of the
pagedaemon in half while not reducing its effectiveness.

Submitted by:	me & John
1995-02-09 07:41:42 +00:00
dg
7fc0fd1f47 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
1995-02-02 09:09:15 +00:00
dg
fc5dd24ded Completed the fix for attempting to page out pages via the device_pager.
Submitted by:	John Dyson
1995-01-28 02:02:25 +00:00
dg
a9e08ab1e3 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
1995-01-24 10:14:09 +00:00
dg
6491ec70c9 Fixed some formatting weirdness that I overlooked in the previous commit. 1995-01-10 07:32:52 +00:00
dg
1707d41102 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
1995-01-09 16:06:02 +00:00
ats
ee512aac9e Submitted by: Ben Jackson
just a missing newline in a kernel printf added.
1995-01-02 22:56:00 +00:00
dg
b995c28ccc 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
1994-11-25 07:58:29 +00:00
dg
245c52ff2f Don't ever try to kill off process 1 - even if we are out of swap space
and it's the candidate pig.
1994-11-17 06:24:25 +00:00
dg
3f1b0f5075 Set laundry flag when transitioning an inactive page from clean to dirty.
This fixes a performance bug where pages would sometimes not be paged
out when they could be.

Submitted by:	John Dyson
1994-11-14 02:57:40 +00:00
dg
5cf4605dc7 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
1994-11-06 05:07:53 +00:00
dg
5461dd7c15 #if 0'd out the object cache trimming code - there are multiple ways
that the pageout daemon can deadlock otherwise.

Submitted by:	John Dyson
1994-10-25 05:35:44 +00:00
dg
5727d2fc7e Fixed object cache trimming policy so it actually works.
Submitted by:	John Dyson
1994-10-23 21:03:09 +00:00
dg
ee0022da28 Adjusted reserved levels to fix a deadlock condition.
Submitted by:	John Dyson
1994-10-23 20:53:33 +00:00
dg
e8b2d4b14c Various changes to allow operation without any swapspace configured. Note
that this is intended for use only in floppy situations and is done at
the sacrifice of performance in that case (in ther words, this is not the
best solution, but works okay for this exceptional situation).

Submitted by:	John Dyson
1994-10-22 02:18:03 +00:00
dg
2d52a86c44 Fix the remaining vmmeter counters. They all now work correctly. 1994-10-18 14:59:20 +00:00
dg
eb282b107c 1) Some of the counters in the vmmeter struct don't fit well into the Mach VM
scheme of things, so I've changed them to be more appropriate. page in/ous
   are now associated with the pager that did them. Nuked v_fault as the
   only fault of interest that wouldn't be already counted in v_trap is a VM
   fault, and this is counted seperately.
2) Implemented most of the remaining counters and corrected the counting of
   some that were done wrong. They are all almost correct now...just a few
   minor ones left to fix.
1994-10-15 13:33:09 +00:00
dg
bb709a3eec Fixed an object reference count problem that was caused by a call to
vm_object_lookup() being outside of some parens. The bug was introduced
via some recently added code.

Reviewed by:	John Dyson
1994-10-13 21:01:39 +00:00
phk
09c3293a0f Cosmetics: unused vars, ()'s, #include's &c &c to silence gcc.
Reviewed by:	davidg
1994-10-09 01:52:19 +00:00
phk
633ef15194 Cosmetics. Unused vars and other warnings. 1994-10-07 07:23:04 +00:00
dg
66cba7eaa5 Fixed minor bug caused by some missing parens that can result in slightly
reduced paging performance by missing a clustering opportunity. Found
by Poul-Henning Kamp with gcc -Wall.
1994-10-05 09:02:53 +00:00
dg
467ebd6849 Fixed bug related to proper sensing of page modification that we
inadvertantly introduced in pre-1.1.5. This could cause page modifications
to go unnoticed during certain extreme low memory/high paging rate conditions.

Submitted by:	John Dyson and David Greenman
1994-10-04 03:05:09 +00:00
dg
71d8424950 Fixed a bug I introduced when fixing the rss limit code. Changed swapout
policy to be a bit more selective about what processes get swapped out.

Reviewed by:	John Dyson
1994-09-12 15:06:14 +00:00
dg
4c73f2ffb4 Don't deactivate pages in 0-refcount objects. Added a couple of missing
paging stats. Fixed problem with free_reserved becoming depleted during
certain swap_pager operations.

Submitted by:	John Dyson, with a little help from me
1994-09-12 11:31:36 +00:00
dg
0a37b9feee Simple changes to paging algorithms...but boy do they make a difference.
FreeBSD's paging performance has never been better. Wow.

Submitted by:	John Dyson
1994-09-06 11:28:46 +00:00
dg
16e35aa368 Fixed bug caused by change of rlimit variables to quad_t's. The bug was in
using min() to calculate the minimum of rss_cur,rss_max - since these
are now quad_t's and min() takes u_ints...the comparison later for exceeding
the rss limit was always true - resulting in rather serious page thrashing.
Now using new qmin() function for this purpose.

Fixed another bug where PG_BUSY pages would sometimes be paged out (bad!).
This was caused by the PG_BUSY flag not being included in a comparison.
1994-08-30 18:27:44 +00:00
wollman
f9fc827448 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.
1994-08-18 22:36:09 +00:00
dg
8b20309268 Incorporated post 1.1.5 work from John Dyson. This includes performance
improvements via the new routines pmap_qenter/pmap_qremove and pmap_kenter/
pmap_kremove. These routine allow fast mapping of pages for those
architectures that have "normal" MMUs. Also included is a fix to the
pageout daemon to properly check a queue end condition.

Submitted by:	John Dyson
1994-08-06 09:15:42 +00:00
dg
0711a9cff6 Integrated VM system improvements/fixes from FreeBSD-1.1.5. 1994-08-04 03:06:48 +00:00
dg
8d205697aa Added $Id$ 1994-08-02 07:55:43 +00:00
dg
0e87163cbf Removed all code related to the pagescan daemon, and changed 'act_count'
adjustments to compensate for a world without the pagescan daemon.
1994-08-01 11:25:45 +00:00
dg
0d458db402 Don't move the page's position in the active queue if it is busy or
held. John has noticed some stability problems when doing this.
1994-06-06 11:56:27 +00:00
rgrimes
2469c867a1 The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.
Reviewed by:	Rodney W. Grimes
Submitted by:	John Dyson and David Greenman
1994-05-25 09:21:21 +00:00
rgrimes
8fb65ce818 BSD 4.4 Lite Kernel Sources 1994-05-24 10:09:53 +00:00