414 Commits

Author SHA1 Message Date
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
43e1aa7ef6 Fix some serious problems with limits checking in the sbrk(2)/brk(2)
code.
Reviewed by:	bde
1996-06-25 00:36:46 +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
010ba0185a Improve algorithm for page hash queue. It was previously about
as bad as it could be.  This algorithm appears to improve fork
performance (barely) measurably.
1996-06-21 05:39:22 +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
4e8ccabc81 Various bugfixes/cleanups from me and others:
1) Remove potential race conditions on waking up in vm_page_free_wakeup
   by making sure that it is at splvm().
2) Fix another bug in vm_map_simplify_entry.
3) Be more complete about converting from default to swap pager
   when an object grows to be large enough that there can be
   a problem with data structure allocation under low memory
   conditions.
4) Make some madvise code more efficient.
5) Added some comments.
1996-06-16 20:37:31 +00:00
dg
17f7319856 Move a case of PG_MAPPED being set before a pmap_enter(). This will likely
make no difference, but it will make it consistent with other uses of
PG_MAPPED.
1996-06-14 23:26:40 +00:00
dyson
cfc0d659e7 Fix a very significant cnt.v_wire_count leak in vm_page.c, and some
minor leaks in pmap.c.  Bruce Evans made me aware of this problem.
1996-06-12 06:52:12 +00:00
dyson
cc48a94842 Fix some serious errors in vm_map_simplify_entries. 1996-06-12 04:03:21 +00:00
dyson
8a5ac3e758 Mostly superficial code improvements, add a diagnostic. The
code improvements include significant simplification of the reservation
of the swap pager control blocks for reads.  Add a panic for an inconsistent
swap pager control block count.
1996-06-10 04:58:48 +00:00
dyson
c4b1301343 Keep the vm_fault/vm_pageout from getting into an "infinite paging loop", by
reserving "cached" pages before waking up the pageout daemon.  This will reserve
the faulted page, and keep the system from thrashing itself to death given
this condition.
1996-06-10 00:25:40 +00:00
dyson
dca5ec165f Adjust the threshold for blocking on movement of pages from the cache
queue in vm_fault.

Move the PG_BUSY in vm_fault to the correct place.

Remove redundant/unnecessary code in pmap.c.

Properly block on rundown of page table pages, if they are busy.

I think that the VM system is in pretty good shape now, and the following
individuals (among others, in no particular order) have helped with this
recent bunch of bugs, thanks!  If I left anyone out, I apologize!

Stephen McKay, Stephen Hocking, Eric J. Chet, Dan O'Brien, James Raynard,
Marc Fournier.
1996-06-08 06:48:35 +00:00
dyson
7bd5766700 Keep page-table pages from ever being sensed as dirty. This should fix
some problems with the page-table page management code, since it can't
deal with the notion of page-table pages being paged out or in transit.
Also, clean up some stylistic issues per some suggestions from
Stephen McKay.
1996-06-05 03:31:49 +00:00
dyson
e3cb859c13 Disable madvise optimizations for device pager objects (some of the
operations don't work with FICTITIOUS pages.)  Also, close a window
between PG_MANAGED and pmap_enter that can mess up the accounting of
the managed flag.  This problem could likely cause a hold_count error
for page table pages.
1996-06-01 20:50:57 +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
f5f74ba5e1 Make sure that pageout deadlocks cannot occur. There is a problem
that the datastructures needed to support the swap pager can take
enough space to fully deplete system memory, and cause a deadlock.
This change keeps large objects from being filled with dirty pages
without the appropriate swap pager datastructures.  Right now,
default objects greater than 1/4 the size of available system memory
are converted to swap objects, thereby eliminating the risk of deadlock.
1996-05-29 05:12:23 +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
2640e59c23 I think this covers (fixes) the last batch of freeing active/held/busy page
problem.  BY MISTAKE, the vm_page_unqueue (or equiv) was removed from the
vm_fault code.  Really bad things appear to happen if a page is on a queue
while it is being faulted.
1996-05-26 05:30:33 +00:00
dyson
a7dfed03c3 Add an assert to vm_page_cache. We should never cache a dirty page. 1996-05-24 05:20:15 +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
992a2cacdc Eliminate inefficient check for dirty pages for pages in the PQ_CACHE
queue.  Also, modify the MADV_FREE policy (it probably still isn't the final
version.)
1996-05-24 05:17:21 +00:00
dyson
5ff3dd6648 Make the conversion from the default pager to swap pager more robust
in the face of low memory conditions.
1996-05-24 05:14:44 +00:00
dyson
a9f2d60090 Eliminate a vm_page_free, busy panic, in kern_malloc. 1996-05-23 02:24:55 +00:00
dyson
509f02d4a3 Initial support for MADV_FREE, support for pages that we don't care
about the contents anymore.  This gives us alot of the advantage of
freeing individual pages through munmap, but with almost none of the
overhead.
1996-05-23 00:45:58 +00:00
dyson
48a5cbf840 After reviewing the previous commit to vm_object, the page protection
is never necessary, not just for PG_FICTICIOUS.
1996-05-21 17:13:31 +00:00
dyson
89cf8c5641 Don't protect non-managed pages off during object rundown. This fixes
a hang that occurs under certain circumstances when exiting X.
1996-05-21 05:26:27 +00:00
dyson
d3600176f4 Initial support for mincore and madvise. Both are almost fully
supported, except madvise does not page in with MADV_WILLNEED, and
MADV_DONTNEED doesn't force dirty pages out.
1996-05-19 07:36:50 +00:00
dyson
2359f358cc One more file missing from the mega-commit. This inlines some very
simple routines in vm_page.c, so that an unnecessary subroutine call
is removed.
1996-05-18 04:00:18 +00:00
dyson
39bee2738c File mistakenly left out of the previous mega-commit. This provides
a global defn for 'exech_map.'
1996-05-18 03:52:13 +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
wollman
a28a8481af Allocate mbufs from a separate submap so that NMBCLUSTERS works as
expected.
1996-05-10 19:28:55 +00:00
phk
5d01dc3d50 Another sweep over the pmap/vm macros, this time with more focus on
the usage.  I'm not satisfied with the naming, but now at least there is
less bogus stuff around.
1996-05-03 21:01:54 +00:00
phk
5a6fb3a7da removed:
CLBYTES PD_SHIFT PGSHIFT NBPG PGOFSET CLSIZELOG2 CLSIZE pdei()
        ptei() kvtopte() ptetov() ispt() ptetoav() &c &c
new:
        NPDEPG

Major macro cleanup.
1996-05-02 14:21:14 +00:00
phk
7bfc0101cb KGDB is dead. It may come back one day if somebody does it. 1996-05-02 09:34:51 +00:00
dyson
4f2a49e711 Move the map entry allocations from the kmem_map to the kernel_map. As
a side effect, correct the associated object offset.
1996-04-29 22:04:57 +00:00
dyson
6c1ec28cad This fixes kmem_malloc/kmem_free (and malloc/free of objects of > 8K).
A page index was calculated incorrectly in vm_kern, and vm_object_page_remove
removed pages that should not have been.
1996-04-24 04:16:45 +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
a3cc211552 Reinstitute the map lock for processes being swapped out. This
is needed because of the vm_fault used to bring the page table page
for the kernel stack (UPAGES) back in.  The consequence of the
previous incorrect change was a system hang.
1996-04-09 04:36:58 +00:00
dyson
cdc4afc0a8 Map lock checks not needed anymore for swapping out. We don't use
map operations for it anymore.  Certain deadlocks should never happen
anymore.
1996-04-08 03:42:01 +00:00
bde
d75a1370e4 Removed never-used #includes of <machine/cpu.h>. Many were apparently
copied from bad examples.
1996-04-07 17:39:28 +00:00
dyson
ceb23bccb6 Fixed a problem that the UPAGES of a process were being run down
in a suboptimal manner.  I had also noticed some panics that appeared
to be at least superficially caused by this problem.  Also, included
are some minor mods to support more general handling of page table page
faulting.  More details in a future commit.
1996-04-03 05:23:44 +00:00
dg
4d625bffc5 Revert to previous calculation of vm_object_cache_max: it simply works
better in most real-world cases.
1996-03-29 06:28:48 +00:00
bde
edc7662d0a Undid last revision. It duplicated part of second last revision. 1996-03-28 15:40:17 +00:00
scrappy
7dcaa810dc devfs_add_devsw() -> devfs_add_devswf modifications
Reviewed by:	julian@freebsd.org
1996-03-28 14:36:48 +00:00
dyson
b37500ce5f Add a function prototype for pmap_prefault. 1996-03-28 04:54:50 +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
dyson
f766c05521 More map_simplify fixes from Alan Cox. This very significanly improves the
performance when the map has been chopped up.  The map simplify operations
really work now.
Reviewed by: dyson
Submitted by:	Alan Cox <alc@cs.rice.edu>
1996-03-28 04:22:17 +00:00