Commit Graph

66 Commits

Author SHA1 Message Date
Bruce Evans
79624e2147 Removed unused #includes. 1997-09-01 03:17:34 +00:00
Bruce Evans
b1037dcd53 #include <machine/limits.h> explicitly in the few places that it is required. 1997-08-21 20:33:42 +00:00
Peter Wemm
e108835bbc Unused variable (upobj is now purely handled within pmap) 1997-04-14 03:40:42 +00:00
John Dyson
5856e12e69 Fully implement vfork. Vfork is now much much faster than even our
fork. (On my machine, fork is about 240usecs, vfork is 78usecs.)

Implement rfork(!RFPROC !RFMEM), which allows a thread to divorce its memory
	from the other threads of a group.

Implement rfork(!RFPROC RFCFDG), which closes all file descriptors, eliminating
	possible existing shares with other threads/processes.

Implement rfork(!RFPROC RFFDG), which divorces the file descriptors for a
	thread from the rest of the group.

Fix the case where a thread does an exec.  It is almost nonsense for a thread
	to modify the other threads address space by an exec, so we
	now automatically divorce the address space before modifying it.
1997-04-13 01:48:35 +00:00
Peter Wemm
a2a1c95c10 The biggie: Get rid of the UPAGES from the top of the per-process address
space. (!)

Have each process use the kernel stack and pcb in the kvm space.  Since
the stacks are at a different address, we cannot copy the stack at fork()
and allow the child to return up through the function call tree to return
to user mode - create a new execution context and have the new process
begin executing from cpu_switch() and go to user mode directly.
In theory this should speed up fork a bit.

Context switch the tss_esp0 pointer in the common tss.  This is a lot
simpler since than swithching the gdt[GPROC0_SEL].sd.sd_base pointer
to each process's tss since the esp0 pointer is a 32 bit pointer, and the
sd_base setting is split into three different bit sections at non-aligned
boundaries and requires a lot of twiddling to reset.

The 8K of memory at the top of the process space is now empty, and unmapped
(and unmappable, it's higher than VM_MAXUSER_ADDRESS).

Simplity the pmap code to manage process contexts, we no longer have to
double map the UPAGES, this simplifies and should measuably speed up fork().

The following parts came from John Dyson:

Set PG_G on the UPAGES that are now in kernel context, and invalidate
them when swapping them out.

Move the upages object (upobj) from the vmspace to the proc structure.

Now that the UPAGES (pcb and kernel stack) are out of user space, make
rfork(..RFMEM..) do what was intended by sharing the vmspace
entirely via reference counting rather than simply inheriting the mappings.
1997-04-07 07:16:06 +00:00
Peter Wemm
6875d25465 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
John Dyson
996c772f58 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
Bruce Evans
16a02c1105 Removed redundant spl0()'s from kernel processes. They were work-arounds
for a bug in fork().
1997-01-15 19:05:08 +00:00
Jordan K. Hubbard
1130b656e5 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
John Dyson
bc0d333478 EEEK!!! useracc and kernacc didn't lock their respective
maps.  Additionally, eliminate the map->hint distortion
associated with useracc.  That may/may-not be the "right"
thing to do -- but time will tell.
Submitted by:	Partially by Alan Cox <alc@cs.rice.edu>
1996-12-30 03:56:11 +00:00
Joerg Wunsch
e9822d926c Make DFLDSIZ and MAXDSIZ fully-supported options.
"Don't forget to do a ``make depend''" :-)
1996-12-22 23:17:09 +00:00
John Dyson
a669a6e9a9 Make processes waken up eligible for immediate swap-in. 1996-10-17 02:58:20 +00:00
John Dyson
675878e732 Move much of the machine dependent code from vm_glue.c into
pmap.c.  Along with the improved organization, small proc fork
performance is now about 5%-10% faster.
1996-10-15 03:16:45 +00:00
Bruce Evans
dd106ca742 Removed iprintf(). It was copied to db_iprintf() in ddb. 1996-09-15 11:24:21 +00:00
John Dyson
a6e6bcc5f4 Properly set the PG_MAPPED and PG_WRITEABLE flags. This fixes some potential
problems with vm_map_remove/vm_map_delete.
1996-07-02 02:08:02 +00:00
John Dyson
877329e059 Make -current consistant with -stable regarding time that a process
sleeps before being swapped out.  The time is increased from 4 secs to
10 secs.  Originally I had decreased it from 20 to 4, but that is a bit
severe.  20 is too long though.
1996-06-30 21:16:18 +00:00
John Dyson
f35329ac0f 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
John Dyson
b18bfc3da7 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
Poul-Henning Kamp
a8c5fef5e6 KGDB is dead. It may come back one day if somebody does it. 1996-05-02 09:34:51 +00:00
John Dyson
d3a3498598 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
John Dyson
b5cfb15fad 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
Bruce Evans
6ffde942bf Removed never-used #includes of <machine/cpu.h>. Many were apparently
copied from bad examples.
1996-04-07 17:39:28 +00:00
John Dyson
030ad08012 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
Jeffrey Hsu
1b67ec6de9 For Lite2: proc LIST changes.
Reviewed by:	 davidg & bde
1996-03-11 06:11:43 +00:00
John Dyson
9ea857084d Delay forking a process until there are more pages available. It was
possible to deadlock with the low threshold that we had used.
1996-03-09 06:57:53 +00:00
John Dyson
de5f6a7765 1) Eliminate unnecessary bzero of UPAGES.
2) Eliminate unnecessary copying of pages during/after forks.
3) Add user map simplification.
1996-03-02 02:54:24 +00:00
Peter Wemm
dabee6fecc kern_descrip.c: add fdshare()/fdcopy()
kern_fork.c: add the tiny bit of code for rfork operation.
kern/sysv_*: shmfork() takes one less arg, it was never used.
sys/shm.h: drop "isvfork" arg from shmfork() prototype
sys/param.h: declare rfork args.. (this is where OpenBSD put it..)
sys/filedesc.h: protos for fdshare/fdcopy.
vm/vm_mmap.c: add minherit code, add rounding to mmap() type args where
it makes sense.
vm/*: drop unused isvfork arg.

Note: this rfork() implementation copies the address space mappings,
it does not connect the mappings together.  ie: once the two processes
have split, the pages may be shared, but the address space is not. If one
does a mmap() etc, it does not appear in the other.  This makes it not
useful for pthreads, but it is useful in it's own right for having
light-weight threads in a static shared address space.

Obtained from: Original by Ron Minnich, extended by OpenBSD
1996-02-23 18:49:25 +00:00
David Greenman
5afce28270 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
David Greenman
2c68345ab4 Added a check/panic for vm_map_find failing to find space for the page
tables/u-pages when forking. This is a "can't happen" case. :-)
1996-01-29 12:10:30 +00:00
Poul-Henning Kamp
f782b11a04 Don't use %r, we havn't got it anymore.
Submitted by: bde
1996-01-25 07:15:40 +00:00
John Dyson
bd7e5f992e 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
Garrett Wollman
0e41ee3037 Convert DDB to new-style option. 1996-01-04 21:13:23 +00:00
Garrett Wollman
50c73f3620 Convert SYSV IPC to new-style options. (I hope I got everything...)
The LKMs will need an extra file, to come later.
1996-01-04 20:29:06 +00:00
Poul-Henning Kamp
f708ef1b9e Another mega commit to staticize things. 1995-12-14 09:55:16 +00:00
David Greenman
efeaf95a41 Untangled the vm.h include file spaghetti. 1995-12-07 12:48:31 +00:00
Bruce Evans
d841aaa740 Finished (?) cleaning up sysinit stuff. 1995-12-02 17:11:20 +00:00
John Dyson
aef922f514 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
John Dyson
a91c5a7ecd Get rid of machine-dependent NBPG and replace with PAGE_SIZE. 1995-10-23 05:35:48 +00:00
John Dyson
0bc3a91127 Remove an unnecessary tsleep in the swapin code. This tsleep
can defer swapping in processes and is just not the right thing to do.
1995-10-16 05:45:49 +00:00
John Dyson
0e27a03ffb Perform more checking for proper loading of the UPAGES when a process
is swapped in.  Also, remove unnecessary map locking/unlocking during
selection of processes to be swapped out.

This code might afford proper panics as opposed to spontaneous reboots
on certain systems.  This should allow us to debug these problems better.
1995-09-24 19:51:50 +00:00
David Greenman
c87ad37e61 Check the return value from vm_map_pageable() when mapping the process's
UPAGES and associated page table page. Panic on error. This is less than
optimial and will be fixed in the future, but is better than the old
behavior of panicing with a "kernel page directory invalid" in pmap_enter.
1995-09-17 01:46:03 +00:00
David Greenman
4590fd3a2a Fixed init functions argument type - caddr_t -> void *. Fixed a couple of
compiler warnings.
1995-09-09 18:10:37 +00:00
Julian Elischer
2b14f991e6 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
David Greenman
24a1cce34f 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
David Greenman
6306c897b5 swapout_threads() -> swapout_procs(). 1995-07-10 08:53:22 +00:00
David Greenman
f2daac0c69 Increased global RSS limit to total RAM. 1995-07-10 08:48:58 +00:00
Rodney W. Grimes
9b2e535452 Remove trailing whitespace. 1995-05-30 08:16:23 +00:00
David Greenman
c3cb3e12f5 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
Bruce Evans
3aa12267a5 Add and move declarations to fix all of the warnings from `gcc -Wimplicit'
(except in netccitt, netiso and netns) that I didn't notice when I fixed
"all" such warnings before.
1995-03-28 07:58:53 +00:00
David Greenman
2c0bc39683 Panic if u_map allocation fails. 1995-02-21 12:06:06 +00:00