Commit Graph

41 Commits

Author SHA1 Message Date
David Greenman
f6b04d2bfb 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
David Greenman
260295f979 Removed (almost) meaningless "object cache lookups/hits" statistic. In
our framework, these numbers will usually be nearly the same, and not
because of any sort of high 'hit rate'.
1995-03-25 08:42:14 +00:00
David Greenman
a34297995a Removed cnt.v_nzfod: In our current scheme of things it is not possible
to accurately track this. It isn't an indicator of resource consumption
anyway.
Removed cnt.v_kernel_pages: We don't implement this and doing so accurately
would be very difficult (and ambiguous - since process pages are often
double mapped in the kernel and the process address spaces).
1995-03-25 06:09:33 +00:00
David Greenman
d7a0fc9360 Fixed warning caused by returning a value in a void function (introduced
in a recent commit by me). Relaxed checks before calling vm_object_remove;
a non-internal object always has a pager.
1995-03-23 05:19:44 +00:00
David Greenman
f5cf85d40a Removed unused fifth argument to vm_object_page_clean(). Fixed bug with
VTEXT not always getting cleared when it is supposed to. Added check to
make sure that vm_object_remove() isn't called with a NULL pager or for
a pager for an OBJ_INTERNAL object (neither of which will be on the hash
list). Clear OBJ_CANPERSIST if we decide to terminate it because of no
resident pages.
1995-03-22 12:24:11 +00:00
David Greenman
563128e49e Fixed potential sleep/wakeup race conditional with splhigh().
Submitted by:	John Dyson
1995-03-22 08:08:44 +00:00
David Greenman
7c1f6cedec Added a new boolean argument to vm_object_page_clean that causes it to
only toss out clean pages if TRUE.
1995-03-21 01:11:44 +00:00
David Greenman
0426122fa0 Don't gain/lose an object reference in vnode_pager_setsize(). It will
cause vnode locking problems in vm_object_terminate().
Implement proper vnode locking in vm_object_terminate().
1995-03-20 10:20:42 +00:00
David Greenman
83edfd47d8 Removed an unnecessary call to vinvalbuf after the page clean. 1995-03-20 02:06:09 +00:00
Bruce Evans
b5e8ce9f12 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
David Greenman
c4ed5a07a5 Fixed obsolete comment. 1995-03-12 08:11:34 +00:00
David Greenman
61ca29b0e5 Deleted vm_object_setpager(). 1995-03-12 07:58:29 +00:00
David Greenman
be6d5bfac7 Don't attempt to reverse collapse non OBJ_INTERNAL objects. 1995-03-07 17:25:46 +00:00
David Greenman
f919ebde54 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
David Greenman
a7ac758ec7 Removed bogus copy object collapse check (the idea is right, but the
spcific check was bogus).
Removed old copy of vm_object_page_clean and took out the #if 1 around
the remaining one.

Submitted by:	John Dyson
1995-02-22 10:00:16 +00:00
David Greenman
c0503609a0 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
David Greenman
7fb0c17ed2 Deprecated remaining use of vm_deallocate. Deprecated vm_allocate_with_
pager(). Almost completely rewrote vm_mmap(); when John gets done with
the bottom half, it will be a complete rewrite. Deprecated most use of
vm_object_setpager(). Removed side effect of setting object persist
in vm_object_enter and moved this into the pager(s). A few other
cosmetic changes.
1995-02-21 01:22:48 +00:00
David Greenman
ba8da83911 Panic if object is deallocated too many times.
Slight change to reverse collapsing so that vm_object_deallocate doesn't
have to be called recursively.
Removed half of a previous fix - the renamed page during a collapse doesn't
need to be marked dirty because the pager backing store pointers are copied
- thus preserving the page's data. This assumes that pages without backing
store are always dirty (except perhaps for when they are first zeroed, but
this doesn't matter).
Switch order of two lines of code so that the correct pager is removed
from the hash list. The previous code bogusly passed a NULL pointer to
vm_object_remove(). The call to vm_object_remove() should be unnecessary
if named anonymous objects were being dealt with correctly. They are
currently marked as OBJ_INTERNAL, which really screws up things (such as
this).
1995-02-20 14:21:58 +00:00
David Greenman
9b4814bba2 1) Added protection against collapsing OBJ_DEAD objects.
2) bump reference counts by 2 instead of 1 so that an object deallocate
   doesn't try to recursively collapse the object.
3) mark pages renamed during the collapse as dirty so that their contents
   are preserved.

Submitted by:	John and me.
1995-02-18 06:48:33 +00:00
David Greenman
0217125f2b Carefully choose the value for vm_object_cache_max. The previous calculation
was rather bogus in most cases; the new value works very well for both
large and small memory machines.
1995-02-12 09:19:44 +00:00
David Greenman
a1f6d91cc2 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
David Greenman
a465acdaf8 Don't attempt to clean device_pager backed objects at terminate time.
There is similar bogusness in the pageout daemon that will be fixed soon.
This fixes a panic pointed out to me by Bruce Evans that occurs when
/dev/mem is used to map managed memory.
1995-01-25 20:36:29 +00:00
David Greenman
6d40c3d394 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
David Greenman
b9921222a2 Protect a qcollapse call with an object lock before calling. The locks
need to be moved into the qcollapse and rcollapse routines, but I don't
have time at the moment to make all the required changes...this will do
for now.
1995-01-13 13:30:24 +00:00
David Greenman
8b4dd3c473 Improve my previous change to use the same tests as are used in qcollapse. 1995-01-11 20:19:20 +00:00
David Greenman
a748978457 Fixed a panic that Garrett reported to me...the OBJ_INTERNAL flag wasn't
being cleared in some cases for vnode backed objects; we now do this in
vnode_pager_alloc proper to guarantee it. Also be more careful in the
rcollapse code about messing with busy/bmapped pages.
1995-01-11 20:00:10 +00:00
David Greenman
0d94caffca 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
David Greenman
010cf3b9e3 Make sure that the object being collapsed doesn't go away on us...by
gaining extra references to it.

Submitted by:	John Dyson
Obtained from:
1995-01-05 04:30:40 +00:00
David Greenman
45cbbb298d Do vm_page_rename more conservatively in rcollapse and qcollapse, and
change list walk so that it doesn't get stuck in an infinite loop.

Submitted by:	 John Dyson
1994-12-23 05:00:19 +00:00
David Greenman
7b18a71899 Don't put objects that have no parent on the reverse_shadow_list. Problem
identified and explained by Gene Stark (thanks Gene!).

Submitted by:	John Dyson
1994-12-11 01:36:53 +00:00
David Greenman
eadf9e27cd 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
David Greenman
2fe6e4d71e 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
David Greenman
a08a17a3ce Properly count object lookups and hits. 1994-10-15 10:28:47 +00:00
Poul-Henning Kamp
05f0fdd26a Cosmetics: unused vars, ()'s, #include's &c &c to silence gcc.
Reviewed by:	davidg
1994-10-09 01:52:19 +00:00
David Greenman
8e58bf6875 Stuff object into v_vmdata rather than pager. Not important which at
the moment, but will be in the future. Other changes mostly cosmetic,
but are made for future VMIO considerations.

Submitted by:	John Dyson
1994-10-05 09:48:45 +00:00
David Greenman
8a129caed5 1) Changed ddb into a option rather than a pseudo-device (use options DDB
in your kernel config now).
2) Added ps ddb function from 1.1.5. Cleaned it up a bit and moved into its
   own file.
3) Added \r handing in db_printf.
4) Added missing memory usage stats to statclock().
5) Added dummy function to pseudo_set so it will be emitted if there
   are no other pseudo declarations.
1994-08-27 16:14:39 +00:00
Garrett Wollman
f23b4c91c4 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
David Greenman
a481f20029 Provide support for upcoming merged VM/buffer cache, and fixed a few bugs
that haven't appeared to manifest themselves (yet).

Submitted by:	John Dyson
1994-08-07 13:10:43 +00:00
David Greenman
3c4dd3568f Added $Id$ 1994-08-02 07:55:43 +00:00
Rodney W. Grimes
26f9a76710 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
Rodney W. Grimes
df8bae1de4 BSD 4.4 Lite Kernel Sources 1994-05-24 10:09:53 +00:00