Commit Graph

97 Commits

Author SHA1 Message Date
Eivind Eklund
a128794977 - Remove a number of extra newlines that do not belong here according to
style(9)
- Minor space adjustment in cases where we have "( ", " )", if(), return(),
  while(), for(), etc.
- Add /* SYMBOL */ after a few #endifs.

Reviewed by:	alc
2002-03-10 21:52:48 +00:00
Alan Cox
2be21c5e68 o Create vm_pageq_enqueue() to encapsulate code that is duplicated time
and again in vm_page.c and vm_pageq.c.
 o Delete unusused prototypes.  (Mainly a result of the earlier renaming
   of various functions from vm_page_*() to vm_pageq_*().)
2002-03-04 18:55:26 +00:00
Alan Cox
5714577006 Remove some long dead code. 2002-03-02 22:21:42 +00:00
Tor Egge
d2760948fe Add a page queue, PQ_HOLD, that temporarily owns pages with nonzero hold
count that would otherwise be on one of the free queues.  This eliminates a
panic when broken programs unmap memory that still has pending IO from raw
devices.

Reviewed by:	dillon, alc
2002-02-19 23:19:30 +00:00
Peter Wemm
3516c025ff Implement idle zeroing of pages. I've been tinkering with this
on and off since John Dyson left his work-in-progress.

It is off by default for now.  sysctl vm.zeroidle_enable=1 to turn it on.

There are some hacks here to deal with the present lack of preemption - we
yield after doing a small number of pages since we wont preempt otherwise.

This is basically Matt's algorithm [with hysteresis] with an idle process
to call it in a similar way it used to be called from the idle loop.

I cleaned up the includes a fair bit here too.
2001-08-25 05:00:44 +00:00
Jake Burkholder
3a9b5daf48 Oops. Last commit to vm_object.c should have got these files too.
Remove the use of atomic ops to manipulate vm_object and vm_page flags.
Giant is required here, so they are superfluous.

Discussed with:	dillon
2001-07-31 04:09:52 +00:00
Assar Westerlund
d3e5863fa9 make vm_page_select_cache static
Requested by:	bde
2001-07-23 12:34:31 +00:00
Assar Westerlund
0379d76358 (vm_page_select_cache): add prototype 2001-07-21 17:08:15 +00:00
Matthew Dillon
6d03d577a5 Reorg vm_page.c into vm_page.c, vm_pageq.c, and vm_contig.c (for contigmalloc).
Also removed some spl's and added some VM mutexes, but they are not actually
used yet, so this commit does not really make any operational changes
to the system.

vm_page.c relates to vm_page_t manipulation, including high level deactivation,
activation, etc...  vm_pageq.c relates to finding free pages and aquiring
exclusive access to a page queue (exclusivity part not yet implemented).
And the world still builds... :-)
2001-07-04 23:27:09 +00:00
Matthew Dillon
1b40f8c036 Change inlines back into mainline code in preparation for mutexing. Also,
most of these inlines had been bloated in -current far beyond their
original intent.  Normalize prototypes and function declarations to be ANSI
only (half already were).  And do some general cleanup.

(kernel size also reduced by 50-100K, but that isn't the prime intent)
2001-07-04 20:15:18 +00:00
Matthew Dillon
0cddd8f023 With Alfred's permission, remove vm_mtx in favor of a fine-grained approach
(this commit is just the first stage).  Also add various GIANT_ macros to
formalize the removal of Giant, making it easy to test in a more piecemeal
fashion. These macros will allow us to test fine-grained locks to a degree
before removing Giant, and also after, and to remove Giant in a piecemeal
fashion via sysctl's on those subsystems which the authors believe can
operate without Giant.
2001-07-04 16:20:28 +00:00
Matthew Dillon
ac8f990bde This patch implements O_DIRECT about 80% of the way. It takes a patchset
Tor created a while ago, removes the raw I/O piece (that has cache coherency
problems), and adds a buffer cache / VM freeing piece.

Essentially this patch causes O_DIRECT I/O to not be left in the cache, but
does not prevent it from going through the cache, hence the 80%.  For
the last 20% we need a method by which the I/O can be issued directly to
buffer supplied by the user process and bypass the buffer cache entirely,
but still maintain cache coherency.

I also have the code working under -stable but the changes made to sys/file.h
may not be MFCable, so an MFC is not on the table yet.

Submitted by:	tegge, dillon
2001-05-24 07:22:27 +00:00
Alfred Perlstein
2395531439 Introduce a global lock for the vm subsystem (vm_mtx).
vm_mtx does not recurse and is required for most low level
vm operations.

faults can not be taken without holding Giant.

Memory subsystems can now call the base page allocators safely.

Almost all atomic ops were removed as they are covered under the
vm mutex.

Alpha and ia64 now need to catch up to i386's trap handlers.

FFS and NFS have been tested, other filesystems will need minor
changes (grabbing the vm lock when twiddling page properties).

Reviewed (partially) by: jake, jhb
2001-05-19 01:28:09 +00:00
Matthew Dillon
2b6b0df712 This implements a better launder limiting solution. There was a solution
in 4.2-REL which I ripped out in -stable and -current when implementing the
low-memory handling solution.  However, maxlaunder turns out to be the saving
grace in certain very heavily loaded systems (e.g. newsreader box).  The new
algorithm limits the number of pages laundered in the first pageout daemon
pass.  If that is not sufficient then suceessive will be run without any
limit.

Write I/O is now pipelined using two sysctls, vfs.lorunningspace and
vfs.hirunningspace.  This prevents excessive buffered writes in the
disk queues which cause long (multi-second) delays for reads.  It leads
to more stable (less jerky) and generally faster I/O streaming to disk
by allowing required read ops (e.g. for indirect blocks and such) to occur
without interrupting the write stream, amoung other things.

NOTE: eventually, filesystem write I/O pipelining needs to be done on a
per-device basis.  At the moment it is globalized.
2000-12-26 19:41:38 +00:00
Matthew Dillon
936524aa02 Implement a low-memory deadlock solution.
Removed most of the hacks that were trying to deal with low-memory
    situations prior to now.

    The new code is based on the concept that I/O must be able to function in
    a low memory situation.  All major modules related to I/O (except
    networking) have been adjusted to allow allocation out of the system
    reserve memory pool.  These modules now detect a low memory situation but
    rather then block they instead continue to operate, then return resources
    to the memory pool instead of cache them or leave them wired.

    Code has been added to stall in a low-memory situation prior to a vnode
    being locked.

    Thus situations where a process blocks in a low-memory condition while
    holding a locked vnode have been reduced to near nothing.  Not only will
    I/O continue to operate, but many prior deadlock conditions simply no
    longer exist.

Implement a number of VFS/BIO fixes

	(found by Ian): in biodone(), bogus-page replacement code, the loop
        was not properly incrementing loop variables prior to a continue
        statement.  We do not believe this code can be hit anyway but we
        aren't taking any chances.  We'll turn the whole section into a
        panic (as it already is in brelse()) after the release is rolled.

	In biodone(), the foff calculation was incorrectly
        clamped to the iosize, causing the wrong foff to be calculated
        for pages in the case of an I/O error or biodone() called without
        initiating I/O.  The problem always caused a panic before.  Now it
        doesn't.  The problem is mainly an issue with NFS.

	Fixed casts for ~PAGE_MASK.  This code worked properly before only
        because the calculations use signed arithmatic.  Better to properly
        extend PAGE_MASK first before inverting it for the 64 bit masking
        op.

	In brelse(), the bogus_page fixup code was improperly throwing
        away the original contents of 'm' when it did the j-loop to
        fix the bogus pages.  The result was that it would potentially
        invalidate parts of the *WRONG* page(!), leading to corruption.

	There may still be cases where a background bitmap write is
        being duplicated, causing potential corruption.  We have identified
        a potentially serious bug related to this but the fix is still TBD.
        So instead this patch contains a KASSERT to detect the problem
  	and panic the machine rather then continue to corrupt the filesystem.
	The problem does not occur very often..  it is very hard to
	reproduce, and it may or may not be the cause of the corruption
	people have reported.

Review by: (VFS/BIO: mckusick, Ian Dowse <iedowse@maths.tcd.ie>)
Testing by: (VM/Deadlock) Paul Saab <ps@yahoo-inc.com>
2000-11-18 23:06:26 +00:00
David E. O'Brien
ee2fd03885 Make the arguments match the functionality of the functions. 2000-08-26 04:51:39 +00:00
Alfred Perlstein
4c8545c13d #elsif -> #elif
Noticed by: green
2000-07-11 09:41:29 +00:00
John Baldwin
9a20f99adf Replace the PQ_*CACHE options with a single PQ_CACHESIZE option that you
set equal to the number of kilobytes in your cache.  The old options are
still supported for backwards compatibility.

Submitted by:	Kelly Yancey <kbyanc@posi.net>
2000-07-04 08:55:18 +00:00
Matthew Dillon
8b03c8ed5e This is a cleanup patch to Peter's new OBJT_PHYS VM object type
and sysv shared memory support for it.  It implements a new
    PG_UNMANAGED flag that has slightly different characteristics
    from PG_FICTICIOUS.

    A new sysctl, kern.ipc.shm_use_phys has been added to enable the
    use of physically-backed sysv shared memory rather then swap-backed.
    Physically backed shm segments are not tracked with PV entries,
    allowing programs which use a large shm segment as a rendezvous
    point to operate without eating an insane amount of KVM in the
    PV entry management.  Read: Oracle.

    Peter's OBJT_PHYS object will also allow us to eventually implement
    page-table sharing and/or 4MB physical page support for such segments.
    We're half way there.
2000-05-29 22:40:54 +00:00
Jake Burkholder
e39756439c Back out the previous change to the queue(3) interface.
It was not discussed and should probably not happen.

Requested by:		msmith and others
2000-05-26 02:09:24 +00:00
Jake Burkholder
740a1973a6 Change the way that the queue(3) structures are declared; don't assume that
the type argument to *_HEAD and *_ENTRY is a struct.

Suggested by:	phk
Reviewed by:	phk
Approved by:	mdodd
2000-05-23 20:41:01 +00:00
Peter Wemm
0385347c1a Implement an optimization of the VM<->pmap API. Pass vm_page_t's directly
to various pmap_*() functions instead of looking up the physical address
and passing that.  In many cases, the first thing the pmap code was doing
was going to a lot of trouble to get back the original vm_page_t, or
it's shadow pv_table entry.

Inspired by: John Dyson's 1998 patches.

Also:
Eliminate pv_table as a seperate thing and build it into a machine
dependent part of vm_page_t.  This eliminates having a seperate set of
structions that shadow each other in a 1:1 fashion that we often went to
a lot of trouble to translate from one to the other. (see above)
This happens to save 4 bytes of physical memory for each page in the
system.  (8 bytes on the Alpha).

Eliminate the use of the phys_avail[] array to determine if a page is
managed (ie: it has pv_entries etc).  Store this information in a flag.
Things like device_pager set it because they create vm_page_t's on the
fly that do not have pv_entries.  This makes it easier to "unmanage" a
page of physical memory (this will be taken advantage of in subsequent
commits).

Add a function to add a new page to the freelist.  This could be used
for reclaiming the previously wasted pages left over from preloaded
loader(8) files.

Reviewed by:	dillon
2000-05-21 12:50:18 +00:00
Peter Wemm
c447342094 Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot).  This is consistant with the other
BSD's who made this change quite some time ago.  More commits to come.
1999-12-29 05:07:58 +00:00
Matthew Dillon
4f79d873c1 Add MAP_NOSYNC feature to mmap(), and MADV_NOSYNC and MADV_AUTOSYNC to
madvise().

    This feature prevents the update daemon from gratuitously flushing
    dirty pages associated with a mapped file-backed region of memory.  The
    system pager will still page the memory as necessary and the VM system
    will still be fully coherent with the filesystem.  Modifications made
    by other means to the same area of memory, for example by write(), are
    unaffected.  The feature works on a page-granularity basis.

    MAP_NOSYNC allows one to use mmap() to share memory between processes
    without incuring any significant filesystem overhead, putting it in
    the same performance category as SysV Shared memory and anonymous memory.

Reviewed by: julian, alc, dg
1999-12-12 03:19:33 +00:00
Alan Cox
be72f78813 The core of this patch is to vm/vm_page.h. The effects are two-fold: (1) to
eliminate an extra (useless) level of indirection in half of the page
queue accesses and (2) to use a single name for each queue throughout,
instead of, e.g., "vm_page_queue_active" in some places and
"vm_page_queues[PQ_ACTIVE]" in others.

Reviewed by:	dillon
1999-10-30 07:37:14 +00:00
Matthew Dillon
90ecac61c0 Reviewed by: Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
Replace various VM related page count calculations strewn over the
    VM code with inlines to aid in readability and to reduce fragility
    in the code where modules depend on the same test being performed
    to properly sleep and wakeup.

    Split out a portion of the page deactivation code into an inline
    in vm_page.c to support vm_page_dontneed().

    add vm_page_dontneed(), which handles the madvise MADV_DONTNEED
    feature in a related commit coming up for vm_map.c/vm_object.c.  This
    code prevents degenerate cases where an essentially active page may
    be rotated through a subset of the paging lists, resulting in premature
    disposal.
1999-09-17 04:56:40 +00:00
Peter Wemm
c3aac50f28 $Id$ -> $FreeBSD$ 1999-08-28 01:08:13 +00:00
Brian Feldman
38c808edb7 Unbreak the nfs KLD_MODULE. It needs a bit more of vm_page.h than was
exported (notably vm_page_undirty()). Also, let vm_page_dirty() work
in a KLD.
1999-08-17 22:48:10 +00:00
Alan Cox
2c28a10540 Add the (inline) function vm_page_undirty for clearing the dirty bitmask
of a vm_page.

Use it.

Submitted by:	dillon
1999-08-17 04:02:34 +00:00
Alan Cox
175d1f69bf contigmalloc1 (currently) depends on PQ_FREE and PQ_CACHE not being 0
to tell a valid "struct vm_page" from an invalid one in the vm_page_array.
This isn't a very robust method.
1999-08-15 05:36:43 +00:00
Matt Jacob
3739d7da89 Add back in old definitions if we're compiling for alpha. 1999-08-15 01:16:53 +00:00
Alan Cox
514bfcc440 Don't create a "struct vpgqueues" for PQ_NONE. 1999-08-14 06:25:54 +00:00
Alan Cox
1aefb1d957 Make the default page coloring parameters match a (non-Xeon) Pentium II/III.
This setting is also acceptable for Celerons and Pentium Pros
with less than 1MB L2 caches.

Note: PQ_L2_SIZE is a misnomer.  The correct number of colors is
a function of the cache's degree of associativity as well as its size.

Submitted by:	bde and alc
1999-08-12 21:16:53 +00:00
Alan Cox
5d2aec8927 Change the type of vpgqueues::lcnt from "int *" to "int". The indirection
served no purpose.
1999-07-31 18:31:00 +00:00
Alan Cox
3b21348301 Reduce the number of "magic constants" used for page coloring
by one: PQ_PRIME2 and PQ_PRIME3 are used to accomplish the same
thing at different places in the kernel.  Drop PQ_PRIME3.
1999-07-22 06:04:17 +00:00
Alan Cox
9c89c228fe Remove (1) "extern" declarations for variables that were previously
made "static" and (2) initialized but unused variables.
1999-06-22 07:18:20 +00:00
Alan Cox
6ea5bd80fe Remove some unused function and variable declarations. 1999-06-19 18:42:53 +00:00
Alan Cox
4221e284a3 The VFS/BIO subsystem contained a number of hacks in order to optimize
piecemeal, middle-of-file writes for NFS.  These hacks have caused no
end of trouble, especially when combined with mmap().  I've removed
them.  Instead, NFS will issue a read-before-write to fully
instantiate the struct buf containing the write.  NFS does, however,
optimize piecemeal appends to files.  For most common file operations,
you will not notice the difference.  The sole remaining fragment in
the VFS/BIO system is b_dirtyoff/end, which NFS uses to avoid cache
coherency issues with read-merge-write style operations.  NFS also
optimizes the write-covers-entire-buffer case by avoiding the
read-before-write.  There is quite a bit of room for further
optimization in these areas.

The VM system marks pages fully-valid (AKA vm_page_t->valid =
VM_PAGE_BITS_ALL) in several places, most noteably in vm_fault.  This
is not correct operation.  The vm_pager_get_pages() code is now
responsible for marking VM pages all-valid.  A number of VM helper
routines have been added to aid in zeroing-out the invalid portions of
a VM page prior to the page being marked all-valid.  This operation is
necessary to properly support mmap().  The zeroing occurs most often
when dealing with file-EOF situations.  Several bugs have been fixed
in the NFS subsystem, including bits handling file and directory EOF
situations and buf->b_flags consistancy issues relating to clearing
B_ERROR & B_INVAL, and handling B_DONE.

getblk() and allocbuf() have been rewritten.  B_CACHE operation is now
formally defined in comments and more straightforward in
implementation.  B_CACHE for VMIO buffers is based on the validity of
the backing store.  B_CACHE for non-VMIO buffers is based simply on
whether the buffer is B_INVAL or not (B_CACHE set if B_INVAL clear,
and vise-versa).  biodone() is now responsible for setting B_CACHE
when a successful read completes.  B_CACHE is also set when a bdwrite()
is initiated and when a bwrite() is initiated.  VFS VOP_BWRITE
routines (there are only two - nfs_bwrite() and bwrite()) are now
expected to set B_CACHE.  This means that bowrite() and bawrite() also
set B_CACHE indirectly.

There are a number of places in the code which were previously using
buf->b_bufsize (which is DEV_BSIZE aligned) when they should have
been using buf->b_bcount.  These have been fixed.  getblk() now clears
B_DONE on return because the rest of the system is so bad about
dealing with B_DONE.

Major fixes to NFS/TCP have been made.  A server-side bug could cause
requests to be lost by the server due to nfs_realign() overwriting
other rpc's in the same TCP mbuf chain.  The server's kernel must be
recompiled to get the benefit of the fixes.

Submitted by:	Matthew Dillon <dillon@apollo.backplane.com>
1999-05-02 23:57:16 +00:00
Julian Elischer
8d17e69460 Catch a case spotted by Tor where files mmapped could leave garbage in the
unallocated parts of the last page when the file ended on a frag
but not a page boundary.
Delimitted by tags PRE_MATT_MMAP_EOF and POST_MATT_MMAP_EOF,
in files alpha/alpha/pmap.c i386/i386/pmap.c nfs/nfs_bio.c vm/pmap.h
    vm/vm_page.c vm/vm_page.h vm/vnode_pager.c miscfs/specfs/spec_vnops.c
    ufs/ufs/ufs_readwrite.c kern/vfs_bio.c

Submitted by: Matt Dillon <dillon@freebsd.org>
Reviewed by: Alan Cox <alc@freebsd.org>
1999-04-05 19:38:30 +00:00
Julian Elischer
811c2e1a76 Fix breakage in last commit
Submitted by: Brian Feldman <green@unixhelp.org>
1999-03-15 05:09:48 +00:00
Julian Elischer
0237469f43 A bit of a hack, but allows the vn device to be a module again.
Submitted by: Matt Dillon <dillon@freebsd.org>
1999-03-14 20:40:15 +00:00
Matthew Dillon
efcae3d355 Minor reorganization of vm_page_alloc(). No functional changes have
been made but the code has been reorganized and documented to make
    it more readable, reduce the size of the code, and optimize the branch
    path caching capabilities that most modern processors have.
1999-02-15 06:52:14 +00:00
Matthew Dillon
faa273d5c2 Rip out PQ_ZERO queue. PQ_ZERO functionality is now combined in with
PQ_FREE.  There is little operational difference other then the kernel
    being a few kilobytes smaller and the code being more readable.

    * vm_page_select_free() has been *greatly* simplified.
    * The PQ_ZERO page queue and supporting structures have been removed
    * vm_page_zero_idle() revamped (see below)

    PG_ZERO setting and clearing has been migrated from vm_page_alloc()
    to vm_page_free[_zero]() and will eventually be guarenteed to remain
    tracked throughout a page's life ( if it isn't already ).

    When a page is freed, PG_ZERO pages are appended to the appropriate
    tailq in the PQ_FREE queue while non-PG_ZERO pages are prepended.
    When locating a new free page, PG_ZERO selection operates from within
    vm_page_list_find() ( get page from end of queue instead of beginning
    of queue ) and then only occurs in the nominal critical path case.  If
    the nominal case misses, both normal and zero-page allocation devolves
    into the same _vm_page_list_find() select code without any specific
    zero-page optimizations.

    Additionally, vm_page_zero_idle() has been revamped.  Hysteresis has been
    added and zero-page tracking adjusted to conform with the other changes.
    Currently hysteresis is set at 1/3 (lo) and 1/2 (hi) the number of free
    pages.  We may wish to increase both parameters as time permits.  The
    hysteresis is designed to avoid silly zeroing in borderline allocation/free
    situations.
1999-02-08 00:37:36 +00:00
Matthew Dillon
a0e7b3e5ce Remove L1 cache coloring optimization ( leave L2 cache coloring opt ).
Rewrite vm_page_list_find() and vm_page_select_free() - make inline out
    of nominal case.
1999-02-07 20:45:15 +00:00
Matthew Dillon
161a8f6519 Add vm_page_dirty() inline with PQ_CACHE sanity check 1999-01-24 05:57:50 +00:00
Matthew Dillon
a7039a1d42 Add invariants to vm_page_busy() and vm_page_wakeup() to check for
PG_BUSY stupidity.
1999-01-24 01:05:15 +00:00
Matthew Dillon
41dbefba28 The TAILQ hashq has been turned into a singly-linked=list link,
reducing the size of vm_page_t.

    SWAPBLK_NONE and SWAPBLK_MASK are defined here.  These actually are
    more generalized then their names imply, but their placement is somewhat
    of a legacy issue from a prior test version of this code that put
    the swapblk in the vm_page_t structure.  That test code was eventually
    thrown away.  The legacy remains.

    Added vm_page_flash() inline.  Similar to vm_page_wakeup() except that
    it does not clear PG_BUSY ( one assumes that PG_BUSY is already clear ).
    Used by a number of routines to wakeup waiters.

    Collapsed some of the code in inline calls to make other inline calls.
    GCC will optimize this well and it reduces duplication.

    vm_page_free() and vm_page_free_zero() inlines added to convert to
    the proper vm_page_free_toq() call.

    vm_page_sleep_busy() inline added, replacing vm_page_sleep() ( which has
    been removed ).  This implements a much more optimizable page-waiting
    function.
1999-01-21 10:06:24 +00:00
Matthew Dillon
1c7c3c6a86 This is a rather large commit that encompasses the new swapper,
changes to the VM system to support the new swapper, VM bug
    fixes, several VM optimizations, and some additional revamping of the
    VM code.  The specific bug fixes will be documented with additional
    forced commits.  This commit is somewhat rough in regards to code
    cleanup issues.

Reviewed by:	"John S. Dyson" <root@dyson.iquest.net>, "David Greenman" <dg@root.com>
1999-01-21 08:29:12 +00:00
Eivind Eklund
5526d2d920 Split DIAGNOSTIC -> DIAGNOSTIC, INVARIANTS, and INVARIANT_SUPPORT as
discussed on -hackers.

Introduce 'KASSERT(assertion, ("panic message", args))' for simple
check + panic.

Reviewed by:	msmith
1999-01-08 17:31:30 +00:00
David Greenman
730075613a Added a second argument, "activate" to the vm_page_unwire() call so that
the caller can select either inactive or active queue to put the page on.
1998-10-28 13:37:02 +00:00