Commit Graph

164 Commits

Author SHA1 Message Date
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
John Baldwin
7d4ad42de5 Sort includes. 2001-05-22 07:01:11 +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
Mark Murray
fb919e4d5a Undo part of the tangle of having sys/lock.h and sys/mutex.h included in
other "system" header files.

Also help the deprecation of lockmgr.h by making it a sub-include of
sys/lock.h and removing sys/lockmgr.h form kernel .c files.

Sort sys/*.h includes where possible in affected files.

OK'ed by:	bde (with reservations)
2001-05-01 08:13:21 +00:00
John Baldwin
136d8f42b9 Unrevert the pmap_map() changes. They weren't broken on x86.
Sense beaten into me by:	peter
2001-03-07 05:29:21 +00:00
John Baldwin
4a01ebd482 Back out the pmap_map() change for now, it isn't completely stable on the
i386.
2001-03-07 01:04:17 +00:00
John Baldwin
968950e5d1 - Rework pmap_map() to take advantage of direct-mapped segments on
supported architectures such as the alpha.  This allows us to save
  on kernel virtual address space, TLB entries, and (on the ia64) VHPT
  entries.  pmap_map() now modifies the passed in virtual address on
  architectures that do not support direct-mapped segments to point to
  the next available virtual address.  It also returns the actual
  address that the request was mapped to.
- On the IA64 don't use a special zone of PV entries needed for early
  calls to pmap_kenter() during pmap_init().  This gets us in trouble
  because we end up trying to use the zone allocator before it is
  initialized.  Instead, with the pmap_map() change, the number of needed
  PV entries is small enough that we can get by with a static pool that is
  used until pmap_init() is complete.

Submitted by:		dfr
Debugging help:		peter
Tested by:		me
2001-03-06 06:06:42 +00:00
Andrew Gallatin
c909b97167 Allocate vm_page_array and vm_page_buckets from the end of the biggest chunk
of memory, rather than from the start.

This fixes problems allocating bouncebuffers on alphas where there is only
1 chunk of memory (unlike PCs where there is generally at least one small
chunk and a large chunk).  Having 1 chunk had been fatal, because these
structures take over 13MB on a machine with 1GB of ram. This doesn't leave
much room for other structures and bounce buffers if they're at the front.

Reviewed by: dfr, anderson@cs.duke.edu, silence on -arch
Tested by: Yoriaki FUJIMORI <fujimori@grafin.fujimori.cache.waseda.ac.jp>
2001-03-01 19:21:24 +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
Poul-Henning Kamp
065b25803d Fix floppy drives on machines with lots of RAM.
The fix works by reverting the ordering of free memory so that the
chances of contig_malloc() succeeding increases.

PR:		23291
Submitted by:	Andrew Atrens <atrens@nortel.ca>
2000-12-18 20:12:13 +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
Kirk McKusick
c904bbbdd8 Simplify and rationalise the management of the vnode free list
(preparing the code to add snapshots).
2000-07-04 04:32:40 +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
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
Philippe Charnier
5929bcfaba Revert spelling mistake I made in the previous commit
Requested by: Alan and Bruce
2000-03-27 20:41:17 +00:00
Philippe Charnier
956f31353c Spelling 2000-03-26 15:20:23 +00:00
Poul-Henning Kamp
db5f635acc Eliminate the undocumented, experimental, non-delivering and highly
dangerous MAX_PERF option.
2000-03-16 08:51:55 +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
e6ce529511 Two changes: (1) Use vm_page_unqueue_nowakeup in vm_page_alloc
instead of duplicating the code.  (2) If a wired page is passed
to vm_page_free_toq, panic instead of printing a friendly warning.
(If we don't panic here, we'll just panic later in vm_page_unwire
obscuring the problem.)
1999-11-10 05:23:19 +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
Poul-Henning Kamp
923502ff91 useracc() the prequel:
Merge the contents (less some trivial bordering the silly comments)
of <vm/vm_prot.h> and <vm/vm_inherit.h> into <vm/vm.h>.  This puts
the #defines for the vm_inherit_t and vm_prot_t types next to their
typedefs.

This paves the road for the commit to follow shortly: change
useracc() to use VM_PROT_{READ|WRITE} rather than B_{READ|WRITE}
as argument.
1999-10-29 18:09:36 +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
Alan Cox
14068cfed2 vm_page_alloc and contigmalloc1:
Verify that free pages are not dirty.

Submitted by:	dillon
1999-08-20 06:32:00 +00:00
Alan Cox
0e70993526 vm_page_free_toq:
Update the comment to reflect the demise of PQ_ZERO and
	remove a (now) useless test.
1999-08-17 18:09:01 +00:00
Alan Cox
3fc3fec6d3 vm_page_free_toq:
Clear the dirty bit mask (vm_page_undirty) before adding the page
	to the free page queue.

Submitted by:	dillon
1999-08-17 05:08:39 +00:00
Alan Cox
6c91c1dc3f contigmalloc1:
If a page is found in the wrong queue, panic instead
	of silently ignoring the problem.
1999-08-11 05:12:00 +00:00
Peter Wemm
ed6d0b65f0 Add a contigfree() as a corollary to contigmalloc() as it's not clear
which free routine to use and people are tempted to use free() (which
doesn't work)
1999-08-10 22:21:13 +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
755292ace1 vm_page_queue_init:
Remove the initialization of PQ_NONE's cnt and lcnt.  They aren't
	used.

vm_page_insert:
	Remove an unnecessary dereference.

vm_page_wire:
	Remove the one and only (and thus pointless) reference
	to PQ_NONE's lcnt.
1999-07-31 04:19:49 +00:00
Peter Wemm
3efc015bae Fix some int/long printf problems for the Alpha 1999-07-01 19:53:43 +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
60ff97b002 Remove vm_object::cache_count and vm_object::wired_count. They are
not used.  (Nor is there any planned use by John who introduced them.)

Reviewed by:	"John S. Dyson" <toor@dyson.iquest.net>
1999-06-20 21:47:02 +00:00
Alan Cox
c207703465 Set cnt.v_page_size to PAGE_SIZE rather than DEFAULT_PAGE_SIZE so that
"vmstat -s" reports the correct value on the Alpha.

Submitted by:	Hidetoshi Shimokawa <simokawa@sat.t.u-tokyo.ac.jp>
1999-06-20 04:55:29 +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
Alan Cox
61fc5ee627 Construct the free queue(s) in descending order (by physical
address) so that the first 16MB of physical memory is allocated
last rather than first.  On large-memory machines, this avoids
the exhaustion of low physical memory before isa_dmainit has run.
1999-03-19 05:21:03 +00:00
Matthew Dillon
d1bf5d56b6 Remove unnecessary page protects on map_split and collapse operations.
Fix bug where an object's OBJ_WRITEABLE/OBJ_MIGHTBEDIRTY flags do
    not get set under certain circumstances ( page rename case ).

Reviewed by:	Alan Cox <alc@cs.rice.edu>, John Dyson
1999-02-24 21:26:26 +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
8aef171243 Fix warnings in preparation for adding -Wall -Wcast-qual to the
kernel compile
1999-01-28 00:57:57 +00:00
Matthew Dillon
2f586e1b2c Undo last commit - not a bug, just duplicate code. PG_MAPPED and
PG_WRITEABLE are already cleared by vm_page_protect().
1999-01-24 07:06:52 +00:00
Matthew Dillon
68af6d169b vm_map_split() used to dirty the page manually after calling
vm_page_rename(), but never pulled the page off PQ_CACHE if it was on
    PQ_CACHE.  Dirty pages in PQ_CACHE are not allowed and a KASSERT was
    added in -4.x to test for this... and got hit.

    In -4.x, vm_page_rename() automatically dirties the page.  This commit
    also has it deal with the PQ_CACHE case, deactivating the page in that
    case.
1999-01-24 06:00:31 +00:00
Matthew Dillon
e1a4feafd0 Clear PG_MAPPED as well as PG_WRITEABLE when a page is moved to the
cache.
1999-01-24 02:29:26 +00:00
Matthew Dillon
c9fa34cf07 Clear PG_WRITEABLE in vm_page_cache(). This may or may not be a bug,
but the bit should definitely be cleared.
1999-01-24 01:04:04 +00:00
Matthew Dillon
060282de8a The hash table used to be a table of doubly-link list headers ( two
pointers per entry ).  The table has been changed to a singly linked
    list of vm_page_t pointers.  The table has been doubled in size, but
    the entries only take half the space so a net-zero change in memory use.

    The hash function has been changed, hopefully for the better.  The
    combination of the larger hash table size of changed function should
    keep the chain length down to a reasonable number (0-3, average 1).

    vm_object->page_hint has been removed.  This 'optimization' was not
    only never needed, but costs as much as a hash chain link to implement.
    While having page_hint in vm_object might result in better locality
    of reference, the cost is not worth the space in vm_object or the
    extra instructions in my view.

    vm_page_alloc*() functions have been inlined and call a generalized
    non-inlined vm_page_alloc_toq() which combines the standard alloc
    and zero-page alloc functions together, reducing code size and the L1
    cache footprint.  Some reordering has been done... not much.  The
    delinking code should be faster ( because unlinking a doubly-linked list
    requires four memory ops and unlinking a singly linked list only requires
    two ), and we get a hash consistancy check for free.

    vm_page_rename() now automatically sets the page's dirty bits.

    vm_page_alloc() does not try to manually inline freeing a cache page.
    Instead, it now properly calls vm_page_free(m) ... vm_page_free() is
    really too complex to manually inline.

    vm_await(), supporting asleep(), has been added.
1999-01-21 10:01:49 +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
219cbf59f2 KNFize, by bde. 1999-01-10 01:58:29 +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