Commit Graph

54 Commits

Author SHA1 Message Date
Konstantin Belousov
2cc718a11c Do not map the swap i/o pbufs if the geom provider for the swap
partition accepts unmapped requests.

Sponsored by:	The FreeBSD Foundation
Tested by:	pho
2013-03-19 14:39:27 +00:00
Konstantin Belousov
dda4f96087 Implement the linprocfs swaps file, providing information about the
configured swap devices in the Linux-compatible format.

Based on the submission by:	Robert Millan <rmh debian org>
PR:	kern/159281
Reviewed by:	bde
Approved by:	re (kensmith)
MFC after:	2 weeks
2011-08-01 19:12:15 +00:00
John Baldwin
e8865caffb - Move 'struct swdevt' back into swap_pager.h and expose it to userland.
- Restore support for fetching swap information from crash dumps via
  kvm_get_swapinfo(3) to fix pstat -T/-s on crash dumps.

Reviewed by:	arch@, phk
MFC after:	1 week
2007-02-07 17:43:11 +00:00
Pawel Jakub Dawidek
0909f38a3c On shutdown try to turn off all swap devices. This way GEOM providers are
properly closed on shutdown.

Requested by:	ru
Reviewed by:	alc
MFC after:	2 weeks
2006-04-10 10:03:41 +00:00
Warner Losh
60727d8b86 /* -> /*- for license, minor formatting changes 2005-01-07 02:29:27 +00:00
Warner Losh
05eb3785e7 Remove advertising clause from University of California Regent's license,
per letter dated July 22, 1999.

Approved by: core
2004-04-06 20:15:37 +00:00
Poul-Henning Kamp
751221fd32 Staticize swap_pager_putpages()
Eliminate a lot of checkes to make sure requests are not cross-device
which is unnecessary with the new layout.  We know a sequential request
cannot possibly be cross-device because there is a reserved page between
the devices.

Remove a couple of comments which no longer are relevant.
2003-08-06 12:08:27 +00:00
Poul-Henning Kamp
8f60c087e6 Change the layout policy of the swap_pager from a hardcoded width
striping to a per device round-robin algorithm.

Because of the policy of not attempting to retain previous swap
allocation on page-out, this means that a newly added swap device
almost instantly takes its 1/N share of the I/O load but it takes
somewhat longer for it to assume it's 1/N share of the pages if there
is plenty of space on the other devices.

Change the 8G total swapspace limitation to 8G per device instead
by using a per device blist rather than one global blist.  This
reduces the memory footprint by 75% (typically a couple hundred
kilobytes) for the common case with one swapdevice but NSWAPDEV=4.

Remove the compile time constant limit of number of swap devices,
there is no limit now.  Instead of a fixed size array, store the
per swapdev structure in a TAILQ.

Total swap space is still addressed by a 32 bit page number and
therefore the upper limit is now 2^42 bytes = 16TB (for i386).

We still do not allocate the first page of each device in order to
give some amount of protection to any bsdlabel at the start of the
device.

A new device is appended after the existing devices in the swap space,
no attempt is made to fill in holes left behind by swapoff (this can
trivially be changed should it ever become a problem).

The sysctl vm.nswapdev now reflects the number of currently configured
swap devices.

Rename vm_swap_size to swap_pager_avail for consistency with other
exported names.

Change argument type for vm_proc_swapin_all() and swap_pager_isswapped()
to be a struct swdevt pointer rather than an index.

Not changed: we are still using blists to manage the free space,
but since the swapspace is no longer fragmented by the striping
different resource managers might fare better.
2003-08-03 13:35:31 +00:00
Poul-Henning Kamp
8d677ef93f Remove unused stuff.
Move used stuff to swap_pager.c where it belongs.

This file no longer exports anything to userland.
2003-07-31 22:19:28 +00:00
Poul-Henning Kamp
ec38b344cb Move the implementation of the vmspace_swap_count() (used only in
the "toss the largest process" emergency handling) from vm_map.c to
swap_pager.c.

The quantity calculated depends strongly on the internals of the
swap_pager and by moving it, we no longer need to expose the
internal metrics of the swap_pager to the world.
2003-07-18 10:47:58 +00:00
Poul-Henning Kamp
567104a148 Add a new function swap_pager_status() which reports the total size of the
paging space and how much of it is in use (in pages).

Use this interface from the Linuxolator instead of groping around in the
internals of the swap_pager.
2003-07-18 10:26:09 +00:00
Poul-Henning Kamp
e9c0cc157b Merge swap_pager.c and vm_swap.c into swap_pager.c, the separation
is not natural and needlessly exposes a lot of dirty laundry.

Move private interfaces between the two from swap_pager.h to swap_pager.c
and staticize as much as possible.

No functional change.
2003-07-18 10:02:44 +00:00
Poul-Henning Kamp
116b3c2af9 Make sure that SWP_NPAGES always has the same value in all source
files, so that SWAP_META_PAGES does not vary either.

swap_pager.c ended up with a value of 16, everybody else 8.  Go with
the 16 for now.

This should only have any effect in the "kill processes because we
are out of swap" scenario, where it will make some sort of estimate
of something more precise.
2003-07-17 21:58:43 +00:00
Alan Cox
5ea4972cd4 Make swap_pager_haspages() static; remove unused function prototypes. 2003-06-20 20:20:06 +00:00
Alan Cox
875791f63d - Move swap_pager_isswapped()'s prototype to a more logical place. 2003-04-24 05:29:27 +00:00
Alan Cox
26da32cc73 Remove unused declarations. 2003-04-22 06:26:42 +00:00
Poul-Henning Kamp
42c43e6031 Make struct swblock kernel only, to make vm/swap_pager.h userland includable.
Move struct swdevt from sys/conf.h to the more appropriate vm/swap_pager.h.
Adjust #include use in libkvm and pstat(8) to match.
2003-01-03 16:23:12 +00:00
Poul-Henning Kamp
c410df597b Avoid extern decls in .c files by putting them in the vm/swap_pager.h
include file where they belong.
Share the dmmax_mask variable.
2003-01-03 14:30:46 +00:00
Poul-Henning Kamp
3ccbf2d533 Use correct _VM_SWAP_PAGER_H_ to check for multiple inclusion. 2003-01-03 14:22:52 +00:00
Matthew Dillon
92da00bb24 This is David Schultz's swapoff code which I am finally able to commit.
This should be considered highly experimental for the moment.

Submitted by:	David Schultz <dschultz@uclink.Berkeley.EDU>
MFC after:	3 weeks
2002-12-15 19:17:57 +00:00
Bruce Evans
6af7f1e511 Use `struct uma_zone *' instead of uma_zone_t, so that <sys/uma.h> isn't
a prerequisite.
2002-09-05 14:04:34 +00:00
Jeff Roberson
670d17b5c0 Remove references to vm_zone.h and switch over to the new uma API. 2002-03-20 04:02:59 +00:00
Alfred Perlstein
11caded34f Remove __P. 2002-03-19 22:20:14 +00:00
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
Seigo Tanimura
21cd6e6232 - If swap metadata does not fit into the KVM, reduce the number of
struct swblock entries by dividing the number of the entries by 2
until the swap metadata fits.

- Reject swapon(2) upon failure of swap_zone allocation.

This is just a temporary fix. Better solutions include:
(suggested by:	dillon)

o reserving swap in SWAP_META_PAGES chunks, and
o swapping the swblock structures themselves.

Reviewed by:	alfred, dillon
2000-12-13 10:01:00 +00:00
Matthew Dillon
64bcb9c815 The swap bitmap allocator was not calculating the bitmap size properly
in the face of non-stripe-aligned swap areas.  The bug could cause a
      panic during boot.

      Refuse to configure a swap area that is too large (67 GB or so)

      Properly document the power-of-2 requirement for SWB_NPAGES.

      The patch is slightly different then the one Tor enclosed in the P.R.,
      but accomplishes the same thing.

PR: kern/20273
Submitted by: Tor.Egge@fast.no
2000-10-13 16:44:34 +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
Peter Wemm
cdacc6ab42 Remove the non-functional "swap device" userland front-end to the
multiplexed underlying swap devices (/dev/drum).  The only thing it did
was to allow root to open /dev/drum, but not do anything with it.
Various utilities used to grovel around in here, but Matt has written
a much nicer (and clean) front-end to this for libkvm, and nothing uses
the old system any more.

The VM system was calling VOP_STRATEGY() on the vp of the first underlying
swap device (not the /dev/drum one, the first real device), and using
the VOP system to indirectly (and only) call swstrategy() to choose
an underlying device and enqueue it on that device.  I have changed it
to avoid diverting through the VOP system and to call the only possible
target directly, saving a little bit of time and some complexity.

In all, nothing much changes, except some scaffolding to support the
roundabout way of calling swstrategy() is gone.

Matt gave me the ok to do this some time ago, and I apologize for taking
so long to get around to it.
1999-11-18 06:55:40 +00:00
Matthew Dillon
4dcc5c2d1d Fix a number of spl bugs related to reserving and freeing swap space.
Swap space can be freed from an interrupt and so swap reservation and
    freeing must occur at splvm.

    Add swap_pager_reserve() code to support a new swap pre-reservation
    capability for the VN device.

    Generally cleanup the swap code by simplifying the swp_pager_meta_build()
    static function and consolidating the SWAPBLK_NONE test from a bit test
    to an absolute compare.  The bit test was left over from a rejected
    swap allocation scheme that was not ultimately committed.  A few other
    minor cleanups were also made.

    Reorganize the swap strategy code, again for VN support, to not
    reallocate swap when writing as this messes up pre-reservation and
    can fragment I/O unnecessarily as VN-baesd disk is messed around with.

Reviewed by:	Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
1999-09-17 05:09:24 +00:00
Peter Wemm
c3aac50f28 $Id$ -> $FreeBSD$ 1999-08-28 01:08:13 +00:00
Matthew Dillon
e4542174b0 vm_pager_put_pages() is passed an rcval array to hold per-page return
values.  The 'int' return value for the procedure was never used and
    not well defined in any case when there are mixed errors on pages, so
    it has been removed.  vm_pager_put_pages() and associated vm_pager
    functions now return void.
1999-01-24 02:32:15 +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
Alexander Langer
c5b75d8223 Removed no longer valid comment about swb_block being int instead of
daddr_t.

PR:		7238
Submitted by:	Stefan Eggers <seggers@semyam.dinoco.de>
1998-07-10 21:50:17 +00:00
John Dyson
c0877f103f Tighten up management of memory and swap space during map allocation,
deallocation cycles.  This should provide a measurable improvement
on swap and memory allocation on loaded systems.  It is unlikely a
complete solution.  Also, provide more map info with procfs.
Chuck Cranor spurred on this improvement.
1998-04-29 04:28:22 +00:00
John Dyson
660957521c Fix page prezeroing for SMP, and fix some potential paging-in-progress
hangs.  The paging-in-progress diagnosis was a result of Tor Egge's
excellent detective work.
Submitted by:	Partially from Tor Egge.
1998-02-25 03:56:15 +00:00
John Dyson
e47ed70b0f Significantly improve the efficiency of the swap pager, which appears to
have declined due to code-rot over time.  The swap pager rundown code
has been clean-up, and unneeded wakeups removed.  Lots of splbio's
are changed to splvm's.  Also, set the dynamic tunables for the
pageout daemon to be more sane for larger systems (thereby decreasing
the daemon overheadla.)
1998-02-23 08:22:48 +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
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
0a47b48b9f 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
John Dyson
836e5d1360 In order to fix some concurrency problems with the swap pager early
on in the FreeBSD development, I had made a global lock around the
rlist code.  This was bogus, and now the lock is maintained on a
per resource list basis.  This now allows the rlist code to be used for
almost any non-interrupt level application.
1996-03-03 21:11:08 +00:00
Mike Pritchard
6c5e9bbdf5 Fix a bunch of spelling errors in the comment fields of
a bunch of system include files.
1996-01-30 23:02:38 +00:00
Poul-Henning Kamp
f708ef1b9e Another mega commit to staticize things. 1995-12-14 09:55:16 +00:00
John Dyson
a316d390bd Changes to support 1Tb filesizes. Pages are now named by an
(object,index) pair instead of (object,offset) pair.
1995-12-11 04:58:34 +00:00
Bruce Evans
ff98689d2d Fixed recent staticizations. Some protypes for static functions were
left in headers and not staticized.
1995-11-16 09:51:22 +00:00
David Greenman
cd41fc123e Fix argument passing to the "freeer" routine. Added some prototypes. (bde)
Moved extern declaration of swap_pager_full into swap_pager.h and out of
the various files that reference it. (davidg)

Submitted by:	bde & davidg
1995-10-07 19:02:56 +00:00
Bruce Evans
bf25be48a5 Make everything except the unsupported network sources compile cleanly
with -Wnested-externs.
1995-08-16 16:14:28 +00:00
David Greenman
2a4895f4bb 1) Merged swpager structure into vm_object.
2) Changed swap_pager internal interfaces to cope w/#1.
3) Eliminated object->copy as we no longer have copy objects.
4) Minor stylistic changes.
1995-07-16 13:28:37 +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
ee3a64c992 Changed "handle" from type caddr_t to void *; "handle" is several different
types of pointers, and "char *" is a bad choice for the type.
1995-05-10 18:56:09 +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