Commit Graph

164 Commits

Author SHA1 Message Date
Tor Egge
d6844b6bf6 Don't use an uninitialized field reserved for callers in the bio structure
passed to swap_pager_strategy().  Instead, use a field reserved for drivers
and initialize it before usage.

Reviewed by:	dillon
2001-10-15 23:02:54 +00:00
John Baldwin
bd78cece5d Change the kernel's ucred API as follows:
- crhold() returns a reference to the ucred whose refcount it bumps.
- crcopy() now simply copies the credentials from one credential to
  another and has no return value.
- a new crshared() primitive is added which returns true if a ucred's
  refcount is > 1 and false (0) otherwise.
2001-10-11 23:38:17 +00:00
Matthew Dillon
2f9e4e8025 Limit the amount of KVM reserved for the buffer cache and for swap-meta
information.  The default limits only effect machines with > 1GB of ram
and can be overriden with two new kernel conf variables VM_SWZONE_SIZE_MAX
and VM_BCACHE_SIZE_MAX, or with loader variables kern.maxswzone and
kern.maxbcache.  This has the effect of leaving more KVM available for
sizing NMBCLUSTERS and 'maxusers' and should avoid tripups where a sysad
adds memory to a machine and then sees the kernel panic on boot due to
running out of KVM.

Also change the default swap-meta auto-sizing calculation to allocate half
of what it was previously allocating.  The prior defaults were way too high.
Note that we cannot afford to run out of swap-meta structures so we still
stay somewhat conservative here.
2001-08-20 00:41:12 +00:00
Alfred Perlstein
61ce6eeee3 Fixups for the initial allocation by dillon:
1) allocate fewer buckets
  2) when failing to allocate swap zone, keep reducing the zone by
     a third rather than a half in order to reduce the chance of
     allocating way too little.

I also moved around some code for readability.

Suggested by: dillon
Reviewed by: dillon
2001-08-02 07:54:58 +00:00
Matthew Dillon
54d9214595 whitespace / register cleanup 2001-07-04 19:00:13 +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
John Baldwin
6d541bf1ae - Protect all accesses to nsw_[rw]count{,_{,a}sync} with the pbuf mutex.
- Don't drop the vm mutex while grabbing the pbuf mutex to manipulate
  said variables.
2001-06-22 21:12:19 +00:00
John Baldwin
b608320d4a - Fix the sw_alloc_interlock to actually lock itself when the lock is
acquired.
- Assert Giant is held in the strategy, getpages, and putpages methods and
  the getchainbuf, flushchainbuf, and waitchainbuf functions.
- Always call flushchainbuf() w/o the VM lock.
2001-05-23 22:31:15 +00:00
Alfred Perlstein
c5e62505ad aquire Giant when playing with the buffercache and doing IO.
use msleep against the vm mutex while waiting for a page IO to complete.
2001-05-23 10:28:11 +00:00
Alfred Perlstein
240e0fdd93 aquire vm mutex in swp_pager_async_iodone. Don't call swp_pager_async_iodone
with the mutex held.
2001-05-22 19:01:26 +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
Poul-Henning Kamp
a468031ce8 Actually biofinish(struct bio *, struct devstat *, int error) is more general
than the bioerror().

Most of this patch is generated by scripts.
2001-05-06 20:00:03 +00:00
Alfred Perlstein
a9fa2c05fc Protect pager object creation with sx locks.
Protect pager object list manipulation with a mutex.

It doesn't look possible to combine them under a single sx lock because
creation may block and we can't have the object list manipulation block
on anything other than a mutex because of interrupt requests.
2001-04-18 20:24:16 +00:00
Alfred Perlstein
2a758ebe58 protect pbufs and associated counts with a mutex 2001-04-13 10:23:32 +00:00
Robert Watson
edfa785a8e Introduce per-swap area accounting in the VM system, and export
this information via the vm.nswapdev sysctl (number of swap areas)
and vm.swapdevX nodes (where X is the device), which contain the MIBs
dev, blocks, used, and flags.  These changes are required to allow
top and other userland swap-monitoring utilities to run without
setgid kmem.

Submitted by:	Thomas Moestl <tmoestl@gmx.net>
Reviewed by:	freebsd-audit
2001-02-23 18:46:21 +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
David Malone
7cc0979fd6 Convert more malloc+bzero to malloc+M_ZERO.
Submitted by:	josh@zipperup.org
Submitted by:	Robert Drehmel <robd@gmx.net>
2000-12-08 21:51:06 +00:00
Robert Watson
cee313c431 o Export dmmax ("Maximum size of a swap block") using SYSCTL_INT.
This removes a reason that systat requires setgid kmem.  More to
  come.
2000-11-20 00:39:04 +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
Matthew Dillon
279d722604 This patchset fixes a large number of file descriptor race conditions.
Pre-rfork code assumed inherent locking of a process's file descriptor
    array.  However, with the advent of rfork() the file descriptor table
    could be shared between processes.  This patch closes over a dozen
    serious race conditions related to one thread manipulating the table
    (e.g. closing or dup()ing a descriptor) while another is blocked in
    an open(), close(), fcntl(), read(), write(), etc...

PR: kern/11629
Discussed with: Alexander Viro <viro@math.psu.edu>
2000-11-18 21:01:04 +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
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
Poul-Henning Kamp
9626b608de Separate the struct bio related stuff out of <sys/buf.h> into
<sys/bio.h>.

<sys/bio.h> is now a prerequisite for <sys/buf.h> but it shall
not be made a nested include according to bdes teachings on the
subject of nested includes.

Diskdrivers and similar stuff below specfs::strategy() should no
longer need to include <sys/buf.> unless they need caching of data.

Still a few bogus uses of struct buf to track down.

Repocopy by:    peter
2000-05-05 09:59:14 +00:00
Poul-Henning Kamp
0b441832f3 Convert the vm_pager_strategy() interface to take a struct bio instead of
a struct buf.  Don't try to examine B_ASYNC, it is a layering violation
to do so.  The only current user of this interface is vn(4) which, since
it emulates a disk interface, operates on struct bio already.
2000-05-03 07:47:46 +00:00
Poul-Henning Kamp
e4057dbdb0 Move and staticize the bufchain functions so they become local to the
only piece of code using them.  This will ease a rewrite of them.
2000-05-01 19:38:51 +00:00
Poul-Henning Kamp
8177437d85 Complete the bio/buf divorce for all code below devfs::strategy
Exceptions:
        Vinum untouched.  This means that it cannot be compiled.
        Greg Lehey is on the case.

        CCD not converted yet, casts to struct buf (still safe)

        atapi-cd casts to struct buf to examine B_PHYS
2000-04-15 05:54:02 +00:00
Poul-Henning Kamp
c244d2de43 Move B_ERROR flag to b_ioflags and call it BIO_ERROR.
(Much of this done by script)

Move B_ORDERED flag to b_ioflags and call it BIO_ORDERED.

Move b_pblkno and b_iodone_chain to struct bio while we transition, they
will be obsoleted once bio structs chain/stack.

Add bio_queue field for struct bio aware disksort.

Address a lot of stylistic issues brought up by bde.
2000-04-02 15:24:56 +00:00
Matthew Dillon
25db2c5417 Add necessary spl protection for swapper. The problem was located by
Alfred while testing his SPLASSERT stuff.   This is not a complete fix,
    more protections are probably needed.
2000-03-27 21:33:32 +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
912e4ae9f7 Fix one place which knew that B_WRITE was zero.
Fix a stylistic mistake of mine while here.

Found by:	Stephen Hocking <shocking@prth.pgs.com>
2000-03-22 08:40:13 +00:00
Poul-Henning Kamp
b99c307a21 Rename the existing BUF_STRATEGY() to DEV_STRATEGY()
substitute BUF_WRITE(foo) for VOP_BWRITE(foo->b_vp, foo)

substitute BUF_STRATEGY(foo) for VOP_STRATEGY(foo->b_vp, foo)

This patch is machine generated except for the ccd.c and buf.h parts.
2000-03-20 11:29:10 +00:00
Poul-Henning Kamp
21144e3bf1 Remove B_READ, B_WRITE and B_FREEBUF and replace them with a new
field in struct buf: b_iocmd.  The b_iocmd is enforced to have
exactly one bit set.

B_WRITE was bogusly defined as zero giving rise to obvious coding
mistakes.

Also eliminate the redundant struct buf flag B_CALL, it can just
as efficiently be done by comparing b_iodone to NULL.

Should you get a panic or drop into the debugger, complaining about
"b_iocmd", don't continue.  It is likely to write on your disk
where it should have been reading.

This change is a step in the direction towards a stackable BIO capability.

A lot of this patch were machine generated (Thanks to style(9) compliance!)

Vinum users:  Greg has not had time to test this yet, be careful.
2000-03-20 10:44:49 +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
Peter Wemm
ea3aecf5b4 Fix the swap backed vn case - this was broken by my rev 1.128 to
swap_pager.c and related commits.

Essentially swap_pager.c is backed out to before the changes, but
swapdev_vp is converted into a real vnode with just VOP_STRATEGY().
It no longer abuses specfs vnops and no longer needs a dev_t and
/dev/drum (or /dev/swapdev) for the intermediate layer.

This essentially restores the vnode interface as the interface to the
bottom of the swap pager, and vm_swap.c provides a clean vnode interface.

This will need to be revisited when we swap to files (vnodes) - which
is the other reason for keeping the vnode interface between the swap pager
and the swap devices.

OK'ed by:	dillon
1999-12-28 07:30:55 +00:00
Poul-Henning Kamp
24e7ab7c0b Isolate the swapdev_vp "not quite" vnode in the only source file which
needs it now that /dev/drum is gone.

Reviewed by: eivind, peter
1999-11-22 15:27:09 +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
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
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
Bruce Evans
af647dde33 Use devtoname to print dev_t's instead of casting them to u_long for
misprinting with %lx.

Cast pointers to intptr_t instead of casting them to long.  Cosmetic.
1999-08-23 23:55:03 +00:00
Alan Cox
c52e7044cf Correct an accidental omission of one "vm_page_undirty" replacement
from the previous commit.
1999-08-17 05:56:00 +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
9b21395a95 Remove vm_object::last_read. It is used by the old swap pager, but
not by the new one, i.e., vm/swap_pager.c rev 1.108.

Reviewed by:	dillon@backplane.com
1999-07-16 05:11:37 +00:00
Peter Wemm
b890cb2cbd Kirk missed a required BUF_KERNPROC(). Even though this is a non-async
transfer, the b_iodone hook causes biodone() to release it from interrupt
context.
1999-06-27 22:08:38 +00:00
Kirk McKusick
67812eacd7 Convert buffer locking from using the B_BUSY and B_WANTED flags to using
lockmgr locks. This commit should be functionally equivalent to the old
semantics. That is, all buffer locking is done with LK_EXCLUSIVE
requests. Changes to take advantage of LK_SHARED and LK_RECURSIVE will
be done in future commits.
1999-06-26 02:47:16 +00:00
Poul-Henning Kamp
b0eeea2042 remove b_proc from struct buf, it's (now) unused.
Reviewed by:	dillon, bde
1999-05-06 20:00:34 +00:00
Julian Elischer
a5296b05b4 Submitted by: Matt Dillon <dillon@freebsd.org>
The old VN device broke in -4.x when the definition of B_PAGING
changed. This patch fixes this plus implements additional capabilities.
The new VN device can be backed by a file ( as per normal ), or it can
be directly backed by swap.

Due to dependencies in VM include files  (on opt_xxx options) the new
vn device cannot be a module yet. This will be fixed in a later commit.
This commit delimitted by tags {PRE,POST}_MATT_VNDEV
1999-03-14 09:20:01 +00:00
Matthew Dillon
ad3cce2041 Remove conditional sysctl's
Leave swap_async_max sysctl intact, remove swap_cluster_max sysctl.

Reviewed by:	     Alan Cox <alc@cs.rice.edu>
1999-02-21 08:34:15 +00:00
Matthew Dillon
20d3034f39 Reviewed by: Alan Cox <alc@cs.rice.edu>
Fix problem w/ low-swap/low-memory handling as reported by Bruce Evans.
1999-02-21 08:30:49 +00:00