Commit Graph

79 Commits

Author SHA1 Message Date
Alan Cox
78985e424a Complete the transition from pmap_page_protect() to pmap_remove_write().
Originally, I had adopted sparc64's name, pmap_clear_write(), for the
function that is now pmap_remove_write().  However, this function is more
like pmap_remove_all() than like pmap_clear_modify() or
pmap_clear_reference(), hence, the name change.

The higher-level rationale behind this change is described in
src/sys/amd64/amd64/pmap.c revision 1.567.  The short version is that I'm
trying to clean up and fix our support for execute access.

Reviewed by: marcel@ (ia64)
2006-08-01 19:06:06 +00:00
Alan Cox
3cad40e517 Add pmap_clear_write() to the interface between the virtual memory
system's machine-dependent and machine-independent layers.  Once
pmap_clear_write() is implemented on all of our supported
architectures, I intend to replace all calls to pmap_page_protect() by
calls to pmap_clear_write().  Why?  Both the use and implementation of
pmap_page_protect() in our virtual memory system has subtle errors,
specifically, the management of execute permission is broken on some
architectures.  The "prot" argument to pmap_page_protect() should
behave differently from the "prot" argument to other pmap functions.
Instead of meaning, "give the specified access rights to all of the
physical page's mappings," it means "don't take away the specified
access rights from all of the physical page's mappings, but do take
away the ones that aren't specified."  However, owing to our i386
legacy, i.e., no support for no-execute rights, all but one invocation
of pmap_page_protect() specifies VM_PROT_READ only, when the intent
is, in fact, to remove only write permission.  Consequently, a
faithful implementation of pmap_page_protect(), e.g., ia64, would
remove execute permission as well as write permission.  On the other
hand, some architectures that support execute permission have
basically ignored whether or not VM_PROT_EXECUTE is passed to
pmap_page_protect(), e.g., amd64 and sparc64.  This change represents
the first step in replacing pmap_page_protect() by the less subtle
pmap_clear_write() that is already implemented on amd64, i386, and
sparc64.

Discussed with: grehan@ and marcel@
2006-07-20 17:48:41 +00:00
Stephan Uphoff
2053c12705 Remove mpte optimization from pmap_enter_quick().
There is a race with the current locking scheme and removing
it should have no measurable performance impact.
This fixes page faults leading to panics in pmap_enter_quick_locked()
on amd64/i386.

Reviewed by: alc,jhb,peter,ps
2006-06-15 01:01:06 +00:00
Alan Cox
ce142d9ec0 Introduce the function pmap_enter_object(). It maps a sequence of resident
pages from the same object.  Use it in vm_map_pmap_enter() to reduce the
locking overhead of premapping objects.

Reviewed by: tegge@
2006-06-05 20:35:27 +00:00
Peter Wemm
b9eee07e36 Remove the unused sva and eva arguments from pmap_remove_pages(). 2006-04-03 21:16:10 +00:00
Alan Cox
97a0c226d6 Eliminate pmap_init2(). It's no longer used. 2005-11-20 06:09:49 +00:00
Alan Cox
7a35a21e7b Reimplement the reclamation of PV entries. Specifically, perform
reclamation synchronously from get_pv_entry() instead of
asynchronously as part of the page daemon.  Additionally, limit the
reclamation to inactive pages unless allocation from the PV entry zone
or reclamation from the inactive queue fails.  Previously, reclamation
destroyed mappings to both inactive and active pages.  get_pv_entry()
still, however, wakes up the page daemon when reclamation occurs.  The
reason being that the page daemon may move some pages from the active
queue to the inactive queue, making some new pages available to future
reclamations.

Print the "reclaiming PV entries" message at most once per minute, but
don't stop printing it after the fifth time.  This way, we do not give
the impression that the problem has gone away.

Reviewed by: tegge
2005-11-09 08:19:21 +00:00
Alan Cox
ba8bca610c Pass a value of type vm_prot_t to pmap_enter_quick() so that it determine
whether the mapping should permit execute access.
2005-09-03 18:20:20 +00:00
Alan Cox
1c245ae7d1 Introduce a procedure, pmap_page_init(), that initializes the
vm_page's machine-dependent fields.  Use this function in
vm_pageq_add_new_page() so that the vm_page's machine-dependent and
machine-independent fields are initialized at the same time.

Remove code from pmap_init() for initializing the vm_page's
machine-dependent fields.

Remove stale comments from pmap_init().

Eliminate the Boolean variable pmap_initialized from the alpha, amd64,
i386, and ia64 pmap implementations.  Its use is no longer required
because of the above changes and earlier changes that result in physical
memory that is being mapped at initialization time being mapped without
pv entries.

Tested by: cognet, kensmith, marcel
2005-06-10 03:33:36 +00:00
Warner Losh
60727d8b86 /* -> /*- for license, minor formatting changes 2005-01-07 02:29:27 +00:00
Alan Cox
b14d6acced - pmap_kenter_temporary() is unused by machine-independent code. Therefore,
move its declaration to the machine-dependent header file on those
   machines that use it.  In principle, only i386 should have it.
   Alpha and AMD64 should use their direct virtual-to-physical mapping.
 - Remove pmap_kenter_temporary() from ia64.  It is unused.  Approved
   by: marcel@
2004-04-10 22:41:46 +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
Alan Cox
bdb93eb248 Remove unused arguments from pmap_init(). 2004-04-05 00:37:50 +00:00
Alan Cox
fcffa790e9 Retire pmap_pinit2(). Alpha was the last platform that used it. However,
ever since alpha/alpha/pmap.c revision 1.81 introduced the list allpmaps,
there has been no reason for having this function on Alpha.  Briefly,
when pmap_growkernel() relied upon the list of all processes to find and
update the various pmaps to reflect a growth in the kernel's valid
address space, pmap_init2() served to avoid a race between pmap
initialization and pmap_growkernel().  Specifically, pmap_pinit2() was
responsible for initializing the kernel portions of the pmap and
pmap_pinit2() was called after the process structure contained a pointer
to the new pmap for use by pmap_growkernel().  Thus, an update to the
kernel's address space might be applied to the new pmap unnecessarily,
but an update would never be lost.
2004-03-07 21:06:48 +00:00
Bruce M Simpson
2bc7dd5661 Move pmap_resident_count() from the MD pmap.h to the MI pmap.h.
Add a definition of pmap_wired_count().
Add a definition of vmspace_wired_count().

Reviewed by:	truckman
Discussed with:	peter
2003-10-06 01:47:12 +00:00
Alan Cox
566526a957 Migrate pmap_prefault() into the machine-independent virtual memory layer.
A small helper function pmap_is_prefaultable() is added.  This function
encapsulate the few lines of pmap_prefault() that actually vary from
machine to machine.  Note: pmap_is_prefaultable() and pmap_mincore() have
much in common.  Going forward, it's worth considering their merger.
2003-10-03 22:46:53 +00:00
Alan Cox
b9850eb224 Add a new parameter to pmap_extract_and_hold() that is needed to eliminate
Giant from vmapbuf().

Idea from:	tegge
2003-09-12 07:07:49 +00:00
Alan Cox
ba2157f218 Introduce a new pmap function, pmap_extract_and_hold(). This function
atomically extracts and holds the physical page that is associated with the
given pmap and virtual address.  Such a function is needed to make the
memory mapping optimizations used by, for example, pipes and raw disk I/O
MP-safe.

Reviewed by:	tegge
2003-09-08 02:45:03 +00:00
Alan Cox
1f78f902a8 Background: pmap_object_init_pt() premaps the pages of a object in
order to avoid the overhead of later page faults.  In general, it
implements two cases: one for vnode-backed objects and one for
device-backed objects.  Only the device-backed case is really
machine-dependent, belonging in the pmap.

This commit moves the vnode-backed case into the (relatively) new
function vm_map_pmap_enter().  On amd64 and i386, this commit only
amounts to code rearrangement.  On alpha and ia64, the new machine
independent (MI) implementation of the vnode case is smaller and more
efficient than their pmap-based implementations.  (The MI
implementation takes advantage of the fact that objects in -CURRENT
are ordered collections of pages.)  On sparc64, pmap_object_init_pt()
hadn't (yet) been implemented.
2003-07-03 20:18:02 +00:00
Alan Cox
dca96f1adc - Export pmap_enter_quick() to the MI VM. This will permit the
implementation of a largely MI pmap_object_init_pt() for vnode-backed
   objects.  pmap_enter_quick() is implemented via pmap_enter() on sparc64
   and powerpc.
 - Correct a mismatch between pmap_object_init_pt()'s prototype and its
   various implementations.  (I plan to keep pmap_object_init_pt() as
   the MD hook for device-backed objects on i386 and amd64.)
 - Correct an error in ia64's pmap_enter_quick() and adjust its interface
   to match the other versions.  Discussed with: marcel
2003-06-29 21:20:04 +00:00
Alan Cox
49a2507bd1 Migrate the thread stack management functions from the machine-dependent
to the machine-independent parts of the VM.  At the same time, this
introduces vm object locking for the non-i386 platforms.

Two details:

1. KSTACK_GUARD has been removed in favor of KSTACK_GUARD_PAGES.  The
different machine-dependent implementations used various combinations
of KSTACK_GUARD and KSTACK_GUARD_PAGES.  To disable guard page, set
KSTACK_GUARD_PAGES to 0.

2. Remove the (unnecessary) clearing of PG_ZERO in vm_thread_new.  In
5.x, (but not 4.x,) PG_ZERO can only be set if VM_ALLOC_ZERO is passed
to vm_page_alloc() or vm_page_grab().
2003-06-14 23:23:55 +00:00
Alan Cox
89f4fca265 Move the *_new_altkstack() and *_dispose_altkstack() functions out of the
various pmap implementations into the machine-independent vm.  They were
all identical.
2003-06-14 06:20:25 +00:00
John Baldwin
d8fed0f0f2 - Kill the pv_flags member of the alpha mdpage since it stop being used
in rev 1.61 of pmap.c.
- Now that pmap_page_is_free() is empty and since it is just a hack for
  the Alpha pmap, remove it.
2003-04-10 18:42:06 +00:00
Jake Burkholder
227f9a1c58 - Add vm_paddr_t, a physical address type. This is required for systems
where physical addresses larger than virtual addresses, such as i386s
  with PAE.
- Use this to represent physical addresses in the MI vm system and in the
  i386 pmap code.  This also changes the paddr parameter to d_mmap_t.
- Fix printf formats to handle physical addresses >4G in the i386 memory
  detection code, and due to kvtop returning vm_paddr_t instead of u_long.

Note that this is a name change only; vm_paddr_t is still the same as
vm_offset_t on all currently supported platforms.

Sponsored by:	DARPA, Network Associates Laboratories
Discussed with:	re, phk (cdevsw change)
2003-03-25 00:07:06 +00:00
Jake Burkholder
5501d40bb9 Made the prototypes for pmap_kenter and pmap_kremove MD. These functions
are machine dependent because they are not required to update the tlb when
mappings are added or removed, and doing so is machine dependent.
In addition, an implementation may require that pages mapped with pmap_kenter
have a backing vm_page_t, which is not necessarily true of all physical
pages, and so may choose to pass the vm_page_t to pmap_kenter instead of the
physical address in order to make this requirement clear.
2003-03-16 04:16:03 +00:00
Maxime Henrion
07159f9c56 Cleanup of the d_mmap_t interface.
- Get rid of the useless atop() / pmap_phys_address() detour.  The
  device mmap handlers must now give back the physical address
  without atop()'ing it.
- Don't borrow the physical address of the mapping in the returned
  int.  Now we properly pass a vm_offset_t * and expect it to be
  filled by the mmap handler when the mapping was successful.  The
  mmap handler must now return 0 when successful, any other value
  is considered as an error.  Previously, returning -1 was the only
  way to fail.  This change thus accidentally fixes some devices
  which were bogusly returning errno constants which would have been
  considered as addresses by the device pager.
- Garbage collect the poorly named pmap_phys_address() now that it's
  no longer used.
- Convert all the d_mmap_t consumers to the new API.

I'm still not sure wheter we need a __FreeBSD_version bump for this,
since and we didn't guarantee API/ABI stability until 5.1-RELEASE.

Discussed with:		alc, phk, jake
Reviewed by:		peter
Compile-tested on:	LINT (i386), GENERIC (alpha and sparc64)
Runtime-tested on:	i386
2003-02-25 03:21:22 +00:00
Alan Cox
53b1963649 Move kernel_vm_end's declaration to pmap.h; add a comment regarding the
synchronization of access to kernel_vm_end.
2003-02-15 19:38:23 +00:00
Alan Cox
eea85e9bb6 Move pmap_collect() out of the machine-dependent code, rename it
to reflect its new location, and add page queue and flag locking.

Notes: (1) alpha, i386, and ia64 had identical implementations
of pmap_collect() in terms of machine-independent interfaces;
(2) sparc64 doesn't require it; (3) powerpc had it as a TODO.
2002-11-13 05:39:58 +00:00
Alan Cox
6372d61e3e - Clear the page's PG_WRITEABLE flag in the i386's pmap_changebit()
if we're removing write access from the page's PTEs.
 - Export pmap_remove_all() on alpha, i386, and ia64.  (It's already
   exported on sparc64.)
2002-11-11 05:17:34 +00:00
Scott Long
316ec49abd Some kernel threads try to do significant work, and the default KSTACK_PAGES
doesn't give them enough stack to do much before blowing away the pcb.
This adds MI and MD code to allow the allocation of an alternate kstack
who's size can be speficied when calling kthread_create.  Passing the
value 0 prevents the alternate kstack from being created.  Note that the
ia64 MD code is missing for now, and PowerPC was only partially written
due to the pmap.c being incomplete there.
Though this patch does not modify anything to make use of the alternate
kstack, acpi and usb are good candidates.

Reviewed by:	jake, peter, jhb
2002-10-02 07:44:29 +00:00
Alan Cox
6508a194aa o Retire pmap_pageable(). It's an advisory routine that none
of our platforms implements.
2002-08-25 04:20:05 +00:00
Peter Wemm
a58b3a6878 Add a special page zero entry point intended to be called via the single
threaded VM pagezero kthread outside of Giant.  For some platforms, this
is really easy since it can just use the direct mapped region.  For others,
IPI sending is involved or there are other issues, so grab Giant when
needed.

We still have preemption issues to deal with, but Alan Cox has an
interesting suggestion on how to minimize the problem on x86.

Use Luigi's hack for preserving the (lack of) priority.

Turn the idle zeroing back on since it can now actually do something useful
outside of Giant in many cases.
2002-07-08 04:24:26 +00:00
Peter Wemm
a136efe9b6 Collect all the (now equivalent) pmap_new_proc/pmap_dispose_proc/
pmap_swapin_proc/pmap_swapout_proc functions from the MD pmap code
and use a single equivalent MI version.  There are other cleanups
needed still.

While here, use the UMA zone hooks to keep a cache of preinitialized
proc structures handy, just like the thread system does.  This eliminates
one dependency on 'struct proc' being persistent even after being freed.
There are some comments about things that can be factored out into
ctor/dtor functions if it is worth it.  For now they are mostly just
doing statistics to get a feel of how it is working.
2002-07-07 23:05:27 +00:00
Peter Wemm
db17c6fc07 Tidy up some loose ends.
i386/ia64/alpha - catch up to sparc64/ppc:
- replace pmap_kernel() with refs to kernel_pmap
- change kernel_pmap pointer to (&kernel_pmap_store)
  (this is a speedup since ld can set these at compile/link time)
all platforms (as suggested by jake):
- gc unused pmap_reference
- gc unused pmap_destroy
- gc unused struct pmap.pm_count
(we never used pm_count - we track address space sharing at the vmspace)
2002-04-29 07:43:16 +00:00
Peter Wemm
1a87a0da66 Pass vm_page_t instead of physical addresses to pmap_zero_page[_area]()
and pmap_copy_page().  This gets rid of a couple more physical addresses
in upper layers, with the eventual aim of supporting PAE and dealing with
the physical addressing mostly within pmap.  (We will need either 64 bit
physical addresses or page indexes, possibly both depending on the
circumstances.  Leaving this to pmap itself gives more flexibilitly.)

Reviewed by:	jake
Tested on:	i386, ia64 and (I believe) sparc64. (my alpha was hosed)
2002-04-15 16:00:03 +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
Mike Silbersack
7f3a40933b Fix a horribly suboptimal algorithm in the vm_daemon.
In order to determine what to page out, the vm_daemon checks
reference bits on all pages belonging to all processes.  Unfortunately,
the algorithm used reacted badly with shared pages; each shared page
would be checked once per process sharing it; this caused an O(N^2)
growth of tlb invalidations.  The algorithm has been changed so that
each page will be checked only 16 times.

Prior to this change, a fork/sleepbomb of 1300 processes could cause
the vm_daemon to take over 60 seconds to complete, effectively
freezing the system for that time period.  With this change
in place, the vm_daemon completes in less than a second.  Any system
with hundreds of processes sharing pages should benefit from this change.

Note that the vm_daemon is only run when the system is under extreme
memory pressure.  It is likely that many people with loaded systems saw
no symptoms of this problem until they reached the point where swapping
began.

Special thanks go to dillon, peter, and Chuck Cranor, who helped me
get up to speed with vm internals.

PR:		33542, 20393
Reviewed by:	dillon
MFC after:	1 week
2002-02-27 18:03:02 +00:00
Julian Elischer
b40ce4165d KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after:    ha ha ha ha
2001-09-12 08:38:13 +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
Paul Saab
c794ceb56a Implement write combining for crashdumps. This is useful when
write caching is disabled on both SCSI and IDE disks where large
memory dumps could take up to an hour to complete.

Taking an i386 scsi based system with 512MB of ram and timing (in
seconds) how long it took to complete a dump, the following results
were obtained:

Before:				After:
	WCE           TIME		WCE           TIME
	------------------		------------------
	1	141.820972		1	 15.600111
	0	797.265072		0	 65.480465

Obtained from:	Yahoo!
Reviewed by:	peter
2000-10-17 10:05:49 +00:00
Doug Rabson
1536418a84 Brucify the pmap_enter_temporary() changes. 2000-05-29 19:21:01 +00:00
Doug Rabson
31891bc2bd Add a new pmap entry point, pmap_enter_temporary() to be used during
dumps to create temporary page mappings. This replaces the use of CADDR1
which is fairly x86 specific.

Reviewed by: dillon
2000-05-28 15:49:55 +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
Peter Wemm
c3aac50f28 $Id$ -> $FreeBSD$ 1999-08-28 01:08:13 +00:00
Alan Cox
d4da2dbae6 Fix the following problem:
When creating new processes (or performing exec), the new page
directory is initialized too early.  The kernel might grow before
p_vmspace is initialized for the new process.  Since pmap_growkernel
doesn't yet know about the new page directory, it isn't updated, and
subsequent use causes a failure.

The fix is (1) to clear p_vmspace early, to stop pmap_growkernel
from stomping on memory, and (2) to defer part of the initialization
of new page directories until p_vmspace is initialized.

PR:		kern/12378
Submitted by:	tegge
Reviewed by:	dfr
1999-07-21 18:02:27 +00:00
Dmitrij Tejblum
11a9f83f80 Make pmap_collect() an official pmap interface. 1999-04-23 20:29:58 +00:00