Commit Graph

342 Commits

Author SHA1 Message Date
Alexander Motin
97b53e3634 Switch the GENERIC kernels for all architectures to the new CAM-based ATA
stack. It means that all legacy ATA drivers are disabled and replaced by
respective CAM drivers. If you are using ATA device names in /etc/fstab or
other places, make sure to update them respectively (adX -> adaY,
acdX -> cdY, afdX -> daY, astX -> saY, where 'Y's are the sequential
numbers for each type in order of detection, unless configured otherwise
with tunables, see cam(4)).

ataraid(4) functionality is now supported by the RAID GEOM class.
To use it you can load geom_raid kernel module and use graid(8) tool
for management. Instead of /dev/arX device names, use /dev/raid/rX.
2011-04-24 08:58:58 +00:00
Marius Strobl
740ba39a51 Correct spelling in comments.
Submitted by:	brucec
2011-04-22 12:42:41 +00:00
Marius Strobl
e128764faa MF sparc64: r181701 (partial), r182020 (partial), r182730 (partial), r216628,
r216801

- cosmetic changes and style fixes
- Trick GAS/GCC into compiling access to TICK/(S)TICK_COMPARE independently
  of the selected instruction set. Moreover, sun4v doesn't need the WAR for
  BlackBird CPUs.
- Rename the "xor" parameter to "xorval" as the former is a reserved keyword
  in C++.
2011-04-22 12:39:48 +00:00
Marius Strobl
3a8a826af3 Remove the advertising clause from the UCB license according to the
July 22, 1999 addendum.
2011-03-13 13:42:43 +00:00
Marius Strobl
273fb3dc7c Sync licenses and the corresponding RCS IDs with NetBSD, mainly switching
the licenses of Matthew R. Green and the TNF to 2-clause.

Obtained from:	NetBSD
2011-03-12 14:33:32 +00:00
Matthew D Fleming
c77715ef6c Mostly revert r219468, as I had misremembered the C standard regarding
the size of an extern array.

Keep one change from strncpy to strlcpy.
2011-03-11 18:56:55 +00:00
Matthew D Fleming
cd67ac41ae Use MAXPATHLEN rather than the size of an extern array when copying the
kernel name.  Also consistenly use strlcpy().

Suggested by:	Warner Losh
2011-03-10 22:56:00 +00:00
Julian Elischer
a8066a9d3b Add a small change to the comment in the GENRIC config files that include udbp
Submitted by:	Chris Forgron, cforgeron at acsi dot ca
MFC after:	1 week
2011-03-09 17:15:11 +00:00
Alan Cox
e6ffa21488 Remove pmap fields that are either unused or not fully implemented.
Discussed with:	kib
2011-02-17 15:36:29 +00:00
Matthew D Fleming
08b163fa51 Put the general logic for being a CPU hog into a new function
should_yield().  Use this in various places.  Encapsulate the common
case of check-and-yield into a new function maybe_yield().

Change several checks for a magic number of iterations to use
should_yield() instead.

MFC after:	1 week
2011-02-02 16:35:10 +00:00
Sergey Kandaurov
4053b05b91 Make MSGBUF_SIZE kernel option a loader tunable kern.msgbufsize.
Submitted by:	perryh pluto.rain.com (previous version)
Reviewed by:	jhb
Approved by:	kib (mentor)
Tested by:	universe
2011-01-21 10:26:26 +00:00
Jung-uk Kim
2fea643112 Add reader/writer lock around mem_range_attr_get() and mem_range_attr_set().
Compile sys/dev/mem/memutil.c for all supported platforms and remove now
unnecessary dev_mem_md_init().  Consistently define mem_range_softc from
mem.c for all platforms.  Add missing #include guards for machine/memdev.h
and sys/memrange.h.  Clean up some nearby style(9) nits.

MFC after:	1 month
2011-01-17 22:58:28 +00:00
John Baldwin
58ccf5b41c Remove unneeded includes of <sys/linker_set.h>. Other headers that use
it internally contain nested includes.

Reviewed by:	bde
2011-01-11 13:59:06 +00:00
Konstantin Belousov
50a57dfbec Move repeated MAXSLP definition from machine/vmparam.h to sys/vmmeter.h.
Update the outdated comments describing MAXSLP and the process
selection algorithm for swap out.

Comments wording and reviewed by:	alc
2011-01-09 12:50:44 +00:00
David Schultz
633bd99821 Fix the value for DECIMAL_DIG on UltraSparcs. The previous value of
35 wasn't quite big enough to ensure correct rounding for very-close-
to-halfway cases.
2011-01-09 06:05:48 +00:00
Tijl Coosemans
a56e818f29 On mixed 32/64 bit architectures (mips, powerpc) use __LP64__ rather than
architecture macros (__mips_n64, __powerpc64__) when 64 bit types (and
corresponding macros) are different from 32 bit. [1]

Correct the type of INT64_MIN, INT64_MAX and UINT64_MAX.

Define (U)INTMAX_C as an alias for (U)INT64_C matching the type definition
for (u)intmax_t. Do this on all architectures for consistency.

Suggested by:	bde [1]
Approved by:	kib (mentor)
2011-01-08 12:43:05 +00:00
Tijl Coosemans
9858863cd4 Fix types of some values in machine/_limits.h.
On some architectures UCHAR_MAX and USHRT_MAX had type unsigned int.
However, lacking integer suffixes for types smaller than int, their type
should correspond to that of an object of type unsigned char (or short)
when used in an expression with objects of type int. In that case unsigned
char (short) are promoted to int (i.e. signed) so the type of UCHAR_MAX and
USHRT_MAX should also be int.

Where MIN/MAX constants implicitly have the correct type the suffix has
been removed.

While here, correct some comments.

Reviewed by:	bde
Approved by:	kib (mentor)
2011-01-08 11:13:34 +00:00
Konstantin Belousov
39198f15ee Add AT_STACKPROT elf aux vector. Will be used to inform rtld about the
initial stack protection set by the kernel image activator.
2011-01-07 14:22:34 +00:00
Rebecca Cran
c90f7d9b44 Revert r216134. This checkin broke platforms where bus_space are macros:
they need to be a single statement, and do { } while (0) doesn't work in this
situation so revert until a solution can be devised.
2010-12-03 07:09:23 +00:00
Rebecca Cran
15b4888a24 Disallow passing in a count of zero bytes to the bus_space(9) functions.
Passing a count of zero on i386 and amd64 for [I386|AMD64]_BUS_SPACE_MEM
causes a crash/hang since the 'loop' instruction decrements the counter
before checking if it's zero.

PR:	kern/80980
Discussed with:	jhb
2010-12-02 22:19:30 +00:00
John Baldwin
dffa73fb38 Fix a few more places to use cpumask_t rather than 'u_int'. These are
just cosmetic.
2010-11-11 16:06:47 +00:00
John Baldwin
961135ead8 - Remove <machine/mutex.h>. Most of the headers were empty, and the
contents of the ones that were not empty were stale and unused.
- Now that <machine/mutex.h> no longer exists, there is no need to allow it
  to override various helper macros in <sys/mutex.h>.
- Rename various helper macros for low-level operations on mutexes to live
  in the _mtx_* or __mtx_* namespaces.  While here, change the names to more
  closely match the real API functions they are backing.
- Drop support for including <sys/mutex.h> in assembly source files.

Suggested by:	bde (1, 2)
2010-11-09 20:46:41 +00:00
John Baldwin
0108cce0a4 Adjust the order of operations in spinlock_enter() and spinlock_exit() to
work properly with single-stepping in a kernel debugger.  Specifically,
these routines have always disabled interrupts before increasing the nesting
count and restored the prior state of interrupts after decreasing the nesting
count to avoid problems with a nested interrupt not disabling interrupts
when acquiring a spin lock.  However, trap interrupts for single-stepping
can still occur even when interrupts are disabled.  Now the saved state of
interrupts is not saved in the thread until after interrupts have been
disabled and the nesting count has been increased.  Similarly, the saved
state from the thread cannot be read once the nesting count has been
decreased to zero.  To fix this, use temporary variables to store interrupt
state and shuffle it between the thread's MD area and the appropriate
registers.

In cooperation with:	bde
MFC after:     1 month
2010-11-05 13:42:58 +00:00
Marius Strobl
ba76c33501 Just use the sparc64 version of this header rather than duplicating it. 2010-10-08 14:50:58 +00:00
David Xu
315490e031 Follow r213098, kernel POSIX semaphore module is no longer
needed.
2010-09-26 01:41:53 +00:00
Marius Strobl
4539e94b61 Sync with other platforms:
- make dflt_lock() always panic,
- add kludge to use contigmalloc() when the alignment is larger than the size
  and print a diagnostic when we didn't satisfy the alignment.
2010-09-15 17:11:15 +00:00
Marius Strobl
4c206df38f Remove a KASSERT which will also trigger for perfectly valid combinations
of small maxsize and "large" (including BUS_SPACE_UNRESTRICTED) nsegments
parameters. Generally using a presz of 0 (which indeed might indicate the
use of bogus parameters for DMA tag creation) is not fatal, it just means
that no additional DVMA space will be preallocated.
2010-09-14 20:31:09 +00:00
Alexander Motin
a157e42516 Refactor timer management code with priority to one-shot operation mode.
The main goal of this is to generate timer interrupts only when there is
some work to do. When CPU is busy interrupts are generating at full rate
of hz + stathz to fullfill scheduler and timekeeping requirements. But
when CPU is idle, only minimum set of interrupts (down to 8 interrupts per
second per CPU now), needed to handle scheduled callouts is executed.
This allows significantly increase idle CPU sleep time, increasing effect
of static power-saving technologies. Also it should reduce host CPU load
on virtualized systems, when guest system is idle.

There is set of tunables, also available as writable sysctls, allowing to
control wanted event timer subsystem behavior:
  kern.eventtimer.timer - allows to choose event timer hardware to use.
On x86 there is up to 4 different kinds of timers. Depending on whether
chosen timer is per-CPU, behavior of other options slightly differs.
  kern.eventtimer.periodic - allows to choose periodic and one-shot
operation mode. In periodic mode, current timer hardware taken as the only
source of time for time events. This mode is quite alike to previous kernel
behavior. One-shot mode instead uses currently selected time counter
hardware to schedule all needed events one by one and program timer to
generate interrupt exactly in specified time. Default value depends of
chosen timer capabilities, but one-shot mode is preferred, until other is
forced by user or hardware.
  kern.eventtimer.singlemul - in periodic mode specifies how much times
higher timer frequency should be, to not strictly alias hardclock() and
statclock() events. Default values are 2 and 4, but could be reduced to 1
if extra interrupts are unwanted.
  kern.eventtimer.idletick - makes each CPU to receive every timer interrupt
independently of whether they busy or not. By default this options is
disabled. If chosen timer is per-CPU and runs in periodic mode, this option
has no effect - all interrupts are generating.

As soon as this patch modifies cpu_idle() on some platforms, I have also
refactored one on x86. Now it makes use of MONITOR/MWAIT instrunctions
(if supported) under high sleep/wakeup rate, as fast alternative to other
methods. It allows SMP scheduler to wake up sleeping CPUs much faster
without using IPI, significantly increasing performance on some highly
task-switching loads.

Tested by:	many (on i386, amd64, sparc64 and powerc)
H/W donated by:	Gheorghe Ardelean
Sponsored by:	iXsystems, Inc.
2010-09-13 07:25:35 +00:00
Andriy Gapon
3d844eddb7 bus_add_child: change type of order parameter to u_int
This reflects actual type used to store and compare child device orders.
Change is mostly done via a Coccinelle (soon to be devel/coccinelle)
semantic patch.
Verified by LINT+modules kernel builds.

Followup to:	r212213
MFC after:	10 days
2010-09-10 11:19:03 +00:00
John Baldwin
8c7a92bd4a Remove unused KTRACE includes. 2010-08-19 16:41:27 +00:00
Konstantin Belousov
ee235befcb Supply some useful information to the started image using ELF aux vectors.
In particular, provide pagesize and pagesizes array, the canary value
for SSP use, number of host CPUs and osreldate.

Tested by:	marius (sparc64)
MFC after:	1 month
2010-08-17 08:55:45 +00:00
John Baldwin
60c7b36b7a Update various places that store or manipulate CPU masks to use cpumask_t
instead of int or u_int.  Since cpumask_t is currently u_int on all
platforms this should just be a cosmetic change.
2010-08-11 23:22:53 +00:00
John Baldwin
d9d8d1449d Add a new ipi_cpu() function to the MI IPI API that can be used to send an
IPI to a specific CPU by its cpuid.  Replace calls to ipi_selected() that
constructed a mask for a single CPU with calls to ipi_cpu() instead.  This
will matter more in the future when we transition from cpumask_t to
cpuset_t for CPU masks in which case building a CPU mask is more expensive.

Submitted by:	peter, sbruno
Reviewed by:	rookie
Obtained from:	Yahoo! (x86)
MFC after:	1 month
2010-08-06 15:36:59 +00:00
Alexander Motin
6c8dd81fa9 Adapt sparc64 and sun4v timer code for the new event timers infrastructure.
Reviewed by:	marius@
2010-07-29 12:08:46 +00:00
Matthew D Fleming
d7854da193 Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma
zones for each malloc bucket size.  The purpose is to isolate
different malloc types into hash classes, so that any buffer overruns
or use-after-free will usually only affect memory from malloc types in
that hash class.  This is purely a debugging tool; by varying the hash
function and tracking which hash class was corrupted, the intersection
of the hash classes from each instance will point to a single malloc
type that is being misused.  At this point inspection or memguard(9)
can be used to catch the offending code.

Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files.
The suggestion to have this on by default came from Kostik Belousov on
-arch.

This code is based on work by Ron Steinke at Isilon Systems.

Reviewed by:    -arch (mostly silence)
Reviewed by:    zml
Approved by:    zml (mentor)
2010-07-28 15:36:12 +00:00
John Baldwin
a3870a1826 Very rough first cut at NUMA support for the physical page allocator. For
now it uses a very dumb first-touch allocation policy.  This will change in
the future.
- Each architecture indicates the maximum number of supported memory domains
  via a new VM_NDOMAIN parameter in <machine/vmparam.h>.
- Each cpu now has a PCPU_GET(domain) member to indicate the memory domain
  a CPU belongs to.  Domain values are dense and numbered from 0.
- When a platform supports multiple domains, the default freelist
  (VM_FREELIST_DEFAULT) is split up into N freelists, one for each domain.
  The MD code is required to populate an array of mem_affinity structures.
  Each entry in the array defines a range of memory (start and end) and a
  domain for the range.  Multiple entries may be present for a single
  domain.  The list is terminated by an entry where all fields are zero.
  This array of structures is used to split up phys_avail[] regions that
  fall in VM_FREELIST_DEFAULT into per-domain freelists.
- Each memory domain has a separate lookup-array of freelists that is
  used when fulfulling a physical memory allocation.  Right now the
  per-domain freelists are listed in a round-robin order for each domain.
  In the future a table such as the ACPI SLIT table may be used to order
  the per-domain lookup lists based on the penalty for each memory domain
  relative to a specific domain.  The lookup lists may be examined via a
  new vm.phys.lookup_lists sysctl.
- The first-touch policy is implemented by using PCPU_GET(domain) to
  pick a lookup list when allocating memory.

Reviewed by:	alc
2010-07-27 20:33:50 +00:00
Attilio Rao
651aa2d896 KTR_CTx are long time aliased by existing classes so they can't serve
their purpose anymore. Axe them out.

Sponsored by:	Sandvine Incorporated
Discussed with:	jhb, emaste
Possible MFC:	TBD
2010-07-21 10:05:07 +00:00
Alexander Motin
a448e0d827 Allocate proper ammount of memory for interrupt names on sparc64 and
sun4v, same as done on other architectures. This removes garbage from
`vmstat -ia` output.

Reviewed by:	marius@
2010-07-16 22:09:29 +00:00
Nathan Whitehorn
8d6a514f4a Add a missing architecture declaration to the machine specification
for sun4v.
2010-07-13 01:24:02 +00:00
John Baldwin
fc0de8f0b6 Move prototypes for kern_sigtimedwait() and kern_sigprocmask() to
<sys/syscallsubr.h> where all other kern_<syscall> prototypes live.
2010-06-30 18:03:42 +00:00
Nathan Whitehorn
6bb9bbbfd2 Missed change to sun4v while adding iparent lookup to the OFW interrupt
map interface.
2010-06-18 16:29:03 +00:00
Alan Cox
9124d0d6a3 Relax one of the new assertions in pmap_enter() a little. Specifically,
allow pmap_enter() to be performed on an unmanaged page that doesn't have
VPO_BUSY set.  Having VPO_BUSY set really only matters for managed pages.
(See, for example, pmap_remove_write().)
2010-06-11 15:49:39 +00:00
Alan Cox
ce18658792 Reduce the scope of the page queues lock and the number of
PG_REFERENCED changes in vm_pageout_object_deactivate_pages().
Simplify this function's inner loop using TAILQ_FOREACH(), and shorten
some of its overly long lines.  Update a stale comment.

Assert that PG_REFERENCED may be cleared only if the object containing
the page is locked.  Add a comment documenting this.

Assert that a caller to vm_page_requeue() holds the page queues lock,
and assert that the page is on a page queue.

Push down the page queues lock into pmap_ts_referenced() and
pmap_page_exists_quick().  (As of now, there are no longer any pmap
functions that expect to be called with the page queues lock held.)

Neither pmap_ts_referenced() nor pmap_page_exists_quick() should ever
be passed an unmanaged page.  Assert this rather than returning "0"
and "FALSE" respectively.

ARM:

Simplify pmap_page_exists_quick() by switching to TAILQ_FOREACH().

Push down the page queues lock inside of pmap_clearbit(), simplifying
pmap_clear_modify(), pmap_clear_reference(), and pmap_remove_write().
Additionally, this allows for avoiding the acquisition of the page
queues lock in some cases.

PowerPC/AIM:

moea*_page_exits_quick() and moea*_page_wired_mappings() will never be
called before pmap initialization is complete.  Therefore, the check
for moea_initialized can be eliminated.

Push down the page queues lock inside of moea*_clear_bit(),
simplifying moea*_clear_modify() and moea*_clear_reference().

The last parameter to moea*_clear_bit() is never used.  Eliminate it.

PowerPC/BookE:

Simplify mmu_booke_page_exists_quick()'s control flow.

Reviewed by:	kib@
2010-06-10 16:56:35 +00:00
Alan Cox
6039d0b777 Merge portions of r208645 and supporting code from the i386 pmap:
When I pushed down the page queues lock into pmap_is_modified(), I created
  an ordering dependence: A pmap operation that clears PG_WRITEABLE and calls
  vm_page_dirty() must perform the call first.  Otherwise, pmap_is_modified()
  could return FALSE without acquiring the page queues lock because the page
  is not (currently) writeable, and the caller to pmap_is_modified() might
  believe that the page's dirty field is clear because it has not seen the
  effect of the vm_page_dirty() call.

  When I pushed down the page queues lock into pmap_is_modified(), I
  overlooked one place where this ordering dependence is violated:
  pmap_enter().  In a rare situation pmap_enter() can be called to replace a
  dirty mapping to one page with a mapping to another page.  (I say rare
  because replacements generally occur as a result of a copy-on-write fault,
  and so the old page is not dirty.)  This change delays clearing PG_WRITEABLE
  until after vm_page_dirty() has been called.

  Fixing the ordering dependency also makes it easy to introduce a small
  optimization: When pmap_enter() used to replace a mapping to one page with a
  mapping to another page, it freed the pv entry for the first mapping and
  later called the pv entry allocator for the new mapping.  Now, pmap_enter()
  attempts to recycle the old pv entry, saving two calls to the pv entry
  allocator.

  There is no point in setting PG_WRITEABLE on unmanaged pages, so don't.
2010-06-01 05:18:48 +00:00
Alan Cox
b2830a9649 Eliminate a stale comment. 2010-05-31 06:06:10 +00:00
Alan Cox
c68c71f9b8 Simplify the inner loop of get_pv_entry(): While iterating over the page's
pv list, there is no point in checking whether or not the pv list is empty,
wait instead until the loop completes.
2010-05-30 20:31:12 +00:00
Alan Cox
c46b90e90a Push down page queues lock acquisition in pmap_enter_object() and
pmap_is_referenced().  Eliminate the corresponding page queues lock
acquisitions from vm_map_pmap_enter() and mincore(), respectively.  In
mincore(), this allows some additional cases to complete without ever
acquiring the page queues lock.

Assert that the page is managed in pmap_is_referenced().

On powerpc/aim, push down the page queues lock acquisition from
moea*_is_modified() and moea*_is_referenced() into moea*_query_bit().
Again, this will allow some additional cases to complete without ever
acquiring the page queues lock.

Reorder a few statements in vm_page_dontneed() so that a race can't lead
to an old reference persisting.  This scenario is described in detail by a
comment.

Correct a spelling error in vm_page_dontneed().

Assert that the object is locked in vm_page_clear_dirty(), and restrict the
page queues lock assertion to just those cases in which the page is
currently writeable.

Add object locking to vnode_pager_generic_putpages().  This was the one
and only place where vm_page_clear_dirty() was being called without the
object being locked.

Eliminate an unnecessary vm_page_lock() around vnode_pager_setsize()'s call
to vm_page_clear_dirty().

Change vnode_pager_generic_putpages() to the modern-style of function
definition.  Also, change the name of one of the parameters to follow
virtual memory system naming conventions.

Reviewed by:	kib
2010-05-26 18:00:44 +00:00
Alan Cox
567e51e18c Roughly half of a typical pmap_mincore() implementation is machine-
independent code.  Move this code into mincore(), and eliminate the
page queues lock from pmap_mincore().

Push down the page queues lock into pmap_clear_modify(),
pmap_clear_reference(), and pmap_is_modified().  Assert that these
functions are never passed an unmanaged page.

Eliminate an inaccurate comment from powerpc/powerpc/mmu_if.m:
Contrary to what the comment says, pmap_mincore() is not simply an
optimization.  Without a complete pmap_mincore() implementation,
mincore() cannot return either MINCORE_MODIFIED or MINCORE_REFERENCED
because only the pmap can provide this information.

Eliminate the page queues lock from vfs_setdirty_locked_object(),
vm_pageout_clean(), vm_object_page_collect_flush(), and
vm_object_page_clean().  Generally speaking, these are all accesses
to the page's dirty field, which are synchronized by the containing
vm object's lock.

Reduce the scope of the page queues lock in vm_object_madvise() and
vm_page_dontneed().

Reviewed by:	kib (an earlier version)
2010-05-24 14:26:57 +00:00
Konstantin Belousov
afe1a68827 Reorganize syscall entry and leave handling.
Extend struct sysvec with three new elements:
sv_fetch_syscall_args - the method to fetch syscall arguments from
  usermode into struct syscall_args. The structure is machine-depended
  (this might be reconsidered after all architectures are converted).
sv_set_syscall_retval - the method to set a return value for usermode
  from the syscall. It is a generalization of
  cpu_set_syscall_retval(9) to allow ABIs to override the way to set a
  return value.
sv_syscallnames - the table of syscall names.

Use sv_set_syscall_retval in kern_sigsuspend() instead of hardcoding
the call to cpu_set_syscall_retval().

The new functions syscallenter(9) and syscallret(9) are provided that
use sv_*syscall* pointers and contain the common repeated code from
the syscall() implementations for the architecture-specific syscall
trap handlers.

Syscallenter() fetches arguments, calls syscall implementation from
ABI sysent table, and set up return frame. The end of syscall
bookkeeping is done by syscallret().

Take advantage of single place for MI syscall handling code and
implement ptrace_lwpinfo pl_flags PL_FLAG_SCE, PL_FLAG_SCX and
PL_FLAG_EXEC. The SCE and SCX flags notify the debugger that the
thread is stopped at syscall entry or return point respectively.  The
EXEC flag augments SCX and notifies debugger that the process address
space was changed by one of exec(2)-family syscalls.

The i386, amd64, sparc64, sun4v, powerpc and ia64 syscall()s are
changed to use syscallenter()/syscallret(). MIPS and arm are not
converted and use the mostly unchanged syscall() implementation.

Reviewed by:	jhb, marcel, marius, nwhitehorn, stas
Tested by:	marcel (ia64), marius (sparc64), nwhitehorn (powerpc),
	stas (mips)
MFC after:	1 month
2010-05-23 18:32:02 +00:00
Alan Cox
9ab6032f73 On entry to pmap_enter(), assert that the page is busy. While I'm
here, make the style of assertion used by pmap_enter() consistent
across all architectures.

On entry to pmap_remove_write(), assert that the page is neither
unmanaged nor fictitious, since we cannot remove write access to
either kind of page.

With the push down of the page queues lock, pmap_remove_write() cannot
condition its behavior on the state of the PG_WRITEABLE flag if the
page is busy.  Assert that the object containing the page is locked.
This allows us to know that the page will neither become busy nor will
PG_WRITEABLE be set on it while pmap_remove_write() is running.

Correct a long-standing bug in vm_page_cowsetup().  We cannot possibly
do copy-on-write-based zero-copy transmit on unmanaged or fictitious
pages, so don't even try.  Previously, the call to pmap_remove_write()
would have failed silently.
2010-05-16 23:45:10 +00:00