Commit Graph

1949 Commits

Author SHA1 Message Date
Alan Cox
e4b8a2fc5a Eliminate a stale comment. It describes another use case for the pmap in
Mach that doesn't exist in FreeBSD.
2012-09-28 05:30:59 +00:00
Attilio Rao
324e57150d userret() already checks for td_locks when INVARIANTS is enabled, so
there is no need to check if Giant is acquired after it.

Reviewed by:	kib
MFC after:	1 week
2012-09-08 18:27:11 +00:00
Marcel Moolenaar
5435dbc676 Use pmap_kextract(x) rather than pmap_extract(kernel_pmap, x). The
former knows about all the special mappings, like PBVM. The kernel
text and data are in the PBVM.
2012-08-18 23:28:34 +00:00
Marcel Moolenaar
85e6303e05 Remove support for SKI: HP's Itanium simulator. It's pretty much not
used, serves very little value given that FreeBSD runs on real H/W
for a long time.
Note that SKI is open-source (see http://ski.sourceforge.net), so
if there's interest and value again, then this code can be revived.

Discussed with: jhb
2012-08-18 22:59:06 +00:00
John Baldwin
9ea9af5281 Add locking for sscdisk(4) and mark it MPSAFE. Since this driver just
makes calls out to the emulator, the locking is fairly simple.  A global
mutex protects the list of ssc disks, and each ssc disk has a mutex
to protect it's bioq.

Approved by:	marcel
2012-08-16 17:17:08 +00:00
Konstantin Belousov
1c771f9222 After the PHYS_TO_VM_PAGE() function was de-inlined, the main reason
to pull vm_param.h was removed.  Other big dependency of vm_page.h on
vm_param.h are PA_LOCK* definitions, which are only needed for
in-kernel code, because modules use KBI-safe functions to lock the
pages.

Stop including vm_param.h into vm_page.h. Include vm_param.h
explicitely for the kernel code which needs it.

Suggested and reviewed by:	alc
MFC after:    2 weeks
2012-08-05 14:11:42 +00:00
Marcel Moolenaar
0aa31a3393 Move PCPU initialization to a new function called cpu_pcpu_setup().
This makes it easier to add additional CPU or platform information
to the per-CPU structure without duplicated code.
2012-07-08 18:00:22 +00:00
Marcel Moolenaar
6d5cb58b5f Unleash the APs at SI_SUB_KICK_SCHEDULER so that we have them all
up and running to service interrupts. This is especially important
when the firmware has bound interrupts to CPUs, like for the SGI
Altix 350. We wake up APs at SI_SUB_CPU time and they sit and spin
until we unleash them, so there's nothing fundamentally different
from a MD perspective.
2012-07-08 17:43:25 +00:00
Marcel Moolenaar
373ca4ed22 Implement ia64_physmem_alloc() and use it consistently to get memory
before VM has been initialized. This includes:
1.  Replacing pmap_steal_memory(),
2.  Replace the handcrafted logic to allocate a naturally aligned VHPT,
3.  Properly allocate the DPCPU for the BSP.

Ad 3: Appending the DPCPU to kernend worked as long as we wouldn't
      cross into the next PBVM page. If we were to cross into the next
      page, then there wouldn't be a PTE entry on the page table for it
      and we would end up with a MCA following a page fault. As such,
      this commit fixes MCAs occasionally seen.
2012-07-07 05:17:43 +00:00
Marcel Moolenaar
662d34aff2 Hide the creation of phys_avail behind an API to make it easier to do it
correctly. We now iterate the EFI memory descriptors once and collect all
the information in a single pass. This includes:
1.  The I/O port base address,
2.  The PAL memory region. Have the physmem API track this.
3.  Memory descriptors of memory we can't use, like bad memory, runtime
    services code & data, etc. Have the physmem API track these.
4.  memory descriptors of memory we can use or re-use, such as free
    memory, boot time services code & data, loader code & data, etc.
    These are added by the physmem API.

Since the PBVM page table and pages are in memory described as loader
data, inform the physmem API of chunks that need to be delated from the
available physical memory.

While here, remove Maxmem and replace it with the better named paddr_max.
Maxmem was defined as physmem, which is generally wrong. Now, paddr_max
is properly defined as the largesty physical address.

The upshot of all this is that:
1.  We properly determine realmem.
2.  We maximize physmem by re-using memory where possible.
3.  We remove complexity from ia64_init() in machdep.c.
4.  Remove confusion about realmem, physmem & Maxmem.

The new ia64_physmem_alloc() is to replace pmap_steal_memory() in pmap.c,
as well as replace the handcrafted allocation of the VHPT for the BSP in
pmap_bootstrap() in pmap.c. This is step 2 and addresses the manipulation
of phys_avail after it is being created.
2012-07-07 00:25:17 +00:00
Andrew Turner
74dc547e24 Make the wchar_t type machine dependent.
This is required for ARM EABI. Section 7.1.1 of the Procedure Call for the
ARM Architecture (AAPCS) defines wchar_t as either an unsigned int or an
unsigned short with the former preferred.

Because of this requirement we need to move the definition of __wchar_t to
a machine dependent header. It also cleans up the macros defining the limits
of wchar_t by defining __WCHAR_MIN and __WCHAR_MAX in the same machine
dependent header then using them to define WCHAR_MIN and WCHAR_MAX
respectively.

Discussed with:	bde
2012-06-24 04:15:58 +00:00
Konstantin Belousov
aea810386d Implement mechanism to export some kernel timekeeping data to
usermode, using shared page.  The structures and functions have vdso
prefix, to indicate the intended location of the code in some future.

The versioned per-algorithm data is exported in the format of struct
vdso_timehands, which mostly repeats the content of in-kernel struct
timehands. Usermode reading of the structure can be lockless.
Compatibility export for 32bit processes on 64bit host is also
provided. Kernel also provides usermode with indication about
currently used timecounter, so that libc can fall back to syscall if
configured timecounter is unknown to usermode code.

The shared data updates are initiated both from the tc_windup(), where
a fast task is queued to do the update, and from sysctl handlers which
change timecounter. A manual override switch
kern.timecounter.fast_gettime allows to turn off the mechanism.

Only x86 architectures export the real algorithm data, and there, only
for tsc timecounter. HPET counters page could be exported as well, but
I prefer to not further glue the kernel and libc ABI there until
proper vdso-based solution is developed.

Minimal stubs neccessary for non-x86 architectures to still compile
are provided.

Discussed with:	bde
Reviewed by:	jhb
Tested by:	flo
MFC after:	1 month
2012-06-22 07:06:40 +00:00
Konstantin Belousov
232aa31fb9 Reserve AT_TIMEKEEP auxv entry for providing usermode the pointer to
timekeeping information.

MFC after:  1 week
2012-06-22 06:38:31 +00:00
Alan Cox
6031c68de4 The page flag PGA_WRITEABLE is set and cleared exclusively by the pmap
layer, but it is read directly by the MI VM layer.  This change introduces
pmap_page_is_write_mapped() in order to completely encapsulate all direct
access to PGA_WRITEABLE in the pmap layer.

Aesthetics aside, I am making this change because amd64 will likely begin
using an alternative method to track write mappings, and having
pmap_page_is_write_mapped() in place allows me to make such a change
without further modification to the MI VM layer.

As an added bonus, tidy up some nearby comments concerning page flags.

Reviewed by:	kib
MFC after:	6 weeks
2012-06-16 18:56:19 +00:00
Jung-uk Kim
d3638dc4de Improve style(9) in the previous commit. 2012-06-01 17:07:52 +00:00
Mitsuru IWASAKI
f0a101b7e2 Call AcpiLeaveSleepStatePrep() in interrupt disabled context
(described in ACPICA source code).

- Move intr_disable() and intr_restore() from acpi_wakeup.c to acpi.c
  and call AcpiLeaveSleepStatePrep() in interrupt disabled context.
- Add acpi_wakeup_machdep() to execute wakeup MD procedures and call
  it twice in interrupt disabled/enabled context (ia64 version is
  just dummy).
- Rename wakeup_cpus variable in acpi_sleep_machdep() to suspcpus in
  order to be shared by acpi_sleep_machdep() and acpi_wakeup_machdep().
- Move identity mapping related code to acpi_install_wakeup_handler()
  (i386 version) for preparation of x86/acpica/acpi_wakeup.c
  (MFC candidate).

Reviewed by:	jkim@
MFC after:	2 days
2012-06-01 15:26:32 +00:00
Alan Cox
2865094134 pmap_alloc_vhpt() doesn't need the pages that it allocates to be mapped
into the kernel map, so vm_page_alloc_contig() can be used in place of
contigmalloc().

Reviewed by:	marcel
2012-06-01 03:56:12 +00:00
Bjoern A. Zeeb
920b965865 MFp4 bz_ipv6_fast:
in_cksum.h required ip.h to be included for struct ip.  To be
  able to use some general checksum functions like in_addword()
  in a non-IPv4 context, limit the (also exported to user space)
  IPv4 specific functions to the times, when the ip.h header is
  present and IPVERSION is defined (to 4).

  We should consider more general checksum (updating) functions
  to also allow easier incremental checksum updates in the L3/4
  stack and firewalls, as well as ponder further requirements by
  certain NIC drivers needing slightly different pseudo values
  in offloading cases.  Thinking in terms of a better "library".

  Sponsored by:	The FreeBSD Foundation
  Sponsored by:	iXsystems

Reviewed by:	gnn (as part of the whole)
MFC After:	3 days
2012-05-24 22:00:48 +00:00
Marcel Moolenaar
a48b6a8585 Don't assume we have legacy PICs (i.e. 8259A in cascade) at the legacy
I/O port addresses. Even if we do, this is hardly the place to mask
interrupts. It's not clear that this was at all needed. The code came
with CVS revision 1.2 of nexus.c when interrupt support was first added.
What is known is that ia64 has always been designed around the IOSAPIC,
and that doing I/O like this prevents Altix from booting.
2012-05-04 23:16:29 +00:00
Dimitry Andric
460378bf13 Add a convenience macro for the returns_twice attribute, and apply it to
the prototypes of the appropriate functions (getcontext, savectx,
setjmp, sigsetjmp and vfork).

MFC after:	2 weeks
2012-04-29 11:04:31 +00:00
Ed Schouten
92396a3174 Remove pty(4) from our kernel configurations.
As of FreeBSD 8, this driver should not be used. Applications that use
posix_openpt(2) and openpty(3) use the pts(4) that is built into the
kernel unconditionally. If it turns out high profile depend on the
pty(4) module anyway, I'd rather get those fixed. So please report any
issues to me.

The pty(4) module is still available as a kernel module of course, so a
simple `kldload pty' can be used to run old-style pseudo-terminals.
2012-03-21 08:38:42 +00:00
Tijl Coosemans
2c7879ea84 Copy i386 specialreg.h to x86 and merge with amd64 specialreg.h. Replace
amd64/i386/pc98 specialreg.h with stubs.
2012-03-19 21:34:11 +00:00
Tijl Coosemans
68156ad982 Copy i386 psl.h to x86 and replace amd64/i386/pc98 psl.h with stubs. 2012-03-19 21:29:57 +00:00
Tijl Coosemans
bcde3b9f67 Move userland bits (and some common kernel bits) from amd64 and i386
segments.h to a new x86 segments.h.

Add __packed attribute to some structs (just to be sure).
Also make it clear that i386 GDT and LDT entries are used in ia64 code.
2012-03-19 21:24:50 +00:00
Tijl Coosemans
6e310b206f Eliminate ia32_reg.h by moving its contents to x86 and ia64 reg.h.
Reviewed by:	kib
2012-03-18 19:12:11 +00:00
Attilio Rao
9c170fd168 Disable the option VFS_ALLOW_NONMPSAFE by default on all the supported
platforms.
This will make every attempt to mount a non-mpsafe filesystem to the
kernel forbidden, unless it is expressely compiled with
VFS_ALLOW_NONMPSAFE option.

This patch is part of the effort of killing non-MPSAFE filesystems
from the tree.

No MFC is expected for this patch.
2012-03-06 20:01:25 +00:00
John Baldwin
831ce4cb3d - Change contigmalloc() to use the vm_paddr_t type instead of an unsigned
long for specifying a boundary constraint.
- Change bus_dma tags to use bus_addr_t instead of bus_size_t for boundary
  constraints.

These allow boundary constraints to be fully expressed for cases where
sizeof(bus_addr_t) != sizeof(bus_size_t).  Specifically, it allows a
driver to properly specify a 4GB boundary in a PAE kernel.

Note that this cannot be safely MFC'd without a lot of compat shims due
to KBI changes, so I do not intend to merge it.

Reviewed by:	scottl
2012-03-01 19:58:34 +00:00
Gavin Atkinson
1748d1e513 Correct capitalization of "Hz" in user-visible text (manpages, printf(),
etc).

MFC after:	3 days
2012-02-28 13:19:34 +00:00
Marcel Moolenaar
2cb3783b57 Rev. 228360 moved the call to cpu_set_upcall() to happen before
td_proc gets initialized in td (=newtd). Use td0 instead.

MFC after:	3 days
2012-02-08 04:05:38 +00:00
David Schultz
2ee7b1d4ae Add C11 macros describing subnormal numbers to float.h.
Reviewed by:	bde
2012-01-23 06:36:41 +00:00
David Schultz
9fa03ecd01 Add parentheses where required. Without them, `sizeof LDBL_MAX'
is a syntax error and shouldn't be, while `1 FLT_ROUNDS' isn't a
syntax error and should be.  Thanks to bde for the examples.
2012-01-20 06:51:41 +00:00
Kenneth D. Merry
130f4520cb Add the CAM Target Layer (CTL).
CTL is a disk and processor device emulation subsystem originally written
for Copan Systems under Linux starting in 2003.  It has been shipping in
Copan (now SGI) products since 2005.

It was ported to FreeBSD in 2008, and thanks to an agreement between SGI
(who acquired Copan's assets in 2010) and Spectra Logic in 2010, CTL is
available under a BSD-style license.  The intent behind the agreement was
that Spectra would work to get CTL into the FreeBSD tree.

Some CTL features:

 - Disk and processor device emulation.
 - Tagged queueing
 - SCSI task attribute support (ordered, head of queue, simple tags)
 - SCSI implicit command ordering support.  (e.g. if a read follows a mode
   select, the read will be blocked until the mode select completes.)
 - Full task management support (abort, LUN reset, target reset, etc.)
 - Support for multiple ports
 - Support for multiple simultaneous initiators
 - Support for multiple simultaneous backing stores
 - Persistent reservation support
 - Mode sense/select support
 - Error injection support
 - High Availability support (1)
 - All I/O handled in-kernel, no userland context switch overhead.

(1) HA Support is just an API stub, and needs much more to be fully
    functional.

ctl.c:			The core of CTL.  Command handlers and processing,
			character driver, and HA support are here.

ctl.h:			Basic function declarations and data structures.

ctl_backend.c,
ctl_backend.h:		The basic CTL backend API.

ctl_backend_block.c,
ctl_backend_block.h:	The block and file backend.  This allows for using
			a disk or a file as the backing store for a LUN.
			Multiple threads are started to do I/O to the
			backing device, primarily because the VFS API
			requires that to get any concurrency.

ctl_backend_ramdisk.c:	A "fake" ramdisk backend.  It only allocates a
			small amount of memory to act as a source and sink
			for reads and writes from an initiator.  Therefore
			it cannot be used for any real data, but it can be
			used to test for throughput.  It can also be used
			to test initiators' support for extremely large LUNs.

ctl_cmd_table.c:	This is a table with all 256 possible SCSI opcodes,
			and command handler functions defined for supported
			opcodes.

ctl_debug.h:		Debugging support.

ctl_error.c,
ctl_error.h:		CTL-specific wrappers around the CAM sense building
			functions.

ctl_frontend.c,
ctl_frontend.h:		These files define the basic CTL frontend port API.

ctl_frontend_cam_sim.c:	This is a CTL frontend port that is also a CAM SIM.
			This frontend allows for using CTL without any
			target-capable hardware.  So any LUNs you create in
			CTL are visible in CAM via this port.

ctl_frontend_internal.c,
ctl_frontend_internal.h:
			This is a frontend port written for Copan to do
			some system-specific tasks that required sending
			commands into CTL from inside the kernel.  This
			isn't entirely relevant to FreeBSD in general,
			but can perhaps be repurposed.

ctl_ha.h:		This is a stubbed-out High Availability API.  Much
			more is needed for full HA support.  See the
			comments in the header and the description of what
			is needed in the README.ctl.txt file for more
			details.

ctl_io.h:		This defines most of the core CTL I/O structures.
			union ctl_io is conceptually very similar to CAM's
			union ccb.

ctl_ioctl.h:		This defines all ioctls available through the CTL
			character device, and the data structures needed
			for those ioctls.

ctl_mem_pool.c,
ctl_mem_pool.h:		Generic memory pool implementation used by the
			internal frontend.

ctl_private.h:		Private data structres (e.g. CTL softc) and
			function prototypes.  This also includes the SCSI
			vendor and product names used by CTL.

ctl_scsi_all.c,
ctl_scsi_all.h:		CTL wrappers around CAM sense printing functions.

ctl_ser_table.c:	Command serialization table.  This defines what
			happens when one type of command is followed by
			another type of command.

ctl_util.c,
ctl_util.h:		CTL utility functions, primarily designed to be
			used from userland.  See ctladm for the primary
			consumer of these functions.  These include CDB
			building functions.

scsi_ctl.c:		CAM target peripheral driver and CTL frontend port.
			This is the path into CTL for commands from
			target-capable hardware/SIMs.

README.ctl.txt:		CTL code features, roadmap, to-do list.

usr.sbin/Makefile:	Add ctladm.

ctladm/Makefile,
ctladm/ctladm.8,
ctladm/ctladm.c,
ctladm/ctladm.h,
ctladm/util.c:		ctladm(8) is the CTL management utility.
			It fills a role similar to camcontrol(8).
			It allow configuring LUNs, issuing commands,
			injecting errors and various other control
			functions.

usr.bin/Makefile:	Add ctlstat.

ctlstat/Makefile
ctlstat/ctlstat.8,
ctlstat/ctlstat.c:	ctlstat(8) fills a role similar to iostat(8).
			It reports I/O statistics for CTL.

sys/conf/files:		Add CTL files.

sys/conf/NOTES:		Add device ctl.

sys/cam/scsi_all.h:	To conform to more recent specs, the inquiry CDB
			length field is now 2 bytes long.

			Add several mode page definitions for CTL.

sys/cam/scsi_all.c:	Handle the new 2 byte inquiry length.

sys/dev/ciss/ciss.c,
sys/dev/ata/atapi-cam.c,
sys/cam/scsi/scsi_targ_bh.c,
scsi_target/scsi_cmds.c,
mlxcontrol/interface.c:	Update for 2 byte inquiry length field.

scsi_da.h:		Add versions of the format and rigid disk pages
			that are in a more reasonable format for CTL.

amd64/conf/GENERIC,
i386/conf/GENERIC,
ia64/conf/GENERIC,
sparc64/conf/GENERIC:	Add device ctl.

i386/conf/PAE:		The CTL frontend SIM at least does not compile
			cleanly on PAE.

Sponsored by:	Copan Systems, SGI and Spectra Logic
MFC after:	1 month
2012-01-12 00:34:33 +00:00
Adrian Chadd
3d090dd20d Flip on IEEE80211_SUPPORT_MESH and AH_SUPPORT_AR5416, the
wlan and ath modules respectively assume this is set.

Pointy hat to:	adrian
2012-01-05 17:28:05 +00:00
Robert Watson
009d2032af Add "options CAPABILITY_MODE" and "options CAPABILITIES" to GENERIC kernel
configurations for various architectures in FreeBSD 10.x.  This allows
basic Capsicum functionality to be used in the default FreeBSD
configuration on non-embedded architectures; process descriptors are not
yet enabled by default.

MFC after:	3 months
Sponsored by:	Google, Inc
2011-12-29 22:48:36 +00:00
Andriy Gapon
9976156f12 kern cons: introduce infrastructure for console grabbing by kernel
At the moment grab and ungrab methods of all console drivers are no-ops.

Current intended meaning of the calls is that the kernel takes control of
console input.  In the future the semantics may be extended to mean that
the calling thread takes full ownership of the console (e.g. console
output from other threads could be suspended).

Inspired by:	bde
MFC after:	2 months
2011-12-17 15:08:43 +00:00
Alan Cox
3b03ca3bbe Eliminate vestiges of page coloring. 2011-12-15 05:07:16 +00:00
Ed Schouten
53627e400f Replace __signed by signed.
The signed keyword is an integral part of the C syntax. There's no need
to use __signed.
2011-12-13 13:38:03 +00:00
Attilio Rao
ed1f6dc235 Introduce the option VFS_ALLOW_NONMPSAFE and turn it on by default on
all the architectures.
The option allows to mount non-MPSAFE filesystem. Without it, the
kernel will refuse to mount a non-MPSAFE filesytem.

This patch is part of the effort of killing non-MPSAFE filesystems
from the tree.

No MFC is expected for this patch.

Tested by:	gianni
Reviewed by:	kib
2011-11-08 10:18:07 +00:00
Ed Schouten
6472ac3d8a Mark all SYSCTL_NODEs static that have no corresponding SYSCTL_DECLs.
The SYSCTL_NODE macro defines a list that stores all child-elements of
that node. If there's no SYSCTL_DECL macro anywhere else, there's no
reason why it shouldn't be static.
2011-11-07 15:43:11 +00:00
Ed Schouten
d745c852be Mark MALLOC_DEFINEs static that have no corresponding MALLOC_DECLAREs.
This means that their use is restricted to a single C file.
2011-11-07 06:44:47 +00:00
Ken Smith
6168545a11 Adjust the debugger options slightly. This should help me do the right
thing when changing the debugging options as part of head becoming a new
stable branch.  It may also help people who for one reason or another want
to run head but don't want it slowed down by the debugging support.

Reviewed by:	kib
2011-10-27 13:07:49 +00:00
Ken Smith
36d7cf2f1c Move the debugging support to its own section. This matches what is
in the other architectures' GENERIC and makes removing it at the point
we're creating a new stable branch a bit easier.

Discussed with:	marcel
2011-10-26 22:28:28 +00:00
David Schultz
a50079b7ff People porting FreeBSD to new architectures ought not have to
implement a deprecated FPU control interface in addition to the
standard one.  To make this clearer, further deprecate ieeefp.h
by not declaring the function prototypes except on architectures
that implement them already.

Currently i386 and amd64 implement the ieeefp.h interface for
compatibility, and for fp[gs]etprec(), which doesn't exist on
most other hardware.  Powerpc, sparc64, and ia64 partially implement
it and probably shouldn't, and other architectures don't implement it
at all.
2011-10-21 06:41:46 +00:00
Ken Smith
7042aba738 Add a warning about why sbp(4) is commented out so that curious folks
are forewarned they might wind up with a hole in their foot if they
decide to give it a try.

Suggested by:	dougb
2011-10-19 21:55:20 +00:00
Ken Smith
4c0ba9b742 Comment out the sbp(4) driver for architectures that support it.
As part of the 8.0-RELEASE cycle this was done in stable/8 (r199112)
but was left alone in head so people could work on fixing an issue that
caused boot failure on some motherboards.  Apparently nobody has worked
on it and we are getting reports of boot failure with the 9.0 test builds.
So this time I'll comment out the driver in head (still hoping someone
will work on it) and MFC to stable/9.

Submitted by:	Alberto Villa <avilla at FreeBSD dot org>
2011-10-18 13:45:16 +00:00
Konstantin Belousov
6bfe4c78c8 Remove unused define.
MFC after:	1 month
2011-10-07 16:09:44 +00:00
Konstantin Belousov
578113aaa3 Remove locking of the vm page queues from several pmaps, which only
protected the dirty mask updates. The dirty mask updates are handled
by atomics after the r225840.

Submitted by:	alc
Tested by:	flo (sparc64)
MFC after:	2 weeks
2011-09-28 15:01:20 +00:00
Kip Macy
8451d0dd78 In order to maximize the re-usability of kernel code in user space this
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.

Reviewed by:	rwatson
Approved by:	re (bz)
2011-09-16 13:58:51 +00:00
Konstantin Belousov
26ccf4f10f Inline the syscallenter() and syscallret(). This reduces the time measured
by the syscall entry speed microbenchmarks by ~10% on amd64.

Submitted by:	jhb
Approved by:	re (bz)
MFC after:	2 weeks
2011-09-11 16:05:09 +00:00
Konstantin Belousov
3407fefef6 Split the vm_page flags PG_WRITEABLE and PG_REFERENCED into atomic
flags field. Updates to the atomic flags are performed using the atomic
ops on the containing word, do not require any vm lock to be held, and
are non-blocking. The vm_page_aflag_set(9) and vm_page_aflag_clear(9)
functions are provided to modify afalgs.

Document the changes to flags field to only require the page lock.

Introduce vm_page_reference(9) function to provide a stable KPI and
KBI for filesystems like tmpfs and zfs which need to mark a page as
referenced.

Reviewed by:    alc, attilio
Tested by:      marius, flo (sparc64); andreast (powerpc, powerpc64)
Approved by:	re (bz)
2011-09-06 10:30:11 +00:00