(PICs) rather than interrupt sources. This allows interrupt controllers
with no interrupt pics (such as the 8259As when APIC is in use) to
participate in suspend/resume.
- Always register the 8259A PICs even if we don't use any of their pins.
- Explicitly reset the 8259As on resume on amd64 if 'device atpic' isn't
included.
- Add a "dummy" PIC for the local APIC on the BSP to reset the local APIC
on resume. This gets suspend/resume working with APIC on UP systems.
SMP still needs more work to bring the APs back to life.
The MFC after is tentative.
Tested by: anholt (i386)
Submitted by: Andrea Bittau <a.bittau at cs.ucl.ac.uk> (3)
MFC after: 1 week
unsuspecting users.
- Add a comment in NOTES about experimental status of SCHED_ULE.
- Make warning about experimental status in sched_ule(4) a bit
stronger.
Suggested and reviewed by: dougb
Discussed on: developers
MFC after: 3 days
Submitted by:
Reviewed by:
Approved by:
Obtained from:
MFC after:
Security:
Move the relocation definitions to the common elf header so that DTrace
can use them on one architecture targeted to a different one.
Add the additional ELF types defines in Sun's "Linker and Libraries"
manual.
Split subr_clock.c in two parts (by repo-copy):
subr_clock.c contains generic RTC and calendaric stuff. etc.
subr_rtc.c contains the newbus'ified RTC interface.
Centralize the machdep.{adjkerntz,disable_rtc_set,wall_cmos_clock}
sysctls and associated variables into subr_clock.c. They are
not machine dependent and we have generic code that relies on being
present so they are not even optional.
timer interrupt servicing for disabled HTT cores in ULE case. Should be
probably fixed in ULE code instead, but we have no real maintainer for
ULE to do it.
PR: 103697
GDT to be loaded into FS.base and GS.base, these values of course
are not the values set by sysarch() with I386_SET_FSBASE and
I386_SET_GSBASE, the change fixed a crash for 32bit libthr after
signal handler returned and normal code is accessing thread pointer,
for example: movl %gs:8, %eax.
- Split out the communication protocols into their own files and use
a couple of function pointers in the softc that the commuication
protocols setup in their own attach routine.
- Add support for the SSIF interface (talking to IPMI over SMBus).
- Add an ACPI attachment.
- Add a PCI attachment that attaches to devices with the IPMI interface
subclass.
- Split the ISA attachment out into its own file: ipmi_isa.c.
- Change the code to probe the SMBIOS table for an IPMI entry to just use
pmap_mapbios() to map the table in rather than trying to setup a fake
resource on an isa device and then activating the resource to map in the
table.
- Make bus attachments leaner by adding attach functions for each
communication interface (ipmi_kcs_attach(), ipmi_smic_attach(), etc.)
that setup per-interface data.
- Formalize the model used by the driver to handle requests by adding an
explicit struct ipmi_request object that holds the state of a given
request and reply for the entire lifetime of the request. By bundling
the request into an object, it is easier to add retry logic to the various
communication backends (as well as eventually support BT mode which uses
a slightly different message format than KCS, SMIC, and SSIF).
- Add a per-softc lock and remove D_NEEDGIANT as the driver is now MPSAFE.
- Add 32-bit compatibility ioctl shims so you can use a 32-bit ipmitool
on FreeBSD/amd64.
- Add ipmi(4) to i386 and amd64 NOTES.
Submitted by: ambrisko (large portions of 2 and 3)
Sponsored by: IronPort Systems, Yahoo!
MFC after: 6 days
pmap_invalidate_cache() in the SMP case so pmap_mapdev() in multiuser
doesn't panic with a trap 30. I broke this many months ago when I
added pmap_invalidate_cache() as early parts of the PAT work.
Patience from: jmg
Pointy hat: jhb
for overlaps, but more importantly, it collapses adjacent free regions.
This is needed to cope with BIOSen that split up ports for system devices
(like IPMI controllers) across multiple system resource entries.
- Now that rman_manage_region() is not so dumb, remove extra logic in the
x86 nexus drivers to populate the IRQ rman that manually coalesced the
regions.
MFC after: 1 week
and dump_avail[] arrays so they are in sync (previously it was possible
to store more entries in the physmap[] then we could store in phys_avail[],
which was pointless). While I'm here, bump up the length of these tables
to hold 30 entries on amd64 and 16 on i386. This allows machines with
fairly fragmented memory maps to boot ok (at least one machine would
not boot FreeBSD/i386 but would boot FreeBSD/amd64 because amd64 allowed
for more fragments).
MFC after: 3 days
any threads to them. However, it still counts those cores as "active but
permanently idle" when calculating system-wide CPUs statistics. It is
incorrect, since it skews statistics quite a bit and creates real problems
for certain types of applications (monitoring applications for example),
by making them believe that the system does have enough idle CPU resources,
while in fact it does not.
Correct the problem by not calling performance counting routines on "disabled"
cores. The cleaner solution would be to just disable APIC timer interrupts on
those cores completely, but ENOTIME here and it is not clear if the
additional complexity really worth minor performance gain.
Reviewed by: ssouhlal
Sponsored by: Sippy Software, Inc.
MFC after: 2 weeks
but further on -current (still not successful, but a step into the right
direction).
Sponsored by: Google SoC 2006
Submitted by: rdivacky
Tested by: Paul Mather <paul@gromit.dlib.vt.edu>
we can do the stuff we need to do with linux processes at fork and
don't panic the kernel at exit of the child.
Submitted by: rdivacky
Tested with: tst-vfork* (glibc regression tests)
Tested by: netchild
handling for amd64 in the common code. The MD parts for amd64 are still
outstanding, but at least this fixes some panics on amd64.
Sponsored by: Google SoC 2006
Submitted by: rdivacky
Tested by: bsam
- Send the systrace_args files for all the compat ABIs to /dev/null for
now. Right now makesyscalls.sh generates a file with a hardcoded
function name, so it wouldn't work for any of the ABIs anyway. Probably
the function name should be configurable via a 'systracename' variable
and the functions should be stored in a function pointer in the sysvec
structure.
- TLS - complete
- pid/tid mangling - complete
- thread area - complete
- futexes - complete with issues
- clone() extension - complete with some possible minor issues
- mq*/timer*/clock* stuff - complete but untested and the mq* stuff is
disabled when not build as part of the kernel with native FreeBSD mq*
support (module support for this will come later)
Tested with:
- linux-firefox - works, tested
- linux-opera - works, tested
- linux-realplay - doesnt work, issue with futexes
- linux-skype - doesnt work, issue with futexes
- linux-rt2-demo - works, tested
- linux-acroread - doesnt work, unknown reason (coredump) and sometimes
issue with futexes
- various unix utilities in linux-base-gentoo3 and linux-base-fc4:
everything tried worked
On amd64 not everything is supported like on i386, the catchup is planned for
later when the remaining bugs in the new functions are fixed.
To test this new stuff, you have to run
sysctl compat.linux.osrelease=2.6.16
to switch back use
sysctl compat.linux.osrelease=2.4.2
Don't switch while running a linux program, strange things may or may not
happen.
Sponsored by: Google SoC 2006
Submitted by: rdivacky
Some suggestions/help by: jhb, kib, manu@NetBSD.org, netchild
compat.linux.osrelease is changed to "2.6.16" or similar).
On amd64 not everything is supported like on i386, the catchup is planned for
later when the remaining bugs in the new functions are fixed.
Sponsored by: Google SoC 2006
Submitted by: rdivacky
aren't mapped via pmap_enter() (KVA). We will eventually support PAT bits
on user pages, but those will require some sort of MI caching mode stored
in the vm_page.
Reviewed by: alc
WB (write-back) on x86 via control bits in PTEs and PDEs (including making
use of the PAT MSR). Changes include:
- A new pmap_mapdev_attr() function for amd64 and i386 which takes an
additional parameter (relative to pmap_mapdev()) specifying the cache
mode for this mapping. Note that on amd64 only WB mappings are done with
the direct map, all other modes result in a private mapping.
- pmap_mapdev() on i386 and amd64 now defaults to using UC (uncached)
mappings rather than WB. Previously we relied on the BIOS setting up
MTRR's to enforce memio regions being treated as UC. This might make
hw.cbb_start_memory unnecessary in some cases now for example.
- A new pmap_mapbios()/pmap_unmapbios() API has been added to allow places
that used pmap_mapdev() to map non-device memory (such as ACPI tables)
to do so using WB as before.
- A new pmap_change_attr() function for amd64 and i386 that changes the
caching mode for a range of KVA.
Reviewed by: alc
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)
and pc98 MD files. Remove nodevice and nooption lines specific
to sio(4) from ia64, powerpc and sparc64 NOTES. There were no
such lines for arm yet.
sio(4) is usable on less than half the platforms, not counting
a future mips platform. Its presence in MI files is therefore
increasingly becoming a burden.
mark system calls as being MPSAFE:
- Stop conditionally acquiring Giant around system call invocations.
- Remove all of the 'M' prefixes from the master system call files.
- Remove support for the 'M' prefix from the script that generates the
syscall-related files from the master system call files.
- Don't explicitly set SYF_MPSAFE when registering nfssvc.
implementations and adjust some of the checks while I'm here:
- Add a new check to make sure we don't return from a syscall in a critical
section.
- Add a new explicit check before userret() to make sure we don't return
with any locks held. The advantage here is that we can include the
syscall number and name in syscall() whereas that info is not available
in userret().
- Drop the mtx_assert()'s of sched_lock and Giant. They are replaced by
the more general checks just added.
MFC after: 2 weeks
map was obtained from the SMAP. SMAP is trustworthy, and the memory
extending feature is a band-aid for older systems where FreeBSD's methods
of detecting memory were not always trustworthy. This fixes the issue
where using hw.physmem could result in the ACPI tables getting trashed
breaking ACPI.
MFC after: 3 days
Tested on: i386
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@
pmap_remove_all() before rather than after the pmap is unlocked. At
present, the page queues lock provides sufficient sychronization. In the
future, the page queues lock may not always be held when free_pv_entry() is
called.
install custom pager functions didn't actually happen in practice (they
all just used the simple pager and passed in a local quit pointer). So,
just hardcode the simple pager as the only pager and make it set a global
db_pager_quit flag that db commands can check when the user hits 'q' (or a
suitable variant) at the pager prompt. Also, now that it's easy to do so,
enable paging by default for all ddb commands. Any command that wishes to
honor the quit flag can do so by checking db_pager_quit. Note that the
pager can also be effectively disabled by setting $lines to 0.
Other fixes:
- 'show idt' on i386 and pc98 now actually checks the quit flag and
terminates early.
- 'show intr' now actually checks the quit flag and terminates early.
ibcs2_getdents(), ibcs2_read(), ogetdirentries(), svr4_sys_getdents(),
and svr4_sys_getdents64() similar to that in getdirentries().
- Mark ibcs2_getdents(), ibcs2_read(), linux_getdents(), linux_getdents64(),
linux_readdir(), ogetdirentries(), svr4_sys_getdents(), and
svr4_sys_getdents64() MPSAFE.
to a copied-in copy of the 'union semun' and a uioseg to indicate which
memory space the 'buf' pointer of the union points to. This is then used
in linux_semctl() and svr4_sys_semctl() to eliminate use of the stackgap.
- Mark linux_ipc() and svr4_sys_semsys() MPSAFE.
from going away. mount(2) is now MPSAFE.
- Expand the scope of Giant some in unmount(2) to protect the mp structure
(or rather, to handle concurrent unmount races) from going away.
umount(2) is now MPSAFE, as well as linux_umount() and linux_oldumount().
- nmount(2) and linux_mount() were already MPSAFE.
pmap_copy() if the mapping is VM_INHERIT_SHARE. Suppose the mapping
is also wired. vmspace_fork() clears the wiring attributes in the vm
map entry but pmap_copy() copies the PG_W attribute in the PTE. I
don't think this is catastrophic. It blocks pmap_remove_pages() from
destroying the mapping and corrupts the pmap's wiring count.
This revision fixes the problem by changing pmap_copy() to clear the
PG_W attribute.
Reviewed by: tegge@
This driver was ported from OpenBSD by Shigeaki Tagashira
<shigeaki@se.hiroshima-u.ac.jp> and posted at
http://www.se.hiroshima-u.ac.jp/~shigeaki/software/freebsd-nfe.html
It was additionally cleaned up by me.
It is still a work-in-progress and thus is purposefully not in GENERIC.
And it conflicts with nve(4), so only one should be loaded.
in 1999, and there are changes to the sysctl names compared to PR,
according to that discussion. The description is in sys/conf/NOTES.
Lines in the GENERIC files are added in commented-out form.
I'll attach the test script I've used to PR.
PR: kern/14584
Submitted by: babkin
VM_ALLOC_NORMAL instead of VM_ALLOC_SYSTEM when try is TRUE. In other
words, when get_pv_entry() is permitted to fail, it no longer tries as
hard to allocate a page.
Change pmap_enter_quick_locked() to fail rather than wait if it is
unable to allocate a page table page. This prevents a race between
pmap_enter_object() and the page daemon. Specifically, an inactive
page that is a successor to the page that was given to
pmap_enter_quick_locked() might become a cache page while
pmap_enter_quick_locked() waits and later pmap_enter_object() maps
the cache page violating the invariant that cache pages are never
mapped. Similarly, change
pmap_enter_quick_locked() to call pmap_try_insert_pv_entry() rather
than pmap_insert_entry(). Generally speaking,
pmap_enter_quick_locked() is used to create speculative mappings. So,
it should not try hard to allocate memory if free memory is scarce.
Add an assertion that the object containing m_start is locked in
pmap_enter_object(). Remove a similar assertion from
pmap_enter_quick_locked() because that function no longer accesses the
containing object.
Remove a stale comment.
Reviewed by: ups@
syscalls. This way there will be a log message printed to the console
(this time for real).
Note: UNIMPL should be used for syscalls we do not implement ever, e.g.
syscalls to load linux kernel modules.
Submitted by: rdivacky
Sponsored by: Goole SoC 2006
P4 IDs: 99600, 99602
when we're about to call kdb_trap() because the latter MI
function can disable interrupts by itself now.
Pointed out by: bde
X-MFC remark: depends on kern/subr_kdb.c#1.18
Sponsored by: RiNet (Cronyx Plus LLC)
Use the method described in IA-32 Intel Architecture Software
Developer's Manual chapter 11.6.6 to get valid mxcsr bits,
use the mxcsr mask to clear invalid bits passed by user code.
an explicit comment that it's needed for the linuxolator. This is not the
case anymore. For all other architectures there was only a "KEEP THIS".
I'm (and other people too) running a COMPAT_43-less kernel since it's not
necessary anymore for the linuxolator. Roman is running such a kernel for a
for longer time. No problems so far. And I doubt other (newer than ia32
or alpha) architectures really depend on it.
This may result in a small performance increase for some workloads.
If the removal of COMPAT_43 results in a not working program, please
recompile it and all dependencies and try again before reporting a
problem.
The only place where COMPAT_43 is needed (as in: does not compile without
it) is in the (outdated/not usable since too old) svr4 code.
Note: this does not remove the COMPAT_43TTY option.
Nagging by: rdivacky
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
Update of syscall.master:
o Adding of several new dummy syscalls (268-310)
o Synchronization of amd64 syscall.master with i386 one
o Auditing added to amd64 syscall.master
o Change auditing type for lstat syscall (bugfix). [1]
P4-Changes: 98672, 98674
Noticed by: rwatson [1]
Sponsored by: Google SoC 2006
Submitted by: rdivacky
I picked it up again. The scheduler is forked from ULE, but the
algorithm to detect an interactive process is almost completely
different with ULE, it comes from Linux paper "Understanding the
Linux 2.6.8.1 CPU Scheduler", although I still use same word
"score" as a priority boost in ULE scheduler.
Briefly, the scheduler has following characteristic:
1. Timesharing process's nice value is seriously respected,
timeslice and interaction detecting algorithm are based
on nice value.
2. per-cpu scheduling queue and load balancing.
3. O(1) scheduling.
4. Some cpu affinity code in wakeup path.
5. Support POSIX SCHED_FIFO and SCHED_RR.
Unlike scheduler 4BSD and ULE which using fuzzy RQ_PPQ, the scheduler
uses 256 priority queues. Unlike ULE which using pull and push, the
scheduelr uses pull method, the main reason is to let relative idle
cpu do the work, but current the whole scheduler is protected by the
big sched_lock, so the benefit is not visible, it really can be worse
than nothing because all other cpu are locked out when we are doing
balancing work, which the 4BSD scheduelr does not have this problem.
The scheduler does not support hyperthreading very well, in fact,
the scheduler does not make the difference between physical CPU and
logical CPU, this should be improved in feature. The scheduler has
priority inversion problem on MP machine, it is not good for
realtime scheduling, it can cause realtime process starving.
As a result, it seems the MySQL super-smack runs better on my
Pentium-D machine when using libthr, despite on UP or SMP kernel.
the arm to compile without all the extras that don't appear, at least
not in the flavors of ARM I deal with. This helps us save about 100k.
If I've botched the available devices on a platform, please let me
know and I'll correct ASAP.
that it just warns the user with a printf when it misaligns a piece
of memory that was requested through a busdma tag.
Some drivers (such as mpt, and probably others) were asking for alignments
that could not be satisfied, but as far as driver operation was concerned,
that did not matter. In the theory that other drivers will fall into
this same category, we agreed that panicing or making the allocation
fail will cause more hardship than is necessary. The printf should
be sufficient motivation to get the driver glitch fixed.
Add a quick hack to ensure that bus_dmamem_alloc properly aligns
small allocations with large alignment requirements.
Add a panic to detect cases where we've still failed to properly align.
conformance with the mbuf and uio load routines. ENOMEM can only happen
with BUS_DMA_NOWAIT is passed in, thus the deferals are disabled. I don't
like doing this, but fixing this fixes assumptions in other important drivers,
which is a net benefit for now.
o Properly use rman(9) to manage resources. This eliminates the
need to puc-specific hacks to rman. It also allows devinfo(8)
to be used to find out the specific assignment of resources to
serial/parallel ports.
o Compress the PCI device "database" by optimizing for the common
case and to use a procedural interface to handle the exceptions.
The procedural interface also generalizes the need to setup the
hardware (program chipsets, program clock frequencies).
o Eliminate the need for PUC_FASTINTR. Serdev devices are fast by
default and non-serdev devices are handled by the bus.
o Use the serdev I/F to collect interrupt status and to handle
interrupts across ports in priority order.
o Sync the PCI device configuration to include devices found in
NetBSD and not yet merged to FreeBSD.
o Add support for Quatech 2, 4 and 8 port UARTs.
o Add support for a couple dozen Timedia serial cards as found
in Linux.
entry (PTE) have the same meaning. The exception to this rule is the
eighth bit (0x080). It is the PS bit in a PDE and the PAT bit in a
PTE. This change avoids the possibility that pmap_enter() confuses a
PAT bit with a PS bit, avoiding a panic().
Eliminate a diagnostic printf() from the i386 pmap_enter() that serves
no current purpose, i.e., I've seen no bug reports in the last two
years that are helped by this printf().
Reviewed by: jhb
caches are dangerous" to "a shared L1 data cache is dangerous". This
is a compromise between paranoia and performance: Unlike the L1 cache,
nobody has publicly demonstrated a cryptographic side channel which
exploits the L2 cache -- this is harder due to the larger size, lower
bandwidth, and greater associativity -- and prohibiting shared L2
caches turns Intel Core Duo processors into Intel Core Solo processors.
As before, the 'machdep.hyperthreading_allowed' sysctl will allow even
the L1 data cache to be shared.
Discussed with: jhb, scottl
Security: See FreeBSD-SA-05:09.htt for background material.
via the debug.minidump sysctl and tunable.
Traditional dumps store all physical memory. This was once a good thing
when machines had a maximum of 64M of ram and 1GB of kvm. These days,
machines often have many gigabytes of ram and a smaller amount of kvm.
libkvm+kgdb don't have a way to access physical ram that is not mapped
into kvm at the time of the crash dump, so the extra ram being dumped
is mostly wasted.
Minidumps invert the process. Instead of dumping physical memory in
in order to guarantee that all of kvm's backing is dumped, minidumps
instead dump only memory that is actively mapped into kvm.
amd64 has a direct map region that things like UMA use. Obviously we
cannot dump all of the direct map region because that is effectively
an old style all-physical-memory dump. Instead, introduce a bitmap
and two helper routines (dump_add_page(pa) and dump_drop_page(pa)) that
allow certain critical direct map pages to be included in the dump.
uma_machdep.c's allocator is the intended consumer.
Dumps are a custom format. At the very beginning of the file is a header,
then a copy of the message buffer, then the bitmap of pages present in
the dump, then the final level of the kvm page table trees (2MB mappings
are expanded into a 4K page mappings), then the sparse physical pages
according to the bitmap. libkvm can now conveniently access the kvm
page table entries.
Booting my test 8GB machine, forcing it into ddb and forcing a dump
leads to a 48MB minidump. While this is a best case, I expect minidumps
to be in the 100MB-500MB range. Obviously, never larger than physical
memory of course.
minidumps are on by default. It would want be necessary to turn them off
if it was necessary to debug corrupt kernel page table management as that
would mess up minidumps as well.
Both minidumps and regular dumps are supported on the same machine.
to reduce the pv_entry_count counter. This was found by Tor Egge. In the
same email, Tor also pointed out the pv_stats problem in the previous
commit, but I'd forgotten about it until I went looking for this email
about this allocation problem.
create managed mappings within the clean submap. To prevent regressions,
add assertions blocking the creation of managed mappings within the clean
submap.
Reviewed by: tegge
so that we only have to do an ioapic_write() instead of an ioapic_read()
followed by an ioapic_write() every time we mask and unmask level triggered
interrupts. This cuts the execution time for these operations roughly in
half.
Profiled by: Paolo Pisati <p.pisati@oltrelinux.com>
MFC after: 1 week
PCB in which the context of stopped CPUs is stored. To access this
PCB from KDB, we introduce a new define, called KDB_STOPPEDPCB. The
definition, when present, lives in <machine/kdb.h> and abstracts
where MD code saves the context. Define KDB_STOPPEDPCB on i386,
amd64, alpha and sparc64 in accordance to previous code.
with large mmap files mapped into many processes, this saves hundreds of
megabytes of ram.
pv entries were individually allocated and had two tailq entries and two
pointers (or addresses). Each pv entry was linked to a vm_page_t and
a process's address space (pmap). It had the virtual address and a
pointer to the pmap.
This change replaces the individual allocation with a per-process
allocation system. A page ("pv chunk") is allocated and this provides
168 pv entries for that process. We can now eliminate one of the 16 byte
tailq entries because we can simply iterate through the pv chunks to find
all the pv entries for a process. We can eliminate one of the 8 byte
pointers because the location of the pv entry implies the containing
pv chunk, which has the pointer. After overheads from the pv chunk
bitmap and tailq linkage, this works out that each pv entry has an
effective size of 24.38 bytes.
Future work still required, and other problems:
* when running low on pv entries or system ram, we may need to defrag
the chunk pages and free any spares. The stats (vm.pmap.*) show that
this doesn't seem to be that much of a problem, but it can be done if
needed.
* running low on pv entries is now a much bigger problem. The old
get_pv_entry() routine just needed to reclaim one other pv entry.
Now, since they are per-process, we can only use pv entries that are
assigned to our current process, or by stealing an entire page worth
from another process. Under normal circumstances, the pmap_collect()
code should be able to dislodge some pv entries from the current
process. But if needed, it can still reclaim entire pv chunk pages
from other processes.
* This should port to i386 really easily, except there it would reduce
pv entries from 24 bytes to about 12 bytes.
(I have integrated Alan's recent changes.)
