o push much of the i386 and amd64 MD interrupt handling code
(intr_machdep.c::intr_execute_handlers()) into MI code
(kern_intr.c::ithread_loop())
o move filter handling to kern_intr.c::intr_filter_loop()
o factor out the code necessary to mask and ack an interrupt event
(intr_machdep.c::intr_eoi_src() and intr_machdep.c::intr_disab_eoi_src()),
and make them part of 'struct intr_event', passing them as arguments to
kern_intr.c::intr_event_create().
o spawn a private ithread per handler (struct intr_handler::ih_thread)
with filter and ithread functions.
Approved by: re (implicit?)
VM_PHYSSEG_SPARSE depending on whether the physical address space is
densely or sparsely populated with memory. The effect of this
definition is to determine which of two implementations of
vm_page_array and PHYS_TO_VM_PAGE() is used. The legacy
implementation is obtained by defining VM_PHYSSEG_DENSE, and a new
implementation that trades off time for space is obtained by defining
VM_PHYSSEG_SPARSE. For now, all architectures except for ia64 and
sparc64 define VM_PHYSSEG_DENSE. Defining VM_PHYSSEG_SPARSE on ia64
allows the entirety of my Itanium 2's memory to be used. Previously,
only the first 1 GB could be used. Defining VM_PHYSSEG_SPARSE on
sparc64 allows USIIIi-based systems to boot without crashing.
This change is a combination of Nathan Whitehorn's patch and my own
work in perforce.
Discussed with: kmacy, marius, Nathan Whitehorn
PR: 112194
- Simplify the amount of work that has be done for each architecture by
pushing more of the truly MI code down into the PCI bus driver.
- Don't bind MSI-X indicies to IRQs so that we can allow a driver to map
multiple MSI-X messages into a single IRQ when handling a message
shortage.
The changes include:
- Add a new pcib_if method: PCIB_MAP_MSI() which is called by the PCI bus
to calculate the address and data values for a given MSI/MSI-X IRQ.
The x86 nexus drivers map this into a call to a new 'msi_map()' function
in msi.c that does the mapping.
- Retire the pcib_if method PCIB_REMAP_MSIX() and remove the 'index'
parameter from PCIB_ALLOC_MSIX(). MD code no longer has any knowledge
of the MSI-X index for a given MSI-X IRQ.
- The PCI bus driver now stores more MSI-X state in a child's ivars.
Specifically, it now stores an array of IRQs (called "message vectors" in
the code) that have associated address and data values, and a small
virtual version of the MSI-X table that specifies the message vector
that a given MSI-X table entry uses. Sparse mappings are permitted in
the virtual table.
- The PCI bus driver now configures the MSI and MSI-X address/data
registers directly via custom bus_setup_intr() and bus_teardown_intr()
methods. pci_setup_intr() invokes PCIB_MAP_MSI() to determine the
address and data values for a given message as needed. The MD code
no longer has to call back down into the PCI bus code to set these
values from the nexus' bus_setup_intr() handler.
- The PCI bus code provides a callout (pci_remap_msi_irq()) that the MD
code can call to force the PCI bus to re-invoke PCIB_MAP_MSI() to get
new values of the address and data fields for a given IRQ. The x86
MSI code uses this when an MSI IRQ is moved to a different CPU, requiring
a new value of the 'address' field.
- The x86 MSI psuedo-driver loses a lot of code, and in fact the separate
MSI/MSI-X pseudo-PICs are collapsed down into a single MSI PIC driver
since the only remaining diff between the two is a substring in a
bootverbose printf.
- The PCI bus driver will now restore MSI-X state (including programming
entries in the MSI-X table) on device resume.
- The interface for pci_remap_msix() has changed. Instead of accepting
indices for the allocated vectors, it accepts a mini-virtual table
(with a new length parameter). This table is an array of u_ints, where
each value specifies which allocated message vector to use for the
corresponding MSI-X message. A vector of 0 forces a message to not
have an associated IRQ. The device may choose to only use some of the
IRQs assigned, in which case the unused IRQs must be at the "end" and
will be released back to the system. This allows a driver to use the
same remap table for different shortage values. For example, if a driver
wants 4 messages, it can use the same remap table (which only uses the
first two messages) for the cases when it only gets 2 or 3 messages and
in the latter case the PCI bus will release the 3rd IRQ back to the
system.
MFC after: 1 month
fault. The previous method zero'd out the page tables, invalidated the
TLB, and then entered a spin loop. The idea was that the instruction after
the TLB invalidate would result in a page fault and the page fault and
subsequent double fault wouldn't be able to determine the physical page
for their fault handlers' first instruction. This stopped working when
PGE (PG_G PTE/PDE bit) support was added as a TLB invalidate via %cr3
reload doesn't clear TLB entries with PG_G set. Thus, the CPU was still
able to map the virtual address for the spin loop and happily performed
its infinite loop.
The triple fault now uses a much more deterministic sledge-hammer approach
to generate a triple fault. First, the IDT descriptor is set to point to
an empty IDT, so any interrupts (including a double fault) will instantly
fault. Second, we trigger a int 3 breakpoint to force an interrupt and
kick off a triple fault.
MFC after: 3 days
the introduction of priv(9) and MAC Framework entry points for privilege
checking/granting. These entry points exactly aligned with privileges and
provided no additional security context:
- mac_check_sysarch_ioperm()
- mac_check_kld_unload()
- mac_check_settime()
- mac_check_system_nfsd()
Add mpo_priv_check() implementations to Biba and LOMAC policies, which,
for each privilege, determine if they can be granted to processes
considered unprivileged by those two policies. These mostly, but not
entirely, align with the set of privileges granted in jails.
Obtained from: TrustedBSD Project
vm.kmem_size_min. Useful when using ZFS to make sure that vm.kmem size will
be at least 256mb (for example) without forcing a particular value via vm.kmem_size.
Approved by: njl (mentor)
Reviewed by: alc
obtaining and releasing shared and exclusive locks. The algorithms for
manipulating the lock cookie are very similar to that rwlocks. This patch
also adds support for exclusive locks using the same algorithm as mutexes.
A new sx_init_flags() function has been added so that optional flags can be
specified to alter a given locks behavior. The flags include SX_DUPOK,
SX_NOWITNESS, SX_NOPROFILE, and SX_QUITE which are all identical in nature
to the similar flags for mutexes.
Adaptive spinning on select locks may be enabled by enabling the
ADAPTIVE_SX kernel option. Only locks initialized with the SX_ADAPTIVESPIN
flag via sx_init_flags() will adaptively spin.
The common cases for sx_slock(), sx_sunlock(), sx_xlock(), and sx_xunlock()
are now performed inline in non-debug kernels. As a result, <sys/sx.h> now
requires <sys/lock.h> to be included prior to <sys/sx.h>.
The new kernel option SX_NOINLINE can be used to disable the aforementioned
inlining in non-debug kernels.
The size of struct sx has changed, so the kernel ABI is probably greatly
disturbed.
MFC after: 1 month
Submitted by: attilio
Tested by: kris, pjd
watchdog might hide the succesful arming of an earlier one. Accept that on
failing to arm any watchdog (because of non-supported timeouts) EOPNOTSUPP is
returned instead of the more appropriate EINVAL.
MFC after: 3 days
code.
# There is some question about whether this code is even relevant any
# longer (it dates back to prehistoric times, i.e. present in r1.1),
# especially on amd64.
Reviewed by: jhb
cpufreq_pre_change is called before the change, giving each driver a chance
to revoke the change. cpufreq_post_change provides the results of the
change (success or failure). cpufreq_levels_changed gives the unit number
of the cpufreq device whose number of available levels has changed. Hook
in all the drivers I could find that needed it.
* TSC: update TSC frequency value. When the available levels change, take the
highest possible level and notify the timecounter set_cputicker() of that
freq. This gets rid of the "calcru: runtime went backwards" messages.
* identcpu: updates the sysctl hw.clockrate value
* Profiling: if profiling is active when the clock changes, let the user
know the results may be inaccurate.
Reviewed by: bde, phk
MFC after: 1 month
temporary mapping created by locore so that the lowest two to four
megabytes can become a permanent identity mapping. This implementation
avoids any use of a large page mapping.
handles when activating a resource via bus_activate_resource() rather than
doing some of the work in bus_alloc_resource() and some of it in
bus_activate_resource().
One note is that when using isa_alloc_resourcev() on PC-98, drivers now
need to just use bus_release_resource() without explicitly calling
bus_deactivate_resource() first. nyan@ has already fixed all of the PC-98
drivers.
address ranges used by local and I/O APICs in the system. Some systems
also reserve these ranges as system resources via either PnPBIOS or
ACPI, so this device currently attaches after acpi0 and legacy0 so that
the system resources are given precedence.
addresses corresponding to system RAM. On amd64 ram0 uses the SMAP
and claims all the type 1 SMAP regions. On i386 ram0 uses the
dump_avail[] array. Note that on i386 we have to ignore regions above
4G in PAE kernels since bus resources use longs.
boot. Then, just switch to the kernel pmap when suspending instead of
allocating/freeing our own mapping every time. This should solve a panic
of pmap_remove() being called with interrupts disabled. Thanks to Alan
Cox for developing this patch.
Note: this means that ACPI requires super page (PG_PS) support in the CPU.
This has been present since the Pentium and first documented in the
Pentium Pro. However, it may need to be revisited later.
Submitted by: alc
MFC after: 1 month
GETATTRs being generated - one from lookup()/namei() and the other
from nfs_open() (for cto consistency). This change eliminates the
GETATTR in nfs_open() if an otw GETATTR was done from the namei()
path. Instead of extending the vop interface, we timestamp each attr
load, and use this to detect whether a GETATTR was done from namei()
for this syscall. Introduces a thread-local variable that counts the
syscalls made by the thread and uses <pid, tid, thread syscalls> as
the attrload timestamp. Thanks to jhb@ and peter@ for a discussion on
thread state that could be used as the timestamp with minimal overhead.
For example, during a buildworld more than half of the calls do not
generate an IPI because the only TLB entry invalidated is on the calling
processor. This revision pushes down the acquisition and release of
smp_ipi_mtx into smp_tlb_shootdown() and smp_targeted_tlb_shootdown() and
instead uses sched_pin() and sched_unpin() in pmap_invalidate_*() so that
thread migration doesn't lead to a missed TLB invalidation.
Reviewed by: jhb
MFC after: 3 weeks
RTC state, then it may clobber the RTC index register, so the index
register must be restored before using it to restore control registers
in rtc_restore().
The following problems remain:
- rtc_restore() is only called if pmtimer is configured. Buggy
suspend/resumes are more likely to clobber the index register than
a control register, so pmtimer is more needed than it used to be.
- pmtimer doesn't exist for amd64.
- Restoring of the RTC state may race with rtcintr(). If an RTC
interrupt is handled before the state is restored, then rtcin(RTC_INTR)
in rtcintr() may read from the wrong register, so rtcintr() may spin
forever. This may be mitigated by the most common state clobbering
being to turn off RTC interrupts.
Linux does not check file descriptor when MAP_ANONYMOUS is set.
This should fix recent LTP test regressions.
Reported by: Scot Hetzel (swhetzel at gmail dot com)
netchild
- Dont "return" in linux_clone() after we forked the new process in a case
of problems.
- Move the copyout of p2->p_pid outside the emul_lock coverage in
linux_clone().
- Cache the em->pdeath_signal in a local variable and move the copyout
out of the emul_lock coverage.
- Move the free() out of the emul_shared_lock coverage in a preparation
to switch emul_lock to non-sleepable lock (mutex).
Submitted by: rdivacky
- PROT_READ, PROT_WRITE, or PROT_EXEC implies PROT_READ and PROT_EXEC.
Linux/ia64's i386 emulation layer does this and it complies with Linux
header files. This fixes mmap05 LTP test case on amd64.
- Do not adjust stack size when failure has occurred.
- Synchronize i386 mmap/mprotect with amd64.
partitioning class that supports multiple schemes. Current
schemes supported are APM (Apple Partition Map) and GPT.
Change all GEOM_APPLE anf GEOM_GPT options into GEOM_PART_APM
and GEOM_PART_GPT (resp).
The ctlreq interface supports verbs to create and destroy
partitioning schemes on a disk; to add, delete and modify
partitions; and to commit or undo changes made.
variable to avoid invalid constraints in dead code. Use an array of
u_char's (inside a struct) instead of a char/short/int/long variable so
that the variable and its accesses can be spelled in the same way in all
cases and code doesn't need to be cloned just to hold the spelling
differences.
Fixed strict-aliasing errors in PCPU_SET() and in the amd64 PCPU_GET().
Cast to (void *) as in rev.1.37 of the i386 version where the errors
were fixed for the i386 PCPU_GET() only. It would be more correct to
copy to and from the temp. variable using memcpy(), but then an
ifdef tangle would be required to ensure using the builtin memcpy().
We depend on fairly aggressive optimization to put the temp. variable
only in a register despite it being copied using
*(type *)(void *)&anothertype and could depend on this when using
memcpy() too. This seems to work right even for -O0, but the -O0 case
has not been completely tested.
This change gives identical object code for all object files in LINT
on amd64 (except for one file with a __TIME__ stamp). For LINT on
i386 it gives unimportant differences in instruction order and padding
in a few object files. This was only tested for -O.
This change (actually a previous version of it) gives the following
reductions in the number of object files in LINT that fail to compile
with -O2 but without the -fno-strict-aliasing kludge:
- amd64: 29 (down from 211)
- i386: 36 (down from 47)
gcc-3.4.6 actually allows the invalid constraints that result from not
using the temp. variable, at least with -O[1-2], but gcc-3.3.3 crashes
on them and I don't want to depend on compiler bugs.
o remove errata_a0 and introduce the corresponding flags into 'errata'.
o introduce a new errata for K8, namely some platform might set the
PENDING_BIT but aren't able to unset it, also don't loop forever
waiting PENDING_BIT being cleared.
o try to introduce a workaround for the PENDING_BIT stuck problem,
o support now half multipliers for K8.
Tested by: Abdullah Al-Marrie
Approved by: njl
setrunqueue() was mostly empty. The few asserts and thread state
setting were moved to the individual schedulers. sched_add() was
chosen to displace it for naming consistency reasons.
- Remove adjustrunqueue, it was 4 lines of code that was ifdef'd to be
different on all three schedulers where it was only called in one place
each.
- Remove the long ifdef'd out remrunqueue code.
- Remove the now redundant ts_state. Inspect the thread state directly.
- Don't set TSF_* flags from kern_switch.c, we were only doing this to
support a feature in one scheduler.
- Change sched_choose() to return a thread rather than a td_sched. Also,
rely on the schedulers to return the idlethread. This simplifies the
logic in choosethread(). Aside from the run queue links kern_switch.c
mostly does not care about the contents of td_sched.
Discussed with: julian
- Move the idle thread loop into the per scheduler area. ULE wants to
do something different from the other schedulers.
Suggested by: jhb
Tested on: x86/amd64 sched_{4BSD, ULE, CORE}.
used by clock code, so don't export it to the world for machdep.c to
initialize. There is a minor problem initializing it before it is
used, since although clock initialization is split up so that parts
of it can be done early, the first part was never done early enough
to actually work. Split it up a bit more and do the first part as
late as possible to document the necessary order. The functions that
implement the split are still bogusly exported.
Cleaned up initialization of the i8254 clock hardware using the new
split. Actually initialize it early enough, and don't work around it
not being initialized in DELAY() when DELAY() is called early for
initialization of some console drivers.
This unfortunately moves a little more code before the early debugger
breakpoint so that it is harder to debug. The ordering of console and
related initialization is delicate because we want to do as little as
possible before the breakpoint, but must initialize a console.
- First off, device drivers really do need to know if they are allocating
MSI or MSI-X messages. MSI requires allocating powerof2() messages for
example where MSI-X does not. To address this, split out the MSI-X
support from pci_msi_count() and pci_alloc_msi() into new driver-visible
functions pci_msix_count() and pci_alloc_msix(). As a result,
pci_msi_count() now just returns a count of the max supported MSI
messages for the device, and pci_alloc_msi() only tries to allocate MSI
messages. To get a count of the max supported MSI-X messages, use
pci_msix_count(). To allocate MSI-X messages, use pci_alloc_msix().
pci_release_msi() still handles both MSI and MSI-X messages, however.
As a result of this change, drivers using the existing API will only
use MSI messages and will no longer try to use MSI-X messages.
- Because MSI-X allows for each message to have its own data and address
values (and thus does not require all of the messages to have their
MD vectors allocated as a group), some devices allow for "sparse" use
of MSI-X message slots. For example, if a device supports 8 messages
but the OS is only able to allocate 2 messages, the device may make the
best use of 2 IRQs if it enables the messages at slots 1 and 4 rather
than default of using the first N slots (or indicies) at 1 and 2. To
support this, add a new pci_remap_msix() function that a driver may call
after a successful pci_alloc_msix() (but before allocating any of the
SYS_RES_IRQ resources) to allow the allocated IRQ resources to be
assigned to different message indices. For example, from the earlier
example, after pci_alloc_msix() returned a value of 2, the driver would
call pci_remap_msix() passing in array of integers { 1, 4 } as the
new message indices to use. The rid's for the SYS_RES_IRQ resources
will always match the message indices. Thus, after the call to
pci_remap_msix() the driver would be able to access the first message
in slot 1 at SYS_RES_IRQ rid 1, and the second message at slot 4 at
SYS_RES_IRQ rid 4. Note that the message slots/indices are 1-based
rather than 0-based so that they will always correspond to the rid
values (SYS_RES_IRQ rid 0 is reserved for the legacy INTx interrupt).
To support this API, a new PCIB_REMAP_MSIX() method was added to the
pcib interface to change the message index for a single IRQ.
Tested by: scottl
Dont expose em->shared to the outside world before its properly
initialized. Might not affect anything but its at least a better
coding style.
Dont expose em via p->p_emuldata until its properly initialized.
This also enables us to get rid of some locking and simplify the
code because we are workin on a local copy.
In linux_fork and linux_vfork create the process in stopped state
to be sure that the new process runs with fully initialized emuldata
structure [1]. Also fix the vfork (both in linux_clone and linux_vfork)
race that could result in never woken up process [2].
Reported by: Scot Hetzel [1]
Suggested by: jhb [2]
Reviewed by: jhb (at least some important parts)
Submitted by: rdivacky
Tested by: Scot Hetzel (on amd64)
Change 2 comments (in the new code) to comply to style(9).
Suggested by: jhb
KERNBASE for the first 1 MB of RAM instead of calling pmap_mapdev().
pmap_mapdev() knows how to handle the first 1 MB (and has known for a
while now) and properly maps the memory as UC to boot.
MFC after: 2 weeks
we actually issue preemptions.
- Remove the #ifdef IPI_PREEMPTION so it is always compiled in. Leave
the option which optionally enables support in sched_4bsd. sched_ule.c
will soon use this functionality as a run time rather than compile time
option.
- Compare against the idlethread rather than the priority. There are some
idle prio tasks that we can preempt.
Discussed with: ups
Tested on: i386, amd64
MPLOCKED. The cleaning in rev.1.25 was supposed to have been undone
by rev.1.26, but 1.26 could never have actually affected asm files
since atomic.h is full of C declarations so including it in asm files
would just give syntax errors. The asm MPLOCKED is even less needed
than when misplaced definitions of it were first removed, and is now
unused in any asm file in the src tree except in anachronismns in
sys/i386/i386/support.s.
These functions are used a lot for mutexes, so this reduces the text
size of an average kernel by about 0.75%. This wasn't intended to
be a significant optimization, but it somehow increased the maximum
number of packets per second that can be transmitted by my bge hardware
from 320000 to 460000 (this benchmark is CPU-bound and remarkably
sensitive to changes in the text section).
Details: we would prefer to leave the result of the cmpxchg in %al,
but cannot tell gcc that it is there, so we have to convert it to an
integer register. We converted to %al, then to %[re]ax, but the
latter step is usually wasted since gcc usually only wants the condition
code and can recover it from %al just as easily as from %[re]ax. Let
gcc promote %al in the few cases where this is needed.
Nearby style fixes;
- let gcc manage the load of `res', and don't abuse `res' for a copy of `exp'
- don't echo `res's name in comments
- consistently spell the condition code as 'e' after comparison for equality
- don't hard-code %al anywhere except in constraints
- for the version that doesn't use cmpxchg, there is no requirement to use
%al anywhere, so don't hard-code it in the constraints either.
Style non-fix:
- for the versions that use cmpxchg, keep using "a" (was %[re]ax, now %al)
for the main output operand, although this is not required. The input
and output operands that use the "a" constraint are now decoupled, and
this makes things clearer except for the reason that the output register
is hard-coded. It is now just a hack to tell gcc that the input "a" has
been clobbered without increasing the number of operands.
- Move linux_nanosleep() from src/sys/amd64/linux32/linux32_machdep.c to
src/sys/compat/linux/linux_time.c.
- Validate timespec ranges before use as Linux kernel does.
- Fix l_timespec structure.
- Clean up style(9) nits.
running thread's id on each cpu. This allow us to add in-kernel adaptive
spin for user level mutex. While spinning in user space is possible,
without correct thread running state exported from kernel, it hardly
can be implemented efficiently without wasting cpu cycles, however
exporting thread running state unlikely will be implemented soon as
it has to design and stablize interfaces. This implementation is
transparent to user space, it can be disabled dynamically. With this
change, mutex ping-pong program's performance is improved massively on
SMP machine. performance of mysql super-smack select benchmark is increased
about 7% on Intel dual dual-core2 Xeon machine, it indicates on systems
which have bunch of cpus and system-call overhead is low (athlon64, opteron,
and core-2 are known to be fast), the adaptive spin does help performance.
Added sysctls:
kern.threads.umtx_dflt_spins
if the sysctl value is non-zero, a zero umutex.m_spincount will
cause the sysctl value to be used a spin cycle count.
kern.threads.umtx_max_spins
the sysctl sets upper limit of spin cycle count.
Tested on: Athlon64 X2 3800+, Dual Xeon 5130
passed by value (trap frames) as if they were in fact being passed by
reference. For better or worse, this incorrect behaviour is no longer
present in gcc 4.1. In this patch I convert all trapframe arguments to
be explicitly pass by reference. I also remove vm86_initflags, pushing
the very little work that it actually does up into vm86_prepcall.
Reviewed by: kan
Tested by: kan
behave as expected.
Also:
- Return an error if WD_PASSIVE is passed in to the ioctl as only
WD_ACTIVE is implemented at the moment. See sys/watchdog.h for an
explanation of the difference between WD_ACTIVE and WD_PASSIVE.
- Remove the I_HAVE_TOTALLY_LOST_MY_SENSE_OF_HUMOR define. If you've
lost your sense of humor, than don't add a define.
Specific changes:
i80321_wdog.c
Don't roll your own passive watchdog tickle as this would defeat the
purpose of an active (userland) watchdog tickle.
ichwd.c / ipmi.c:
WD_ACTIVE means active patting of the watchdog by a userland process,
not whether the watchdog is active. See sys/watchdog.h.
kern_clock.c:
(software watchdog) Remove a check for WD_ACTIVE as this does not make
sense here. This reverts r1.181.
pcib_alloc_msix() methods instead of using the method from the generic
PCI-PCI bridge driver as the PCI-PCI methods will be gaining some PCI-PCI
specific logic soon.
to workaround the problem with SMP kernels on Turion64 X2 processors
described in kern/104678 and may be useful in other situations too.
MFC after: 3 days
Make part of John Birrell's KSE patch permanent..
Specifically, remove:
Any reference of the ksegrp structure. This feature was
never fully utilised and made things overly complicated.
All code in the scheduler that tried to make threaded programs
fair to unthreaded programs. Libpthread processes will already
do this to some extent and libthr processes already disable it.
Also:
Since this makes such a big change to the scheduler(s), take the opportunity
to rename some structures and elements that had to be moved anyhow.
This makes the code a lot more readable.
The ULE scheduler compiles again but I have no idea if it works.
The 4bsd scheduler still reqires a little cleaning and some functions that now do
ALMOST nothing will go away, but I thought I'd do that as a separate commit.
Tested by David Xu, and Dan Eischen using libthr and libpthread.
and by only delaying when an RTC register is written to. The delay
after writing to the data register is now not just a workaround.
This reduces the number of ISA accesses in the usual case from 4 to
1. The usual case is 2 rtcin()'s for each RTC interrupt. The index
register is almost always RTC_INTR for this. The 3 extra ISA accesses
were 1 for writing the index and 2 for delays. Some delays are needed
in theory, but in practice they now just slow down slow accesses some
more since almost eveyone including us does them wrong so modern systems
enforce sufficient delays in hardware. I used to have the delays ifdefed
out, but with the index register optimization the delays are rarely
executed so the old magic ones can be kept or even implemented non-
magically without significant cost.
Optimizing RTC interrupt handling is more interesting than it used to
be because RTC interrupts are currently needed to fix the more efficient
apic timer interrupts on some systems. apic_timer_hz is normally 2000
so the RTC interrupt rate needs to be 2048 to keep the apic timer
firing on such systems. Without these changes, each RTC interrupt
normally took 10 ISA accesses (2 PIC accesses and 2 sets of 4 RTC
accesses). Each ISA access takes 1-1.5uS so 10 of then at 2048 Hz
takes 2-3% of a CPU. Now 4 of them take 0.8-1.2% of a CPU.
by default for sun4v where it is absolutely required.
This change moves the buffer from struct pcpu to the stack to avoid
using the critical section which created a LOR in a couple of cases
due to interaction with the tty code and kqueue. The LOR can't be
fixed with the critical section and the pcpu buffer can't be used
without the critical section.
Putting the buffer on the stack was my initial solution, but it was
pointed out that the stress on the stack might cause problems
depending on the call path. We don't have a way of creating tests
for those possible cases, so it's best to leave this as an option
for the time being. In time we may get enough data to enable this
option more generally.
of various scattered magic values.
- Pretty print the address of hardware watchpoints in 'show watch' rather
than just displaying hex.
- Expand address field width on amd64 for 64-bit pointers.
- Drop the printf in intr_machdep.c when we assign an interrupt souce to
a CPU. Each source already has a more detailed printf.
- Don't output a line for each ioapic pin showing its initial state, this
has outlived its usefulness.
- When an APIC enumerator sets the bus, polarity, or trigger mode of an
ioapic pin, just return success without printing anything if the new
value matches the current one.
MFC after: 2 weeks
- Add a new apic_alloc_vectors() method to the local APIC support code
to allocate N contiguous IDT vectors (aligned on a M >= N boundary).
This function is used to allocate IDT vectors for a group of MSI
messages.
- Add MSI and MSI-X PICs. The PIC code here provides methods to manage
edge-triggered MSI messages as x86 interrupt sources. In addition to
the PIC methods, msi.c also includes methods to allocate and release
MSI and MSI-X messages. For x86, we allow for up to 128 different
MSI IRQs starting at IRQ 256 (IRQs 0-15 are reserved for ISA IRQs,
16-254 for APIC PCI IRQs, and IRQ 255 is reserved).
- Add pcib_(alloc|release)_msi[x]() methods to the MD x86 PCI bridge
drivers to bubble the request up to the nexus driver.
- Add pcib_(alloc|release)_msi[x]() methods to the x86 nexus drivers that
ask the MSI PIC code to allocate resources and IDT vectors.
MFC after: 2 months
of NKPT is no longer enough to run amd64 with 16G of RAM, as it
doesn't have space for mapping a kernel (16M kernel would require
additionally 8 page tables).
specific privilege names to a broad range of privileges. These may
require some future tweaking.
Sponsored by: nCircle Network Security, Inc.
Obtained from: TrustedBSD Project
Discussed on: arch@
Reviewed (at least in part) by: mlaier, jmg, pjd, bde, ceri,
Alex Lyashkov <umka at sevcity dot net>,
Skip Ford <skip dot ford at verizon dot net>,
Antoine Brodin <antoine dot brodin at laposte dot net>
it as a default.
For the record, the KDTRACE option caused _no_ additional source files
to be compiled in; certainly no CDDL source files. All it did was to
allow existing BSD licensed kernel files to include one or more CDDL
header files.
By removing this from DEFAULTS, the onus is on a kernel builder to add
the option to the kernel config, possibly by including GENERIC and
customising from there. It means that DTrace won't be a feature
available in FreeBSD by default, which is the way I intended it to be.
Without this option, you can't load the dtrace module (which contains
the dtrace device and the DTrace framework). This is equivalent to
requiring an option in a kernel config before you can load the linux
emulation module, for example.
I think it is a mistake to have DTrace ported to FreeBSD, but not
to have it available to everyone, all the time. The only exception
to this is the companies which distribute systems with FreeBSD embedded.
Those companies will customise their systems anyway. The KDTRACE
option was intended for them, and only them.
adds the hooks that DTrace modules register with, and adds a few functions
which have the dtrace_ prefix to allow the DTrace FBT (function boundary
trace) provider to avoid tracing because they are called from the DTtrace
probe context.
Unlike other forms of tracing and debug, DTrace support in the kernel
incurs negligible run-time cost.
I think the only reason why anyone wouldn't want to have kernel support
enabled for DTrace would be due to the license (CDDL) under which DTrace
is released.
a lock to prevent interspersed strings written from different CPUs
at the same time.
To avoid putting a buffer on the stack or having to malloc one,
space is incorporated in the per-cpu structure. The buffer
size if 128 bytes; chosen because it's the next power of 2 size
up from 80 characters.
String writes to the console are buffered up the end of the line
or until the buffer fills. Then the buffer is flushed to all
console devices.
Existing low level console output via cnputc() is unaffected by
this change. ithread calls to log() are also unaffected to avoid
blocking those threads.
A minor change to the behaviour in a panic situation is that
console output will still be buffered, but won't be written to
a tty as before. This should prevent interspersed panic output
as a number of CPUs panic before we end up single threaded
running ddb.
Reviewed by: scottl, jhb
MFC after: 2 weeks
dynamic nature (if no native aio code is available, the linux part
returns ENOSYS because of missing requisites) should be solved differently
than it is.
All this will be done in P4.
Not included in this commit is a backout of the changes to the native aio
code (removing static in some places). Those changes (and some more) will
also be needed when the reworked linux aio stuff will reenter the tree.
Requested by: rwatson
Discussed with: rwatson
not completely decided at config time. Just don't default to using
the TSC if there are multiple active CPUs. Also, don't default to
using the TSC if it is broken. SMP ifdefs are still used to disallow
using perfmon since perfmon is always broken if SMP is just configured.
This only helps much for SMP kernels running on 1 CPU. The overheads
for using the i8254 cputime clock were a bit too high on 486/33's, and
now on multi-GHz CPUs they are usually in the 99-99.9% range. Switching
from the old default of an i8254 clock to the TSC works poorly because
the overheads are not recalibrated.
Use the same condition for declaring perfmon stuff as for using it.
Fixed a syntax error for the (!__KERNEL && !__GNUCLIKE_ASM) case in
rev.1.36. Apparently, this case has never been reached even by lint.
Submitted by: stefanf
{amd64,i386}/include/profile.h:
In case the above case is actually reached, break it properly by
providing null support that will fail at link time instead of a stub
that gives wrong (null) profiling at runtime.
was only used in the GUPROF case, so the messes to get its i386 prerequisites
included shouldn't have been needed.
Fixed some style bugs. Quote #error contents, and don't repeat an #error
directive on amd64.
this used to be slightly cleaner than using ifdefs in a few places to
support both a.out and elf, but using it now just causes messes and
unportabilities. It seems to be impossible to implement the elf
HIDENAME() portably in cpp (since token pasting of "." and <name> is
invalid).
*/prof_machdep.c:
- Removed all uses of CNAME(). CNAME() is easy enough to use in pure
asm code, but using it in inline asm requires messy quoting. The
core pure asm code has been hacked on more and all uses of CNAME() in
it have already gone away. Just assume the elf convention here too.
- Removed now-uneeded include of <machine/asmacros.h>.
- Removed the workaround for a namespace conflict with this include.
profiling is configured but high resolution profiling is not configured.
Only functions in *.[Ss] called the stub, so efficiency was not
significantly affected.
The 'nooption' kernel config entry has to be used to turn KSE off now.
This isn't my preferred way of dealing with this, but I'll defer to
scottl's experience with the io/mem kernel option change and the grief
experienced over that.
Submitted by: scottl@
except sun4v.
This change makes the transition from a default to an option more
transparent and is an attempt to head off all the compliants that are
likely from people who don't read UPDATING, based on experience with
the io/mem change.
Submitted by: scottl@
begun with a repo-copy of mac.h to mac_framework.h. sys/mac.h now
contains the userspace and user<->kernel API and definitions, with all
in-kernel interfaces moved to mac_framework.h, which is now included
across most of the kernel instead.
This change is the first step in a larger cleanup and sweep of MAC
Framework interfaces in the kernel, and will not be MFC'd.
Obtained from: TrustedBSD Project
Sponsored by: SPARTA
be displayed specially, and debug registers are among of the least
interesting special registers (far behind %cr3). The debug registers
are still accessible as variables and displayed in another bogus place
("show watches").
Implement the linux_io_* syscalls (AIO). They are only enabled if the native
AIO code is available (either compiled in to the kernel or as a module) at
the time the functions are used. If the AIO stuff is not available there
will be a ENOSYS.
From the submitter:
---snip---
DESIGN NOTES:
1. Linux permits a process to own multiple AIO queues (distinguished by
"context"), but FreeBSD creates only one single AIO queue per process.
My code maintains a request queue (STAILQ of queue(3)) per "context",
and throws all AIO requests of all contexts owned by a process into
the single FreeBSD per-process AIO queue.
When the process calls io_destroy(2), io_getevents(2), io_submit(2) and
io_cancel(2), my code can pick out requests owned by the specified context
from the single FreeBSD per-process AIO queue according to the per-context
request queues maintained by my code.
2. The request queue maintained by my code stores contrast information between
Linux IO control blocks (struct linux_iocb) and FreeBSD IO control blocks
(struct aiocb). FreeBSD IO control block actually exists in userland memory
space, required by FreeBSD native aio_XXXXXX(2).
3. It is quite troubling that the function io_getevents() of libaio-0.3.105
needs to use Linux-specific "struct aio_ring", which is a partial mirror
of context in user space. I would rather take the address of context in
kernel as the context ID, but the io_getevents() of libaio forces me to
take the address of the "ring" in user space as the context ID.
To my surprise, one comment line in the file "io_getevents.c" of
libaio-0.3.105 reads:
Ben will hate me for this
REFERENCE:
1. Linux kernel source code: http://www.kernel.org/pub/linux/kernel/v2.6/
(include/linux/aio_abi.h, fs/aio.c)
2. Linux manual pages: http://www.kernel.org/pub/linux/docs/manpages/
(io_setup(2), io_destroy(2), io_getevents(2), io_submit(2), io_cancel(2))
3. Linux Scalability Effort: http://lse.sourceforge.net/io/aio.html
The design notes: http://lse.sourceforge.net/io/aionotes.txt
4. The package libaio, both source and binary:
http://rpmfind.net/linux/rpm2html/search.php?query=libaio
Simple transparent interface to Linux AIO system calls.
5. Libaio-oracle: http://oss.oracle.com/projects/libaio-oracle/
POSIX AIO implementation based on Linux AIO system calls (depending on
libaio).
---snip---
Submitted by: Li, Xiao <intron@intron.ac>
(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
just use the COULD_BOUNCE flag for both and retire the USE_FILTER flag.
This fixes the problem that rev 1.81 introduced with the if_bfe driver
(and possibly others).
- 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
of directory reading system calls.
Respell a mis-spelled event name.
Clean up white space/line wraps in a couple of places.
Assign event numbers to some new system call entries that have turned
up in the list since audit support was added.
Obtained from: TrustedBSD Project
behaves. This fixes a lot of test which failed before. For amd64 there
are still some problems, but without any testers which apply patches
and run some predefines tests we can't do more ATM.
Submitted by: Marcin Cieslak <saper@SYSTEM.PL> (minor fixups by myself)
Tested with: LTP
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
old/broken hardware. Unfortunately, it adds cache pressure and possible
mispredicted branches to the fast path of the bus_dmamap_load collection of
functions. Since it's meant for slow path exception processing, de-inline
it and allow its conditions to be pre-computed at tag_create time and thus
short-circuited at runtime.
While here, cut down on the size of _bus_dmamap_load_buffer() by pushing the
bounce page logic into a non-inlined function. Again, this helps with
cache pressure and mispredicted branches.
According to the TSC, this shaves off a few cycles on average. Unfortunately,
the data varies quite a bit due to interrupts and preemption, so it's hard to
get a good measurement. Real world measurements of network PPS are welcomed.
A merge to amd64 and other arches is pending more testing.
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
from both the acpi module build directory and a kernel build directory.
The latter didn't work when one attempted to build a kernel which had
"device acpi" with the "make kernel-toolchain buildkernel" command
because a cross-compiler couldn't find anything in the standard system
include path (it's empty in the kernel-toolchain case).
Fix this by passing a better root path to kernel headers (src/sys)
which works for both cases, kernel and module (-I@ only worked for
module).
Also, while here, pass -nostdinc (and a different spelling for icc) --
it's a feature that the kernel source tree is self-contained, and this
change enforces this.
Reported by: glebius
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
other stuff) in the osrelease=2.6.16 case:
- implement CLONE_PARENT semantic
- fix TLS loading in clone CLONE_SETTLS
- lock proc in the currently disabled part of CLONE_THREAD
I suggest to not unload the linux module after testing this, there are
some "<defunct>" processes hanging around after exiting (they aren't
with osrelease=2.4.2) and they may panic your kernel when unloading the
linux module. They are in state Z and some of them consume CPU according
to ps. But I don't trust the CPU part, the idle threads gets too much CPU
that this may be possible (accumulating idle, X and 2 defunct processes
results in 104.7%, this looks to much to be a rounding error).
Noticed by: Intron <mag@intron.ac>
Submitted by: rdivacky (in collaboration with Intron)
Tested by: Intron, netchild
Reviewed by: jhb (previous version)
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
- 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.
line switch. Other files which may make the same mistake (according to
fxr.watson.org) but aren't fixed in this commit (people with more clue
about those files should fix this):
- i386/xbox/xbox.c
- arm/arm/elf_trampoline.c
- arm/arm/mem.c
Noticed by: cognet
- 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
Giant VFS locking in that function.
- Remove bogus code to handle the case where namei() returns success but a
NULL vnode pointer.
- Note that this code duplicates exec_check_permissions() and annotate
where it differs.
- Hold the vnode lock longer to protect the write to set VV_TEXT in
v_vflag.
- Mark linux_uselib() MPSAFE.
Reviewed by: rwatson
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_clear_ptes() is already convoluted. This will worsen with the
implementation of superpages. Eliminate it and add pmap_clear_write().
There are no functional changes. Checked by: md5
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.
Make three simplifications to pmap_ts_referenced():
Eliminate an initialized but otherwise unused variable.
Eliminate an unnecessary test.
Exit the loop in a shorter way.
