a fast interrupt handler doing an swi_sched(). This fixed the lockups I
saw on my laptop when using xmms in KDE and on rwatson's MySQL benchmarks
on SMP. This will eventually be removed and/or modified when I figure out
what the root cause is and fix that.
pmap_remove_page(). The reason being that pmap_pte_quick() requires
the page queues lock, which is already held, rather than Giant.
- Assert that the page queues lock is held in pmap_remove_page() and
pmap_remove_pte().
future:
rename ttyopen() -> tty_open() and ttyclose() -> tty_close().
We need the ttyopen() and ttyclose() for the new generic cdevsw
functions for tty devices in order to have consistent naming.
pmap_protect() and pmap_remove(). In general, they require the lock in
order to modify a page's pv list or flags. In some cases, however,
pmap_protect() can avoid acquiring the lock.
for unknown events.
A number of modules return EINVAL in this instance, and I have left
those alone for now and instead taught MOD_QUIESCE to accept this
as "didn't do anything".
pmap_remove_pages(). (The implementation of pmap_remove_pages() is
optional. If pmap_remove_pages() is unimplemented, the acquisition and
release of the page queues lock is unnecessary.)
Remove spl calls from the alpha, arm, and ia64 pmap_remove_pages().
a problem that could also be fixed differently without reverting previous
attempts to fix DELAY while the debugger is active (rev 1.204). The bug
was that the i8254 implements a countdown timer, while for (k)db_active
a countup timer was implemented. This resulted in premature termination
and consequently the breakage of DELAY. The fix (relative to rev 1.211)
is to implement a countdown timer for the kdb_active case. As such the
ability to step clock initialization is preserved and DELAY does what is
expected of it.
Blushed: bde :-)
Submitted by: bde
Most of the changes are a direct result of adding thread awareness.
Typically, DDB_REGS is gone. All registers are taken from the
trapframe and backtraces use the PCB based contexts. DDB_REGS was
defined to be a trapframe on all platforms anyway.
Thread awareness introduces the following new commands:
thread X switch to thread X (where X is the TID),
show threads list all threads.
The backtrace code has been made more flexible so that one can
create backtraces for any thread by giving the thread ID as an
argument to trace.
With this change, ia64 has support for breakpoints.
o Make debugging code conditional upon KDB instead of DDB.
o Declare ksym_start and ksym_end as extern and initialize them.
This was previously and bogusly handled by DDB itself.
o Call kdb_enter() instead of Debugger().
o Remove implementation of Debugger().
debugger is not active. The fixes breakages of DELAY() when
running in the debugger, because not calling getit() when the
debugger is active yields a DELAY that doesn't.
o s/ddb_on_nmi/kdb_on_nmi/g
o Rename sysctl machdep.ddb_on_nmi to machdep.kdb_on_nmi
o Make debugging support conditional upon KDB instead of DDB.
o Call kdb_reenter() when kdb_active is non-zero.
o Call kdb_trap() to enter the debugger when not already active.
o Update comments accordingly.
o Remove misplaced prototype of kdb_trap().
o Make debugging code conditional upon KDB instead of DDB.
o Call kdb_enter() instead of Debugger().
o Remove local (static) variable in_debugger. Use kdb_active instead.
a PCB from a trapframe for purposes of unwinding the stack. The PCB
is used as the thread context and all but the thread that entered the
debugger has a valid PCB.
This function can also be used to create a context for the threads
running on the CPUs that have been stopped when the debugger got
entered. This however is not done at the time of this commit.
in which multiple (presumably different) debugger backends can be
configured and which provides basic services to those backends.
Besides providing services to backends, it also serves as the single
point of contact for any and all code that wants to make use of the
debugger functions, such as entering the debugger or handling of the
alternate break sequence. For this purpose, the frontend has been
made non-optional.
All debugger requests are forwarded or handed over to the current
backend, if applicable. Selection of the current backend is done by
the debug.kdb.current sysctl. A list of configured backends can be
obtained with the debug.kdb.available sysctl. One can enter the
debugger by writing to the debug.kdb.enter sysctl.
backend improves over the old GDB support in the following ways:
o Unified implementation with minimal MD code.
o A simple interface for devices to register themselves as debug
ports, ala consoles.
o Compression by using run-length encoding.
o Implements GDB threading support.
bootp -> BOOTP
bootp.nfsroot -> BOOTP_NFSROOT
bootp.nfsv3 -> BOOTP_NFSV3
bootp.compat -> BOOTP_COMPAT
bootp.wired_to -> BOOTP_WIRED_TO
- i.e. back out the previous commit. It's already possible to
pxeboot(8) with a GENERIC kernel.
Pointed out by: dwmalone
BOOTP -> bootp
BOOTP_NFSROOT -> bootp.nfsroot
BOOTP_NFSV3 -> bootp.nfsv3
BOOTP_COMPAT -> bootp.compat
BOOTP_WIRED_TO -> bootp.wired_to
This lets you PXE boot with a GENERIC kernel by putting this sort of thing
in loader.conf:
bootp="YES"
bootp.nfsroot="YES"
bootp.nfsv3="YES"
bootp.wired_to="bge1"
or even setting the variables manually from the OK prompt.
When two drivers share an ISA DMA channel, they both call isa_dmainit()
and the second call fails if DIAGNOSTIC is on.
If isa_dmainit() was already called successfully, just return silently.
This only works if both drivers agree on the bounce buffer size,
but since sharing DMA is usually only possible on very special
hardware and then typically only for devices of the same type (which
would have multiple instances of the same device driver), this is
not a problem in practice.
belong in the respective drivers. I've not removed ALL of them, as a
few still haven't moved. I've just removed the ones that aren't used.
# these can be removed from amd64, but I'm having issues getting to
# sledge at the moment for a build.
honor the alignment and boundary constraints in the dma tag when loading
buffers. Previously, these constraints were only honored when allocating
memory via bus_dmamem_alloc(). Now, bus_dmamap_load() will automatically
use bounce buffers when needed.
Also add a set of sysctls to monitor the global busdma stats. These are:
hw.busdma.free_bpages
hw.busdma.reserved_bpages
hw.busdma.active_bpages
hw.busdma.total_bpages
hw.busdma.total_bounced
hw.busdma.total_deferred
than as one-off hacks in various other parts of the kernel:
- Add a function maybe_preempt() that is called from sched_add() to
determine if a thread about to be added to a run queue should be
preempted to directly. If it is not safe to preempt or if the new
thread does not have a high enough priority, then the function returns
false and sched_add() adds the thread to the run queue. If the thread
should be preempted to but the current thread is in a nested critical
section, then the flag TDF_OWEPREEMPT is set and the thread is added
to the run queue. Otherwise, mi_switch() is called immediately and the
thread is never added to the run queue since it is switch to directly.
When exiting an outermost critical section, if TDF_OWEPREEMPT is set,
then clear it and call mi_switch() to perform the deferred preemption.
- Remove explicit preemption from ithread_schedule() as calling
setrunqueue() now does all the correct work. This also removes the
do_switch argument from ithread_schedule().
- Do not use the manual preemption code in mtx_unlock if the architecture
supports native preemption.
- Don't call mi_switch() in a loop during shutdown to give ithreads a
chance to run if the architecture supports native preemption since
the ithreads will just preempt DELAY().
- Don't call mi_switch() from the page zeroing idle thread for
architectures that support native preemption as it is unnecessary.
- Native preemption is enabled on the same archs that supported ithread
preemption, namely alpha, i386, and amd64.
This change should largely be a NOP for the default case as committed
except that we will do fewer context switches in a few cases and will
avoid the run queues completely when preempting.
Approved by: scottl (with his re@ hat)
pv entries per 1GB of user virtual memory. (eg: if we had 1GB file was
mmaped into 30 processes, that would theoretically reduce the KVA demand by
30MB for pv entries. In reality though, we limit pv entries so we don't
have that many at once.)
We used to store the vm_page_t for the page table page. But we recently
had the pa of the ptp, or can calculate it fairly quickly. If we wanted
to avoid the shift/mask operation in pmap_pde(), we could recover the
pa but that means we have to store it for a while.
This does not measurably change performance.
Suggested by: alc
Tested by: alc
