compile option. All FreeBSD packet filters now use the PFIL_HOOKS API and
thus it becomes a standard part of the network stack.
If no hooks are connected the entire packet filter hooks section and related
activities are jumped over. This removes any performance impact if no hooks
are active.
Both OpenBSD and DragonFlyBSD have integrated PFIL_HOOKS permanently as well.
The C code assumes that the carry bit is always kept from the previous
operation. However, the pointer indexing requires another add operation.
Thus, the carry bit from the first operation is tromped over by the
"addl" operation that ends up following it, so the "adcl" that follows
that has no effect because the carry bit is cleared before it.
The result is checksum failure on received packets.
The larger issue is that there isn't any other way of preventing the compiler
inserting arbitrary instructions between different __asm statements (and
that the commit message in revision 1.13 of in_cksum.h is wrong on
this point). From
http://developer.apple.com/documentation/DeveloperTools/gcc-3.3/gcc/Extended-Asm.html
---8<---8<---8<---
You can't expect a sequence of volatile asm instructions to remain
perfectly consecutive. If you want consecutive output, use a single
asm. Also, GCC will perform some optimizations across a volatile
asm instruction; GCC does not "forget everything" when it encounters
a volatile asm instruction the way some other compilers do.
---8<---8<---8<---
Also, this change also makes the ASM code much easier to read.
PR: 69257
Submitted by: Mike Bristow <mike@urgle.com>, Qing Li <qing.li@bluecoat.com>
directly. This removes a few more users of the stackgap and also marks
the syscalls using these wrappers MP safe where appropriate.
Tested on: i386 with linux acroread5
Compiled on: i386, alpha LINT
We were obtaining different spin mutexes (which disable interrupts after
aquisition) and spin waiting for delivery. For example, KSE processes
do LDT operations which use smp_rendezvous, while other parts of the
system are doing things like tlb shootdowns with a different mutex.
This patch uses the common smp_rendezvous mutex for all MD home-grown
IPIs that spinwait for delivery. Having the single mutex means that
the spinloop to aquire it will enable interrupts periodically, thus
avoiding the cross-ipi deadlock.
Obtained from: dwhite, alc
Reviewed by: jhb
with VmWare 4.x. At least with VmWare version 4.5.2, i386 version of
atomic_cmpset_int() is about 30 times slower than non-i386 version. It
makes this delta a good 5.3 MFC candidate, since otherwise it will
mislead users who run FreeBSD under modern VmWare otherwise.
Since pmap_enter() calls pmap_invalidate_page(), which needs interrupts
enabled in the SMP case, we defer the disable to right before saving the
register context. This has been incorrect for about a year but caused no
real problems because the identity page never actually replaces a previously
mapped page and suspend/resume on SMP systems has been uncommon.
Tested by: sos
MFC after: 3 days
parent rather than track resources locally. The original code
was incomplete in that it would only honor requests for resources
that already exist in its resource list. This prevented many ISA
identify routines from allocating temporary resources. Passing
the requests up to legacy's parent losing no functionality and
allows these requests to succeed.
Reviewed by: imp, jhb
Approved by: RE
logical CPUs on a system to be used as a dedicated watchdog to cause a
drop to the debugger and/or generate an NMI to the boot processor if
the kernel ceases to respond. A sysctl enables the watchdog running
out of the processor's idle thread; a callout is launched to reset a
timer in the watchdog. If the callout fails to reset the timer for ten
seconds, the watchdog will fire. The sysctl allows you to select which
CPU will run the watchdog.
A sample "debug.leak_schedlock" is included, which causes a sysctl to
spin holding sched_lock in order to trigger the watchdog. On my Xeons,
the watchdog is able to detect this failure mode and break into the
debugger, which cannot otherwise be done without an NMI button.
This option does not currently work with sched_ule due to ule's push
notion of scheduling, similar to machdep.hlt_logical_cpus failing to
work with that scheduler.
On face value, this might seem somewhat inefficient, but there are a
lot of dual-processor Xeons with HTT around, so using one as a watchdog
for testing is not as inefficient as one might fear.
* Serialize access to the sysctl routines and the notify handler
* Assert that the sx lock is held in any functions they call.
* Note that recursively calling to re-enable the hotkeys is sub-optimal.
to allow dumping per-thread machine specific notes. On ia64 we use this
function to flush the dirty registers onto the backingstore before we
write out the PRSTATUS notes.
Tested on: alpha, amd64, i386, ia64 & sparc64
Not tested on: arm, powerpc
a standard configuration similar to [NO_]ADAPTIVE_MUTEXES. This
feature causes Giant to be included in the set of mutexes adaptively
spun on. It appears to have a positive effect on performance on SMP
across several workloads, including measurements of a 16% improvement
on buildworld, and 30%+ improvement for MySQL using the supersmack
benchmark with Giant over the network stack; a 6% improvement without
Giant on the network stack (as a result of less giant contention).
fix the obvious bugs, nastier ones reside below the surfac), and having
it commented out here just encourages people to try it.
# I'm not removing it from the base system, yet.
calls. Note that the information included is a bit different from the
existing KTR traces generated on powerpc, as I'm primarily interested
in kernel context (thread, syscall #, proc, etc), not the user
arguments to the system call. Some convergence would be useful here.
location (for the wake code). It should not be needed since we don't
map other pages at the same location and if there was an old mapping, it
would be restored by a fault. The old code had serious problems, namely
that it was restoring the new page it had just removed (not opage) and
it could only guess at the right protection (since there's no
pmap_extract_protect function). Thanks to Alan Cox for explaining much
of this to me.
Also, remove a commented-out initializecpu() call since it is not needed.
Restoring the cpu context is better than attempting to init from scratch.
Reviewed by: alc (earlier version)
spin-wait code to use the same spin mutex (smp_tlb_mtx) as the TLB ipi
and spin-wait code snippets so that you can't get into the situation of
one CPU doing a TLB shootdown to another CPU that is doing a lazy pmap
shootdown each of which are waiting on each other. With this change, only
one of the CPUs would do an IPI and spin-wait at a time.
vm_page_sleep_if_busy() and the page table page's busy flag as a
synchronization mechanism on page table pages.
Also, relocate the inline pmap_unwire_pte_hold() so that it can be used
to shorten _pmap_unwire_pte_hold() on alpha and amd64. This places
pmap_unwire_pte_hold() next to a comment that more accurately describes
it than _pmap_unwire_pte_hold().
being defined, define and use a new MD macro, cpu_spinwait(). It only
expands to something on i386 and amd64, so the compiled code should be
identical.
Name of the macro found by: jhb
Reviewed by: jhb
pic_eoi_source() into one call. This halves the number of spinlock operations
and indirect function calls in the normal case of handling a normal (ithread)
interrupt. Optimize the atpic and ioapic drivers to use inlines where
appropriate in supporting the intr_execute_handlers() change.
This knocks 900ns, or roughly 1350 cycles, off of the time spent servicing an
interrupt in the common case on my 1.5GHz P4 uniprocessor system. SMP systems
likely won't see as much of a gain due to the ioapic being more efficient than
the atpic. I'll investigate porting this to amd64 soon.
Reviewed by: jhb
their own directory and module, leaving the MD parts in the MD
area (the MD parts _are_ part of the modules). /dev/mem and /dev/io
are now loadable modules, thus taking us one step further towards
a kernel created entirely out of modules. Of course, there is nothing
preventing the kernel from having these statically compiled.
- Enable recursion on the page queues lock. This allows calls to
vm_page_alloc(VM_ALLOC_NORMAL) and UMA's obj_alloc() with the page
queues lock held. Such calls are made to allocate page table pages
and pv entries.
- The previous change enables a partial reversion of vm/vm_page.c
revision 1.216, i.e., the call to vm_page_alloc() by vm_page_cowfault()
now specifies VM_ALLOC_NORMAL rather than VM_ALLOC_INTERRUPT.
- Add partial locking to pmap_copy(). (As a side-effect, pmap_copy()
should now be faster on i386 SMP because it no longer generates IPIs
for TLB shootdown on the other processors.)
- Complete the locking of pmap_enter() and pmap_enter_quick(). (As of now,
all changes to a user-level pmap on alpha, amd64, and i386 are performed
with appropriate locking.)
dereference curthread. It is called only from critical_{enter,exit}(),
which already dereferences curthread. This doesn't seem to affect SMP
performance in my benchmarks, but improves MySQL transaction throughput
by about 1% on UP on my Xeon.
Head nodding: jhb, bmilekic
the thread ID and call db_trace_thread().
Since arm has all the logic in db_stack_trace_cmd(), rename the
new DB_COMMAND function to db_stack_trace to avoid conflicts on
arm.
While here, have db_stack_trace parse its own arguments so that
we can use a more natural radix for IDs. If the ID is not a thread
ID, or more precisely when no thread exists with the ID, try if
there's a process with that ID and return the first thread in it.
This makes it easier to print stack traces from the ps output.
requested by: rwatson@
tested on: amd64, i386, ia64
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
