- add rm_try_rlock().
- add RM_SLEEPABLE to use sx(9) as the back-end lock in order to sleep while
holding the write lock.
- change rm_noreadtoken to a cpu bitmask to indicate which CPUs need to go
through the lock/unlock in order to synchronize. As a side effect, this
also avoids IPI to CPUs without any readers during rm_wlock.
Discussed with: ups@, rwatson@ on arch@
Sponsored by: Isilon Systems, Inc.
o Enforce TX/RX descriptor ring alignment. NS data sheet says the
controller needs 4 bytes alignment but use 16 to cover both SiS
and NS controllers. I don't have SiS data sheet so I'm not sure
what is alignment restriction of SiS controller but 16 would be
enough because it's larger than the size of a TX/RX descriptor.
Previously sis(4) ignored the alignment restriction.
o Enforce RX buffer alignment, 4.
Previously sis(4) ignored RX buffer alignment restriction.
o Limit number of TX DMA segment to be used to 16. It seems
controller has no restriction on number of DMA segments but
using more than 16 looks resource waste.
o Collapse long mbuf chains with m_collapse(9) instead of calling
expensive m_defrag(9).
o TX/RX side bus_dmamap_load_mbuf_sg(9) support and remove
unnecessary callbacks.
o Initial endianness support.
o Prefer local alignment fixup code to m_devget(9).
o Pre-allocate TX/RX mbuf DMA maps instead of creating/destroying
these maps in fast TX/RX path. On non-x86 architectures, this is
very expensive operation and there is no need to do that.
o Add missing bus_dmamap_sync(9) in TX/RX path.
o watchdog is now unarmed only when there are no pending frames
on controller. Previously sis(4) blindly unarmed watchdog
without checking the number of queued frames.
o For efficiency, loaded DMA map is reused for error frames.
o DMA map loading failure is now gracefully handled. Previously
sis(4) ignored any DMA map loading errors.
o Nuke unused macros which are not appropriate for endianness
operation.
o Stop embedding driver maintained structures into descriptor
rings. Because TX/RX descriptor structures are shared between
host and controller, frequent bus_dmamap_sync(9) operations are
required in fast path. Embedding driver structures will increase
the size of DMA map which in turn will slow down performance.
- set cache_coherent_dma flag in cpuinfo for XLR, this will make sure that
BUS_DMA_COHERENT flag is handled correctly in busdma_machdep.c
- iodi.c, call device_get_name() just once
- clear RMI specific EIRR while intializing CPUs
- remove debug print in intr_machdep.c
which also avoids NULL pointer arithmetic, as suggested by jhb. The
available space goes from 11 bytes to 7.
Reviewed by: nyan
Approved by: rpaulo (mentor)
module private type, when private type mutex is locked/unlocked, thread
critical region is entered or leaved. These changes makes fork()
async-signal safe which required by POSIX. Note that user's atfork handler
still needs to be async-signal safe, but it is not problem of libthr, it
is user's responsiblity.
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
not change interrupt vector if it is not pointing the ROM itself. Actually,
we just fail shadowing altogether if that is the case because the shadowed
copy will be useless for sure and POST may not be relocatable or useful.
While I'm here, fix a debugging message under bootverbose, really. r211829
fixed one case but broke another. Mea Culpa.
or not by comparing reported TX consumer index with saved index. So
remove unnecessary check done after freeing transmitted mbufs.
While I'm here nuke unnecessary variable initializations.
tag. All controllers that are not BCM5755 or higher have 4GB
boundary DMA bug. Previously bge(4) used 32bit DMA address to
workaround the bug(r199670). However this caused the use of bounce
buffers such that it resulted in poor performance for systems which
have more than 4GB memory. Because bus_dma(9) honors boundary
restriction requirement of DMA tag for dynamic buffers, having a
separate TX/RX mbuf DMA tag will greatly reduce the possibility of
using bounce buffers. For DMA buffers allocated with
bus_dmamem_alloc(9), now bge(4) explicitly checks whether the
requested memory region crossed the boundary or not.
With this change, only the DMA buffer that crossed the boundary
will use 32bit DMA address. Other DMA buffers are not affected as
separate DMA tag is created for each DMA buffer.
Even if 32bit DMA address space is used for a buffer, the chance to
use bounce buffer is still very low as the size of buffer is small.
This change should eliminate most usage of bounce buffers on
systems that have more than 4GB memory.
More correct fix would be teaching bus_dma(9) to honor boundary
restriction for buffers created with bus_dmamem_alloc(9) but it
seems that is not easy.
While I'm here cleanup bge_dma_map_addr() and remove unnecessary
member variables in bge_dmamap_arg structure.
Tested by: marcel
gnu/lib/libobjc and sys/boot/i386/boot2, so it also works when using
absolute paths and/or options, as in CC="/absolute/path/clang -foo".
Approved by: rpaulo (mentor)
the existing code was very platform specific, and broken for SMP systems
trying to reboot from KDB.
- Add a new PLATFORM_RESET() method to the platform KOBJ interface, and
migrate existing reset functions into platform modules.
- Modify the OF_reboot() routine to submit the request by hand to avoid
the IPIs involved in the regular openfirmware() routine. This fixes
reboot from KDB on SMP machines.
- Move non-KDB reset and poweroff functions on the Powermac platform
into the relevant power control drivers (cuda, pmu, smu), instead of
using them through the Open Firmware backdoor.
- Rename platform_chrp to platform_powermac since it has become
increasingly Powermac specific. When we gain support for IBM systems,
we will grow a new platform_chrp.
signals, because it is managed by debugger, however a normal signal sent to
a interruptibly sleeping thread wakes up the thread so it will handle the
signal when the process leaves the stopped state.
PR: 150138
MFC after: 1 week
of the lower level vnode is incremented to greater than 1 when
the upper level vnode's v_usecount is greater than one. This
is necessary for the NFS clients, so that they will do a silly
rename of the file instead of actually removing it when the
file is still in use. It is "racy", since the v_usecount is
incremented in many places in the kernel with
minimal synchronization, but an extraneous silly rename is
preferred to not doing a silly rename when it is required.
The only other file systems that currently check the value
of v_usecount in their VOP_REMOVE() functions are nwfs and
smbfs. These file systems choose to fail a remove when the
v_usecount is greater than 1 and I believe will function
more correctly with this patch, as well.
Tested by: to.my.trociny at gmail.com
Submitted by: to.my.trociny at gmail.com (earlier version)
Reviewed by: kib
MFC after: 2 weeks
