operations to dump a ktrace event out to an output file are now handled
asychronously by a ktrace worker thread. This enables most ktrace events
to not need Giant once p_tracep and p_traceflag are suitably protected by
the new ktrace_lock.
There is a single todo list of pending ktrace requests. The various
ktrace tracepoints allocate a ktrace request object and tack it onto the
end of the queue. The ktrace kernel thread grabs requests off the head of
the queue and processes them using the trace vnode and credentials of the
thread triggering the event.
Since we cannot assume that the user memory referenced when doing a
ktrgenio() will be valid and since we can't access it from the ktrace
worker thread without a bit of hassle anyways, ktrgenio() requests are
still handled synchronously. However, in order to ensure that the requests
from a given thread still maintain relative order to one another, when a
synchronous ktrace event (such as a genio event) is triggered, we still put
the request object on the todo list to synchronize with the worker thread.
The original thread blocks atomically with putting the item on the queue.
When the worker thread comes across an asynchronous request, it wakes up
the original thread and then blocks to ensure it doesn't manage to write a
later event before the original thread has a chance to write out the
synchronous event. When the original thread wakes up, it writes out the
synchronous using its own context and then finally wakes the worker thread
back up. Yuck. The sychronous events aren't pretty but they do work.
Since ktrace events can be triggered in fairly low-level areas (msleep()
and cv_wait() for example) the ktrace code is designed to use very few
locks when posting an event (currently just the ktrace_mtx lock and the
vnode interlock to bump the refcoun on the trace vnode). This also means
that we can't allocate a ktrace request object when an event is triggered.
Instead, ktrace request objects are allocated from a pre-allocated pool
and returned to the pool after a request is serviced.
The size of this pool defaults to 100 objects, which is about 13k on an
i386 kernel. The size of the pool can be adjusted at compile time via the
KTRACE_REQUEST_POOL kernel option, at boot time via the
kern.ktrace_request_pool loader tunable, or at runtime via the
kern.ktrace_request_pool sysctl.
If the pool of request objects is exhausted, then a warning message is
printed to the console. The message is rate-limited in that it is only
printed once until the size of the pool is adjusted via the sysctl.
I have tested all kernel traces but have not tested user traces submitted
by utrace(2), though they should work fine in theory.
Since a ktrace request has several properties (content of event, trace
vnode, details of originating process, credentials for I/O, etc.), I chose
to drop the first argument to the various ktrfoo() functions. Currently
the functions just assume the event is posted from curthread. If there is
a great desire to do so, I suppose I could instead put back the first
argument but this time make it a thread pointer instead of a vnode pointer.
Also, KTRPOINT() now takes a thread as its first argument instead of a
process. This is because the check for a recursive ktrace event is now
per-thread instead of process-wide.
Tested on: i386
Compiles on: sparc64, alpha
is currently conditional on both the GEOM and GEOM_GPT options to
avoid getting GPT by default and having the MBR and GPT classes
clash.
The correct behaviour of the MBR class would be to back-off (reject)
a MBR if it's a Protective MBR (a MBR with a single partition of type
0xEE that spans the whole disk (as far as the MBR is concerned).
The correct behaviour if the GPT class would be to back-off (reject)
a GPT if there's a MBR that's not a Protective MBR.
At this stage it's inconvenient to destroy a good MBR when working
with GPTs that it's more convenient to have the MBR class back-off
when it detects the GPT signature on disk and have the GPT class
ignore the MBR.
In sys/gpt.h UUIDs (GUIDs) for the following FreeBSD partitions
have been defined:
GPT_ENT_TYPE_FREEBSD
FreeBSD slice with disklabel. This is the equivalent of
the well-known FreeBSD MBR partition type.
GPT_ENT_TYPE_FREEBSD_{SWAP|UFS|UFS2|VINUM}
FreeBSD partitions in the context of disklabel. This is
speculating on the idea to use the GPT to hold partitions
instead if slices and removing the fixed (and low) limits
we have on the number of partitions.
This commit lacks a GPT image for the regression suite.
option is used (not on by default).
- In the case of trying to lock a mutex, if the MTX_CONTESTED flag is set,
then we can safely read the thread pointer from the mtx_lock member while
holding sched_lock. We then examine the thread to see if it is currently
executing on another CPU. If it is, then we keep looping instead of
blocking.
- In the case of trying to unlock a mutex, it is now possible for a mutex
to have MTX_CONTESTED set in mtx_lock but to not have any threads
actually blocked on it, so we need to handle that case. In that case,
we just release the lock as if MTX_CONTESTED was not set and return.
- We do not adaptively spin on Giant as Giant is held for long times and
it slows SMP systems down to a crawl (it was taking several minutes,
like 5-10 or so for my test alpha and sparc64 SMP boxes to boot up when
they adaptively spinned on Giant).
- We only compile in the code to do this for SMP kernels, it doesn't make
sense for UP kernels.
Tested on: i386, alpha, sparc64
IFS had its fingers deep in the belly of the UFS/FFS split. IFS
will be reimplemented by the maintainer at a later date.
Requested by: adrian (maintainer)
ever connect a SCSI Cdrom/Tape/Jukebox/Scanner/Printer/kitty-litter-scooper
to your high-end RAID controller. The interface to the arrays is still
via the block interface; this merely provides a way to circumvent the
RAID functionality and access the SCSI buses directly. Note that for
somewhat obvious reasons, hard drives are not exposed to the da driver
through this interface, though you can still talk to them via the pass
driver. Be the first on your block to low-level format unsuspecting
drives that are part of an array!
To enable this, add the 'aacp' device to your kernel config.
MFC after: 3 days
drivers with MI portions into the MI notes. Device drivers such as busses
like the isa, eisa, and pci devices are now in the MD NOTES section even
though they have some MI code. This will ensure that only the proper bits
of device drivers will be included due to the optional bits dependent on
the busses in sys/conf/files. This commit also takes the stance that since
hints are ignored in NOTES anyways, it is ok to include hints for a bus
that may not be present.
Advice from: bde
Unfortunately, this level doesn't really provide enough granularity. We
probably need several MI NOTES type files for things that are shared by
several architectures but not by all. For example, the PCI options could
live in a NOTES.pci.
This also updates the Makefile for i386 to generate LINT. The only changes
in the generated LINT are the order of various options.
Suggestions for improvement welcome.
and commenting of NETSMB, NETWMBCRYPTO, and SMBFS. In NOTES, they
had all floated to the bottom of the file with the list of seemingly
random and unclassified kernel options. This change moves them back
up to the network protocol and file system areas, and also documents
the dependencies.
the structure definitions come from NetBSD to make it easier to share card
definitions. The driver only acts as a shim between the pci bus and the
sio driver. Later pci parallel ports could also be supported through this
driver. Support for most single and multiport pci serial cards should be
as simple as adding its definition to pucdata.c
Tested with the following pci cards:
Moxa Industio CP-114, 4 port RS-232,RS-422/485
Syba Tech Ltd. PCI-4S2P-550-ECP, 4 port RS-232 + 2 parallel ports
Netmos NM9835 PCI-2S-550, 2 port RS-232
ACPI_NO_SEMAPHORES, ASR_MEASURE_PERFORMANCE, AST_DEBUG, ATAPI_DEBUG,
ATA_DEBUG, BKTR_ALLOC_PAGES, BROOKTREE_ALLOC_PAGES, CAPABILITIES,
COMPAT_SUNOS, CV_DEBUG, MAXFILES, METEOR_TEST_VIDEO, NDEVFSINO,
NDEVFSOVERFLOW, NETGRAPH_BRIDGE, NETSMB, NETSMBCRYPTO, PFIL_HOOKS,
SIMOS, SMBFS, VESA_DEBUG, VGA_DEBUG.
Start using #! to comment out negative options and ## to comment out
broken options.
atapi-all.c:
Fixed rotted bits that were hiding under ATAPI_DEBUG.
atapi-cd.c:
#include "opt_ata.h" so that ACD_DEBUG is actually visible.
ata/atapi-tape.c
#include "opt_ata.h" so that AST_DEBUG is actually visible.
descriptors. This simplifies code for jumbo frames.
- Cleaned up coding conventions to make code more unix-like.
- Cleaned up code in if_em_fxhw.c and if_em_phy.c.
Added relevant comments.
MFC after: 1 week
feature bit on newer Athlon CPUs if the BIOS has forgotten to enable
it.
This patch was constructed using some info made available by John
Clemens at http://www.deater.net/john/PavilionN5430.html
Reviewed by: -audit
MFC after: 3 weeks
prior ICP Vortex models. This driver was developed by Achim Leubner
of Intel (previously with ICP Vortex) and Boji Kannanthanam of Intel.
Submitted by: "Kannanthanam, Boji T" <boji.t.kannanthanam@intel.com>
MFC after: 2 weeks
