to read-locking in the TCP input path, allowing greater TCP
input parallelism where multiple ithreads or ithread and netisr
are able to run in parallel. Previously, most TCP input paths
held a write lock on the global tcbinfo lock, effectively
serializing TCP input.
Before looking up the connection, acquire a write lock if a
potentially state-changing flag is set on the TCP segment header
(FIN, RST, SYN), and otherwise a read lock. We may later have
to upgrade to a write lock in certain cases (ACKs received by the
syncache or during TIMEWAIT) in order to support global state
transitions, but this is never required for steady-state packets.
Upgrading from a write lock to a read lock must be done as a
trylock operation to avoid deadlocks, and actually violates the
lock order as the tcbinfo lock preceeds the inpcb lock held at
the time of upgrade. If the trylock fails, we bump the refcount
on the inpcb, drop both locks, and re-acquire in-order. If
another thread has freed the connection while the locks are
dropped, we free the inpcb and repeat the lookup (this should
hardly ever or never happen in practice).
For now, maintain a number of new counters measuring how many
times various cases execute, and in particular whether various
optimistic assumptions about when read locks can be used, whether
upgrades are done using the fast path, and whether connections
close in practice in the above-described race, actually occur.
MFC after: 6 weeks
Discussed with: kmacy
Reviewed by: bz, gnn, kmacy
Tested by: kmacy
incremented using in_pcbref(), and decremented using in_pcbfree()
or inpcbrele(). Protocols using only current in_pcballoc() and
in_pcbfree() calls will see the same semantics, but it is now
possible for TCP to call in_pcbref() and in_pcbrele() to prevent
an inpcb from being freed when both tcbinfo and per-inpcb locks
are released. This makes it possible to safely transition from
holding only the inpcb lock to both tcbinfo and inpcb lock
without re-looking up a connection in the input path, timer
path, etc.
Notice that in_pcbrele() does not unlock the connection after
decrementing the refcount, if the connection remains, so that
the caller can continue to use it; in_pcbrele() returns a flag
indicating whether or not the inpcb pointer is still valid, and
in_pcbfee() is now a simple wrapper around in_pcbrele().
MFC after: 1 month
Discussed with: bz, kmacy
Reviewed by: bz, gnn, kmacy
Tested by: kmacy
message for r185765.
Noted by: rdivacky
Requested by: des
Commit message for r185765 should be:
In procfs map handler, and in linprocfs maps handler, do not call
vn_fullpath() while having vm map locked. This is done in anticipation
of the vop_vptocnp commit, that would make vn_fullpath sometime
acquire vnode lock.
Also, in linprocfs, maps handler already acquires vnode lock.
No objections from: des
MFC after: 2 week
sbuf instead of doing uiomove. This allows for reads from non-zero
offsets to work.
Patch is forward-ported des@' one, and was adopted to current code
by dchagin@ and me.
Reviewed by: des (linprocfs part)
PR: kern/101453
MFC after: 1 week
does final drop of the the dq reference to put it onto the free list.
There is a possibility that the dq would be found by another thread
after sync and before the dqh lock is acquired. If that other thread
drops the dq before we have taken the dqh lock, the dirty dq is put on
the free list.
Recheck the DQ_MOD after the dqh lock is relocked. Repeat dqsync() if
the dq is dirty. This ensures that up to date dq is written in the quota
file and fixes assertion in dqget().
Reported and tested by: Frode Nordahl <frode nordahl net>
MFC after: 3 days
Waiting for 1ms for each GMII register access looks overkill and it
may also decrease overall performance of driver because re(4)
invokes mii_tick for every hz.
Tested by: rpaulo
laptops. This includes battery presence detection, charging status, current
and voltage readouts, and charge level indication. The sysctl interface
is somewhat ACPI-like.
established a valid link or not. In miibus_statchg handler add a
check for established link is valid one for the controller(e.g.
1000baseT is not a valid link for fastethernet controllers.)
o Added a flag RE_FLAG_FASTETHER to mark fastethernet controllers.
o Added additional check to know whether we've really encountered
watchdog timeouts or missed Tx completion interrupts. This change
may help to track down the cause of watchdog timeouts.
o In interrupt handler, removed a check for link state change
interrupt. Not all controllers have the bit and re(4) did not
rely on the event for a long time. In addition, re(4) didn't
request the interrupt in RL_IMR register.
Tested by: rpaulo
drivers, there should be a 1us delay after every write when
bit-banging the MII. Also insert barriers in order to ensure
the intended ordering. These changes hopefully will solve the
bus wedging occasionally experienced with DM9102A since r182461.
- Deobfuscate dc_mii_readreg() a bit.
loader_conf_files="foo bar baz"
should cause loading the files listed, and then resume with the
remaining config files (from previous values of the variable).
Unfortunately, sometimes the line was ignored -- actually even
modifying the line in /boot/default/loader.conf sometimes doesn't work.
ANALYSIS: After much investigation, turned out to be a bug in the logic.
The existing code detected a new assignment by looking at the address
of the the variable containing the string. This only worked by pure
chance, i.e. if the new string is longer than the previous value
then the memory allocator may return a different address
to store the string hence triggering the detection.
SOLUTION: This commit contains a minimal change to fix the problem,
without altering too much the existing structure of the code.
However, as a step towards improving the quality and reliability of
this code, I have introduced a handful of one-line functions
(strget, strset, strfree, string= ) that could be used in dozens
of places in the existing code.
HOWEVER:
There is a much bigger problem here. Even though I am no Forth
expert (as most fellow src committers) I can tell that much of the
forth code (in support.4th at least) is in severe need of a
review/refactoring:
+ pieces of code are replicated multiple times instead of writing
functions (see e.g. set_module_*);
+ a lot of stale code (e.g. "structure" definitions for
preloaded_files, kernel_module, pnp stuff) which is not used
or at least belongs elsewhere.
The code bload is extremely bad as the loader runs with very small
memory constraints, and we already hit the limit once (see
http://svn.freebsd.org/viewvc/base?view=revision&revision=185132
Reducing the footprint of the forth files is critical.
+ two different styles of coding, one using pure stack functions
(maybe beautiful but surely highly unreadable), one using
high level mechanisms to give names to arguments and local
variables (which leads to readable code).
Note that this code is used by default by all FreeBSD installations,
so the fragility and the code bloat are extremely damaging.
I will try to work fixing the three items above, but if others have
time, please have a look at these issues.
MFC after: 4 weeks
multiple algorithms and potentially collect multiple samples.
Instead of a single calibration interval we now have short and long
intervals; the long interval roughly corresponds to the previous
single interval. The short interval is used to speedup collection
of samples and happens much quicker. We make calls using the short
interval until we're told the calibration work is complete at which
point we fallback to the long interval. In addition there is a
much longer reset interval used to flush all calibration state and
cause everthing to start anew.
With these changes you can also disable calibration entirely by
setting the long interval to zero.
at. I don't think this will make a huge difference, but I have
received a report of a interrupt storm on one 16-bit card that this
might fix (chances are it won't, since I think that we may need to
check both the CBB registers for the 16-bit card as well as the PCIC
registers for power state change).
Submitted by: jhb@
the power interrupt and init code waiting for the interrupt are
running on different CPUs. I haven't seen this make any real
difference, but I've also had some reports of odd behavior I can't
otherwise explain. It is an infrequent operation, and certainly
wouldn't hurt.
my right mouse button and keyboard LEDs from working due to mangled
configuration packets. Fixed several other races and associated problems in the
main ADB stack that were exposed while fixing this.
Now it is possible to suspend/resume with inserted and active card.
To reinitialize card on resume and to detect card change while suspended,
implement bus rescan routines. It can also be used by controllers without
card presence detection signals or with multiple cards per slot support.
While there, cleanup msleep() usage. We have no any rights to exit without
"request done" signal from driver as it could lead to modify after free.
RTFREE_LOCKED() here. This macro makes sure the reference count
on the route is being managed properly. This elimates another
case which results in the following message being printed to the
console:
rtfree: 0xc841ee88 has 1 refs
Reviewed by: bz
MFC after: 2 weeks
bit of debugging afterwards):
- Fix protection code for notification generation.
- Decouple associd from vtag
- Allow vtags to have less strigent requirements in non-uniqueness.
o don't pre-hash them when you issue one in a cookie.
o Allow duplicates and use addresses and ports to
discriminate amongst the duplicates during lookup.
- Add support for the NAT draft draft-ietf-behave-sctpnat-00, this
is still experimental and needs more extensive testing with the
Jason Butt ipfw changes.
- Support for the SENDER_DRY event to get DTLS in OpenSSL working
with a set of patches from Michael Tuexen (hopefully heading to OpenSSL soon).
- Update the support of SCTP-AUTH by Peter Lei.
- Use macros for refcounting.
- Fix MTU for UDP encapsulation.
- Fix reporting back of unsent data.
- Update assoc send counter handling to be consistent with endpoint sent counter.
- Fix a bug in PR-SCTP.
- Fix so we only send another FWD-TSN when a SACK arrives IF and only
if the adv-peer-ack point progressed. However we still make sure
a timer is running if we do have an adv_peer_ack point.
- Fix PR-SCTP bug where chunks were retransmitted if they are sent
unreliable but not abandoned yet.
With the help of: Michael Teuxen and Peter Lei :-)
MFC after: 4 weeks
an unclean shutdown would make it impossible to mount rootfs at boot.
PR: kern/128529
Reviewed by: pjd
Approved by: rwatson (mentor)
Sponsored by: FreeBSD Foundation
do not need any locking. Opening and closing translators is serialized
using an sx lock.
Note: This depends on the earlier fix to kern_module.c to properly order
MOD_UNLOAD events.
MFC after: 2 months
memory barriers on i386. It works as a serialization instruction on
all IA32 CPUs.
Alternative solution of using {s,l,}fence requires run-time checking
of the presense of the corresponding SSE or SSE2 extensions, and
possible boot-time patching of the kernel text.
Suggested by: many
parent threads sleep on the parent' struct proc until corresponding
child releases the vmspace. Each sleep is interlocked with proc mutex of
the child, that triggers assertion in the sleepq_add(). The assertion
requires that at any time, all simultaneous sleepers for the channel use
the same interlock.
Silent the assertion by using conditional variable allocated in the
child. Broadcast the variable event on exec() and exit().
Since struct proc * sleep wait channel is overloaded for several
unrelated events, I was unable to remove wakeups from the places where
cv_broadcast() is added, except exec().
Reported and tested by: ganbold
Suggested and reviewed by: jhb
MFC after: 2 week
move that module to the head of the associated linker file's list of modules.
The end result is that once all the modules are loaded, they are sorted in
the reverse of their load order. This causes the kernel linker to invoke
the MOD_QUIESCE and MOD_UNLOAD events in the reverse of the order that
MOD_LOAD was invoked. This means that the ordering of MOD_LOAD events that
is set by the SI_* paramters to DECLARE_MODULE() are now honored in the same
order they would be for SYSUNINIT() for the MOD_QUIESCE and MOD_UNLOAD
events.
MFC after: 1 month
