recursing on a lock instead of before. This fixes a bug where WITNESS
could get a little confused if you did an sx_tryslock() on a sx lock that
you already had an slock on. WITNESS would still function correctly but
it could result in weirdness in the output of 'show locks'. This also
makes it possible for mtx_trylock() to recurse on a lock.
used popped into my head during my morning commute a few weeks ago, but
it is also very similar (though a bit simpler) to a patch that mini@
developed a while ago. Basically, each eventhandler list has a mutex and
a run count. During an eventhandler invocation, the mutex is held while
we traverse the list but is dropped while we execute actual handlers. Also,
a runcount counter is incremented at the start of an invocation and
decremented at the end of an invocation. Adding to the list is not a big
deal since the reference of a thread currently executing the handlers
remains valid across an add operation. Whether or not new handlers are
executed by threads currently executing the handlers for a given list is
indeterminate however. The harder case is when a handler is removed from
the list. If the runcount is zero, the handler is simply removed from the
list directly. If the runcount is not zero, then another thread is
currently executing the handlers of this list, so the priority of this
handler is set to a magic value (currently -1) to mark it as dead. Dead
handlers are not executed during an invocation. If the runcount is zero
after it is decremented at the end of an invocation, then a new
eventhandler_prune_list() function is called to remove dead handlers from
the list.
Additional minor notes:
- All the common parts of EVENTHANDLER_INVOKE() and
EVENTHANDLER_FAST_INVOKE() have been merged into a common
_EVENTHANDLER_INVOKE() macro to reduce duplication and ease maintenance.
- KTR logging for eventhandlers is now available via the KTR_EVH mask.
- The global eventhander_mutex is no longer recursive.
Tested by: scottl (SMP i386)
monitors the entropy data harvested by crypto drivers to verify it complies
with FIPS 140-2. If data fails any test then the driver discards it and
commences continuous testing of harvested data until it is deemed ok.
Results are collected in a statistics block and, optionally, reported on
the console. In normal use the overhead associated with this driver is
not noticeable.
Note that drivers must (currently) be compiled specially to enable use.
Obtained from: original code by Jason L. Wright
attach routine, calling WIUNLOCK in the error case of one of the ifs
for that routine is now bogus. This should have been removed when the
WILOCK() was removed, but wasn't.
Submitted by: "Harti Brandt" <brandt@fokus.fraunhofer.de>
it is expected that they will not be enabled at the time that it
is called. This is reported to work around a problem in RELENG_4
where the kernel panics on boot if FAST_IPSEC and crypto support
are enabled.
Tested by: Scott Johnson <scottj@insane.com>
- Issue the io that we will later block on prior to doing cluster read ahead
so that it is more likely to be ready when we block.
- Loop issuing clustered reads until we've exhausted the seq count supplied
by the file system.
- Use a sysctl tunable "vfs.read_max" to determine the maximum number of
blocks that we'll read ahead.
kern_sig.c 1.215
kern_thread.c 1.103
kern_exit.c 1.199
proc.h 1.302
Orignal code would suspend an already suspended thread,
if user presses ^Z while a threaded program is running. Also
there is a race between job control and thread_exit(), the
new code tests job control requesting before thread exits,
in wait() syscall, be sure to check child process is fully
stopped, this avoids a later SIGCHILD and returns STOPPED
status twice for a threaded child proc. A thread_stopped()
function is added for common code in several places.
use the underlying AsahiOptical USB chip and thus this quirk may need to
be generalized in the future.
PR: kern/46369
Submitted by: Tim Vanderhoek <vanderh@ecf.utoronto.ca>
MFC After: 3 days
I had commented the #ifdef INVARIANTS checks out to make sure I ran this
code in all kernels and forgot to comment the #ifdefs back in before I
committed.
Spotted by: bmilekic
[1] PHCC = Pointy Hat Correction Commit
ddb 'show locks' command. Thus, move witness_list() to the #ifdef DDB
section and remove extra checks for calling this function outside of
DDB. Also, witness_list() now returns void instead of returning an int.
Reported by: Steve Ames <steve@energistic.com>
Prodded by: davidxu
