function symbols in the kernel in a list of C strings, with an extra
nul-termination at the end.
This sysctl requires addition of a new linker operation. Now,
linker_file_t's need to respond to "each_function_name" to export
their function symbols.
Note that the sysctl doesn't currently allow distinguishing multiple
symbols with the same name from different modules, but could quite
easily without a change to the linker operation. This will be a nicety
to have when it can be used.
Obtained from: NAI Labs CBOSS project
Funded by: DARPA
by the profiler on a running system. This is not done sparsely, as
memory is cheaper than processor speed and each gprof mcount() and
mexitcount() operation is already very expensive.
Obtained from: NAI Labs CBOSS project
Funded by: DARPA
number) instead of allocating next free unit for them. If someone needs
fixed place, he must specify it correctly. "Allocating next" is especially bad
because leads to double device detection and to "repeat make_dev panic" as
result. This can happens if the same devices present somewhere on PCI bus,
hints and ACPI. Making them present in one place only not always
possible, "sc" f.e. can't be removed from hints, it results to no console at
all.
2) In make_device(), detect when devclass_add_device() fails, free dev and
return. I.e. add missing error checking. This part needed to finish fix in 1),
but must be done this way in anycase, with old variant too.
non-existent disk in a legacy /dev on a DEVFS system would panic the system
if stat(2)'ed.
Do not whine about anonymous device nodes not having a si_devsw, they're
not supposed to.
Make it a panic to repeat make_dev() or destroy_dev(), this check
should maybe be neutered when -current goes -stable.
Whine if devsw() is called on anon dev_t's in a devfs system.
Make a hack to avoid our lazy-eval disk code triggering the above whine.
Fix the multiple make_dev() in disk code by making ${disk}${unit}s${slice}
an alias/symlink to ${disk}${unit}s${slice}c
it has not yet returned. Use this flag to deny debugging requests while
the process is execve()ing, and close once and for all any race conditions
that might occur between execve() and various debugging interfaces.
Reviewed by: jhb, rwatson
strip the space from '( struct thread *...', wrap long lines.
o Remove an unneeded comment on the topic of no lock being required as
part of the NDINIT() in __acl_get_file(), as it's really not required
there.
Obtained from: TrustedBSD Project
of Giant during the Giant unwinding phase, and start work on instrumenting
Giant for the file and proc mutexes.
These wrappers allow developers to turn on and off Giant around various
subsystems. DEVELOPERS SHOULD NEVER TURN OFF GIANT AROUND A SUBSYSTEM JUST
BECAUSE THE SYSCTL EXISTS! General developers should only considering
turning on Giant for a subsystem whos default is off (to help track down
bugs). Only developers working on particular subsystems who know what
they are doing should consider turning off Giant.
These wrappers will greatly improve our ability to unwind Giant and test
the kernel on a (mostly) subsystem by subsystem basis. They allow Giant
unwinding developers (GUDs) to emplace appropriate subsystem and structural
mutexes in the main tree and then request that the larger community test
the work by turning off Giant around the subsystem(s), without the larger
community having to mess around with patches. These wrappers also allow
GUDs to boot into a (more likely to be) working system in the midst of
their unwinding work and to test that work under more controlled
circumstances.
There is a master sysctl, kern.giant.all, which defaults to 0 (off). If
turned on it overrides *ALL* other kern.giant sysctls and forces Giant to
be turned on for all wrapped subsystems. If turned off then Giant around
individual subsystems are controlled by various other kern.giant.XXX sysctls.
Code which overlaps multiple subsystems must have all related subsystem Giant
sysctls turned off in order to run without Giant.
while it is on a queue with the queue lock and remove the per-task locks.
- Remove TASK_DESTROY now that it is no longer needed.
- Go back to inlining TASK_INIT now that it is short again.
Inspired by: dfr
userland. The per thread ucred reference is immutable and thus needs no
locks to be read. However, until all the proc locking associated with
writes to p_ucred are completed, it is still not safe to use the per-thread
reference.
Tested on: x86 (SMP), alpha, sparc64
queue, and a mutex to protect the global list of taskqueues. The only
visible change is that a TASK_DESTROY() macro has been added to mirror
the TASK_INIT() macro to destroy a task before it is free'd.
Submitted by: Andrew Reiter <awr@watson.org>
splhigh() before the mtx_unlock and tsleep(). The splhigh() was probably
correct in the original code using simplelocks but is not correct in
5.0-current.
Noticed by: Andrew Reiter <awr@FreeBSD.org>
real effect.
Optimize vfs_msync(). Avoid having to continually drop and re-obtain
mutexes when scanning the vnode list. Improves looping case by 500%.
Optimize ffs_sync(). Avoid having to continually drop and re-obtain
mutexes when scanning the vnode list. This makes a couple of assumptions,
which I believe are ok, in regards to vnode stability when the mount list
mutex is held. Improves looping case by 500%.
(more optimization work is needed on top of these fixes)
MFC after: 1 week
or the cluster will not be properly merged. Dup the code from
cluster_wbuild() and add some printf()s to see if bad cases are present.
MFC after: 2 weeks
returns an success/failure code rather than the actual value.
- Add getenv_string() which copies a string from the environment to another
string and returns true on success.
all successful calls to VOP_OPEN() might be reflected in a call to
VOP_CLOSE(). For now, simply add a comment reflecting this problem;
this should be fixed at some point.
terminated and flushes pending dirty pages it is possible for the
object to be ref'd (0->1) and then deref'd (1->0) during termination.
We do not terminate the object a second time.
Document vop_stdgetvobject() to explicitly allow it to be called without
the vnode interlock held (for upcoming sync_msync() and ffs_sync()
performance optimizations)
MFC after: 3 days
the system load average. Previously, the load average measurement
was susceptible to synchronisation with processes that run at
regular intervals such as the system bufdaemon process.
Each interval is now chosen at random within the range of 4 to 6
seconds. This large variation is chosen so that over the shorter
5-minute load average timescale there is a good dispersion of
samples across the 5-second sample period (the time to perform 60
5-second samples now has a standard deviation of approx 4.5 seconds).
to kern_synch.c in preparation for adding some jitter to the
inter-sample time.
Note that the "vm.loadavg" sysctl still lives in vm_meter.c which
isn't the right place, but it is appropriate for the current (bad)
name of that sysctl.
Suggested by: jhb (some time ago)
Reviewed by: bde
off to witness_init() making the check for double intializating a lock by
testing the LO_INITIALIZED flag moot. Workaround this by checking the
LO_INITIALIZED flag ourself before we bzero the lock structure.
be so dangerous it isn't funny. eg: if you panic inside NFS or softdep,
and then try and sync you run into held locks and cause either deadlocks,
recursive panics or other interesting chaos. Default is unchanged.
