Make state transitions of a thread on a mutex queue
atomic (with respect to other threads and signal handlers).
This includes:
o Introduce two functions to implement atomicity with respect
to other threads and signal handlers. Basically,
_thread_critical_enter() locks the calling thread and blocks
signals. _thread_critical_exit() unblocks signals and unlocks
the thread.
o Introduce two new functions:
get_muncontested() locks a mutex that is not owned by
another thread.
get_mcontested() places a thread on a contested mutex's
queue, taking care to use the _thread_critical_enter/exit
functions to protect thread state.
o Modify mutex_unlock_common() to also protect state transitions.
In this case it needs the cooperation of mutex_queue_deq(), which
must return with the thread locked and signals disabled *before*
it takes the thread off the queue.
Combine _pthread_mutex_lock() and _pthread_mutex_trylock()
into one function: mutex_lock_common(), that can handle
both cases. Its behaviour is controlled by an argument,
int nonblock, which if not zero means do not attempt
to acquire a contested mutex if the uncontested case fails.
BTW, when I write about contested and uncontested mutexes, I'm writing
about it from the application's point of view. I'm not writing about
internal locking of pthread_mutex->lock, which is achieved differently.
While internal mutex locking is mostly done, there's still a bit more
work left in this area.
Approved by: markm/mentor, re/blanket libthr
Reviewed by: jeff (slightly diff. revision)
common code, the non-trivial part is #ifdef'ed and only executes when
loading amd64 kernels. The rest is trivial but needed for the the amd64
case. (Two variables changed from char ** to Elf_Addr).
Approved by: re (amd64 "low-risk" stuff)
bus_dma MD code for AMD64. (And a trivial ifdef update in dev/kbd because
of this). More updates are needed here to take advantage of the 64 bit
instructions.
Approved by: re (blanket amd64/*)
value on entry and exit. This isn't as easy as it sounds because when
we recursively trap or interrupt, we have to avoid duplicating the
swapgs instruction or we end up back with the userland %gs. I implemented
this by testing TF_CS to see if we're coming from supervisor mode
already, and check for returning to supervisor. To avoid a race with
interrupts in the brief period after beginning executing the handler and
before the swapgs, convert all trap gates to interrupt gates, and reenable
interrupts immediately after the swapgs. I am not happy with this.
There are other possible ways to do this that should be investigated.
(eg: storing the GS.base MSR value in the trapframe)
Add some sysarch functions to let the userland code get to this.
Approved by: re (blanket amd64/*)
inode birthtime display, and quite a bit of mdoc cleanup, which brings
it much more in line with our mdoc style.
Approved by: re (bmah)
Obtained from: Andrew Brown <atatat@NetBSD.org> (content), Grant Beattie <grant@NetBSD.org> (mdoc)
the new inode birthtime field, a few other small cleanups, and
synchronization with our #include <sys/types.h>.
Approved by: re (bmah)
Obtained from: Andrew Brown <atatat@NetBSD.org>
of conflicting with other, similarly named functions in static
libraries. This is done mostly by renaming the var if it is shared
amongst modules, or making it static otherwise.
OK'ed by: re(scottl)
- Simplify and correct the bus manager election process.
- Check link_active when choosing cycle master.
- Fix location of the cmr bit.
Approved by: re (scottl)
series. This driver was generously developed and released by David
Jeffreys and Adaptec. I've updated it to work with 5.x and fixed a
few bugs.
MFC After: 1 week
has been fixed to not need the missing files.
The firmware files themselves still now need to be fetched from the internet.
The README there gives the location.
Approved by: re@ (part of bluetooth upgrade)
changed to use libufs in revision 1.71. Without this, any write
failures in newfs were silently ignored.
Note that this will display a meaningless errno string in the case
of a short write as opposed to a write error, since bwrite()'s
return value does not allow the caller to determine if errno is
valid.
Reported by: Lukas Ertl <l.ertl@univie.ac.at>
Reviewed by: jmallett
Approved by: re (bmah)
reason for the duplication was that m_freem() was meant to eventually
be optimized to hold the lock of the cache being freed to as long as
possible across frees but the difficulty of implementing said
optimization right now is too high, given that in some cases (see MAC
and non-cluster external buffers), we need to call into other subsytems,
something not permissible when the cache lock is held.
This change minimizes code duplication while keeping at least the
atomic mbuf+cluster free optimization.
Suggested by: luigi
