This patch implements basic rubber-banding. Perhaps this mechanism can
be generalized somehow, but it's not clear to me how that would work
at the moment.
This patch adds these API's:
- pthread_mutex_init()
- pthread_mutex_lock()
- pthread_mutex_unlock()
No mutex attributes are supported yet, so we only do the simplest mutex
wihout recursive locking.
We were forgetting to adopt the WeakLink, causing a reference leak.
This ended up costing us one allocation per exec(), with this stack:
kmalloc_impl()
Inode::set_vmo()
InodeVMObject::create_with_inode()
Process::do_exec()
Process::exec()
Process::sys$execve()
This was a pain to track down, in the end I caught it by dumping out
every live kmalloc pointer between runs and diffing the sets. Then it
was just a matter of matching the pointer to a call stack and looking
at what went wrong. :^)
Now that the kernel supports startup-time constructors, we were first
doing slab_alloc_init(), and then the constructors ran later on,
zeroing out the freelist pointers.
This meant that all slab allocators thought they were completelty
exhausted and forwarded all requests to kmalloc() instead.
It's now possible to block until another thread in the same process has
exited. We can also retrieve its exit value, which is whatever value it
passed to pthread_exit(). :^)
The Shell also puts each command into its own process group,
which interferes with us trying to do the same here. We don't
really need the shell here anyway, but it means we'll have to
do command splitting ourselves.
While executing in the kernel, a thread can acquire various resources
that need cleanup, such as locks and references to RefCounted objects.
This cleanup normally happens on the exit path, such as in destructors
for various RAII guards. But we weren't calling those exit paths when
killing threads that have been executing in the kernel, such as threads
blocked on reading or sleeping, thus causing leaks.
This commit changes how killing threads works. Now, instead of killing
a thread directly, one is supposed to call thread->set_should_die(),
which will unblock it and make it unwind the stack if it is blocked
in the kernel. Then, just before returning to the userspace, the thread
will automatically die.
This patch adds pthread_create() and pthread_exit(), which currently
simply wrap our existing create_thread() and exit_thread() syscalls.
LibThread is also ported to using LibPthread.
Also added an option in the run script to force PIO operation mode with
the IDE controller.
In addition, we're no longer limited to PIIX3 and PIIX4 chipsets for DMA
Now that the WindowServer's menu is the primary way to start apps,
it is especially noticable that it leaks the /dev/fb0 fd to the apps
that it spawns. Fix that by opening it with O_CLOEXEC.
Now that the SystemMonitor queries which open files can be read and written to,
having can_read()/can_write() unconditionally call ASSERT_NOT_REACHED() leads
to system crashes when inspecting the WindowServer.
Instead, just return true from can_read()/can_write() (indicating that the
read()/write() syscalls should not block) and return -EINVAL when trying to
actually read from or write to these devices.
