- Add sx_xholder member to sx struct which is used for INVARIANTS-enabled
assertions. It indicates the thread that presently owns the xlock.
- Add some assertions to the sx lock code that will detect the fatal
API abuse:
xlock --> xlock
xlock --> slock
which now works thanks to sx_xholder.
Notice that the remaining two problematic cases:
slock --> xlock
slock --> slock (a little less problematic, but still recursion)
will need to be handled by witness eventually, as they are more
involved.
Reviewed by: jhb, jake, jasone
aiocb's allocated by zalloc(). In other words, zfree() was never
called. Now, we call zfree(). Why eliminate this micro-
optimization? At some later point, when we multithread the AIO
system, we would need a mutex to synchronize access to aio_freejobs,
making its use nearly indistinguishable in cost from zalloc() and
zfree().
Remove unnecessary fhold() and fdrop() calls from aio_qphysio(),
undo'ing a part of revision 1.86. The reference count on the file
structure is already incremented by _aio_aqueue() before it calls
aio_qphysio(). (Update the comments to document this fact.)
Remove unnecessary casts from _aio_aqueue(), aio_read(), aio_write()
and aio_waitcomplete().
Remove an unnecessary "return;" from aio_process().
Add "static" in various places.
related code from aio_read() and aio_write(). This field was
intended, but never used, to allow a mythical user-level library to
make an aio_read() or aio_write() behave like an ordinary read() or
write(), i.e., a blocking I/O operation.
- Add a KASSERT() to ensure an ithread has a backing kernel thread when we
schedule it.
- Don't attempt to preemptively switch to an ithread if p_stat of curproc
is not SRUN.
An initial tidyup of the mount() syscall and VFS mount code.
This code replaces the earlier work done by jlemon in an attempt to
make linux_mount() work.
* the guts of the mount work has been moved into vfs_mount().
* move `type', `path' and `flags' from being userland variables into being
kernel variables in vfs_mount(). `data' remains a pointer into
userspace.
* Attempt to verify the `type' and `path' strings passed to vfs_mount()
aren't too long.
* rework mount() and linux_mount() to take the userland parameters
(besides data, as mentioned) and pass kernel variables to vfs_mount().
(linux_mount() already did this, I've just tidied it up a little more.)
* remove the copyin*() stuff for `path'. `data' still requires copyin*()
since its a pointer into userland.
* set `mount->mnt_statf_mntonname' in vfs_mount() rather than in each
filesystem. This variable is generally initialised with `path', and
each filesystem can override it if they want to.
* NOTE: f_mntonname is intiailised with "/" in the case of a root mount.
`rootvnode' pointer, but vfs_syscalls.c's checkdirs() assumed that
it did. This bug reliably caused a panic at reboot time if any
filesystem had been mounted directly over /.
The checkdirs() function is called at mount time to find any process
fd_cdir or fd_rdir pointers referencing the covered mountpoint
vnode. It transfers these to point at the root of the new filesystem.
However, this process was not reversed at unmount time, so processes
with a cwd/root at a mount point would unexpectedly lose their
cwd/root following a mount-unmount cycle at that mountpoint.
This change should fix both of the above issues. Start_init() now
holds an extra vnode reference corresponding to `rootvnode', and
dounmount() releases this reference when the root filesystem is
unmounted just before reboot. Dounmount() now undoes the actions
taken by checkdirs() at mount time; any process cdir/rdir pointers
that reference the root vnode of the unmounted filesystem are
transferred to the now-uncovered vnode.
Reviewed by: bde, phk
hit on the client side and prevent the server side from retiring writes.
Pipeline operations turned off for all READs (no big loss since reads are
usually synchronous) and for NFS writes, and left on for the default bwrite().
(MFC expected prior to 4.3 freeze)
Testing by: mjacob, dillon
update native priority, it is diffcult to get right and likely
to end up horribly wrong. Use an honestly wrong fixed value
that seems to work; PUSER for user threads, and the interrupt
priority for ithreads. Set it once when the process is created
and forget about it.
Suggested by: bde
Pointy hat: me
process's priority go through the roof when it released a (contested)
mutex. Only set the native priority in mtx_lock if hasn't already
been set.
Reviewed by: jhb
to be more like Xint0x80_syscall and less like c function syscall().
- Reduce code duplication between the int0x80 and lcall handlers by
shuffling the elfags into the right place, saving the sizeof the
instruction in tf_err and jumping into the common int0x80 code.
Reviewed by: peter
passed in filename and line number in the KTR tracepoint message.
- Even though it is #if 0'd code, change the code to detect that a process
is an interrupt thread to check p->p_ithd against NULL rather than
checking non-existant process flags from BSD/OS.
- Use '%p' to print pointers in KTR log messages instead of assuming
sizeof(int) == sizeof(void *).
- Don't set p_mtxname to NULL when releasing a mutex. It doesn't hurt
to leave it set (we don't clear w_mesg for example) and at least at
one time in the past, there used to be race conditions in the kernel
that would result in setting this to NULL causing the kernel to
dereference NULL.
- Make the _mtx_assert() function be compiled in if INVARIANTS_SUPPORT is
defined rather than if INVARIANTS is defined so that a KLD compiled
with INVARIANTS that uses mtx_assert() can be used with a kernel that
just has INVARIANT_SUPPORT compiled in.
allow the watermark to be passed in via the data field during the EV_ADD
operation.
Hook this up to the socket read/write filters; if specified, it overrides
the so_{rcv|snd}.sb_lowat values in the filter.
Inspired by: "Ronald F. Guilmette" <rfg@monkeys.com>
the current socket error in fflags. This may be useful for determining
why a connect() request fails.
Inspired by: "Jonathan Graehl" <jonathan@graehl.org>
depend on this. The linux ABI emulator tries to use it for some linux
binaries too. VM86 had a bigger cost than this and it was made default
a while ago.
Reviewed by: jhb, imp
interrupts.
Protect usage of the per processor switchtime variable against
interrupts in calcru().
This seem to eliminate the "microuptime() went backwards" warnings.
the the original trapframe of the syscall, trap, or interrupt that entered
the kernel. Before SMPng, ast's were handled via a psuedo trap at the
end of doerti. With the SMPng commit, ast's were broken out into a
separate ast() function that was called from doreti to match the behavior
of other architectures. Unfortunately, when this was done, the
p_md.md_regs member of curproc was not updateda in ast(), thus when
signals are handled by userret() after an interrupt that returns to
userland, we end up using a stale trapframe that will result in the
registers from the old trapframe overwriting the real trapframe and
smashing all the registers right before we return to usermode. The saved
%cs:%eip from where we were in usermode are saved in the trapframe for
example.
- Don't use an atomic operation to update cnt.v_soft in ast(). This is
the only place the variable is written to, and sched_lock is always
held when it is written, so it is already protected and the mutex release
of sched_lock asserts a memory barrier that ensures the value will be
updated in a timely fashion.
- Don't hold sched_lock around addupc_task() as this apparently breaks
profiling badly due to sched_lock being held across copyin().
Reported by: bde (2)
an interrupt thread while the interrupt thread is blocked on Giant waiting
to execute the interrupt handler being removed. The result was that the
intrhand structure would be free'd, and we would call 0xdeadc0de. The work
around is to check to see if the interrupt thread is idle when removing a
handler. If not, then we mark the interrupt handler as being dead using
the new IH_DEAD flag and don't remove it from the interrupt threads' list
of handlers. When the interrupt thread resumes, it will see a dead handler
while traversing the list of handlers and will remove the handler then.
