When using meta mode with filemon, the build is reliably incremental
safe. Bmake will use the meta files, along with filemon information,
to rebuild targets when their dependencies change, commands change,
or files they generate are missing.
Sponsored by: EMC / Isilon Storage Division
This corrects an error in r296947 in that it is not possible to assert
which thread holds a shared (or read) lock, but it is possible to assert
that one is held. Just not very useful.
MFC after: 1 week
Submitted by: wblock, jhb
Reviewed by: kib (earlier version), jhb, wblock
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D5659
sounds like some kind of horrific theme park. "Hey kids, want to go to
User Land?" "No! We'll be good!"
The obvious replacement is "userland", a compound word replete with
term-of-art meaning and just a hint of cautionary tale. The alternate
terms "flugelhorn" and "bullfrog", while also good, are less well-known
and were voted down in committee.
MFC after: 1 week
Skip the log entry as there is nothing good to write out. Don't fail
the syscall though since it already succeeded. There's no reason
filemon's tracing failure should fail the already-succeeded syscall.
Record the error for later to return from close(2) on the filemon devfs
file descriptor.
Discussed with: markj, sjg, kib (briefly with kib)
Reported by: mjg
MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division
None of lstat(2), fstat(2), fstatat(2) were tracked either.
The other filemon implementations also do not track stat(2), nor
does bmake utilize it. The act of opening a file for read should
be enough to decide that a file is a dependency. There could be
rare cases where just having a file would cause a dependency but it
is unlikely.
MFC after: 2 weeks
Also noted by: sjg
Sponsored by: EMC / Isilon Storage Division
- proc.p_filemon is added which is protected by PROC_LOCK. This improves
performance and avoids double-fork issues, taking allproc_lock
while in syscalls, and walking the process tree in syscalls. A
particular proc.p_filemon can only be changed to NULL or another
filemon, or the filemon inherited, while the filemon->lock is held.
- Filemon are reference counted. On the last reference the log will be closed.
- When closing the devfs file handle, the filemon will be detached from all
processes and inheritance prevented.
- Disallow attaching to a process already being traced since filemon is
typically intended to be used on children only. This is allowed for
curproc as bmake relies on this behavior for rare cases when combining
.MAKE with .META.
- Detach any previously tracked process on ioctl(FILEMON_SET_PID).
- Handle error from devfs_set_cdevpriv() in filemon_open().
- The global filemon lock and lists are removed.
- A free list is no longer kept. Previously this list was
forever-expanding and never garbage cleaned.
- No longer loses track of double-forks. If the process holding the filemon
handle closes it will close the log rather than wait on a daemonized process,
but it will log all activity until it closes its handle. The filemon
will be removed from the process and not inherited.
- A separate process count is kept only as an optimization for
forced detachment to avoid taking allproc_lock and walking the entire
process tree.
- struct filemon access is protected by sx(9) filemon->lock as it was before.
- Add more comments and KASSERTS.
MFC after: 2 weeks
Reviewed by: kib, mjg, markj (all on previous versions)
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D5520
SYSCTL_COUNTER_U64_ARRAY() macro.
- Add proper asserts to the SYSCTL_COUNTER_U64_ARRAY() macro that checks
the size of the first element of the array.
- Add an example to the counter(9) manual page how to use the
SYSCTL_COUNTER_U64_ARRAY() macro.
- Add some missing symbolic links for counter(9) while at it.
This is several year's worth of fail point upgrades done at EMC Isilon. They
are interdependent enough that it makes sense to put a single diff up for them.
Primarily, we added:
- Changing all mainline execution paths to be lockless, which lets us use fail
points in more sleep-sensitive areas, and allows more parallel execution
- A number of additional commands, including 'pause' that lets us do some
interesting deterministic repros of race conditions
- The ability to dump the stacks of all threads sleeping on a fail point
- A number of other API changes to allow marking up the fail point's context in
the code, and firing callbacks before and after execution
- A man page update
Submitted by: Matthew Bryan <matthew.bryan@isilon.com>
Reviewed by: cem (earlier version), jhb, kib, pho
With feedback from: bdrewery
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D5427
Code may still be executing from the wrappers at unload time and thus is
not generally safe to unload. Converting the wrappers to use
EVENTHANDLER(9) will allow this to safely drain on active threads in
hooks. More work on EVENTHANDLER(9) is needed first.
MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division
Since m_cat() may copy data from the second mbuf chain into the last mbuf
of the first chain, it may free the first mbuf of the second chain. Thus,
the second chain is not guaranteed to be valid after m_cat() returns.
Reviewed by: glebius
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D5497
