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
constants in question refer to the number of label slots, not the
maximum number of policies that may be loaded. This should reduce
confusion regarding an element in the MAC sysctl MIB, as well as
make it more clear what the affect of changing the compile-time
constants is.
Approved by: re (jhb)
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
(1) Accept that we're now going to use mutexes, so don't attempt
to avoid treating them as mutexes. This cleans up locking
accessor function names some.
(2) Rename variables to _mtx, _cv, _count, simplifying the naming.
(3) Add a new form of the _busy() primitive that conditionally
makes the list busy: if there are entries on the list, bump
the busy count. If there are no entries, don't bump the busy
count. Return a boolean indicating whether or not the busy
count was bumped.
(4) Break mac_policy_list into two lists: one with the same name
holding dynamic policies, and a new list, mac_static_policy_list,
which holds policies loaded before mac_late and without the
unload flag set. The static list may be accessed without
holding the busy count, since it can't change at run-time.
(5) In general, prefer making the list busy conditionally, meaning
we pay only one mutex lock per entry point if all modules are
on the static list, rather than two (since we don't have to
lower the busy count when we're done with the framework). For
systems running just Biba or MLS, this will halve the mutex
accesses in the network stack, and may offer a substantial
performance benefits.
(6) Lay the groundwork for a dynamic-free kernel option which
eliminates all locking associated with dynamically loaded or
unloaded policies, for pre-configured systems requiring
maximum performance but less run-time flexibility.
These changes have been running for a few weeks on MAC development
branch systems.
Approved by: re (jhb)
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
does the copyin stuff and then calls the second part kern_sendit to do
the hard work. Don't bother holding Giant during the copyin phase.
The intent of this is to allow the Linux emulator to impliment send*
syscalls without using the stackgap.
argument to the functions shm{at,ctl}1 and shm_find_segment_by_shmid{x}.
The BSD semantics didn't allow the usage of shared segment after
being marked for removal through IPC_RMID.
The patch involves the following functions:
- shmat
- shmctl
- shm_find_segment_by_shmid
- shm_find_segment_by_shmidx
- linux_shmat
- linux_shmctl
Submitted by: Orlando Bassotto <orlando.bassotto@ieo-research.it>
Reviewed by: marcel
trustworthy for vnode-backed objects.
- Restore the old behavior of vm_object_page_remove() when the end
of the given range is zero. Add a comment to vm_object_page_remove()
regarding this behavior.
Reported by: iedowse
double free of a mbuf occurs and cause an immediate panic, rather
than allowing free list corruption to occur.
This code is trapped under INVARIANTS, so it should not cause any
change in default performance.
Reviewed by: a bunch of people on -net
MFC after: 1 week
fini routines instead of in fork() and wait(). This has the nice side
benefit that the proc lock of any process on the allproc list is always
valid and sched_lock doesn't have to be used to test against PRS_NEW
anymore.
uptime. Where necessary, convert it back to Unix time by adding boottime
to it. This fixes a potential problem in the accounting code, which would
compute the elapsed time incorrectly if the Unix time was stepped during
the lifetime of the process.
- Eliminate an odd, special-case feature:
if start == end == 0 then all pages are removed. Only one caller
used this feature and that caller can trivially pass the object's
size.
- Assert that the vm_object is locked on entry; don't bother testing
for a NULL vm_object.
- Style: Fix lines that are longer than 80 characters.
- Mark the ktrace() and utrace() syscalls as being MP safe.
- Validate the facs argument to ktrace() prior to doing any vnode
operations or acquiring any locks.
- Share lock the proctree lock over the entire section that calls
ktrsetchildren() and ktrops(). We already did this for process groups.
Doing it for the process case closes a small race where a process might
go away after we look it up. As a result of this, ktrstchildren() now
just asserts that the proctree lock is locked rather than acquiring the
lock itself.
- Add some missing comments to #else and #endif.
syscall return values should be cleared. The system calls
getcontext() and swapcontext() want to return 0 on success
but these contexts can be switched to at a later time so
the return values need to be cleared in the saved register
sets. Other callers of get_mcontext() would normally want
the context without clearing the return values.
Remove the i386-specific context saving from the KSE code.
get_mcontext() is not i386-specific any more.
Fix a bad pointer in the alpha get_mcontext() code. The
context was being bcopy()'d from &td->tf_frame, but tf_frame
is itself a pointer, so the thread was being copied instead.
Spotted by jake.
Glanced at by: jake
Reviewed by: bde (months ago)
Instead of applying the adjustment to processes with a start time of 1,
apply it to all processes with a start time of less than 3600.
None of this would be necessary if the start times were recorded in ticks
instead of seconds and microseconds.
don't include the kernel stacks of swapped-out threads in the page count,
but do include the alternate kernel stack. jhb provided some helpful
comments on this.
PR: 49102
- Add a parameter to vm_pageout_flush() that tells vm_pageout_flush()
whether its caller has locked the vm_object. (This is a temporary
measure to bootstrap vm_object locking.)
whose p_stats->p_start has the magic value 1, replace it with boottime.
Some users were apparently confused by the fact that ps(1) reported a
start time in early 1970 for system processes.
do all the various sigstack dances, unlock the proc lock, and finally do
the copyout. This more closely resembles the behavior of
kern_sigaltstack() and closes a small race.
- Remove Giant from osigstack as it is no longer needed.
rename them appropriately. Protect both flags with both the proc lock
and the sched_lock.
- Protect p_profthreads with the proc lock.
- Remove Giant from profil(2).
- For the 4BSD scheduler, this means that all callers of the static
function resetpriority() now always hold sched_lock, so don't lock
sched_lock explicitly in that function.
kg_nice is now protected by both. Being protected by both means that
other places in the kernel that want to read kg_nice only need one of the
two locks.
their prototypes.
- Remove sched_lock locking from kse_purge() as all callers already lock
the sched_lock before calling it.
- Hold the proc lock slightly longer to protect P_SHOULDSTOP().
o KMF_NOUPCALL
Ask kse_release to not return to userland upcall entry, but instead
direct returns to userland by using current thread's stack and return
address on stack. This flags is intended to be used by UTS in critical
region to wait another UTS thread to leave critical region, by using
kse_release with this flag to avoid spinnng and burning CPU. Also this
flags can be used by UTS to poll completed context when there is nothing
to do in userland and needn't restart from its entry like normal upcall.
o KMF_NOCOMPLETED
Ask kernel to not bring completed thread contexts back to userland when
doing upcall, this flags is intend to be used with above flag when an
upcall thread is in critical region and can not process completed contexts
at that time.
Tested by: deischen
the poll bits when there's actually something in the queue.
Otherwise, select always returned '2' when there were no items to be
read, and '3' when there were. This would preclude being able to read
in a threaded (libc_r) program, as well as checking to see if there
were pending events or not.
lock assertion to it.
- SIGPENDING() no longer needs sched_lock, so only grab sched_lock to set
the TDF_NEEDSIGCHK and TDF_ASTPENDING flags in signotify().
- Add a proc lock assertion to tdsigwakeup().
- Since we always set TDF_OLDMASK while holding the proc lock, the proc
lock is sufficient protection to check its state in postsig() and we only
need sched_lock when clearing the actual flag.
a process group.
- Call pgadjustjobc() twice in fixjobc() to avoid code duplication and
improve readability.
- Use the proc lock to protect P_SHOULDSTOP() instead of sched_lock.
- Check to see if a process is PRS_NEW with sched_lock before trying to
lock its proc lock since the lock may not be constructed yet.
since they are going on the current cpu and not their previously assigned
cpu.
- sched_runnable() should only return true in the SMP case if the other
processor has more than one thread that is runnable. We can not steal
curthread.
- Change kseq_print() to accept the cpuid instead of a kseq pointer. This
makes use of this function in ddb much easier.
the process and session. Instead, cache a true reference to the session
when we do the hold and release our reference on that session. This avoids
the need for the proc lock when dropping the reference.
protects, so don't bother locking it while we assign it to a ucred's
cr_prison.
- Fully construct the new credential for a process before assigning it to
p_ucred.
- Set p_acflag earlier while already hold the proc lock in fork1().
- Mark the realitexpire() callout MPSAFE for new processes. It was already
marked safe for proc0 a long while ago.
