Includes some minor whitespace changes, and re-ordering to be able to document
properly (e.g, grouping of variables and the SYSCTL macro calls for them, where
the documentation has been added.)
Reviewed by: phk (but all errors are mine)
New locks are:
- pgrpsess_lock which locks the whole pgrps and sessions,
- pg_mtx which protects the pgrp members, and
- s_mtx which protects the session members.
Please refer to sys/proc.h for the coverage of these locks.
Changes on the pgrp/session interface:
- pgfind() needs the pgrpsess_lock held.
- The caller of enterpgrp() is responsible to allocate a new pgrp and
session.
- Call enterthispgrp() in order to enter an existing pgrp.
- pgsignal() requires a pgrp lock held.
Reviewed by: jhb, alfred
Tested on: cvsup.jp.FreeBSD.org
(which is a quad-CPU machine running -current)
this is a low-functionality change that changes the kernel to access the main
thread of a process via the linked list of threads rather than
assuming that it is embedded in the process. It IS still embeded there
but remove all teh code that assumes that in preparation for the next commit
which will actually move it out.
Reviewed by: peter@freebsd.org, gallatin@cs.duke.edu, benno rice,
sleeping on a process object but changed the corresponding
wakeup()s to the thread object. The result was that non-raw
aio ops waited for an aio daemon to timeout before action
was taken. Now, we sleep on the thread object.
PR: kern/34016
than necessary.
o Move a rarely-used goto label inside a critical section so that we don't
perform an splnet() for which there is no corresponding splx().
o Remove unnecessary splnet()/splx() around accesses to kaioinfo::kaio_jobdone
in aio_return().
o Use TAILQ_FOREACH for simple cases of iteration over kaioinfo::kaio_jobdone.
Remove the explicit call to aio_proc_rundown() from exit1(), instead AIO
will use at_exit(9).
Add functions at_exec(9), rm_at_exec(9) which function nearly the
same as at_exec(9) and rm_at_exec(9), these functions are called
on behalf of modules at the time of execve(2) after the image
activator has run.
Use a modified version of tegge's suggestion via at_exec(9) to close
an exploitable race in AIO.
Fix SYSCALL_MODULE_HELPER such that it's archetecuterally neutral,
the problem was that one had to pass it a paramater indicating the
number of arguments which were actually the number of "int". Fix
it by using an inline version of the AS macro against the syscall
arguments. (AS should be available globally but we'll get to that
later.)
Add a primative system for dynamically adding kqueue ops, it's really
not as sophisticated as it should be, but I'll discuss with jlemon when
he's around.
o The manual page for kevent says that EVFILT_AIO returns under the same
conditions as aio_error(). With that in mind, set the data field
of the returned struct kevent to the value that would be returned
by aio_error().
o Fix two compilation warnings.
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.
Sorry john! (your next MFC will be a doosie!)
Reviewed by: peter@freebsd.org, dillon@freebsd.org
X-MFC after: ha ha ha ha
Also move the insertion of the request to after the request is validated,
there's still looks like there may be some problems if an invalid address
is passed to the aio routines, basically a possible leak or having a
not completely initialized structure on the queue may still be possible.
A new sig macro was made _SIG_VALID to check the validity of a signal,
it would be advisable to use it from now on (in kern/kern_sig.c) rather
than rolling your own.
PR: kern/17152
used for up to "vfs.aio.max_buf_aio" of the requests. If a request
size is MAXPHYS, but the request base isn't page aligned, vmapbuf()
will map the end of the user space buffer into the start of the kva
allocated for the next physical buffer. Don't use a physical buffer
in this case. (This change addresses problem report 25617.)
When an aio_read/write() on a raw device has completed, timeout() is
used to schedule a signal to the process. Thus, the reporting is
delayed up to 10 ms (assuming hz is 100). The process might have
terminated in the meantime, causing a trap 12 when attempting to
deliver the signal. Thus, the timeout must be cancelled when removing
the job.
aio jobs in state JOBST_JOBQGLOBAL should be removed from the
kaio_jobqueue list during process rundown.
During process rundown, some aio jobs might move from one list to a
different list that has already been "emptied", causing the rundown to
be incomplete. Retry the rundown.
A call to BUF_KERNPROC() is needed after obtaining a physical buffer
to disassociate the lock from the running process since it can return
to userland without releasing that lock.
PR: 25617
Submitted by: tegge
but potentially significant in -4.x.)
Eliminate a pointless parameter to aio_fphysio().
Remove unnecessary casts from aio_fphysio() and aio_physwakeup().
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.
mtx_enter(lock, type) becomes:
mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)
similarily, for releasing a lock, we now have:
mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.
The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.
Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:
MTX_QUIET and MTX_NOSWITCH
The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:
mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.
Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.
Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.
Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.
Finally, caught up to the interface changes in all sys code.
Contributors: jake, jhb, jasone (in no particular order)
from struct proc, which are now unused (p_nthread already was).
Remove process flag P_KTHREADP which was untested and only set
in vfs_aio.c (it should use kthread_create). Move the yield
system call to kern_synch.c as kern_threads.c has been removed
completely.
moral support from: alfred, jhb
a kevent upon completion of the I/O. Specifically, introduce a new type
of sigevent notification, SIGEV_EVENT. If sigev_notify is SIGEV_EVENT,
then sigev_notify_kqueue names the kqueue that should receive the event
and sigev_value contains the "void *" is copied into the kevent's udata
field.
In contrast to the existing interface, this one: 1) works on
the Alpha 2) avoids the extra copyin() call for the kevent because all
of the information needed is in the sigevent and 3) could be
applied to request a single kevent upon completion of an entire lio_listio().
Reviewed by: jlemon
Pre-rfork code assumed inherent locking of a process's file descriptor
array. However, with the advent of rfork() the file descriptor table
could be shared between processes. This patch closes over a dozen
serious race conditions related to one thread manipulating the table
(e.g. closing or dup()ing a descriptor) while another is blocked in
an open(), close(), fcntl(), read(), write(), etc...
PR: kern/11629
Discussed with: Alexander Viro <viro@math.psu.edu>
Otherwise, aio_read() and aio_write() on sockets are broken if a kevent is
registered. (The code after kevent registration for handling sockets assumes
that the struct file pointer "fp" still refers to the socket, not the kqueue.)
performed twice. Eliminate initialization that is already performed
by _aio_aqueue.
aio_physwakeup: Eliminate redundant synchronization that is already
performed by bufdone.
chgsbsize(), which are called rather frequently and may be called from an
interrupt context in the case of chgsbsize(). Instead, do the hash table
lookup and maintenance when credentials are changed, which is a lot less
frequent. Add pointers to the uidinfo structures to the ucred and pcred
structures for fast access. Pass a pointer to the credential to chgproccnt()
and chgsbsize() instead of passing the uid. Add a reference count to the
uidinfo structure and use it to decide when to free the structure rather
than freeing the structure when the resource consumption drops to zero.
Move the resource tracking code from kern_proc.c to kern_resource.c. Move
some duplicate code sequences in kern_prot.c to separate helper functions.
Change KASSERTs in this code to unconditional tests and calls to panic().
!VFS_AIO case. Lots of things have hooks into here (kqueue, exit(),
sockets, etc), I elected to keep the external interfaces the same
rather than spread more #ifdefs around the kernel.
