options, status pointer and rusage pointer as arguments. It is up to
the caller to copyout the status and rusage to userland if needed. This
lets us axe the 'compat' argument and hide all that functionality in
owait(), by the way. This also cleans up some locking in kern_wait()
since it no longer has to drop locks around copyout() since all the
copyout()'s are deferred.
- Convert owait(), wait4(), and the various ABI compat wait() syscalls to
use kern_wait() rather than wait1() or wait4(). This removes a bit
more stackgap usage.
Tested on: i386
Compiled on: i386, alpha, amd64
in the two consumers that need it.. processes using AIO and netncp.
Update docs. Say that process_exec is called with Giant, but not to
depend on it. All our consumers can handle it without Giant.
- no longer serialize on Giant for thread_single*() and family in fork,
exit and exec
- thread_wait() is mpsafe, assert no Giant
- reduce scope of Giant in exit to not cover thread_wait and just do
vm_waitproc().
- assert that thread_single() family are not called with Giant
- remove the DROP/PICKUP_GIANT macros from thread_single() family
- assert that thread_suspend_check() s not called with Giant
- remove manual drop_giant hack in thread_suspend_check since we know it
isn't held.
- remove the DROP/PICKUP_GIANT macros from thread_suspend_check() family
- mark kse_create() mpsafe
- Push Giant down a bit in coredump() and call coredump() with the proc
lock already held rather than unlocking it only to turn around and
relock it.
Requested by: peter
the process state to zombie when a process exits to avoid a lock order
reversal with the sleepqueue locks. This appears to be the only place
that we call wakeup() with sched_lock held.
set to SIGCHLD. This avoids the creation of orphaned Linux-threaded
zombies that init is unable to reap. This can occur when the parent
process sets its SIGCHLD to SIG_IGN. Fix a similar situation in the
PT_DETACH code.
Tested by: "Steven Hartland" <killing AT multiplay.co.uk>
- struct plimit includes a mutex to protect a reference count. The plimit
structure is treated similarly to struct ucred in that is is always copy
on write, so having a reference to a structure is sufficient to read from
it without needing a further lock.
- The proc lock protects the p_limit pointer and must be held while reading
limits from a process to keep the limit structure from changing out from
under you while reading from it.
- Various global limits that are ints are not protected by a lock since
int writes are atomic on all the archs we support and thus a lock
wouldn't buy us anything.
- All accesses to individual resource limits from a process are abstracted
behind a simple lim_rlimit(), lim_max(), and lim_cur() API that return
either an rlimit, or the current or max individual limit of the specified
resource from a process.
- dosetrlimit() was renamed to kern_setrlimit() to match existing style of
other similar syscall helper functions.
- The alpha OSF/1 compat layer no longer calls getrlimit() and setrlimit()
(it didn't used the stackgap when it should have) but uses lim_rlimit()
and kern_setrlimit() instead.
- The svr4 compat no longer uses the stackgap for resource limits calls,
but uses lim_rlimit() and kern_setrlimit() instead.
- The ibcs2 compat no longer uses the stackgap for resource limits. It
also no longer uses the stackgap for accessing sysctl's for the
ibcs2_sysconf() syscall but uses kernel_sysctl() instead. As a result,
ibcs2_sysconf() no longer needs Giant.
- The p_rlimit macro no longer exists.
Submitted by: mtm (mostly, I only did a few cleanups and catchups)
Tested on: i386
Compiled on: alpha, amd64
Presumably, at some point, you had to include jail.h if you included
proc.h, but that is no longer required.
Result of: self injury involving adding something to struct prison
in exit1(), make sure the p_klist is empty after sending NOTE_EXIT.
The process won't report fork() or execve() and won't be able to handle
NOTE_SIGNAL knotes anyway.
This fixes some race conditions with do_tdsignal() calling knote() while
the process is exiting.
Reported by: Stefan Farfeleder <stefan@fafoe.narf.at>
MFC after: 1 week
is currently executing when we try to remove it in exit1(). Without this,
it was possible for the callout to bogusly rearm itself and eventually
refire after the process had been free'd resulting in a panic.
PR: kern/51964
Reported by: Jilles Tjoelker <jilles@stack.nl>
Reviewed by: tegge, bde
- Move struct sigacts out of the u-area and malloc() it using the
M_SUBPROC malloc bucket.
- Add a small sigacts_*() API for managing sigacts structures: sigacts_alloc(),
sigacts_free(), sigacts_copy(), sigacts_share(), and sigacts_shared().
- Remove the p_sigignore, p_sigacts, and p_sigcatch macros.
- Add a mutex to struct sigacts that protects all the members of the struct.
- Add sigacts locking.
- Remove Giant from nosys(), kill(), killpg(), and kern_sigaction() now
that sigacts is locked.
- Several in-kernel functions such as psignal(), tdsignal(), trapsignal(),
and thread_stopped() are now MP safe.
Reviewed by: arch@
Approved by: re (rwatson)
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.
of ksegs since they primarily operation on processes.
- KSEs take ticks so pass the kse through sched_clock().
- Add a sched_class() routine that adjusts a ksegrp pri class.
- Define a sched_fork_{kse,thread,ksegrp} and sched_exit_{kse,thread,ksegrp}
that will be used to tell the scheduler about new instances of these
structures within the same process. These will be used by THR and KSE.
- Change sched_4bsd to reflect this API update.
if (p->p_numthreads > 1) and not a flag because action is only necessary
if there are other threads. The rest of the system has no need to
identify thr threaded processes.
- In kern_thread.c use thr_exit1() instead of thread_exit() if P_THREADED
is not set.
a follow on commit to kern_sig.c
- signotify() now operates on a thread since unmasked pending signals are
stored in the thread.
- PS_NEEDSIGCHK moves to TDF_NEEDSIGCHK.
flexible process_fork, process_exec, and process_exit eventhandlers. This
reduces code duplication and also means that I don't have to go duplicate
the eventhandler locking three more times for each of at_fork, at_exec, and
at_exit.
Reviewed by: phk, jake, almost complete silence on arch@
struct proc as p_tracecred alongside the current cache of the vnode in
p_tracep. This credential is then used for all later ktrace operations on
this file rather than using the credential of the current thread at the
time of each ktrace event.
- Now that we have multiple ktrace-related items in struct proc that are
pointers, rename p_tracep to p_tracevp to make it less ambiguous.
Requested by: rwatson (1)
it from its pgrp to avoid leaving zombies around with p_pgrp == NULL.
This bug was apparent as a NULL-dereference in the pid selection code
in fork1().
sched_lock around accesses to p_stats->p_timer[] to avoid a potential
race with hardclock. getitimer(), setitimer() and the realitexpire()
callout are now Giant-free.
barrier between free'ing filedesc structures. Basically if you want to
access another process's filedesc, you want to hold this mutex over the
entire operation.
I'm not convinced there is anything major wrong with the patch but
them's the rules..
I am using my "David's mentor" hat to revert this as he's
offline for a while.
data structure called kse_upcall to manage UPCALL. All KSE binding
and loaning code are gone.
A thread owns an upcall can collect all completed syscall contexts in
its ksegrp, turn itself into UPCALL mode, and takes those contexts back
to userland. Any thread without upcall structure has to export their
contexts and exit at user boundary.
Any thread running in user mode owns an upcall structure, when it enters
kernel, if the kse mailbox's current thread pointer is not NULL, then
when the thread is blocked in kernel, a new UPCALL thread is created and
the upcall structure is transfered to the new UPCALL thread. if the kse
mailbox's current thread pointer is NULL, then when a thread is blocked
in kernel, no UPCALL thread will be created.
Each upcall always has an owner thread. Userland can remove an upcall by
calling kse_exit, when all upcalls in ksegrp are removed, the group is
atomatically shutdown. An upcall owner thread also exits when process is
in exiting state. when an owner thread exits, the upcall it owns is also
removed.
KSE is a pure scheduler entity. it represents a virtual cpu. when a thread
is running, it always has a KSE associated with it. scheduler is free to
assign a KSE to thread according thread priority, if thread priority is changed,
KSE can be moved from one thread to another.
When a ksegrp is created, there is always N KSEs created in the group. the
N is the number of physical cpu in the current system. This makes it is
possible that even an userland UTS is single CPU safe, threads in kernel still
can execute on different cpu in parallel. Userland calls kse_create to add more
upcall structures into ksegrp to increase concurrent in userland itself, kernel
is not restricted by number of upcalls userland provides.
The code hasn't been tested under SMP by author due to lack of hardware.
Reviewed by: julian
dereferenced when a process exits due to the vmspace ref-count being
bumped. Change shmexit() and shmexit_myhook() to take a vmspace instead
of a process and call it in vmspace_dofree(). This way if it is missed
in exit1()'s early-resource-free it will still be caught when the zombie is
reaped.
Also fix a potential race in shmexit_myhook() by NULLing out
vmspace->vm_shm prior to calling shm_delete_mapping() and free().
MFC after: 7 days
resource starvation we clean-up as much of the vmspace structure as we
can when the last process using it exits. The rest of the structure
is cleaned up when it is reaped. But since exit1() decrements the ref
count it is possible for a double-free to occur if someone else, such as
the process swapout code, references and then dereferences the structure.
Additionally, the final cleanup of the structure should not occur until
the last process referencing it is reaped.
This commit solves the problem by introducing a secondary reference count,
calling 'vm_exitingcnt'. The normal reference count is decremented on exit
and vm_exitingcnt is incremented. vm_exitingcnt is decremented when the
process is reaped. When both vm_exitingcnt and vm_refcnt are 0, the
structure is freed for real.
MFC after: 3 weeks
in struct proc. While the process label is actually stored in the
struct ucred pointed to by p_ucred, there is a need for transient
storage that may be used when asynchronous (deferred) updates need to
be performed on the "real" label for locking reasons. Unlike other
label storage, this label has no locking semantics, relying on policies
to provide their own protection for the label contents, meaning that
a policy leaf mutex may be used, avoiding lock order issues. This
permits policies that act based on historical process behavior (such
as audit policies, the MAC Framework port of LOMAC, etc) can update
process properties even when many existing locks are held without
violating the lock order. No currently committed policies implement use
of this label storage.
Approved by: re
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
processes forked with RFTHREAD.
- Use a goto to a label for common code when exiting from fork1() in case
of an error.
- Move the RFTHREAD linkage setup code later in fork since the ppeers_lock
cannot be locked while holding a proc lock. Handle the race of a task
leader exiting and killing its peers while a peer is forking a new child.
In that case, go ahead and let the peer process proceed normally as the
parent is about to kill it. However, the task leader may have already
gone to sleep to wait for the peers to die, so the new child process may
not receive a SIGKILL from the task leader. Rather than try to destruct
the new child process, just go ahead and send it a SIGKILL directly and
add it to the p_peers list. This ensures that the task leader will wait
until both the peer process doing the fork() and the new child process
have received their KILL signals and exited.
Discussed with: truckman (earlier versions)
- Begin moving scheduler specific functionality into sched_4bsd.c
- Replace direct manipulation of scheduler data with hooks provided by the
new api.
- Remove KSE specific state modifications and single runq assumptions from
kern_switch.c
Reviewed by: -arch
in specific situations. The owner thread must be blocked, and the
borrower can not proceed back to user space with the borrowed KSE.
The borrower will return the KSE on the next context switch where
teh owner wants it back. This removes a lot of possible
race conditions and deadlocks. It is consceivable that the
borrower should inherit the priority of the owner too.
that's another discussion and would be simple to do.
Also, as part of this, the "preallocatd spare thread" is attached to the
thread doing a syscall rather than the KSE. This removes the need to lock
the scheduler when we want to access it, as it's now "at hand".
DDB now shows a lot mor info for threaded proceses though it may need
some optimisation to squeeze it all back into 80 chars again.
(possible JKH project)
Upcalls are now "bound" threads, but "KSE Lending" now means that
other completing syscalls can be completed using that KSE before the upcall
finally makes it back to the UTS. (getting threads OUT OF THE KERNEL is
one of the highest priorities in the KSE system.) The upcall when it happens
will present all the completed syscalls to the KSE for selection.
gets signals operating based on a TailQ, and is good enough to run X11,
GNOME, and do job control. There are some intricate parts which could be
more refined to match the sigset_t versions, but those require further
evaluation of directions in which our signal system can expand and contract
to fit our needs.
After this has been in the tree for a while, I will make in kernel API
changes, most notably to trapsignal(9) and sendsig(9), to use ksiginfo
more robustly, such that we can actually pass information with our
(queued) signals to the userland. That will also result in using a
struct ksiginfo pointer, rather than a signal number, in a lot of
kern_sig.c, to refer to an individual pending signal queue member, but
right now there is no defined behaviour for such.
CODAFS is unfinished in this regard because the logic is unclear in
some places.
Sponsored by: New Gold Technology
Reviewed by: bde, tjr, jake [an older version, logic similar]
constants VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS, USRSTACK and PS_STRINGS.
This is mainly so that they can be variable even for the native abi, based
on different machine types. Get stack protections from the sysentvec too.
This makes it trivial to map the stack non-executable for certain abis, on
machines that support it.
- Use ucontext_t's to store KSE thread state.
- Synthesize state for the UTS upon each upcall, rather than
saving and copying a trapframe.
- Deliver signals to KSE-aware processes via upcall.
- Rename kse mailbox structure fields to be more BSD-like.
- Store the UTS's stack in struct proc in a stack_t.
Reviewed by: bde, deischen, julian
Approved by: -arch
next step is to allow > 1 to be allocated per process. This would give
multi-processor threads. (when the rest of the infrastructure is
in place)
While doing this I noticed libkvm and sys/kern/kern_proc.c:fill_kinfo_proc
are diverging more than they should.. corrective action needed soon.
The process allocator now caches and hands out complete process structures
*including substructures* .
i.e. it get's the process structure with the first thread (and soon KSE)
already allocated and attached, all in one hit.
For the average non threaded program (non KSE that is) the allocated thread and its stack remain attached to the process, even when the process is
unused and in the process cache. This saves having to allocate and attach it
later, effectively bringing us (hopefully) close to the efficiency
of pre-KSE systems where these were a single structure.
Reviewed by: davidxu@freebsd.org, peter@freebsd.org
s/SNGL/SINGLE/
s/SNGLE/SINGLE/
Fix abbreviation for P_STOPPED_* etc flags, in original code they were
inconsistent and difficult to distinguish between them.
Approved by: julian (mentor)
other references to that vnode as a trace vnode in other processes as well
as in any pending requests on the todo list. Thus, it is possible for a
ktrace request structure to have a NULL ktr_vp when it is destroyed in
ktr_freerequest(). We shouldn't call vrele() on the vnode in that case.
Reported by: bde
The ability to schedule multiple threads per process
(one one cpu) by making ALL system calls optionally asynchronous.
to come: ia64 and power-pc patches, patches for gdb, test program (in tools)
Reviewed by: Almost everyone who counts
(at various times, peter, jhb, matt, alfred, mini, bernd,
and a cast of thousands)
NOTE: this is still Beta code, and contains lots of debugging stuff.
expect slight instability in signals..
obtained, when all other scheduling activity is suspended. This is needed
on sparc64 to deactivate the vmspace of the exiting process on all cpus.
Otherwise if another unrelated process gets the exact same vmspace structure
allocated to it (same address), its address space will not be activated
properly. This seems to fix some spontaneous signal 11 problems with smp
on sparc64.
(P_CONTINUED) is set when a stopped process receives a SIGCONT and
cleared after it has notified a parent process that has requested
notification via waitpid(2) with WCONTINUED specified in its options
operand. The status value can be checked with the new WIFCONTINUED()
macro.
Reviewed by: jake
be done internally.
Ensure that no one can fsetown() to a dying process/pgrp. We need
to check the process for P_WEXIT to see if it's exiting. Process
groups are already safe because there is no such thing as a pgrp
zombie, therefore the proctree lock completely protects the pgrp
from having sigio structures associated with it after it runs
funsetownlst.
Add sigio lock to witness list under proctree and allproc, but over
proc and pgrp.
Seigo Tanimura helped with this.
exit1() we don't have to release it until we acquire schd_lock to
call cpu_throw().
- Since we can switch at any time due to preemption or a lock release
prior to acquiring sched_lock, don't update switchtime and switchticks
until the very end of exit1() after we have acquired sched_lock.
- Interlock the proctree_lock and proc lock in wait1() and exit1() to
avoid lost wakeups when a parent blocks waiting for a child to exit at
the bottom of wait1(). In exit1() the proc lock interlocked with
proctree_lock (and released after acquiring sched_lock) is that of
the parent process.
- In wait1() use an exclusive lock of proctree lock while we are
looking for a process to harvest. This allows us to completely
remove all references to the process once we've found one (i.e.,
disconnect it from pgrp's, session's, zombproc list, and it's parent's
children list) "atomically" without needing to worry about a lock
upgrade.
- We don't need sched_lock to test if p_stat is SZOMB or SSTOP when holding
the proc lock since the proc lock is always held with p_stat is set to
SZOMB or SSTOP.
- Protect nprocs with an xlock of the allproc_lock.
SIGCHLD handler is SIG_IGN. This is a reimplementation of the
problematic revision 1.131 of kern_exit.c. To avoid accessing process
UPAGES, we set a new procsig flag when the SIGCHLD handler is SIG_IGN
and use that instead.
p_pgrp since the pgrp locking went in. We also don't need it to check for
invalid values in the options argument to wait1(), so push Giant down
slightly.
while holding the proc lock, and by holding the pargs structure when
accessing it from outside of the owner.
Submitted by: Jonathan Mini <mini@haikugeek.com>
There is still some locations where the PROC lock should be held
in order to prevent inconsistent views from outside (like the
proc->p_fd fix for kern/vfs_syscalls.c:checkdirs()) that can be
fixed later.
Submitted by: Jonathan Mini <mini@haikugeek.com>
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)
shared.
Also introduce vm_endcopy instead of using pointer tricks when
initializing new vmspaces.
The race occured because of how the reference was utilized:
test vmspace reference,
possibly block,
decrement reference
When sharing a vmspace between multiple processes it was possible
for two processes exiting at the same time to test the reference
count, possibly block and neither one free because they wouldn't
see the other's update.
Submitted by: green
fifesystem problems could prevent the release from completing and
this could result in init being blocked indefinitely.
This was looked over by Matt ages ago.
Approved by: dillon
mutex releases to not require flags for the cases when preemption is
not allowed:
The purpose of the MTX_NOSWITCH and SWI_NOSWITCH flags is to prevent
switching to a higher priority thread on mutex releease and swi schedule,
respectively when that switch is not safe. Now that the critical section
API maintains a per-thread nesting count, the kernel can easily check
whether or not it should switch without relying on flags from the
programmer. This fixes a few bugs in that all current callers of
swi_sched() used SWI_NOSWITCH, when in fact, only the ones called from
fast interrupt handlers and the swi_sched of softclock needed this flag.
Note that to ensure that swi_sched()'s in clock and fast interrupt
handlers do not switch, these handlers have to be explicitly wrapped
in critical_enter/exit pairs. Presently, just wrapping the handlers is
sufficient, but in the future with the fully preemptive kernel, the
interrupt must be EOI'd before critical_exit() is called. (critical_exit()
can switch due to a deferred preemption in a fully preemptive kernel.)
I've tested the changes to the interrupt code on i386 and alpha. I have
not tested ia64, but the interrupt code is almost identical to the alpha
code, so I expect it will work fine. PowerPC and ARM do not yet have
interrupt code in the tree so they shouldn't be broken. Sparc64 is
broken, but that's been ok'd by jake and tmm who will be fixing the
interrupt code for sparc64 shortly.
Reviewed by: peter
Tested on: i386, alpha
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.
userland. The per thread ucred reference is immutable and thus needs no
locks to be read. However, until all the proc locking associated with
writes to p_ucred are completed, it is still not safe to use the per-thread
reference.
Tested on: x86 (SMP), alpha, sparc64
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
it to the MI area. KSE touched cpu_wait() which had the same change
replicated five ways for each platform. Now it can just do it once.
The only MD parts seemed to be dealing with fpu state cleanup and things
like vm86 cleanup on x86. The rest was identical.
XXX: ia64 and powerpc did not have cpu_throw(), so I've put a functional
stub in place.
Reviewed by: jake, tmm, dillon
This paniced my one of my machines one time too many :-( and there is
no sign of a solution in the pipeline. The deltas are still easily
available in cvs. The problem is that if the parent has been swapped
out, the child process cannot grope around in the parent's UPAGES to
see the sigact[] array or it will fault. This probably is a showstopper
for this implementation anyway.
an unexpected user-visible side effect with the sigaction flags. Also cleanup
a minor union issue.
Submitted by: Rudolf Cejka <cejkar@dcse.fee.vutbr.cz>
MFC addendum: MFC will be combined w/ original commit
MFC after: 3 days
(this commit is just the first stage). Also add various GIANT_ macros to
formalize the removal of Giant, making it easy to test in a more piecemeal
fashion. These macros will allow us to test fine-grained locks to a degree
before removing Giant, and also after, and to remove Giant in a piecemeal
fashion via sysctl's on those subsystems which the authors believe can
operate without Giant.
processes.
- Don't construct fake call args and then call kill(). psignal is not
anymore complicated and is quicker and not prone to locking problems.
Calling psignal() avoids having to do a pfind() since we already have a
proc pointer and also allows us to keep the task leader locked while we
kill all the peer processes so the list is kept coherent.
- When a kthread exits, do a wakeup() on its proc pointers. This can be
used by kernel modules that have kthreads and want to ensure they have
safely exited before completely the MOD_UNLOAD event.
Connectivity provided by: Usenix wireless
real uid, saved uid, real gid, and saved gid to ucred, as well as the
pcred->pc_uidinfo, which was associated with the real uid, only rename
it to cr_ruidinfo so as not to conflict with cr_uidinfo, which
corresponds to the effective uid.
o Remove p_cred from struct proc; add p_ucred to struct proc, replacing
original macro that pointed.
p->p_ucred to p->p_cred->pc_ucred.
o Universally update code so that it makes use of ucred instead of pcred,
p->p_ucred instead of p->p_pcred, cr_ruidinfo instead of p_uidinfo,
cr_{r,sv}{u,g}id instead of p_*, etc.
o Remove pcred0 and its initialization from init_main.c; initialize
cr_ruidinfo there.
o Restruction many credential modification chunks to always crdup while
we figure out locking and optimizations; generally speaking, this
means moving to a structure like this:
newcred = crdup(oldcred);
...
p->p_ucred = newcred;
crfree(oldcred);
It's not race-free, but better than nothing. There are also races
in sys_process.c, all inter-process authorization, fork, exec, and
exit.
o Remove sigio->sio_ruid since sigio->sio_ucred now contains the ruid;
remove comments indicating that the old arrangement was a problem.
o Restructure exec1() a little to use newcred/oldcred arrangement, and
use improved uid management primitives.
o Clean up exit1() so as to do less work in credential cleanup due to
pcred removal.
o Clean up fork1() so as to do less work in credential cleanup and
allocation.
o Clean up ktrcanset() to take into account changes, and move to using
suser_xxx() instead of performing a direct uid==0 comparision.
o Improve commenting in various kern_prot.c credential modification
calls to better document current behavior. In a couple of places,
current behavior is a little questionable and we need to check
POSIX.1 to make sure it's "right". More commenting work still
remains to be done.
o Update credential management calls, such as crfree(), to take into
account new ruidinfo reference.
o Modify or add the following uid and gid helper routines:
change_euid()
change_egid()
change_ruid()
change_rgid()
change_svuid()
change_svgid()
In each case, the call now acts on a credential not a process, and as
such no longer requires more complicated process locking/etc. They
now assume the caller will do any necessary allocation of an
exclusive credential reference. Each is commented to document its
reference requirements.
o CANSIGIO() is simplified to require only credentials, not processes
and pcreds.
o Remove lots of (p_pcred==NULL) checks.
o Add an XXX to authorization code in nfs_lock.c, since it's
questionable, and needs to be considered carefully.
o Simplify posix4 authorization code to require only credentials, not
processes and pcreds. Note that this authorization, as well as
CANSIGIO(), needs to be updated to use the p_cansignal() and
p_cansched() centralized authorization routines, as they currently
do not take into account some desirable restrictions that are handled
by the centralized routines, as well as being inconsistent with other
similar authorization instances.
o Update libkvm to take these changes into account.
Obtained from: TrustedBSD Project
Reviewed by: green, bde, jhb, freebsd-arch, freebsd-audit
vm_mtx does not recurse and is required for most low level
vm operations.
faults can not be taken without holding Giant.
Memory subsystems can now call the base page allocators safely.
Almost all atomic ops were removed as they are covered under the
vm mutex.
Alpha and ia64 now need to catch up to i386's trap handlers.
FFS and NFS have been tested, other filesystems will need minor
changes (grabbing the vm lock when twiddling page properties).
Reviewed (partially) by: jake, jhb
uses lockmgr locks and this leads to a lock order reversal. At this point
in wait1() the process is not on any process lists or in the process tree,
so no other process should be able to find it or have a reference to it
anyways, so the locking is not needed.
than dinking around in the process lists explicitly.
- Hold both the proctree lock and proc lock of the child process when
reparenting a process via proc_reparent.
- Lock processes while sending them signals.
- Miscellaenous proc locking.
- proc_reparent() now asserts that the child is locked in addition to an
exclusive proctree lock.
interrupts.
Protect usage of the per processor switchtime variable against
interrupts in calcru().
This seem to eliminate the "microuptime() went backwards" warnings.
credential structure, ucred (cr->cr_prison).
o Allow jail inheritence to be a function of credential inheritence.
o Abstract prison structure reference counting behind pr_hold() and
pr_free(), invoked by the similarly named credential reference
management functions, removing this code from per-ABI fork/exit code.
o Modify various jail() functions to use struct ucred arguments instead
of struct proc arguments.
o Introduce jailed() function to determine if a credential is jailed,
rather than directly checking pointers all over the place.
o Convert PRISON_CHECK() macro to prison_check() function.
o Move jail() function prototypes to jail.h.
o Emulate the P_JAILED flag in fill_kinfo_proc() and no longer set the
flag in the process flags field itself.
o Eliminate that "const" qualifier from suser/p_can/etc to reflect
mutex use.
Notes:
o Some further cleanup of the linux/jail code is still required.
o It's now possible to consider resolving some of the process vs
credential based permission checking confusion in the socket code.
o Mutex protection of struct prison is still not present, and is
required to protect the reference count plus some fields in the
structure.
Reviewed by: freebsd-arch
Obtained from: TrustedBSD Project
- I can't seem to reproduce the warning I got from WITNESS anymore.
- The fix was wrong. Since a uidinfo struct is a member of proc, it
makes sense for the locking order to be such that you are allowed to
hold proc and then grab the uidinfo lock.
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)
of explicit calls to lockmgr. Also provides macros for the flags
pased to specify shared, exclusive or release which map to the
lockmgr flags. This is so that the use of lockmgr can be easily
replaced with optimized reader-writer locks.
- Add some locking that I missed the first time.
lock. Otherwise, if we block on the backing mutex while releasing the
allproc lock, then when we resume, we will be at SRUN, and we will stay
that way all the way through cpu_exit. As a result, our parent will never
harvest us.
include:
* Mutual exclusion is used instead of spl*(). See mutex(9). (Note: The
alpha port is still in transition and currently uses both.)
* Per-CPU idle processes.
* Interrupts are run in their own separate kernel threads and can be
preempted (i386 only).
Partially contributed by: BSDi (BSD/OS)
Submissions by (at least): cp, dfr, dillon, grog, jake, jhb, sheldonh
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().
gcc's internal exit() prototypes and the (futile) hackery that we did to
try and avoid warnings. main() was renamed for similar reasons.
Remove an exit related hack from makesyscalls.sh.
1) while allocating a uidinfo struct malloc is called with M_WAITOK,
it's possible that while asleep another process by the same user
could have woken up earlier and inserted an entry into the uid
hash table. Having redundant entries causes inconsistancies that
we can't handle.
fix: do a non-waiting malloc, and if that fails then do a blocking
malloc, after waking up check that no one else has inserted an entry
for us already.
2) Because many checks for sbsize were done as "test then set" in a non
atomic manner it was possible to exceed the limits put up via races.
fix: instead of querying the count then setting, we just attempt to
set the count and leave it up to the function to return success or
failure.
3) The uidinfo code was inlining and repeating, lookups and insertions
and deletions needed to be in their own functions for clarity.
Reviewed by: green
to wake up any processes waiting via PIOCWAIT on process exit, and truss
needs to be more aware that a process may actually disappear while it's
waiting.
Reviewed by: Paul Saab <ps@yahoo-inc.com>
commit to kern_synch.c:
----------------------------
revision 1.55
date: 1999/02/23 02:56:03; author: ross; state: Exp; lines: +39 -10
Scheduler bug fixes and reorganization
* fix the ancient nice(1) bug, where nice +20 processes incorrectly
steal 10 - 20% of the CPU, (or even more depending on load average)
* provide a new schedclk() mechanism at a new clock at schedhz, so high
platform hz values don't cause nice +0 processes to look like they are
niced
* change the algorithm slightly, and reorganize the code a lot
* fix percent-CPU calculation bugs, and eliminate some no-op code
=== nice bug === Correctly divide the scheduler queues between niced and
compute-bound processes. The current nice weight of two (sort of, see
`algorithm change' below) neatly divides the USRPRI queues in half; this
should have been used to clip p_estcpu, instead of UCHAR_MAX. Besides
being the wrong amount, clipping an unsigned char to UCHAR_MAX is a no-op,
and it was done after decay_cpu() which can only _reduce_ the value. It
has to be kept <= NICE_WEIGHT * PRIO_MAX - PPQ or processes can
scheduler-penalize themselves onto the same queue as nice +20 processes.
(Or even a higher one.)
=== New schedclk() mechansism === Some platforms should be cutting down
stathz before hitting the scheduler, since the scheduler algorithm only
works right in the vicinity of 64 Hz. Rather than prescale hz, then scale
back and forth by 4 every time p_estcpu is touched (each occurance an
abstraction violation), use p_estcpu without scaling and require schedhz
to be generated directly at the right frequency. Use a default stathz (well,
actually, profhz) / 4, so nothing changes unless a platform defines schedhz
and a new clock. Define these for alpha, where hz==1024, and nice was
totally broke.
=== Algorithm change === The nice value used to be added to the
exponentially-decayed scheduler history value p_estcpu, in _addition_ to
be incorporated directly (with greater wieght) into the priority calculation.
At first glance, it appears to be a pointless increase of 1/8 the nice
effect (pri = p_estcpu/4 + nice*2), but it's actually at least 3x that
because it will ramp up linearly but be decayed only exponentially, thus
converging to an additional .75 nice for a loadaverage of one. I killed
this, it makes the behavior hard to control, almost impossible to analyze,
and the effect (~~nothing at for the first second, then somewhat increased
niceness after three seconds or more, depending on load average) pointless.
=== Other bugs === hz -> profhz in the p_pctcpu = f(p_cpticks) calcuation.
Collect scheduler functionality. Try to put each abstraction in just one
place.
----------------------------
The details are a little different in FreeBSD:
=== nice bug === Fixing this is the main point of this commit. We use
essentially the same clipping rule as NetBSD (our limit on p_estcpu
differs by a scale factor). However, clipping at all is fundamentally
bad. It gives free CPU the hoggiest hogs once they reach the limit, and
reaching the limit is normal for long-running hogs. This will be fixed
later.
=== New schedclk() mechanism === We don't use the NetBSD schedclk()
(now schedclock()) mechanism. We require (real)stathz to be about 128
and scale by an extra factor of 2 compared with NetBSD's statclock().
We scale p_estcpu instead of scaling the clock. This is more accurate
and flexible.
=== Algorithm change === Same change.
=== Other bugs === The p_pctcpu bug was fixed long ago. We don't try as
hard to abstract functionality yet.
Related changes: the new limit on p_estcpu must be exported to kern_exit.c
for clipping in wait1().
Agreed with by: dufault
linked list to store the callbak routines. The patch converts the
lists to queue(3) TAILQs, making the code slightly clearer and ensuring
that callbacks are executed in FIFO order.
Man page also updated as necesary.
(discontinued use of M_TEMP malloc type while here anyway /phk)
Submitted by: Jake Burkholder jake@checker.org
PR: 14912
This fixes some nasty procfs problems for SMP, makes ps(1) run much faster,
and makes ps(1) even less dependent on /proc which will aid chroot and
jails alike.
To disable this facility and revert to previous behaviour:
sysctl -w kern.ps_arg_cache_limit=0
For full details see the current@FreeBSD.org mail-archives.
Alot of the code in sys/kern directly accesses the *Q_HEAD and *Q_ENTRY
structures for list operations. This patch makes all list operations
in sys/kern use the queue(3) macros, rather than directly accessing the
*Q_{HEAD,ENTRY} structures.
This batch of changes compile to the same object files.
Reviewed by: phk
Submitted by: Jake Burkholder <jake@checker.org>
PR: 14914
can provide the correct context to each signal handler.
Fix broken sigsuspend(): don't use p_oldsigmask as a flag, use SAS_OLDMASK
as we did before the linuxthreads support merge (submitted by bde).
Move ps_sigstk from to p_sigacts to the main proc structure since signal
stack should not be shared among threads.
Move SAS_OLDMASK and SAS_ALTSTACK flags from sigacts::ps_flags to proc::p_flag.
Move PS_NOCLDSTOP and PS_NOCLDWAIT flags from proc::p_flag to procsig::ps_flag.
Reviewed by: marcel, jdp, bde
-----------------------------
The core of the signalling code has been rewritten to operate
on the new sigset_t. No methodological changes have been made.
Most references to a sigset_t object are through macros (see
signalvar.h) to create a level of abstraction and to provide
a basis for further improvements.
The NSIG constant has not been changed to reflect the maximum
number of signals possible. The reason is that it breaks
programs (especially shells) which assume that all signals
have a non-null name in sys_signame. See src/bin/sh/trap.c
for an example. Instead _SIG_MAXSIG has been introduced to
hold the maximum signal possible with the new sigset_t.
struct sigprop has been moved from signalvar.h to kern_sig.c
because a) it is only used there, and b) access must be done
though function sigprop(). The latter because the table doesn't
holds properties for all signals, but only for the first NSIG
signals.
signal.h has been reorganized to make reading easier and to
add the new and/or modified structures. The "old" structures
are moved to signalvar.h to prevent namespace polution.
Especially the coda filesystem suffers from the change, because
it contained lines like (p->p_sigmask == SIGIO), which is easy
to do for integral types, but not for compound types.
NOTE: kdump (and port linux_kdump) must be recompiled.
Thanks to Garrett Wollman and Daniel Eischen for pressing the
importance of changing sigreturn as well.
discussed on current.
The following variables are defined (for now):
osname (defaults to "Linux")
Allow users to change the name of the OS as returned by uname(2),
specially added for all those Linux Netscape users and statistics
maniacs :-) We now have what we all wanted!
osrelease (defaults to "2.2.5")
Allow users to change the version of the OS as returned by uname(2).
Since -current supports glibc2.1 now, change the default to 2.2.5
(was 2.0.36).
oss_version (defaults to 198144 [0x030600])
This one will be used by the OSS_GETVERSION ioctl (PR 12917) which I
can commit now that we have the MIB. The default version number is the
lowest version possible with the current 'encoding'.
A note about imprisoned processes (see jail(2)):
These variables are copy-on-write (as suggested by phk). This means that
imprisoned processes will use the system wide value unless it is written/set
by the process. From that moment on, a copy local to the prison will be
used.
A note about the implementation:
I choose to add a single pointer to struct prison, because I didn't like the
idea of changing struct prison every time I come up with a new variable. As
a side effect, the extra storage is only needed when a variable is set from
within the prison. This also minimizes kernel bloat when the Linuxulator is
not used; both compiled in or as a module.
Reviewed by: bde (first version only) and phk
- this causes POSIX locking to use the thread group leader
(p->p_leader) as the locking thread for all advisory locks.
In non-kernel-threaded code p->p_leader == p, so this will have
no effect.
This results in (more) correct POSIX threaded flock-ing semantics.
It also prevents the leader from exiting before any of the children.
(so that p->p_leader will never be stale) in exit1().
We have been running this patch for over a month now in our lab
under load and at customer sites.
Submitted by: John Plevyak <jplevyak@inktomi.com>
This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
- %fs register is added to trapframe and saved/restored upon kernel entry/exit.
- Per-cpu pages are no longer mapped at the same virtual address.
- Each cpu now has a separate gdt selector table. A new segment selector
is added to point to per-cpu pages, per-cpu global variables are now
accessed through this new selector (%fs). The selectors in gdt table are
rearranged for cache line optimization.
- fask_vfork is now on as default for both UP and SMP.
- Some aio code cleanup.
Reviewed by: Alan Cox <alc@cs.rice.edu>
John Dyson <dyson@iquest.net>
Julian Elischer <julian@whistel.com>
Bruce Evans <bde@zeta.org.au>
David Greenman <dg@root.com>
was discarded on every call to calcru(). Hacking on the `switchtime'
global for a related fix in rev.1.38 of kern_resource.c was too fragile
and broke when p_switchtime went away.
PR: 10402
is the preparation step for moving pmap storage out of vmspace proper.
Reviewed by: Alan Cox <alc@cs.rice.edu>
Matthew Dillion <dillon@apollo.backplane.com>
This takes the conditionals out of the code that has been tested by
various people for a while.
ps and friends (libkvm) will need a recompile as some proc structure
changes are made.
Submitted by: "Richard Seaman, Jr." <dick@tar.com>
shared signal handling when there is shared signal handling being
used.
This removes the main objection to making the shared signal handling
a standard ability in rfork() and friends and 'unconditionalising'
this code. (i.e. the allocation of an extra 328 bytes per process).
Signal handling information remains in the U area until such a time as
it's reference count would be incremented to > 1. At that point a new
struct is malloc'd and maintained in KVM so that it can be shared between
the processes (threads) using it.
A function to check the reference count and move the struct back to the U
area when it drops back to 1 is also supplied. Signal information is
therefore now swapable for all processes that are not sharing that
information with other processes. THis should addres the concerns raised
by Garrett and others.
Submitted by: "Richard Seaman, Jr." <dick@tar.com>
Submitted by: "Richard Seaman, Jr." <lists@tar.com>
Obtained from: linux :-)
Code to allow Linux Threads to run under FreeBSD.
By default not enabled
This code is dependent on the conditional
COMPAT_LINUX_THREADS (suggested by Garret)
This is not yet a 'real' option but will be within some number of hours.
by bde, a few other tweaks to get the patch to apply cleanly again and
some improvements to the comments.
This change closes some fairly minor security holes associated with
F_SETOWN, fixes a few bugs, and removes some limitations that F_SETOWN
had on tty devices. For more details, see the description on the PR.
Because this patch increases the size of the proc and pgrp structures,
it is necessary to re-install the includes and recompile libkvm,
the vinum lkm, fstat, gcore, gdb, ipfilter, ps, top, and w.
PR: kern/7899
Reviewed by: bde, elvind
1) Start using TSM.
Struct procs continue to point to upages structure, after being freed.
Struct vmspace continues to point to pte object and kva space for kstack.
u_map is now superfluous.
2) vm_map's don't need to be reference counted. They always exist either
in the kernel or in a vmspace. The vmspaces are managed by reference
counts.
3) Remove the "wired" vm_map nonsense.
4) No need to keep a cache of kernel stack kva's.
5) Get rid of strange looking ++var, and change to var++.
6) Change more data structures to use our "zone" allocator. Added
struct proc, struct vmspace and struct vnode. This saves a significant
amount of kva space and physical memory. Additionally, this enables
TSM for the zone managed memory.
7) Keep ioopt disabled for now.
8) Remove the now bogus "single use" map concept.
9) Use generation counts or id's for data structures residing in TSM, where
it allows us to avoid unneeded restart overhead during traversals, where
blocking might occur.
10) Account better for memory deficits, so the pageout daemon will be able
to make enough memory available (experimental.)
11) Fix some vnode locking problems. (From Tor, I think.)
12) Add a check in ufs_lookup, to avoid lots of unneeded calls to bcmp.
(experimental.)
13) Significantly shrink, cleanup, and make slightly faster the vm_fault.c
code. Use generation counts, get rid of unneded collpase operations,
and clean up the cluster code.
14) Make vm_zone more suitable for TSM.
This commit is partially as a result of discussions and contributions from
other people, including DG, Tor Egge, PHK, and probably others that I
have forgotten to attribute (so let me know, if I forgot.)
This is not the infamous, final cleanup of the vnode stuff, but a necessary
step. Vnode mgmt should be correct, but things might still change, and
there is still some missing stuff (like ioopt, and physical backing of
non-merged cache files, debugging of layering concepts.)
Note that an unload facility should be used to call rm_at_exit() (if
procfs is being loaded as an LKM and is subsequently removed), but it
was non-obvious how to do this in the VFS framework.
Reviewed by: Julian Elischer
surprise, procfs actually is optional, and some people truly do generate
kernels without it. Wow. I built a kernel without 'options PROCFS' and
it compiled and linked.
Disallow wait options that are not a combination of the standard POSIX
options WUNTRACED and WNOHANG, as is required by POSIX. BSD doesn't
have any extensions here, but the code was `#ifdef notyet' for some
reason.
it in struct proc instead.
This fixes a boatload of compiler warning, and removes a lot of cruft
from the sources.
I have not removed the /*ARGSUSED*/, they will require some looking at.
libkvm, ps and other userland struct proc frobbing programs will need
recompiled.
Distribute all but the most fundamental malloc types. This time I also
remembered the trick to making things static: Put "static" in front of
them.
A couple of finer points by: bde
Add support for "interrupt driven configuration hooks".
A component of the kernel can register a hook, most likely
during auto-configuration, and receive a callback once
interrupt services are available. This callback will occur before
the root and dump devices are configured, so the configuration
task can affect the selection of those two devices or complete
any tasks that need to be performed prior to launching init.
System boot is posponed so long as a hook is registered. The
hook owner is responsible for removing the hook once their task
is complete or the system boot can continue.
kern_acct.c kern_clock.c kern_exit.c kern_synch.c kern_time.c:
Change the interface and implementation for the kernel callout
service. The new implemntaion is based on the work of
Adam M. Costello and George Varghese, published in a technical
report entitled "Redesigning the BSD Callout and Timer Facilities".
The interface used in FreeBSD is a little different than the one
outlined in the paper. The new function prototypes are:
struct callout_handle timeout(void (*func)(void *),
void *arg, int ticks);
void untimeout(void (*func)(void *), void *arg,
struct callout_handle handle);
If a client wishes to remove a timeout, it must store the
callout_handle returned by timeout and pass it to untimeout.
The new implementation gives 0(1) insert and removal of callouts
making this interface scale well even for applications that
keep 100s of callouts outstanding.
See the updated timeout.9 man page for more details.
The implementation is done (unlike what i've originally been
contemplating) by reparenting kids of processes that have the
appropriate bit set to PID 1, and let PID 1 handle the zombie. This
is far less problematical than what would seem to be ``doing it
right'', for a number of reasons.
Of our currently shipping PID-1-intended programs, 50 % fail the above
assumption. ;-) (Read this: sysinstall doesn't do it right. This is
no problem as long as no program called by sysinstall actually uses
SA_NOCLDWAIT.)
ToDo: . clarify the correct SA_* flag inheritance, compared
to other systems,
. decide whether the compat cruft (osigvec(9)) should
deal with new system additions or not,
. merge OpenBSD's SA_SIGINFO implementation. ;)
Reviewed by: bde
POSIX.4. Additionally, there is some initial code that supports LIO.
This code supports AIO/LIO for all types of file descriptors, with
few if any restrictions. There will be a followup very soon that
will support significantly more efficient operation for VCHR type
files (raw.) This code is also dependent on some kernel features
that don't work under SMP yet. After I commit the changes to the
kernel to support proper address space sharing on SMP, this code
will also work under SMP.
space. (!)
Have each process use the kernel stack and pcb in the kvm space. Since
the stacks are at a different address, we cannot copy the stack at fork()
and allow the child to return up through the function call tree to return
to user mode - create a new execution context and have the new process
begin executing from cpu_switch() and go to user mode directly.
In theory this should speed up fork a bit.
Context switch the tss_esp0 pointer in the common tss. This is a lot
simpler since than swithching the gdt[GPROC0_SEL].sd.sd_base pointer
to each process's tss since the esp0 pointer is a 32 bit pointer, and the
sd_base setting is split into three different bit sections at non-aligned
boundaries and requires a lot of twiddling to reset.
The 8K of memory at the top of the process space is now empty, and unmapped
(and unmappable, it's higher than VM_MAXUSER_ADDRESS).
Simplity the pmap code to manage process contexts, we no longer have to
double map the UPAGES, this simplifies and should measuably speed up fork().
The following parts came from John Dyson:
Set PG_G on the UPAGES that are now in kernel context, and invalidate
them when swapping them out.
Move the upages object (upobj) from the vmspace to the proc structure.
Now that the UPAGES (pcb and kernel stack) are out of user space, make
rfork(..RFMEM..) do what was intended by sharing the vmspace
entirely via reference counting rather than simply inheriting the mappings.
changes, so don't expect to be able to run the kernel as-is (very well)
without the appropriate Lite/2 userland changes.
The system boots and can mount UFS filesystems.
Untested: ext2fs, msdosfs, NFS
Known problems: Incorrect Berkeley ID strings in some files.
Mount_std mounts will not work until the getfsent
library routine is changed.
Reviewed by: various people
Submitted by: Jeffery Hsu <hsu@freebsd.org>
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
previous snap. Specifically, kern_exit and kern_exec now makes a
call into the pmap module to do a very fast removal of pages from the
address space. Additionally, the pmap module now updates the PG_MAPPED
and PG_WRITABLE flags. This is an optional optimization, but helpful
on the X86.
1/ session leader
2/ Have a console device vnode (/dev/console)
3/ have NULL pointer for a consoel tty struct.
fix the only case where the tty struct is referenced without a prior
check for existance.
note that at_shutdown has a new parameter to indicate When
during a shutdown the callout should be made. also
add a RB_POWEROFF flag to reboot "howto" parameter..
tells the reboot code in our at_shutdown module to turn off the UPS
and kill the power. bound to be useful eventually on laptops
I've been meaning to do this for AGES as I keep having to patch those routines
whenever I write a proprietary package or similar..
any module that assigns resources to processes needs to know when
these events occur. there are existsing modules that should be modified
to take advantage of these.. e.g. SYSV IPC primatives
presently have #ifdef entries in exit()
this also helps with making LKMs out of such things..
(see the man pages at_exit(9) and at_fork(9))
problem with the 'shell scripts' was found, but there was a 'strange'
problem found with a 486 laptop that we could not find. This commit
backs the code back to 25-jul, and will be re-entered after the snapshot
in smaller (more easily tested) chunks.
performance issues.
1) The pmap module has had too many inlines, and so the
object file is simply bigger than it needs to be.
Some common code is also merged into subroutines.
2) Removal of some *evil* PHYS_TO_VM_PAGE macro calls.
Unfortunately, a few have needed to be added also.
The removal caused the need for more vm_page_lookups.
I added lookup hints to minimize the need for the
page table lookup operations.
3) Removal of some bogus performance improvements, that
mostly made the code more complex (tracking individual
page table page updates unnecessarily). Those improvements
actually hurt 386 processors perf (not that people who
worry about perf use 386 processors anymore :-)).
4) Changed pv queue manipulations/structures to be TAILQ's.
5) The pv queue code has had some performance problems since
day one. Some significant scalability issues are resolved
by threading the pv entries from the pmap AND the physical
address instead of just the physical address. This makes
certain pmap operations run much faster. This does
not affect most micro-benchmarks, but should help loaded system
performance *significantly*. DG helped and came up with most
of the solution for this one.
6) Most if not all pmap bit operations follow the pattern:
pmap_test_bit();
pmap_clear_bit();
That made for twice the necessary pv list traversal. The
pmap interface now supports only pmap_tc_bit type operations:
pmap_[test/clear]_modified, pmap_[test/clear]_referenced.
Additionally, the modified routine now takes a vm_page_t arg
instead of a phys address. This eliminates a PHYS_TO_VM_PAGE
operation.
7) Several rewrites of routines that contain redundant code to
use common routines, so that there is a greater likelihood of
keeping the cache footprint smaller.
Speed up for vfs_bio -- addition of a routine bqrelse to greatly diminish
overhead for merged cache.
Efficiency improvement for vfs_cluster. It used to do alot of redundant
calls to cluster_rbuild.
Correct the ordering for vrele of .text and release of credentials.
Use the selective tlb update for 486/586/P6.
Numerous fixes to the size of objects allocated for files. Additionally,
fixes in the various pagers.
Fixes for proper positioning of vnode_pager_setsize in msdosfs and ext2fs.
Fixes in the swap pager for exhausted resources. The pageout code
will not as readily thrash.
Change the page queue flags (PG_ACTIVE, PG_INACTIVE, PG_FREE, PG_CACHE) into
page queue indices (PQ_ACTIVE, PQ_INACTIVE, PQ_FREE, PQ_CACHE),
thereby improving efficiency of several routines.
Eliminate even more unnecessary vm_page_protect operations.
Significantly speed up process forks.
Make vm_object_page_clean more efficient, thereby eliminating the pause
that happens every 30seconds.
Make sequential clustered writes B_ASYNC instead of B_DELWRI even in the
case of filesystems mounted async.
Fix a panic with busy pages when write clustering is done for non-VMIO
buffers.
sysv_ipc.c: add stub functions that either simply return (for the hooks
in kern_fork/kern_exit) or log() a messgae and call enosys() (for the
syscalls). sysv_ipc.c will become "standard" in conf/files and has
#ifs for all the permutations.
