- Threads lifetime cycle, in particular, counting of the threads in
the process, and interlocking with process mutex and thread lock.
The main reason of this is that turnstile locks are after thread
locks, so you e.g. cannot unlock blockable mutex (think process
mutex) while owning thread lock.
- Virtual and profiling itimers, since the timers activation is done
from the clock interrupt context. Replace the p_slock by p_itimmtx
and PROC_ITIMLOCK().
- Profiling code (profil(2)), for similar reason. Replace the p_slock
by p_profmtx and PROC_PROFLOCK().
- Resource usage accounting. Need for the spinlock there is subtle,
my understanding is that spinlock blocks context switching for the
current thread, which prevents td_runtime and similar fields from
changing (updates are done at the mi_switch()). Replace the p_slock
by p_statmtx and PROC_STATLOCK().
The split is done mostly for code clarity, and should not affect
scalability.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
user. Kqueue now saves the ucred of the allocating thread, to
correctly decrement the counter on close.
Under some specific and not real-world use scenario for kqueue, it is
possible for the kqueues to consume memory proportional to the square
of the number of the filedescriptors available to the process. Limit
allows administrator to prevent the abuse.
This is kernel-mode side of the change, with the user-mode enabling
commit following.
Reported and tested by: pho
Discussed with: jmg
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
response to an rtprio_thread() call, when the priority is different
than the old priority, and either the old or the new priority class is
not RTP_PRIO_NORMAL (timeshare).
The reasoning for the second half of the test is that if it's a change in
timeshare priority, then the scheduler is going to adjust that priority
in a way that completely wipes out the requested change anyway, so
what's the point? (If that's not true, then allowing a thread to change
its own timeshare priority would subvert the scheduler's adjustments and
let a cpu-bound thread monopolize the cpu; if allowed at all, that
should require priveleges.)
On the other hand, if either the old or new priority class is not
timeshare, then the scheduler doesn't make automatic adjustments, so we
should honor the request and make the priority change right away. The
reason the old class gets caught up in this is the very reason for this
change: when thread A changes the priority of its child thread B from
idle back to timeshare, thread B never actually gets moved to a
timeshare-range run queue unless there are some idle cycles available
to allow it to first get scheduled again as an idle thread.
Reviewed by: jhb@
Specify that precision of 0.5s is enough for resource limitation.
Sponsored by: Google Summer of Code 2012, iXsystems inc.
Tested by: flo, marius, ian, markj, Fabian Keil
- retrive only one, specified limit for a process, not the whole
array, as it was previously (the sysctl has been added recently and
has not been backported to stable yet, so this change is ok);
- allow to set a resource limit for another process.
Submitted by: Andrey Zonov <andrey at zonov.org>
Discussed with: kib
Reviewed by: kib
MFC after: 2 weeks
in addition to the user priority for threads whose current real priority
is equal to the previous user priority or if the new priority is a
real-time priority. This allows priority changes of other threads to
have an immediate effect.
MFC after: 2 weeks
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.
Reviewed by: rwatson
Approved by: re (bz)
ki_rusage member when KERN_PROC_INC_THREAD is passed to one of the
process sysctls.
- Correctly account for the current thread's cputime in the thread when
doing the runtime fixup in calcru().
- Use TIDs as the key to lookup the previous thread to compute IO stat
deltas in IO mode in top when thread display is enabled.
Reviewed by: kib
Approved by: re (kib)
and per-loginclass resource accounting information, to be used by the new
resource limits code. It's connected to the build, but the code that
actually calls the new functions will come later.
Sponsored by: The FreeBSD Foundation
Reviewed by: kib (earlier version)
- Hold the proc lock while changing the state from PRS_NEW to PRS_NORMAL
in fork to honor the locking requirements. While here, expand the scope
of the PROC_LOCK() on the new process (p2) to avoid some LORs. Previously
the code was locking the new child process (p2) after it had locked the
parent process (p1). However, when locking two processes, the safe order
is to lock the child first, then the parent.
- Fix various places that were checking p_state against PRS_NEW without
having the process locked to use PROC_LOCK(). Every place was already
locking the process, just after the PRS_NEW check.
- Remove or reduce the use of PROC_SLOCK() for places that were checking
p_state against PRS_NEW. The PROC_LOCK() alone is sufficient for reading
the current state.
- Reorder fill_kinfo_proc() slightly so it only acquires PROC_SLOCK() once.
MFC after: 1 week
use sched_lend_user_prio to set lent priority.
- Improve pthread priority-inherit mutex, when a contender's priority is
lowered, repropagete priorities, this may cause mutex owner's priority
to be lowerd, in old code, mutex owner's priority is rise-only.
earlier commit. While here, move the thread lock down in rtp_to_pri().
It is not needed for all of the priority value checks and the computation
of newpri.
Reported by: swell.k @ gmail
MFC after: 3 days
rwlock to protect the table. In old code, thread lookup is done with
process lock held, to find a thread, kernel has to iterate through
process and thread list, this is quite inefficient.
With this change, test shows in extreme case performance is
dramatically improved.
Earlier patch was reviewed by: jhb, julian
on exit, that is done once in thread_exit() and the second time in
proc_reap(), by clearing td_incruntime.
Use the opportunity to revert to the pre-RUSAGE_THREAD exporting of ruxagg()
instead of ruxagg_locked() and use it from thread_exit().
Diagnosed and tested by: neel
MFC after: 3 days
information for thread to allow calcru1() (re)use.
Rename ruxagg()->ruxagg_locked(), ruxagg_tlock()->ruxagg() [1].
The ruxagg_locked() function no longer clears thread ticks nor
td_incruntime.
Requested by: attilio [1]
Discussed with: attilio, bde
Reviewed by: bde
Based on submission by: Alexander Krizhanovsky <ak natsys-lab com>
MFC after: 1 week
X-MFC-Note: td_rux shall be moved to the end of struct thread
function ruxagg_tlock().
Convert the definition of kern_getrusage() to ANSI C.
Submitted by: Alexander Krizhanovsky <ak natsys-lab com>
MFC after: 1 week
processes. It did not return an error but instead
just let garbage be passed back. This I fix so
it actually properly translates the priority the
process is at to a posix's high means more priority.
I also fix it so that if the ULE scheduler has bumped
it up to a realtime process you get back a sane value
i.e. the highest priority (63 for time-share).
sched_setscheduler() had the setting of the
timeshare class priority disabled. With some notes
about rejecting the posix high numbers is greater
priority and use nice instead. This fix also
adjusts that to work, with the cavet that a t-s
process may well get bumped up or down i.e. the
setscheduler() will NOT change the nice value only
the current priority. I think this is reasonable
considering if the user wants to play with nice then
he can. At least all the posix'ish interfaces now
respond sanely.
MFC after: 3 weeks
rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved
for the uid.
The accounting information (charge) is associated with either map entry,
or vm object backing the entry, assuming the object is the first one
in the shadow chain and entry does not require COW. Charge is moved
from entry to object on allocation of the object, e.g. during the mmap,
assuming the object is allocated, or on the first page fault on the
entry. It moves back to the entry on forks due to COW setup.
The per-entry granularity of accounting makes the charge process fair
for processes that change uid during lifetime, and decrements charge
for proper uid when region is unmapped.
The interface of vm_pager_allocate(9) is extended by adding struct ucred *,
that is used to charge appropriate uid when allocation if performed by
kernel, e.g. md(4).
Several syscalls, among them is fork(2), may now return ENOMEM when
global or per-uid limits are enforced.
In collaboration with: pho
Reviewed by: alc
Approved by: re (kensmith)
The last half year I've been working on a replacement TTY layer for the
FreeBSD kernel. The new TTY layer was designed to improve the following:
- Improved driver model:
The old TTY layer has a driver model that is not abstract enough to
make it friendly to use. A good example is the output path, where the
device drivers directly access the output buffers. This means that an
in-kernel PPP implementation must always convert network buffers into
TTY buffers.
If a PPP implementation would be built on top of the new TTY layer
(still needs a hooks layer, though), it would allow the PPP
implementation to directly hand the data to the TTY driver.
- Improved hotplugging:
With the old TTY layer, it isn't entirely safe to destroy TTY's from
the system. This implementation has a two-step destructing design,
where the driver first abandons the TTY. After all threads have left
the TTY, the TTY layer calls a routine in the driver, which can be
used to free resources (unit numbers, etc).
The pts(4) driver also implements this feature, which means
posix_openpt() will now return PTY's that are created on the fly.
- Improved performance:
One of the major improvements is the per-TTY mutex, which is expected
to improve scalability when compared to the old Giant locking.
Another change is the unbuffered copying to userspace, which is both
used on TTY device nodes and PTY masters.
Upgrading should be quite straightforward. Unlike previous versions,
existing kernel configuration files do not need to be changed, except
when they reference device drivers that are listed in UPDATING.
Obtained from: //depot/projects/mpsafetty/...
Approved by: philip (ex-mentor)
Discussed: on the lists, at BSDCan, at the DevSummit
Sponsored by: Snow B.V., the Netherlands
dcons(4) fixed by: kan
requiring the per-process spinlock to only requiring the process lock.
- Reflect these changes in the proc.h documentation and consumers throughout
the kernel. This is a substantial reduction in locking cost for these
fields and was made possible by recent changes to threading support.
uidinfo structure. This entirely removes contention observed on the
ui_mtxp mutex (as it is now gone).
- Convert the uihashtbl_mtx mutex to a rwlock, as most of the time we just
need to read-lock it.
Reviewed by: jhb, jeff, kris & others
Tested by: kris
a jail, etc. by simply calling setpriority(PRIO_PROCESS, <PID>, 0) and
checking the return value: 0 means that the process exists and -1 that
it doesn't exist.
Reviewed by: rwatson
MFC after: 1 week
While the KSE project was quite successful in bringing threading to
FreeBSD, the M:N approach taken by the kse library was never developed
to its full potential. Backwards compatibility will be provided via
libmap.conf for dynamically linked binaries and static binaries will
be broken.
maintain a separate td_incruntime to hold unbilled CPU usage for
the thread that has the previous properties of td_runtime.
When thread information is requested using the thread monitoring
sysctls, export thread td_runtime instead of process rusage runtime
in kinfo_proc.
This restores the display of individual ithread and other kernel
thread CPU usage since inception in ps -H and top -SH, as well for
libthr user threads, valuable debugging information lost with the
move to try kthreads since they are no longer independent processes.
There is universal agreement that we should rewrite the process and
thread export sysctls, but this commit gets things going a bit
better in the mean time. Likewise, there are resevations about the
continued validity of statclock given the speed of modern processors.
Reviewed by: attilio, emaste, jhb, julian
kernels exposed by the recent fixes to resource limits for 32-bit processes
on 64-bit kernels:
- Let ABIs expose their maximum stack size via a new pointer in sysentvec
and use that in preference to maxssiz during exec() rather than always
using maxssiz for all processses.
- Apply the ABI's limit fixup to the previous stack size when adjusting
RLIMIT_STACK to determine if the existing mapping for the stack needs to
be grown or shrunk (as well as how much it should be grown or shrunk).
Approved by: re (kensmith)
or idle priority of another process owned by the same user. This means
that privilege in rtprio(2) (and rtprio_thread(2)) is required indirectly
via p_cansched(9) or directly to set realtime/idle privilege, rather than
directly affecting target process authorization.
some cases, move to priv_check() if it was an operation on a thread and
no other flags were present.
Eliminate caller-side jail exception checking (also now-unused); jail
privilege exception code now goes solely in kern_jail.c.
We can't yet eliminate suser() due to some cases in the KAME code where
a privilege check is performed and then used in many different deferred
paths. Do, however, move those prototypes to priv.h.
Reviewed by: csjp
Obtained from: TrustedBSD Project
