Eliminate recursion from most thread_lock consumers. Return from
sched_add() without the thread_lock held. This eliminates unnecessary
atomics and lock word loads as well as reducing the hold time for
scheduler locks. This will eventually allow for lockless remote adds.
Discussed with: kib
Reviewed by: jhb
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D22626
The line was misedited to change tt to st instead of
changing ut to st.
The use of st as the denominator in mul64_by_fraction() will lead
to an integer divide fault in the intr proc (the process holding
ithreads) where st will be 0. This divide by 0 happens after
the total runtime for all ithreads exceeds 76 hours.
Submitted by: bde
The previous fix was unnecessarily very slow up to 105 hours where the
simple formula used previously worked, and unnecessarily slow by a factor
of about 5/3 up to 388 days, and didn't work above 388 days. 388 days is
not a long time, since it is a reasonable uptime, and for processes the
times being calculated are aggregated over all threads, so with N CPUs
running the same thread a runtime of 388 days is reachable after only
388 / N physical days.
The PRs document overflow at 388 days, but don't try to fix it.
Use the simple formula up to 76 hours. Then use a complicated general
method that reduces to the simple formula up to a bit less than 105
hours, then reduces to the previous method without its extra work up
to almost 388 days, then does more complicated reductions, usually
many bits at a time so that this is not slow. This works up to half
of maximum representable time (292271 years), with accumulated rounding
errors of at most 32 usec.
amd64 can do all this with no avoidable rounding errors in an inline
asm with 2 instructions, but this is too special to use. __uint128_t
can do the same with 100's of instructions on 64-bit arches. Long
doubles with at least 64 bits of precision are the easiest method to
use on i386 userland, but are hard to use in the kernel.
PR: 76972 and duplicates
Reviewed by: kib
PR: 76972 and duplicates
Reported by: Dr. Christopher Landauer <cal AT aero.org>,
Steinar Haug <sthaug AT nethelp.no>
Submitted by: Andrey Zonov <andrey AT zonov.org> (earlier version)
MFC after: 2 weeks
It is a function call only to accomodate *some* ABIs which install a hook.
They only care for 3 types of limits: DATA, STACK, VMEM
Instead of always calling the func, see at compilation time if the requested
limit is something else and just do the read if so.
Sponsored by: The FreeBSD Foundation
Change swap_reserve and swap_total to be in units of pages so that
swap reservations can be done using only atomics instead of using a single
global mutex for swap_reserve and a single mutex for all processes running
under the same uid for uid accounting.
Results in mmap speed up and a 70% increase in brk calls / second.
Reviewed by: alc@, markj@, kib@
Approved by: re (delphij@)
Differential Revision: https://reviews.freebsd.org/D16273
opt_compat.h is mentioned in nearly 180 files. In-progress network
driver compabibility improvements may add over 100 more so this is
closer to "just about everywhere" than "only some files" per the
guidance in sys/conf/options.
Keep COMPAT_LINUX32 in opt_compat.h as it is confined to a subset of
sys/compat/linux/*.c. A fake _COMPAT_LINUX option ensure opt_compat.h
is created on all architectures.
Move COMPAT_LINUXKPI to opt_dontuse.h as it is only used to control the
set of compiled files.
Reviewed by: kib, cem, jhb, jtl
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D14941
This avoids re-reading a variable after it has been updated via an
atomic op. It is just a cosmetic cleanup as the read value was only
used to control a diagnostic printf that should rarely occur (if ever).
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D13768
Mainly focus on files that use BSD 3-Clause license.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
A long long time ago the register keyword told the compiler to store
the corresponding variable in a CPU register, but it is not relevant
for any compiler used in the FreeBSD world today.
ANSIfy related prototypes while here.
Reviewed by: cem, jhb
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D10193
breaking the ABI. Special value is stored in the lock pointer to
indicate shared lock, and offline page in the shared memory is
allocated to store the actual lock.
Reviewed by: vangyzen (previous version)
Discussed with: deischen, emaste, jhb, rwatson,
Martin Simmons <martin@lispworks.com>
Tested by: pho
Sponsored by: The FreeBSD Foundation
during iteration instead of relocking it for each traversed rule.
Reviewed by: mjg@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D4110
Their primary use was in thread_cow_update to free up old resources.
Freeing had to be done with proc lock held and _cow_ funcs already knew
how to free old structs.
Use the same scheme implemented to manage credentials.
Code needing to look at process's credentials (as opposed to thred's) is
provided with *_proc variants of relevant functions.
Places which possibly had to take the proc lock anyway still use the proc
pointer to access limits.
initial thread. It is read by the ELF image activator as the virtual
size of the PT_GNU_STACK program header entry, and can be specified by
the linker option -z stack-size in newer binutils.
The soft RLIMIT_STACK is auto-increased if possible, to satisfy the
binary' request.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
- 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
