There has not been any complaints about the default behavior, so there
is no need to keep a knob that enables the worse alternative.
Now that the hard-stopping of other CPUs is the only behavior, the panic_cpu
spinlock-like logic can be dropped, because only a single CPU is
supposed to win stop_cpus_hard(other_cpus) race and proceed past that
call.
MFC after: 1 month
the unix domain sockets to the next tick, coalescing the serial calls
until the collection fires. The thought is that more work for the
collector could arise in the near time, allowing to clean more and not
spend too much CPU on repeated collection when there is no garbage.
Currently the collection task is fired immediately upon unix domain
socket close if there are any rights in flight, which caused excessive
CPU usage and too long blocking of the threads waiting for
unp_list_lock and unp_link_rwlock in write mode.
Robert noted that it would be nice if we could find some heuristic by
which we decide whether to run GC a bit more quickly. E.g., if the
number of UNIX domain sockets is close to its resource limit, but not
quite.
Reported and tested by: Markus Gebert <markus.gebert@hostpoint.ch>
Reviewed by: rwatson
MFC after: 2 weeks
taskqueue_enqueue_timeout(). Do not rearm the callout if it is
already armed and the ticks is negative. Otherwise rearm it to fire
in abs(ticks) ticks in the future.
The intended use is to call taskqueue_enqueue_timeout() for the given
timeout_task with the same negative ticks argument. As result, the
task is scheduled to execute not further than abs(ticks) ticks in
future, and the consequent enqueues are coalesced until the already
scheduled task is finished.
Reviewed by: rwatson
Tested by: Markus Gebert <markus.gebert@hostpoint.ch>
MFC after: 2 weeks
then:
- assume the lock is held in exclusive mode and remove a moot check
about the lock acquisition.
- in the destructor remove !MPSAFE specific chunk.
Reviewed by: kib
MFC after: 2 weeks
Also remove the checks from vop_lookup_pre and vop_lookup_post, which
are now completely redundant (before this change they were partially
redundant).
Discussed with: kib
MFC after: 10 days
zombie list for the pid. This allows several kern.proc sysctls to
report useful information for zombies.
Hold the allproc_lock around all searches instead of relocking it.
Remove private pfind_locked() from the new nfs client code.
Requested and reviewed by: pjd
Tested by: pho
MFC after: 3 weeks
here is race between decaying the resource usage in containers, and updating
per-process usage; basically, the former may cause per-container usage
to get smaller than per-process usage.
Submitted by: Rudo Tomori
- Implement a function to ensure that all preempted threads have switched
back out at least once. Use this to make sure there are no stale
references to the old ktr_buf or the lock profiling buffers before
updating them.
Reviewed by: marius (sparc64 parts), attilio (earlier patch)
Sponsored by: EMC / Isilon Storage Division
pgrp2 was used only for debugging, but pgrp2 = pgfind(..) was present in compiled code even for kernels without INVARIANTS
Approved by: trasz (mentor)
MFC after: 1 week
designator to select a process which is waited for. The system call
optionally returns siginfo_t which would be otherwise provided to
SIGCHLD handler, as well as extended structure accounting for child
and cumulative grandchild resource usage.
Allow to get the current rusage information for non-exited processes
as well, similar to Solaris.
The explicit WEXITED flag is required to wait for exited processes,
allowing for more fine-grained control of the events the waiter is
interested in.
Fix the handling of siginfo for WNOWAIT option for all wait*(2)
family, by not removing the queued signal state.
PR: standards/170346
Submitted by: "Jukka A. Ukkonen" <jau@iki.fi>
MFC after: 1 month
- Do not try to steal load from other CPUs if there was no contest switches
on this CPU (i.e. it was idle all the time and woke up just for bus mastering
or TLB shutdown). If current CPU was idle, then it is quite unlikely that some
other CPU has load to steal. Under high I/O rate, when TLB shutdowns cause
numerous CPU wakeups, on 24-CPU system load stealing code may consume up to
25% of all CPU time without giving any benefits.
- Change code that implements spinning for load to restart spin in case of
context switch. Previous code periodically called cpu_idle() even under
high interrupt/context switch rate.
- Rise spinning threshold to 10KHz, where it gives at least some effect
that may worth consumed power.
Reviewed by: jeff@
Some hooks are added to clamp down maxusers and nmbclusters for
small address space systems.
VM_MAX_AUTOTUNE_MAXUSERS - the max maxusers that will be autotuned based on
physical memory.
VM_MAX_AUTOTUNE_NMBCLUSTERS - max nmbclusters based on physical memory.
These are set to the old values on i386 to preserve the clamping that was
being done to all arches.
Another macro VM_AUTOTUNE_NMBCLUSTERS is provided to allow an override
for the calculation on a MD basis. Currently no arch defines this.
Reviewed by: peter
MFC after: 2 weeks
to further reduce latency for threads in this queue. This should help
as threads transition from realtime to timeshare. The latency is
bound to a max of sched_slice until we have more than sched_slice / 6
threads runnable. Then the min slice is allotted to all threads and
latency becomes (nthreads - 1) * min_slice.
Discussed with: mav
give rwlock(9) the ability to crunch different type of structures, with
the only constraint that they have a lock cookie named rw_lock.
This name, then, becames reserved from the struct that wants to use
the rwlock(9) KPI and other locking primitives cannot reuse it for
their members.
Namely such structs are the current struct rwlock and the new struct
rwlock_padalign. The new structure will define an object which has the
same layout of a struct rwlock but will be allocated in areas aligned
to the cache line size and will be as big as a cache line.
For further details check comments on above mentioned revisions.
Reviewed by: jimharris, jeff
was still possible to open for write from the lower filesystem. There
is a symmetric situation where the binary could already has file
descriptors opened for write, but it can be executed from the nullfs
overlay.
Handle the issue by passing one v_writecount reference to the lower
vnode if nullfs vnode has non-zero v_writecount. Note that only one
write reference can be donated, since nullfs only keeps one use
reference on the lower vnode. Always use the lower vnode v_writecount
for the checks.
Introduce the VOP_GET_WRITECOUNT to read v_writecount, which is
currently always bypassed to the lower vnode, and VOP_ADD_WRITECOUNT
to manipulate the v_writecount value, which manages a single bypass
reference to the lower vnode. Caling the VOPs instead of directly
accessing v_writecount provide the fix described in the previous
paragraph.
Tested by: pho
MFC after: 3 weeks
cache line in order to avoid manual frobbing but using
struct mtx_padalign.
The sole exception being nvme and sxfge drivers, where the author
redefined CACHE_LINE_SIZE manually, so they need to be analyzed and
dealt with separately.
Reviwed by: jimharris, alc
sharing especially on the default CPU 0 callout_cpu structure.
This will be followed up by attilio@ with a conversion to the new struct
mtx_padalign but doing this manual conversion first gives an easy MFC
candidate since mtx_padalign is a more extensive system change.
Sponsored by: Intel
Reviewed by: jeff, attilio
MFC after: 1 week
only constraint that they have a lock cookie named mtx_lock.
This name, then, becames reserved from the struct that wants to use the
mtx(9) KPI and other locking primitives cannot reuse it for their
members.
Namely such structs are the current struct mtx and the new
struct mtx_padalign. The new structure will define an object which is
the same as the same layout of a struct mtx but will be allocated in
areas aligned to the cache line size and will be as big as a cache line.
This is supposed to give higher performance for highly contented mutexes
both spin or sleep (because of the adaptive spinning), where the cache
line contention results in too much traffic on the system bus.
The struct mtx_padalign can be used in a completely transparent way
with the mtx(9) KPI.
At the moment, a possibility to MFC the patch should be carefully
evaluated because this patch breaks the low level KPI
(not its representation though).
Discussed with: jhb
Reviewed by: jeff, andre
Reviewed by: mdf (earlier version)
Tested by: jimharris
executed. This means past the point where userret() is generally
executed.
Skip the td_pinned check if a callchain tracing is currently happening
and add a more robust check to pmc_capture_user_callchain() in order to
catch td_pinned leak past ast() in hwpmc case.
Reported and tested by: fabient
MFC after: 1 week
X-MFC: r240246
overwriting the return mbuf pointer with newly received data after
a loop. Instead append the new mbuf chain to the existing one.
Fix up sb_lastrecord when dequeuing mbuf's so that sbappend_stream()
doesn't get confused.
For the remainder copy case in the mbuf delivery part deduct the
copied length len instead of the whole mbuf length. Additionally
don't depend on 'n' being being available which isn't true in the
case of MSG_PEEK.
Fix the MSG_WAITALL case by comparing against sb_hiwat. Before
it was looping for every receive as sb_lowat normally is zero.
Add comment about issue with (MSG_WAITALL | MSG_PEEK) which isn't
properly handled.
Submitted by: trociny (except for the change in last paragraph)
