spinning when readers hold a lock. This spinning is speculative because,
unlike the write case, we can not test whether the owners are running.
- Add speculative read spinning for readers who are blocked by pending
writers while a read lock is still held. This allows the thread to
spin until the write lock succeeds after which it may spin until the
writer has released the lock. This prevents excessive context switches
when readers and writers both hold the lock for brief periods.
Sponsored by: Nokia
the fdesc_allocvp(). The caller of the fdesc_allocvp() expects that the
returned vnode is not reclaimed. Do lock the vnode exclusive and drop
the lock after.
Reported by: pho
Reviewed by: jeff
fixed pri boost with '1' or any priority less than the current thread's
priority with a value greater than two. Default the boost to
PRI_MIN_TIMESHARE to prevent regular user-space threads from starving
threads in the kernel. This prevents these user-threads from also
being scheduled as if they are high fixed-priority kernel threads.
- Restore the setting of lowpri in tdq_choose(). It has to be either here
or in sched_switch(). I accidentally removed it from both places.
Tested by: kris
do this either. Simply check P_NOLOAD. It'd be nice if this was
in a thread flag so we didn't have an extra cache miss every time we
add and remove a thread from the run-queue.
- Pull all the code to deal with the trampoline stuff into one
centeralized place and use it from everywhere.
- Some minor style tidiness
Reviewed by: tinguely
The quote predated rev. 1.232, which rev. 1.259 was to correct;
therefore it was protected by the "Don't remove fortunes" rule.
Noticed by: ceri
Pointy hat to: yar
- fma(x, y, z) returns z, not NaN, if z is infinite, x and y are finite,
x*y overflows, and x*y and z have opposite signs.
- fma(x, y, z) doesn't generate an overflow, underflow, or inexact exception
if z is NaN or infinite, as per IEEE 754R.
- If the rounding mode is set to FE_DOWNWARD, fma(1.0, 0.0, -0.0) is -0.0,
not +0.0.
platform, so use the latter in preference to the former. This makes
the fake_preload setup be the same between kb920x_machdep.c and
avila_machdep.c....
and the igb driver static in the kernel. But it also reflects
some other bug fixes in my development stream at Intel.
PR 122373 is also fixed in this code.
mountcritremote REQUIREs FILESYSTEMS, and that script REQUIREs zfs,
so this change is a noop. By removing it we make life a little easier
both for rcorder(8) and for debugging down the road.
Approved by: 2 weeks of silence from pjd
to JB's revision 1.96 change to remove -fno-strict-aliasing from CFLAGS.
This makes the default CFLAGS to match the simple defaults that the
tinderboxes use. By using -fno-strict-aliasing by default we are
choosing to ignore problems in code which had the potential to
shoot ourselves in the foot.
- Move callout thread creation from kern_intr.c to kern_timeout.c
- Call callout_tick() on every processor via hardclock_cpu() rather than
inspecting callout internal details in kern_clock.c.
- Remove callout implementation details from callout.h
- Package up all of the global variables into a per-cpu callout structure.
- Start one thread per-cpu. Threads are not strictly bound. They prefer
to execute on the native cpu but may migrate temporarily if interrupts
are starving callout processing.
- Run all callouts by default in the thread for cpu0 to maintain current
ordering and concurrency guarantees. Many consumers may not properly
handle concurrent execution.
- The new callout_reset_on() api allows specifying a particular cpu to
execute the callout on. This may migrate a callout to a new cpu.
callout_reset() schedules on the last assigned cpu while
callout_reset_curcpu() schedules on the current cpu.
Reviewed by: phk
Sponsored by: Nokia
