adds the hooks that DTrace modules register with, and adds a few functions
which have the dtrace_ prefix to allow the DTrace FBT (function boundary
trace) provider to avoid tracing because they are called from the DTtrace
probe context.
Unlike other forms of tracing and debug, DTrace support in the kernel
incurs negligible run-time cost.
I think the only reason why anyone wouldn't want to have kernel support
enabled for DTrace would be due to the license (CDDL) under which DTrace
is released.
and to make user-level trap handlers work
- add new trap entry to trap table to enable fast fetching of floating point trap
context
- remove unused debug code
- map unimplemented floating point trap to SIGFPE
Approved by: scottl (standing in for mentor rwatson)
argument in parentheses so these macros are safe to use and invocations
with an expression as the argument like __bswap32_const(42 << 23 | 13)
work as expected. Additionally, mask all the individually shifted bytes
as appropriate so the bytes which exceed the width of the respective
__bswapN_const() macro in invocations like __bswap16_const(0xdead600d)
are ignored like it's the case with the corresponding __bswapN_var()
function.
MFC after: 3 days
except sun4v.
This change makes the transition from a default to an option more
transparent and is an attempt to head off all the compliants that are
likely from people who don't read UPDATING, based on experience with
the io/mem change.
Submitted by: scottl@
unsuspecting users.
- Add a comment in NOTES about experimental status of SCHED_ULE.
- Make warning about experimental status in sched_ule(4) a bit
stronger.
Suggested and reviewed by: dougb
Discussed on: developers
MFC after: 3 days
