* by default, warning messages go to stderr
* if -A or -a is used, send warning messages to stdout instead.
The behaviour in 1.50 meant that
somevar=`sysctl -n machdep.booted_kernel 2>/dev/null`
could end up with $somevar="machdep.booted_kernel: the value is not available"
rather than the more useful $somevar="".
(This way, "sysctl -A | grep ..." is still useful.)
for forking the traditional UNIX init(8) and it does the Mach port naming
service. We need mach_init for the naming service, but unfortunately, it
will only act as such if its PID is 1. We introduce a sysctl
(emul.darwin.init_pid) to fool a given process into thinking its PID is 1.
That way we can get mach_init into behaving as the name server.
Typical use:
/sbin/sysctl -w emul.darwin.init_pid=$$ ; exec /emul/darwin/sbin/mach_init
for FreeBSD project. Besides huge speed boost compared with socketpair-based
pipes, this implementation also uses pagable kernel memory instead of mbufs.
Significant differences to FreeBSD version:
* uses uvm_loan() facility for direct write
* async/SIGIO handling correct also for sync writer, async reader
* limits settable via sysctl, amountpipekva and nbigpipes available via sysctl
* pipes are unidirectional - this is enforced on file descriptor level
for now only, the code would be updated to take advantage of it
eventually
* uses lockmgr(9)-based locks instead of home brew variant
* scatter-gather write is handled correctly for direct write case, data
is transferred by PIPE_DIRECT_CHUNK bytes maximum, to avoid running out of kva
All FreeBSD/NetBSD specific code is within appropriate #ifdef, in preparation
to feed changes back to FreeBSD tree.
This pipe implementation is optional for now, add 'options NEW_PIPE'
to your kernel config to use it.
each of the basic types (anonymous data, executable image, cached files)
and prevent the pagedaemon from reusing a given page if that would reduce
the count of that type of page below a sysctl-setable minimum threshold.
the thresholds are controlled via three new sysctl tunables:
vm.anonmin, vm.vnodemin, and vm.vtextmin. these tunables are the
percentages of pageable memory reserved for each usage, and we do not allow
the sum of the minimums to be more than 95% so that there's always some
memory that can be reused.
simonb