- Remove references to cpu_critical_*() as they no longer exist.
- Explain that any preemptions that occur during a critical section are
deferred until the current thread exits the section.
- Remove a bogus example usage of a critical section.
- Note that one can interlock critical sections with spin mutexes in
certain situations.
MFC after: 3 days
- Add arm and ppc to the list of archs not supporting operations on 64-bit
integers.
- Update the sample code for acquiring a mutex to be more recent and to
take into account the recent atomic_foo_ptr() changes.
MFC after: 1 week
implementation. I took the NetBSD man page, and hacked it to, I hope,
to reflect the preliminary version of the bus space that Justin Gibbs
committed as part of the CAM integration in FreeBSD 3.0.
This isn't perfect, but it is better than we have now (which is, ahem,
nothing). Please coordinate changes to the file through me through
the 6.0 release.
Approved by: re (blanket for this one file)
callout is first initialised, using a new function callout_init_mtx().
The callout system will acquire this mutex before calling the callout
function and release it on return.
In addition, the callout system uses the mutex to avoid most of the
complications and race conditions inherent in asynchronous timer
facilities, so mutex-protected callouts have much simpler semantics.
As long as the mutex is held when invoking callout_stop() or
callout_reset(), then these functions will guarantee that the callout
will be stopped, even if softclock() had already begun to process
the callout.
Existing Giant-locked callouts will automatically pick up the new
race-free semantics. This should close a number of race conditions
in the USB code and probably other areas of the kernel too.
There should be no change in behaviour for "MP-safe" callouts; these
still need to use the techniques mentioned in timeout(9) to avoid
race conditions.
man page after Orla, so the mistakes are probably mine. Leave a
note on the door welcoming the mdoc police.
Submitted by: Orla McGann <orly@cnri.dit.ie>
Of particular interest here is the ieee80211_radiotap(9) man page.
TODO: Flesh out ieee80211_node.9, ieee80211_proto.9.
Submitted by: bms (with help from Darron Broad)
