- Avoid atomics in more places.
- Remove the per-descriptor mutex, and just use filedesc_t::fd_lock.
It was only being used to synchronize close, and in any case we needed
to take fd_lock to free the descriptor slot.
- Optimize certain paths for the <NDFDFILE case.
- Sprinkle more comments and assertions.
- Cache more stuff in filedesc_t.
- Fix numerous minor bugs spotted along the way.
- Restructure how the open files array is maintained, for clarity and so
that we can eliminate the membar_consumer() call in fd_getfile(). This is
mostly syntactic sugar; the main functional change is that fd_nfiles now
lives alongside the open file array.
Some measurements with libmicro:
- simple file syscalls are like close() are between 1 to 10% faster.
- some nice improvements, e.g. poll(1000) which is ~50% faster.
channels.
- tested on 232BM, 232RL and 2232D chips.
- now capable of quad channel FT4232H.
- minor format nit and legacy title comment removal.
- non UART type bit stream (!= ucom) support is under planning.
- Fix a preemption bug in CURCPU_IDLE_P() that can lead to a bogus
assertion failure on DEBUG kernels.
- Fix MP/preemption races with timecounter detachment.
complaining that we're "discarding qualifier from pointer target
type".
Use const char * instead of caddr_t to avoid the warning and get
distribution building on hppa again.
- Fix a preemption bug in CURCPU_IDLE_P() that can lead to a bogus
assertion failure on DEBUG kernels.
- Fix MP/preemption races with timecounter detachment.
o close more leaking file descriptors for CGI and daemon mode
o add subdirs for build "debug" and "small" versions
o clean up a bad merge / duplicate code
o make mmap() usage portable, fixes linux & ranges: support
o document the -f option
o daemon mode now serves 6 files per child
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