- 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.
- Add interrupt shielding (direct hardware interrupts away from the
specified CPUs). Not documented just yet but will be soon.
- Redo /dev/cpu time_t compat so no kernel changes are needed.
x86:
- Make intr_establish, intr_disestablish safe to use when !cold.
- Distribute hardware interrupts among the CPUs, instead of directing
everything to the boot CPU.
- Add MD code for interrupt sheilding. This works in most cases but there is
a bug where delivery is not accepted by an LAPIC after redistribution. It
also needs re-balancing to make things fair after interrupts are turned
back on for a CPU.
than one active reference to a file descriptor. It should dislodge threads
sleeping while holding a reference to the descriptor. Implemented only for
sockets but should be extended to pipes, fifos, etc.
Fixes the case of a multithreaded process doing something like the
following, which would have hung until the process got a signal.
thr0 accept(fd, ...)
thr1 close(fd)
address space available to processes. this limit exists in most other
modern unix variants, and like most of them, our defaults are unlimited.
remove the old mmap / rlimit.datasize hack.
- adds the VMCMD_STACK flag to all the stack-creation vmcmd callers.
it is currently unused, but was added a few years ago.
- add a pair of new process size values to kinfo_proc2{}. one is the
total size of the process memory map, and the other is the total size
adjusted for unused stack space (since most processes have a lot of
this...)
- patch sh, and csh to notice RLIMIT_AS. (in some cases, the alias
RLIMIT_VMEM was already present and used if availble.)
- patch ps, top and systat to notice the new k_vm_vsize member of
kinfo_proc2{}.
- update irix, svr4, svr4_32, linux and osf1 emulations to support
this information. (freebsd could be done, but that it's best left
as part of the full-update of compat/freebsd.)
this addresses PR 7897. it also gives correct memory usage values,
which have never been entirely correct (since mmap), and have been
very incorrect since jemalloc() was enabled.
tested on i386 and sparc64, build tested on several other platforms.
thanks to many folks for feedback and testing but most espcially
chuq and yamt for critical suggestions that lead to this patch not
having a special ugliness i wasn't happy with anyway :-)
Fix numerous problems:
1. LDT updates are not atomic.
2. Number of processes running with private LDTs and/or I/O bitmaps
is not capped. System with high maxprocs can be paniced.
3. LDTR can be leaked over context switch.
4. GDT slot allocations can race, giving the same LDT slot to two procs.
5. Incomplete interrupt/trap frames can be stacked.
6. In some rare cases segment faults are not handled correctly.
There are still about 1600 left, but they have ',' or /* ... */
in the actual variable definitions - which my awk script doesn't handle.
There are also many that need () -> (void).
(The script does handle misordered arguments.)
