counters. These counters do not exist on all CPUs, but where they
do exist, can be used for counting events such as dcache misses that
would otherwise be difficult or impossible to instrument by code
inspection or hardware simulation.
pmc(9) is meant to be a general interface. Initially, the Intel XScale
counters are the only ones supported.
* struct sigacts gets a new sigact_sigdesc structure, which has the
sigaction and the trampoline/version. Version 0 means "legacy kernel
provided trampoline". Other versions are coordinated with machine-
dependent code in libc.
* sigaction1() grows two more arguments -- the trampoline pointer and
the trampoline version.
* A new __sigaction_sigtramp() system call is provided to register a
trampoline along with a signal handler.
* The handler is no longer passed to sensig() functions. Instead,
sendsig() looks up the handler by peeking in the sigacts for the
process getting the signal (since it has to look in there for the
trampoline anyway).
* Native sendsig() functions now select the appropriate trampoline and
its arguments based on the trampoline version in the sigacts.
Changes to libc to use the new facility will be checked in later. Kernel
version not bumped; we will ride the 1.6C bump made recently.
- Reinstall the "dynamic page table length" that was removed some
years ago.
- Limit the user page table submap to max 5% of available memory.
- Free the page table space when a process is swapped out.
- If the UPT submap runs out of space, throw away pmap mappings
using the same algorithm as for swapping processes.
As a result of this, 4MB machines are useable again and it's even possible
to compile a kernel for 2MB machines (but it will be slow... :-)
Still to do:
- Multiprocessor fixes.
- More profiling.
Be consistant in the way that MSIZE, MCLSHIFT, MCLBYTES and NMBCLUSTERS
are defined.
Remove old VM constants from cesfic port.
Bump MSIZE to 256 on mipsco (the only one that wasn't already 256).
These are the same values that the hp300 port uses (lesser hp300s
have roughly the same memory constraints as "lesser" vaxen), and
bumping them allows us to run a statically linked ELF groff(1).
This will allow improvements to the pmaps so that they can more easily defer expensive operations, eg tlb/cache flush, til the last possible moment.
Currently this is a no-op on most platforms, so they should see no difference.
Reviewed by Jason.
