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SubjectRe: [PATCH 5/6] syslets: add generic syslets infrastructure
So my radical ultra tired rant o the week...

Rather than adding sys_indirect and syslets as is,

* admit that this is beginning to look like a new ABI. explore the
freedoms that that avenue opens...

* (even more radical) I wonder what a tiny, SANE register-based
bytecode interface might look like. Have a single page shared between
kernel and userland, for each thread. Userland fills that page with
bytecode, for a virtual machines with 256 registers -- where
instructions roughly equate to syscalls.

The common case -- a single syscall like open(2) -- would be a single
byte bytecode, plus a couple VM register stores. The result is stored
in another VM register.

But this format enables more complex cases, where userland programs can
pass strings of syscalls into the kernel, and let them execute until
some exceptional condition occurs. Results would be stored in VM
registers (or userland addresses stored in VM registers...).

This sort of interface would be
* fast

* equate to the current syscall regime (easy to get existing APIs
going... hopefully equivalent to glibc switching to a strange new
SYSENTER variant)

* be flexible enough to support a simple implementation today

* be flexible enough to enable experiments into syscall parallelism (aka
VM instruction parallelism <grin>)

* be flexible enough to enable experiments into syscall batching

One would probably want to add some simple logic opcodes in addition to
opcodes for syscalls and such -- but this should not turn into Forth or
Parrot or Java :)

Thus, this new ABI can easily and immediately support all existing
syscalls, while enabling

Now to come up with a good programming API and model(s) to match this
parallel, batched kernel<->userland interface...

Jeff, very tired and delirious, so feel free to laugh at this,
but I've been pondering this for a while

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