[Sbcl-devel] with-interrupts in get-mutex

[F. <fa...@gm...>]

1- Why does get-mutex have a with-interrupts? as the FIXME note above
says, it's probably wrong. Nikodemus, can you comment?

2- Because of it, I think with-active-processes-lock should NOT
:allow-with-interrupts t least a subtle race condition occurs. Cyrus,
does that fix your issues?

3- While I stand by my previous analysis that what SBCL does with
run-program is probably bad taste, I am proven full of shit in
asserting that it had an obvious race condition in the multithreaded
case: with-active-processes-lock does try (through with-system-mutex)
to both achieve mutex between each thread's main code and signal
handlers (with without-interrupts) and achieve mutex between threads
(with get-mutex) -- in a way I was too dumb to previously guess or
understand. It's somewhat expensive but it should work and provide
race-condition-free low latency reaping of zombies (assuming get-mutex
is free from race-condition, and if one never forks but through
run-program).

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whereas to a socialist the most beautiful word is 'compulsory'.
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