Re: Cancelling Subversion operations

Garrett Rooney <rooneg@electricjellyfish.net> writes:

> it means adding a couple
> of locks inside the callback, but how expensive is that really?

An uncontested mutex, while not free, can be cheap. The problem is
that it becomes expensive when contested, and it generally gets worse
as the number of threads contesting it increases.

Bill has raised a valid point, a single callback/baton is OK as a
simple async-signal handling mechanism, but as a general cancellation
mechanism it's a poor solution.

I'm not sure I agree with his other comment about some operations not
needing to be cancellable (post-commit processing and downloading a
large file were the examples). A process that ignores SIGTERM, or
just delays too long before handling it, is likely to get SIGKILL.

-- 
Philip Martin
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