Re: [PATCH] Alternate futex non-page-pinning and COW fix

From: Jamie Lokier
Date: Fri Sep 05 2003 - 12:57:16 EST


Rusty Russell wrote:
> In message <20030904171609.GA30394@xxxxxxxxxxxxxxxxxx> you write:
> > What does PROT_SEM mean for Linux, btw?
>
> It's a relic: some archs might need a special flag to ensure
> inter-process atomic ops worked as expected. It was never fully
~~~~~~~~~~~
> implemented, with the assumption that such archs just won't be able to
~~~~~~~~~~~
> use futexes, and if someone really wants to fix it, they will.

Looking at the kernel I can confidently say it was never implemented
at all. sys_mprotect mentioned PROT_SEM but it was a misleading logic
error that did nothing useful :)

-- Jamie

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