Re: [Lse-tech] Re: RFC: patch to allow lock-free traversal of lists

Alexander Viro (viro@math.psu.edu)
Sat, 13 Oct 2001 15:15:39 -0400 (EDT)


On 13 Oct 2001, Andi Kleen wrote:

> In article <Pine.LNX.4.33.0110131015410.8707-100000@penguin.transmeta.com>,
> Linus Torvalds <torvalds@transmeta.com> writes:
>
> > - nobody has shown a case where existing normal locking ends up being
> > really a huge problem, and where RCU clearly helps.
>
> The poster child of such a case is module unloading. Keeping reference
> counts for every even non sleeping use of a module is very painful.
> The current "fix" -- putting module count increases in all possible module
> callers to fix the unload races is slow and ugly and far too subtle to
> get everything right. Waiting quiescent periods before unloading is a nice
> alternative.

... while quiescent stuff is _not_ subtle and not prone to breakage. Right.
In the same world where Vomit-Making System is elegant, SGI "designs" are
and NT is The Wave Of Future(tm). Pardon me, but I'll stay in our universe
and away from the drugs of such power.

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