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Date: Tue, 12 Nov 2002 05:21:13 +0000
From: Jamie Lokier <lk@tantalophile.demon.co.uk>
To: "Perez-Gonzalez, Inaky" <inaky.perez-gonzalez@intel.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>,
       "'mingo@redhat.com'" <mingo@redhat.com>,
       "'Mark Mielke'" <mark@mark.mielke.cc>, linux-kernel@vger.kernel.org
Subject: Re: Users locking memory using futexes
Message-ID: <20021112052113.GA12452@bjl1.asuk.net>
References: <A46BBDB345A7D5118EC90002A5072C7806CAC920@orsmsx116.jf.intel.com>
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Perez-Gonzalez, Inaky wrote:
> This raises a good point - I guess we should be doing something like
> checking user limits (against locked memory, 'ulimit -l').

If futexes are limited by user limits, that's going to mean some
threading program gets a surprise when too many threads decide to
block on a resource.  That's really nasty.  (Of course, a program can
get a surprise due to just running out of memory in sys_futex() too,
but that's much rarer).

It would be nice if the futex waitqueues could be re-hashed against
swap entries when pages are swapped out, somehow, but this sounds hard.

-- Jamie
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