From: Grant Grundler <grundler@dsl2.external.hp.com>
To: Matthew Wilcox <willy@debian.org>
Cc: parisc-linux@parisc-linux.org
Subject: Re: [parisc-linux] atomic_t
Date: Mon, 14 Jan 2002 00:12:32 -0700 [thread overview]
Message-ID: <20020114071232.07537482A@dsl2.external.hp.com> (raw)
In-Reply-To: Message from Matthew Wilcox <willy@debian.org> of "Mon, 14 Jan 2002 04:43:37 GMT." <20020114044337.B9193@parcelfarce.linux.theplanet.co.uk>
Matthew Wilcox wrote:
> Not on PA... look at <asm/atomic.h>. There's only 3 primitives, all
> other atomic ops are defined in terms of those.
Ah ok - you are right. atomic_read() doesn't use the lock and
that only leaves the other two.
> > But someone thought it was time to reset the counter. And if
> > it "never happened", then whoever is looking for 'v == 1' will
> > never see it.
>
> It's a race though; they can't guarantee to see it anyway.
hmmm...Most people write code with the intent of seeing *some*
event (eg v < 0). Ie, if it didn't matter, then we don't need
the code. I'd like to believe folks are usually more careful
than that. I need to think about this some more though.
grant
next prev parent reply other threads:[~2002-01-14 7:12 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-13 21:15 [parisc-linux] atomic_t Matthew Wilcox
2002-01-14 4:09 ` Grant Grundler
2002-01-14 4:43 ` Matthew Wilcox
2002-01-14 7:12 ` Grant Grundler [this message]
2002-01-14 9:54 ` Alan Cox
-- strict thread matches above, loose matches on Subject: below --
2002-01-14 6:54 John Marvin
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