From: torvalds@transmeta.com (Linus Torvalds)
To: linux-kernel@vger.kernel.org
Subject: Re: [Lse-tech] Re: RFC: patch to allow lock-free traversal of lists with insertion
Date: Wed, 10 Oct 2001 05:05:10 +0000 (UTC) [thread overview]
Message-ID: <9q0ku6$175$1@penguin.transmeta.com> (raw)
In-Reply-To: <OF296D0EDC.4D1AE07A-ON88256AE0.00568638@boulder.ibm.com> <20011010040502.A726@athlon.random>
In article <20011010040502.A726@athlon.random>,
Andrea Arcangeli <andrea@suse.de> wrote:
>On Tue, Oct 09, 2001 at 08:45:15AM -0700, Paul McKenney wrote:
>> Please see the example above. I do believe that my algorithms are
>> reliably forcing proper read ordering using IPIs, just in an different
>> way. Please note that I have discussed this algorithm with Alpha
>> architects, who believe that it is sound.
>
>The IPI way is certainly safe.
Now, before people get all excited, what is this particular code
actually _good_ for?
Creating a lock-free list that allows insertion concurrently with lookup
is _easy_.
But what's the point? If you insert stuff, you eventually have to remove
it. What goes up must come down. Insert-inane-quote-here.
And THAT is the hard part. Doing lookup without locks ends up being
pretty much worthless, because you need the locks for the removal
anyway, at which point the whole thing looks pretty moot.
Did I miss something?
Linus
next prev parent reply other threads:[~2001-10-10 5:06 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-10-09 15:45 RFC: patch to allow lock-free traversal of lists with insertion Paul McKenney
2001-10-09 17:00 ` Richard Henderson
2001-10-10 3:33 ` Paul Mackerras
2001-10-10 17:02 ` Richard Henderson
2001-10-10 2:05 ` [Lse-tech] " Andrea Arcangeli
2001-10-10 5:05 ` Linus Torvalds [this message]
2001-10-10 5:17 ` BALBIR SINGH
2001-10-10 5:29 ` Davide Libenzi
2001-10-10 5:46 ` Linus Torvalds
2001-10-10 6:01 ` BALBIR SINGH
2001-10-10 15:23 ` Victor Yodaiken
2001-10-10 7:14 ` kdb requires kallsyms Kirill Ratkin
2001-10-10 7:38 ` BALBIR SINGH
2001-10-10 6:16 ` [Lse-tech] Re: RFC: patch to allow lock-free traversal of lists with insertion Paul Mackerras
2001-10-10 6:30 ` Linus Torvalds
2001-10-10 7:36 ` Paul Mackerras
2001-10-10 15:54 ` Victor Yodaiken
2001-10-10 21:56 ` Keith Owens
2001-10-10 22:24 ` Victor Yodaiken
2001-10-10 23:46 ` David S. Miller
2001-10-11 0:24 ` Davide Libenzi
2001-10-10 11:54 ` Keith Owens
2001-10-10 13:42 ` AIC7XXX war
2001-10-10 21:40 ` AIC7XXX Luigi Genoni
2001-10-10 13:24 ` [Lse-tech] Re: RFC: patch to allow lock-free traversal of lists with insertion Ivan Kokshaysky
2001-10-10 13:41 ` Andrea Arcangeli
-- strict thread matches above, loose matches on Subject: below --
2001-10-10 4:43 Paul McKenney
2001-10-10 6:54 Dipankar Sarma
2001-10-10 7:06 Dipankar Sarma
2001-10-10 7:21 ` BALBIR SINGH
2001-10-10 9:06 ` Dipankar Sarma
2001-10-10 7:58 Dipankar Sarma
[not found] <20011010182730.0077454b.rusty@rustcorp.com.au>
2001-10-10 9:36 ` Linus Torvalds
2001-10-11 6:50 ` Rusty Russell
2001-10-10 10:06 Dipankar Sarma
2001-10-10 10:18 ` Linus Torvalds
2001-10-10 11:43 ` Dipankar Sarma
2001-10-12 3:27 ` Rusty Russell
2001-10-12 16:56 ` Linus Torvalds
2001-10-12 18:53 ` Dipankar Sarma
2001-10-13 7:25 ` Rusty Russell
2001-10-10 15:24 Paul McKenney
2001-10-10 16:58 ` Andrea Arcangeli
2001-10-10 17:25 ` Linus Torvalds
2001-10-12 5:06 ` Rusty Russell
2001-10-12 16:28 ` Linus Torvalds
2001-10-12 19:50 ` Al Dunsmuir
2001-10-13 1:07 ` Paul Mackerras
2001-10-13 1:54 ` Davide Libenzi
2001-10-13 2:04 ` Linus Torvalds
2001-10-13 2:31 ` Davide Libenzi
2001-10-13 2:46 ` Davide Libenzi
2001-10-13 3:30 ` Linus Torvalds
2001-10-13 2:49 ` Paul Mackerras
2001-10-13 2:00 ` Linus Torvalds
2001-10-13 7:38 ` Rusty Russell
2001-10-10 16:00 Paul McKenney
2001-10-10 21:44 Paul McKenney
2001-10-11 10:34 Dipankar Sarma
2001-10-13 14:42 Paul McKenney
2001-10-13 17:23 ` Linus Torvalds
2001-10-13 17:28 ` Linus Torvalds
2001-10-14 7:25 ` Dipankar Sarma
2001-10-13 18:42 ` Andi Kleen
2001-10-13 19:15 ` Alexander Viro
2001-10-13 20:44 ` Rusty Russell
2001-10-13 21:19 ` Rusty Russell
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