From: Richard Gooch <rgooch@ras.ucalgary.ca>
To: Anton Altaparmakov <aia21@cus.cam.ac.uk>
Cc: Alexander Viro <viro@math.psu.edu>,
Linus Torvalds <torvalds@transmeta.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] one of $BIGNUM devfs races
Date: Tue, 7 Aug 2001 11:09:16 -0600 [thread overview]
Message-ID: <200108071709.f77H9GD05198@vindaloo.ras.ucalgary.ca> (raw)
In-Reply-To: <Pine.SOL.3.96.1010807111835.6737A-100000@draco.cus.cam.ac.uk>
In-Reply-To: <200108070517.f775HEw30547@vindaloo.ras.ucalgary.ca> <Pine.SOL.3.96.1010807111835.6737A-100000@draco.cus.cam.ac.uk>
Anton Altaparmakov writes:
> If you are introducing a spinlock for the sole purpose of protecting
> a counter, I would suggest to drop the spinlock, make the counter an
> atomic_t and just use atomic operations on it. That should be both
> faster and generate shorter code.
Firstly, I don't see an atomic_get_and_inc(). Sure, I can atomically
increment, and I can atomically read. But I can't read and increment
atomically.
Secondly, the range is 24 bits. While 24 bits is "probably enough",
I'd prefer not to waste bits.
Finally, a spinlock is less code (0) and faster on UP.
Regards,
Richard....
Permanent: rgooch@atnf.csiro.au
Current: rgooch@ras.ucalgary.ca
next prev parent reply other threads:[~2001-08-07 17:09 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-08-06 11:58 [PATCH] one of $BIGNUM devfs races Alexander Viro
2001-08-06 16:47 ` Richard Gooch
2001-08-06 16:56 ` Rik van Riel
2001-08-06 17:11 ` Richard Gooch
2001-08-06 23:50 ` Richard Gooch
2001-08-07 0:34 ` Alexander Viro
2001-08-07 0:51 ` Richard Gooch
2001-08-07 1:10 ` Alexander Viro
2001-08-07 1:27 ` Richard Gooch
2001-08-07 1:42 ` Alexander Viro
2001-08-07 2:00 ` Richard Gooch
2001-08-07 2:15 ` Alexander Viro
2001-08-07 5:17 ` Richard Gooch
2001-08-07 5:28 ` Alexander Viro
2001-08-07 10:21 ` Anton Altaparmakov
2001-08-07 17:09 ` Richard Gooch [this message]
2001-08-07 17:27 ` Arjan van de Ven
2001-08-07 17:28 ` Richard Gooch
2001-08-07 5:53 ` Richard Gooch
2001-08-07 6:23 ` Alexander Viro
2001-08-07 6:36 ` Richard Gooch
2001-08-07 6:40 ` Alexander Viro
2001-08-07 6:47 ` Richard Gooch
2001-08-07 7:31 ` Alexander Viro
2001-08-07 18:11 ` Richard Gooch
2001-08-07 18:23 ` Alexander Viro
2001-08-07 18:55 ` Richard Gooch
2001-08-07 19:10 ` Alexander Viro
2001-08-07 22:13 ` Richard Gooch
2001-08-06 23:59 Alan Cox
[not found] ` <no.id>
2001-08-06 23:54 ` Alan Cox
2001-08-06 23:55 ` Richard Gooch
2001-08-06 23:59 ` Richard Gooch
2001-08-07 16:22 ` Alan Cox
2001-08-07 19:04 ` Alan Cox
2001-08-07 19:16 ` Alexander Viro
2001-08-08 21:16 ` H. Peter Anvin
2001-08-08 21:47 ` Alexander Viro
2001-08-08 23:29 ` Richard Gooch
2001-08-07 19:09 ` Richard Gooch
2001-08-07 19:20 ` Alexander Viro
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