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From: Paul Jackson <pj@sgi.com>
To: Linus Torvalds <torvalds@osdl.org>
Cc: mingo@elte.hu, pwil3058@bigpond.net.au, akpm@osdl.org,
	linux-kernel@vger.kernel.org
Subject: Re: [patch, 2.6.10-rc2] sched: fix ->nr_uninterruptible handling bugs
Date: Thu, 27 Jan 2005 18:14:33 -0800	[thread overview]
Message-ID: <20050127181433.0e63b463.pj@sgi.com> (raw)
In-Reply-To: <Pine.LNX.4.58.0501271658460.2362@ppc970.osdl.org>

True - thanks - including the part about the cost of locking bugs.

My question was poorly phrased - the code speaks the answer to the
real question I had:

  $ grep define.atomic_ include/asm-ia64/atomic.h | head -2
  #define atomic_read(v)          ((v)->counter)
  #define atomic_set(v,i)         (((v)->counter) = (i))

An atomic_read() of a one word counter on ia64 is just a load, and an
atomic_set() is just a store.  This is unlike the more difficult
atomic_inc, atomic_dec, atomic_add, atomic_mutilate, ... calls that
require something fancier, and I presume more painful for that CPUs
innards.

Good.  Thanks.

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.650.933.1373, 1.925.600.0401

  reply	other threads:[~2005-01-28  2:15 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-11-16 11:32 [patch, 2.6.10-rc2] sched: fix ->nr_uninterruptible handling bugs Ingo Molnar
2004-11-16 22:19 ` Peter Williams
2004-11-16 23:28   ` Ingo Molnar
2004-11-16 23:10     ` Linus Torvalds
2004-11-17 10:26       ` Ingo Molnar
2004-11-17 15:52         ` Linus Torvalds
2004-11-18 16:21           ` Ingo Molnar
2005-01-28  0:53       ` Paul Jackson
2005-01-28  1:06         ` Linus Torvalds
2005-01-28  2:14           ` Paul Jackson [this message]
2005-01-28  4:28         ` Ingo Molnar
2005-01-28  5:18           ` Paul Jackson
2005-01-28  6:01           ` Andi Kleen
2004-11-16 23:48     ` Peter Williams
2004-11-16 22:49 ` Nick Piggin
2004-11-16 23:03   ` Nick Piggin
2004-11-16 23:32   ` Peter Williams
2004-11-16 23:37     ` Nick Piggin

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