From: Hugh Dickins <hugh@veritas.com>
To: Arjan van de Ven <arjan@infradead.org>
Cc: Andrew Morton <akpm@osdl.org>,
mingo@elte.hu, nickpiggin@yahoo.com.au,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] break_lock forever broken
Date: Sun, 13 Mar 2005 09:35:59 +0000 (GMT) [thread overview]
Message-ID: <Pine.LNX.4.61.0503130931140.15083@goblin.wat.veritas.com> (raw)
In-Reply-To: <1110702194.6278.31.camel@laptopd505.fenrus.org>
On Sun, 13 Mar 2005, Arjan van de Ven wrote:
> > \
> > + if ((lock)->break_lock) \
> > + (lock)->break_lock = 0; \
> > } \
> if it really worth an conditional there? the cacheline of the lock is
> made dirty anyway on unlock, so writing an extra 0 is like almost free
> (maybe half a cycle) while a conditional jump can be 100+....
I wondered the same, I don't know and would defer to those who do:
really I was just following the style of where break_lock is set above,
which follows soon (unless preempted) after a _raw_whatever_trylock.
Hugh
next prev parent reply other threads:[~2005-03-13 9:37 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-11 18:51 Hugh Dickins
2005-03-12 4:34 ` Andrew Morton
2005-03-12 23:20 ` Hugh Dickins
2005-03-13 8:23 ` Arjan van de Ven
2005-03-13 9:35 ` Hugh Dickins [this message]
2005-03-13 13:52 ` Arjan van de Ven
2005-03-14 5:01 ` Nick Piggin
2005-03-14 7:02 ` Ingo Molnar
2005-03-14 8:03 ` Nick Piggin
2005-03-14 8:14 ` Ingo Molnar
2005-03-14 8:24 ` Nick Piggin
2005-03-14 8:34 ` Arjan van de Ven
2005-03-14 8:43 ` Nick Piggin
2005-03-14 10:46 ` Ingo Molnar
2005-03-14 11:01 ` Nick Piggin
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