From: Benjamin LaHaise <bcrl@kvack.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Andrew Morton <akpm@osdl.org>,
sekharan@us.ibm.com,
Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Avoid calling down_read and down_write during startup
Date: Fri, 24 Feb 2006 09:40:28 -0500 [thread overview]
Message-ID: <20060224144028.GB7101@kvack.org> (raw)
In-Reply-To: <Pine.LNX.4.44L0.0602232211260.19776-100000@netrider.rowland.org>
On Thu, Feb 23, 2006 at 10:18:18PM -0500, Alan Stern wrote:
> Ben, earlier you expressed concern about the extra overhead due to
> cache-line contention (on SMP) in the down_read() call added to
> blocking_notifier_call_chain. I don't remember which notifier chain in
> particular you were worried about; something to do with networking.
>
> Does this still bother you? I can see a couple of ways around it.
Yes it's a problem. Any read lock is going to act as a memory barrier,
and we need fewer of those in hot paths, not more to slow things down.
-ben
--
"Ladies and gentlemen, I'm sorry to interrupt, but the police are here
and they've asked us to stop the party." Don't Email: <dont@kvack.org>.
next prev parent reply other threads:[~2006-02-24 14:45 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-21 15:54 [PATCH] Register atomic_notifiers in atomic context Alan Stern
2006-02-21 23:28 ` Andrew Morton
2006-02-22 16:08 ` Alan Stern
2006-02-22 16:12 ` Randy.Dunlap
2006-02-23 2:26 ` Andrew Morton
2006-02-23 17:15 ` Alan Stern
2006-02-23 19:03 ` Andrew Morton
2006-02-23 22:28 ` [PATCH] The idle notifier chain should be atomic Alan Stern
2006-02-23 23:49 ` Andi Kleen
2006-02-24 3:24 ` Alan Stern
2006-02-24 3:27 ` Andi Kleen
2006-02-24 4:04 ` Alan Stern
2006-02-23 22:36 ` [PATCH] Avoid calling down_read and down_write during startup Alan Stern
2006-02-23 22:37 ` Benjamin LaHaise
2006-02-24 0:16 ` Andrew Morton
2006-02-24 3:18 ` Alan Stern
2006-02-24 14:40 ` Benjamin LaHaise [this message]
2006-02-24 15:04 ` Alan Stern
2006-02-24 15:15 ` Benjamin LaHaise
2006-02-24 16:44 ` Alan Stern
2006-02-24 16:44 ` Benjamin LaHaise
2006-02-24 17:59 ` Alan Stern
2006-02-24 18:37 ` Benjamin LaHaise
2006-02-24 20:21 ` Alan Stern
2006-02-24 14:39 ` Benjamin LaHaise
2006-02-24 15:03 ` Alan Stern
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