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From: Ingo Molnar <mingo@elte.hu>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Arjan van de Ven <arjan@infradead.org>,
	ego@in.ibm.com, rusty@rustcorp.com.au, torvalds@osdl.org,
	akpm@osdl.org, linux-kernel@vger.kernel.org,
	arjan@intel.linux.com, davej@redhat.com, dipankar@in.ibm.com,
	vatsa@in.ibm.com, ashok.raj@intel.com
Subject: Re: [RFC][PATCH 4/4] Rename lock_cpu_hotplug/unlock_cpu_hotplug
Date: Thu, 24 Aug 2006 17:00:26 +0200	[thread overview]
Message-ID: <20060824150026.GA14853@elte.hu> (raw)
In-Reply-To: <44EDBDDE.7070203@yahoo.com.au>


* Nick Piggin <nickpiggin@yahoo.com.au> wrote:

> It really is just like a reentrant rw semaphore... I don't see the 
> point of the name change, but I guess we don't like reentrant locks so 
> calling it something else might go down better with Linus ;)

what would fit best is a per-cpu scalable (on the read-side) 
self-reentrant rw mutex. We are doing cpu hotplug locking in things like 
fork or the slab code, while most boxes will do a CPU hotplug event only 
once in the kernel's lifetime (during bootup), so a classic global 
read-write lock is unjustified.

	Ingo

  reply	other threads:[~2006-08-24 15:08 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-08-24 10:34 [RFC][PATCH 4/4] Rename lock_cpu_hotplug/unlock_cpu_hotplug Gautham R Shenoy
2006-08-24 11:00 ` Arjan van de Ven
2006-08-24 14:03   ` Gautham R Shenoy
2006-08-24 14:16     ` Arjan van de Ven
2006-08-24 14:55       ` Nick Piggin
2006-08-24 15:00         ` Ingo Molnar [this message]
2006-08-24 15:53           ` Nick Piggin
2006-08-25  3:53           ` Gautham R Shenoy
2006-08-27  7:59             ` Paul Jackson
2006-08-27  8:42               ` Keith Owens
2006-08-27  9:10                 ` Paul Jackson
2006-08-29 18:05               ` Paul E. McKenney
2006-08-29 19:31                 ` Paul Jackson
2006-08-29 20:03                   ` Paul E. McKenney
2006-08-30  2:38                     ` Paul Jackson
2006-08-30 15:14                       ` Paul E. McKenney
2006-08-30 17:54                         ` Paul Jackson
2006-08-30 18:13                           ` Paul E. McKenney

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