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From: Christoph Hellwig <hch@infradead.org>
To: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: linux-kernel@vger.kernel.org,
	Christoph Hellwig <hch@infradead.org>,
	Andrew Morton <akpm@osdl.org>, Ingo Molnar <mingo@redhat.com>,
	Greg Kroah-Hartman <gregkh@suse.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Tom Zanussi <zanussi@us.ibm.com>,
	Karim Yaghmour <karim@opersys.com>,
	Paul Mundt <lethal@linux-sh.org>, Jes Sorensen <jes@sgi.com>,
	Richard J Moore <richardj_moore@uk.ibm.com>,
	"Martin J. Bligh" <mbligh@mbligh.org>,
	Michel Dagenais <michel.dagenais@polymtl.ca>,
	Douglas Niehaus <niehaus@eecs.ku.edu>,
	ltt-dev@shafik.org, systemtap@sources.redhat.com
Subject: Re: [PATCH 4/16] LTTng 0.6.36 for 2.6.18 : atomic UP operations on SMP
Date: Mon, 27 Nov 2006 16:56:43 +0000	[thread overview]
Message-ID: <20061127165643.GD5348@infradead.org> (raw)
In-Reply-To: <20061124215518.GE25048@Krystal>

On Fri, Nov 24, 2006 at 04:55:18PM -0500, Mathieu Desnoyers wrote:
> This patch adds a UP flavor of SMP operations which is intended to provide
> atomic modification of per-cpu data without suffering from the LOCK of memory
> barrier performance cost. Note that extreme care must be taken when accessing
> this data from different CPUs : smp_wmb() and smp_rmb() must be used
> explicitely. As this last scenario happens very rarely in LTTng, it provides a

We already have local_t in asm/local.h for this purposed.  Unfortunately
several architecture implementations are rather suboptimal, but I'm sure
the architecture maintainers would be interested in patches to optimize
the various implementations.


  reply	other threads:[~2006-11-27 16:56 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-11-24 21:55 [PATCH 4/16] LTTng 0.6.36 for 2.6.18 : atomic UP operations on SMP Mathieu Desnoyers
2006-11-27 16:56 ` Christoph Hellwig [this message]
2006-12-01  3:11   ` [PATCH 1/2] atomic.h atomic64_t standardization Mathieu Desnoyers
2006-12-01  3:24     ` Mathieu Desnoyers
2006-12-01 22:19       ` Mathieu Desnoyers
2006-12-02  0:43         ` Nick Piggin
2006-12-05 17:08         ` [PATCH 1/2] atomic.h atomic64_t standardization for 2.6.19 Mathieu Desnoyers
2006-12-01  3:34     ` [PATCH 1/2] atomic.h atomic64_t standardization Paul Mundt
2006-12-01  3:41       ` Mathieu Desnoyers
2006-12-01  3:14   ` [PATCH 2/2] local.h modifications Mathieu Desnoyers
2006-12-01  3:24     ` Mathieu Desnoyers
2006-12-01 22:21       ` Mathieu Desnoyers
2006-12-05 17:14         ` [PATCH 2/2] local.h modifications for 2.6.19 Mathieu Desnoyers

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