From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id B6335900086 for ; Thu, 14 Apr 2011 17:10:37 -0400 (EDT) Date: Thu, 14 Apr 2011 16:10:34 -0500 (CDT) From: Christoph Lameter Subject: Re: [PATCH] percpu: preemptless __per_cpu_counter_add In-Reply-To: <1302747263.3549.9.camel@edumazet-laptop> Message-ID: References: <20110413185618.GA3987@mtj.dyndns.org> <1302747263.3549.9.camel@edumazet-laptop> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Eric Dumazet Cc: Tejun Heo , akpm@linux-foundation.org, linux-mm@kvack.org, shaohua.li@intel.com On Thu, 14 Apr 2011, Eric Dumazet wrote: > Not sure its a win for my servers, where CONFIG_PREEMPT_NONE=y Well the fast path would then also be irq safe. Does that bring us anything? We could not do the cmpxchg in the !PREEMPT case and instead simply store the value. The preempt on/off seems to be a bigger deal for realtime. > Maybe use here latest cmpxchg16b stuff instead and get rid of spinlock ? Shaohua already got an atomic in there. You mean get rid of his preempt disable/enable in the slow path? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org