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 ESMTP id 1BA6F900001 for ; Fri, 29 Apr 2011 10:43:28 -0400 (EDT) Received: by fxm18 with SMTP id 18so3701481fxm.14 for ; Fri, 29 Apr 2011 07:43:24 -0700 (PDT) Date: Fri, 29 Apr 2011 16:43:18 +0200 From: Tejun Heo Subject: Re: [PATCH] percpu: preemptless __per_cpu_counter_add Message-ID: <20110429144318.GO16552@htj.dyndns.org> References: <20110426121011.GD878@htj.dyndns.org> <1303883009.3981.316.camel@sli10-conroe> <20110427102034.GE31015@htj.dyndns.org> <1303961284.3981.318.camel@sli10-conroe> <20110428100938.GA10721@htj.dyndns.org> <1304065171.3981.594.camel@sli10-conroe> <20110429084424.GJ16552@htj.dyndns.org> <20110429141817.GN16552@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Shaohua Li , Eric Dumazet , "akpm@linux-foundation.org" , "linux-mm@kvack.org" Hello, On Fri, Apr 29, 2011 at 09:25:09AM -0500, Christoph Lameter wrote: > On Fri, 29 Apr 2011, Tejun Heo wrote: > > > > If someone wants more accuracy then we need the ability to dynamically set > > > the batch limit similar to what the vm statistics do. > > > > So, if you can remove _sum() by doing the above without introducing > > excessive complexity or penalizing use cases which might not have too > > much commonality with vmstat, by all means, but please pay attention > > to the current users. Actually take a look at them. > > I am content to be maintaining the vm statistics.... But Shaohua may want > to have a look at it? It would be nice if vmstat can be merged with percpu counter tho so that the flushing can be done together. If we such piggybacking, the flushing overhead becomes much easier to justify. How does vmstat collect the percpu counters? Does one cpu visit all of them or each cpu flush local counter to global one periodically? Thanks. -- tejun -- 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