From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx137.postini.com [74.125.245.137]) by kanga.kvack.org (Postfix) with SMTP id E7B1C6B005C for ; Wed, 11 Jan 2012 03:28:50 -0500 (EST) Received: by vcge1 with SMTP id e1so414727vcg.14 for ; Wed, 11 Jan 2012 00:28:49 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1326265449_1658@mail4.comsite.net> References: <1326040026-7285-1-git-send-email-gilad@benyossef.com> <1326265449_1658@mail4.comsite.net> Date: Wed, 11 Jan 2012 10:28:49 +0200 Message-ID: Subject: Re: [PATCH v6 0/8] Reduce cross CPU IPI interference From: Gilad Ben-Yossef Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Milton Miller Cc: linux-kernel@vger.kernel.org, Christoph Lameter , Chris Metcalf , Peter Zijlstra , Frederic Weisbecker , Russell King , linux-mm@kvack.org, Pekka Enberg , Matt Mackall , Rik van Riel , Andi Kleen , Sasha Levin , Mel Gorman , Andrew Morton , Alexander Viro , linux-fsdevel@vger.kernel.org, Avi Kivity , Michal Nazarewicz , Kosaki Motohiro On Wed, Jan 11, 2012 at 9:04 AM, Milton Miller wrote: > > Hi Gilad. =A0 A few minor corrections for several of the patch logs, but = some > meater discussions on several of the patches. > > Overall I like the series and hope you see it through. Hi Milton. Thanks so much for the detailed review. As you've no doubt noticed,=A0English is=A0not my mother=A0tongue (as oppos= ed to =A0C),=A0so a special=A0thank you for the patch logs review :-) > > > > > +void on_each_cpu_mask(const struct cpumask *mask, void (*func)(void *)= , > > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 void *info, bool wait) > > +{ > > + =A0 =A0 int cpu =3D get_cpu(); > > + > > + =A0 =A0 smp_call_function_many(mask, func, info, wait); > > + =A0 =A0 if (cpumask_test_cpu(cpu, mask)) { > > + =A0 =A0 =A0 =A0 =A0 =A0 local_irq_disable(); > > + =A0 =A0 =A0 =A0 =A0 =A0 func(info); > > + =A0 =A0 =A0 =A0 =A0 =A0 local_irq_enable(); > > + =A0 =A0 } > > + =A0 =A0 put_cpu(); > > +} > > +EXPORT_SYMBOL(on_each_cpu_mask); > > It should be less code if we rewrite on_each_cpu as the one liner > on_each_cpu_mask(cpu_online_mask). =A0I think the trade off of less > code is worth the cost of the added test of cpu being in online_mask. > > That could be a seperate patch, but will be easier to read the result > if on_each_cpu_mask is placed above on_each_cpu in this one. Yes, it does look cleaner and I agree that the extra test is not a big price to pay for simplee code. However, to do that, on_each_cpu return value need to go away and all caller needs to be adjusted. I=A0figured=A0this is out of scope for thi= s patch set. I did send out a=A0separate patch set to do the needed work =A0(see: https://lkml.org/lkml/2012/1/8/48) and I suggest that after both of them go in, I'll send a patch to do exactly what you suggested. Thanks! Gilad -- Gilad Ben-Yossef Chief Coffee Drinker gilad@benyossef.com Israel Cell: +972-52-8260388 US Cell: +1-973-8260388 http://benyossef.com "Unfortunately, cache misses are an equal opportunity pain provider." -- Mike Galbraith, LKML -- 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