From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx123.postini.com [74.125.245.123]) by kanga.kvack.org (Postfix) with SMTP id DC2086B0082 for ; Fri, 18 May 2012 06:43:49 -0400 (EDT) Message-ID: <1337337824.573.16.camel@twins> Subject: Re: [PATCH 1/2] lib: Proportions with flexible period From: Peter Zijlstra Date: Fri, 18 May 2012 12:43:44 +0200 In-Reply-To: <1337096583-6049-2-git-send-email-jack@suse.cz> References: <1337096583-6049-1-git-send-email-jack@suse.cz> <1337096583-6049-2-git-send-email-jack@suse.cz> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Jan Kara Cc: Wu Fengguang , LKML , linux-mm@kvack.org On Tue, 2012-05-15 at 17:43 +0200, Jan Kara wrote: > +void __fprop_inc_percpu_max(struct fprop_global *p, > + struct fprop_local_percpu *pl, int max_frac) > +{ > + if (unlikely(max_frac < 100)) { > + unsigned long numerator, denominator; > + > + fprop_fraction_percpu(p, pl, &numerator, &denominator); > + if (numerator > ((long long)denominator) * max_frac / 100= ) > + return; Another thing, your fprop_fraction_percpu() can he horribly expensive due to using _sum() (and to a lesser degree the retry), remember that this function is called for _every_ page written out. Esp. on the mega fast storage (multi-spindle or SSD) they're pushing cpu limits as it is with iops, we should be very careful not to make it more expensive than absolutely needed. > + } else > + fprop_reflect_period_percpu(p, pl); > + __percpu_counter_add(&pl->events, 1, PROP_BATCH); > + percpu_counter_add(&p->events, 1); > +}=20 -- 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