From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx174.postini.com [74.125.245.174]) by kanga.kvack.org (Postfix) with SMTP id D1C396B013D for ; Tue, 30 Apr 2013 14:28:09 -0400 (EDT) Subject: Re: [PATCH 1/2] Make the batch size of the percpu_counter configurable From: Tim Chen In-Reply-To: <1367345403.11020.1.camel@edumazet-glaptop> References: <0000013e5b24d2c5-9b899862-e2fd-4413-8094-4f1e5a0c0f62-000000@email.amazonses.com> <1367339009.27102.174.camel@schen9-DESK> <1367345403.11020.1.camel@edumazet-glaptop> Content-Type: text/plain; charset="UTF-8" Date: Tue, 30 Apr 2013 11:28:09 -0700 Message-ID: <1367346489.27102.185.camel@schen9-DESK> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Eric Dumazet Cc: Christoph Lameter , Andrew Morton , Tejun Heo , Al Viro , Dave Hansen , Andi Kleen , linux-kernel , linux-mm On Tue, 2013-04-30 at 11:10 -0700, Eric Dumazet wrote: > On Tue, 2013-04-30 at 09:23 -0700, Tim Chen wrote: > > On Tue, 2013-04-30 at 13:32 +0000, Christoph Lameter wrote: > > > On Mon, 29 Apr 2013, Tim Chen wrote: > > > > > > > diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h > > > > index d5dd465..5ca7df5 100644 > > > > --- a/include/linux/percpu_counter.h > > > > +++ b/include/linux/percpu_counter.h > > > > @@ -22,6 +22,7 @@ struct percpu_counter { > > > > struct list_head list; /* All percpu_counters are on a list */ > > > > #endif > > > > s32 __percpu *counters; > > > > + int *batch ____cacheline_aligned_in_smp; > > > > }; > > > > > > What is this for and why does it have that alignmend? > > > > I was assuming that if batch is frequently referenced, it probably > > should not share a cache line with the counters field. > > But 'counters' field has the same requirement. Its supposed to be read > only field. > > So please remove this '____cacheline_aligned_in_smp', as it makes the > whole struct percpu_counter at least two cache lines wide, for no > obvious reason. > Will do. Thanks. Tim -- 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/ . Don't email: email@kvack.org