From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754476Ab0IOPWZ (ORCPT ); Wed, 15 Sep 2010 11:22:25 -0400 Received: from xenotime.net ([72.52.115.56]:57431 "HELO xenotime.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752497Ab0IOPWY (ORCPT ); Wed, 15 Sep 2010 11:22:24 -0400 Date: Wed, 15 Sep 2010 08:22:17 -0700 From: Randy Dunlap To: Namhyung Kim Cc: Jiri Kosina , linux-kernel@vger.kernel.org Subject: Re: [PATCH RESEND 1/2] ida: document IDA_BITMAP_LONGS calculation Message-Id: <20100915082217.6bf82715.rdunlap@xenotime.net> In-Reply-To: <1284554762-13278-1-git-send-email-namhyung@gmail.com> References: <1284554762-13278-1-git-send-email-namhyung@gmail.com> Organization: YPO4 X-Mailer: Sylpheed 2.7.1 (GTK+ 2.16.6; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 15 Sep 2010 21:46:01 +0900 Namhyung Kim wrote: > IDA_BITMAP_LONGS value is calculated take into account struct ida_bitmap > not to waste memory space. Comment it. > > Signed-off-by: Namhyung Kim > Acked-by: Tejun Heo > --- > include/linux/idr.h | 5 ++++- > 1 files changed, 4 insertions(+), 1 deletions(-) > > diff --git a/include/linux/idr.h b/include/linux/idr.h > index e968db7..3f4b718 100644 > --- a/include/linux/idr.h > +++ b/include/linux/idr.h > @@ -117,10 +117,13 @@ void idr_init(struct idr *idp); > /* > * IDA - IDR based id allocator, use when translation from id to > * pointer isn't necessary. > + * > + * IDA_BITMAP_LONGS is calculated to be one less to accommodate > + * ida_bitmap->nr_busy so that the whole struct fits in 128 bytes. > */ > #define IDA_CHUNK_SIZE 128 /* 128 bytes per chunk */ > #define IDA_BITMAP_LONGS (128 / sizeof(long) - 1) Might as well do: #define IDA_BITMAP_LONGS (IDA_CHUNK_SIZE / sizeof(long) - 1) instead of repeating the 128. > -#define IDA_BITMAP_BITS (IDA_BITMAP_LONGS * sizeof(long) * 8) > +#define IDA_BITMAP_BITS (IDA_BITMAP_LONGS * sizeof(long) * 8) > > struct ida_bitmap { > long nr_busy; > -- --- ~Randy *** Remember to use Documentation/SubmitChecklist when testing your code ***