From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752393AbZKRHln (ORCPT ); Wed, 18 Nov 2009 02:41:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752305AbZKRHlm (ORCPT ); Wed, 18 Nov 2009 02:41:42 -0500 Received: from mail-pw0-f42.google.com ([209.85.160.42]:54324 "EHLO mail-pw0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751661AbZKRHll convert rfc822-to-8bit (ORCPT ); Wed, 18 Nov 2009 02:41:41 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=jAq3xtdHhMNUVbIhreENdWy7fCu9yEnQEDXpQbN5aMK2fs+L7gxjDZUHjxdMnQeOld 7X7uPNpZIBUPOnl2slyB0QH10NBb1W1+7spBIyiB+WNZJrI1AjAdRhYNepHloWccwQ0/ BpYdwl4JIvjbxKtTyFxknTUTNMpVNGTNMS2Zc= MIME-Version: 1.0 In-Reply-To: <2375c9f90911172317x781e22a9y56ecb8e682e8e061@mail.gmail.com> References: <2375c9f90911172317x781e22a9y56ecb8e682e8e061@mail.gmail.com> Date: Wed, 18 Nov 2009 15:41:46 +0800 Message-ID: Subject: Re: [PATCH] vfs: does call expand_files when needed From: Liu Aleaxander To: =?ISO-8859-1?Q?Am=E9rico_Wang?= Cc: Alexander Viro , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 18, 2009 at 3:17 PM, Américo Wang wrote: > > On Wed, Nov 18, 2009 at 1:54 PM, Liu Aleaxander wrote: > > From: Liu Aleaxander > > Date: Wed, 18 Nov 2009 10:59:09 +0800 > > Subject: [PATCH] vfs: does call expand_files when needed > > > > I don't think we should call expand_files every time we open a > > file for a new unused fd, so does the expand when necessary. > > > > Signed-off-by: Liu Aleaxander > > --- > >  fs/file.c |   27 ++++++++++++++------------- > >  1 files changed, 14 insertions(+), 13 deletions(-) > > > > diff --git a/fs/file.c b/fs/file.c > > index 87e1290..3f3d0fc 100644 > > --- a/fs/file.c > > +++ b/fs/file.c > > @@ -452,22 +452,22 @@ repeat: > >        if (fd < files->next_fd) > >                fd = files->next_fd; > > > > -       if (fd < fdt->max_fds) > > +       if (likely(fd < fdt->max_fds)) { > >                fd = find_next_zero_bit(fdt->open_fds->fds_bits, > >                                           fdt->max_fds, fd); > > - > > -       error = expand_files(files, fd); > > -       if (error < 0) > > -               goto out; > > - > > -       /* > > -        * If we needed to expand the fs array we > > -        * might have blocked - try again. > > -        */ > > -       if (error) > > -               goto repeat; > > - > > +       } else { > > +               error = expand_files(files, fd); > > > In expand_files(), it has the check for > ' < fdt->max_fds', so this change is not necessary. Yeah, indeed. But why we should go into an another function to do a _double_ check especially we mostly don't need to do that? > > > +               if (error < 0) > > +                       goto out; > > + > > +               /* > > +                * If we needed to expand the fs array we > > +                * might have blocked - try again. > > +                */ > > +               if (error) > > +                       goto repeat; > > +       } > > + > >        if (start <= files->next_fd) > >                files->next_fd = fd + 1; > > > > -- > > 1.6.2.5 > > > > -- > > regards > > Liu Aleaxander > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at  http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at  http://www.tux.org/lkml/ > > -- regards Liu Aleaxander