From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f42.google.com (mail-wg0-f42.google.com [74.125.82.42]) by kanga.kvack.org (Postfix) with ESMTP id BCA7A6B0031 for ; Mon, 2 Jun 2014 13:15:23 -0400 (EDT) Received: by mail-wg0-f42.google.com with SMTP id y10so5368329wgg.25 for ; Mon, 02 Jun 2014 10:15:23 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTP id u5si26683649wjf.58.2014.06.02.10.15.21 for ; Mon, 02 Jun 2014 10:15:22 -0700 (PDT) Message-ID: <538cb12a.8518c20a.1a51.ffff9761SMTPIN_ADDED_BROKEN@mx.google.com> From: Naoya Horiguchi Subject: Re: [PATCH 1/3] replace PAGECACHE_TAG_* definition with enumeration Date: Mon, 2 Jun 2014 13:14:48 -0400 In-Reply-To: <538CAA13.2080708@intel.com> References: <20140521193336.5df90456.akpm@linux-foundation.org> <1401686699-9723-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1401686699-9723-2-git-send-email-n-horiguchi@ah.jp.nec.com> <538CA269.6010300@intel.com> <1401727052-f7v7kykv@n-horiguchi@ah.jp.nec.com> <538CAA13.2080708@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: Andrew Morton , Konstantin Khlebnikov , Wu Fengguang , Arnaldo Carvalho de Melo , Borislav Petkov , "Kirill A. Shutemov" , Johannes Weiner , Rusty Russell , David Miller , Andres Freund , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Mon, Jun 02, 2014 at 09:45:07AM -0700, Dave Hansen wrote: > On 06/02/2014 09:37 AM, Naoya Horiguchi wrote: > > On Mon, Jun 02, 2014 at 09:12:25AM -0700, Dave Hansen wrote: > >> > On 06/01/2014 10:24 PM, Naoya Horiguchi wrote: > >>> > > -#define PAGECACHE_TAG_DIRTY 0 > >>> > > -#define PAGECACHE_TAG_WRITEBACK 1 > >>> > > -#define PAGECACHE_TAG_TOWRITE 2 > >>> > > +enum { > >>> > > + PAGECACHE_TAG_DIRTY, > >>> > > + PAGECACHE_TAG_WRITEBACK, > >>> > > + PAGECACHE_TAG_TOWRITE, > >>> > > + __NR_PAGECACHE_TAGS, > >>> > > +}; > >> > > >> > Doesn't this end up exposing kernel-internal values out to a userspace > >> > interface? Wouldn't that lock these values in to the ABI? > > Yes, that would. I hope these PAGECACHE_TAG_* stuff is very basic > > things and will never change drastically in the future (only added), > > so it's unlikely to bother people about ABI breakage things. > > OK, so if I'm writing a userspace program, which header do I include > pull these values in to my program? Yes, that's necessary to consider (but I haven't done, sorry), so I'm thinking of moving this definition to the new file include/uapi/linux/pagecache.h and let it be imported from the userspace programs. Is it fine? Thanks, Naoya Horiguchi -- 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