From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753130Ab0CZKBk (ORCPT ); Fri, 26 Mar 2010 06:01:40 -0400 Received: from crca.org.au ([74.207.252.120]:53424 "EHLO crca.org.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752910Ab0CZKBi (ORCPT ); Fri, 26 Mar 2010 06:01:38 -0400 X-Bogosity: Ham, spamicity=0.000000 Message-ID: <4BAC8634.5000703@crca.org.au> Date: Fri, 26 Mar 2010 21:02:28 +1100 From: Nigel Cunningham User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9pre) Gecko/20100301 Shredder/3.0.4pre MIME-Version: 1.0 To: Jiri Slaby CC: "Rafael J. Wysocki" , pavel@ucw.cz, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [RFC 11/15] PM / Hibernate: add chunk i/o support References: <1269361063-3341-1-git-send-email-jslaby@suse.cz> <1269361063-3341-11-git-send-email-jslaby@suse.cz> <201003252338.48513.rjw@sisk.pl> <4BAC79B4.4040200@gmail.com> In-Reply-To: <4BAC79B4.4040200@gmail.com> Content-Type: text/plain; charset=ISO-8859-2; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi. On 26/03/10 20:09, Jiri Slaby wrote: > On 03/25/2010 11:38 PM, Rafael J. Wysocki wrote: >>> +int sws_rw_buffer_init(int writing) >>> +{ >>> + BUG_ON(sws_writer_buffer || sws_writer_buffer_pos); >> >> Please don't do that. Fail the operation instead. You can also use WARN_ON >> or WARN if you _really_ want the user to notice the failure. > > It's not a failure, it's a bug when we leak memory or forgot to > read/write all data. > >> BUG_ON's like this are annoying like hell for testers who trigger them. > > I think BUG is appropriate here (the system or image is in an > inconsitent state for the latter condition), but if you prefer the > WARN-family here, I can switch it to that. > >>> + if (writing) { >>> + ret = sws_io_ops->write_page(sws_writer_buffer, NULL); >>> + clear_page(sws_writer_buffer); >> >> Why do we need that clear_page()? > > Functionally for nothing, it was for my sakeness. Will remove. > >>> +int sws_rw_buffer_flush_page(int writing) >>> +{ >>> + int ret = 0; >>> + if (writing&& sws_writer_buffer_pos) >>> + ret = sws_io_ops->write_page(sws_writer_buffer, NULL); >>> + sws_writer_buffer_pos = writing ? 0 : PAGE_SIZE; >>> + return ret; >>> +} >> >> I'd split the above into two functions, one for writing and the other for >> reading. >> >> Doing the same with sws_rw_buffer() (under a better name), for the sake of >> clarity, also might make some sense, apparently. > > Do you mean adding hib*_buffer_read + hib*_buffer_write which would call > static hib*_rw_buffer? sws_rw_buffer has much common code for R and W, > so I would not make 2 functions from that. > > Nigel, you use _rw_ functions in toi, are there any pros opposing to _r_ > + _w_ (apart from exporting twice as symbols)? I forget now why I used rw functions to begin with (it's been a long time!). I do know I've never worried about exporting twice as many symbols. As I look at the code now, I think it makes more sense to split things up. This is especially true when I consider that a user with 4 cores has driven me to work on scalability, which will only diverge the code paths more. Regards, Nigel