Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933507AbXJRRKv (ORCPT ); Thu, 18 Oct 2007 13:10:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1764183AbXJRRKj (ORCPT ); Thu, 18 Oct 2007 13:10:39 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.31.123]:45429 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932945AbXJRRKi (ORCPT ); Thu, 18 Oct 2007 13:10:38 -0400 Date: Thu, 18 Oct 2007 19:10:41 +0200 From: Pavel Machek To: Yi Yang Cc: Valdis.Kletnieks@vt.edu, linux-kernel@vger.kernel.org, akpm@osdl.org, mj@atrey.karlin.mff.cuni.cz, crutcher+kernel@datastacks.com, schwab@suse.de Subject: Re: [PATCH 2.6.23] SysRq: print hotkey info while pressing undef key, try 2 Message-ID: <20071018171041.GA4510@elf.ucw.cz> References: <471628D2.8010903@gmail.com> <18386.1192651748@turing-police.cc.vt.edu> <47176EED.1050801@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <47176EED.1050801@gmail.com> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2277 Lines: 56 Hi! >> 1) He has been told "recreate the problem, hit alt-sysreq-cokebottle, >> and send me the results". He has a mission, and the only feedback he >> needs is (a) that he hit cokebottle and not pepsibottle, and (b) the >> resulting output. >> >> 2) He's already read the file in Documentation/ and just needs a reminder. >> In this case, the fact it's only 2 or 3 lines and doesn't scroll other >> stuff >> out of sight is more important. >> > Screen scroll isn't a problem. > > "SysRq : HELP : loglevel0-8 reBoot Crashdump tErm Full kIll saK showMem > Nice powerOff showPc show-all-timers(Q) unRaw Sync showTasks Unmount > shoW-blocked-tasks" > > The above help information isn't very user-friendly. Seems perfectly reasonably to me... parhaps "Full" should be replaced with "Force-oom"... >>> In addition, that funtion has a big loop with another big loop >>> embedded which is very inefficient, it is intended to skip some hot >>> >> >> You're optimizing code that hopefully never gets executed, and even if >> it does, you have the optimization *backwards*. If you're worried about >> the efficiency, trim it down to output 3 lines - do you realize how many >> instructions it takes in the VGA and fb drivers to actually *output* all >> these lines? (Seriously - I had a 1.6Ghz P4 laptop, where scrolling the >> screen with vga=791 actually ran so slowly that it horqued up the timer >> initialization code. *That* was a fun bug to figure out..) >> > To remove a bad loop is just a plus fix. That loop is really > inefficient. No, it is not a fix and no, it is not inefficient. >>> +static char __read_mostly sysrq_hot_key_table[36] = { >>> + '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', >>> + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', >>> + 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', >>> + 'u', 'v', 'w', 'x', 'y', 'z' This has to go. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - 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/