From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 24 Mar 2008 17:24:28 +0100 From: Pavel Machek Subject: Re: [PATCH prototype] [0/8] Predictive bitmaps for ELF executables Message-ID: <20080324162428.GA4206@ucw.cz> References: <20080321172644.GG2346@one.firstfloor.org> <20080322071755.GP2346@one.firstfloor.org> <1206170695.2438.39.camel@entropy> <20080322091001.GA7264@one.firstfloor.org> <1206180991.2438.43.camel@entropy> <20080322142949.GB10687@one.firstfloor.org> <20080323132517.GB4580@ucw.cz> <20080323170827.GB5082@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080323170827.GB5082@one.firstfloor.org> Sender: owner-linux-mm@kvack.org Return-Path: To: Andi Kleen Cc: Nicholas Miell , Ulrich Drepper , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Sun 2008-03-23 18:08:27, Andi Kleen wrote: > > Is this good idea? Attacker can send you binary with the bitmap > > inverted, it is now slow on your system and signature matches. > > The first run will fix up any missing bits in the bitmap. Right > now it cannot get rid of unnecessary pages though unless you > disable early_fault. > > > ...might be important for benchmarks... 'here, see, Oracle is slow. > > Feel free to verify the signature'. > > > > ...ok, I guess it is not too serious, because it is similar to > > fragmentation.... > > It is actually far better than fragmentation because the bitmap > loader does IO always in big chunks -- not much seeking will go on. > The only problem is some wasted mmeory and more IO bandwidth > usage (but typically binaries are not bigger than a few MB so > it's not too dramatic) > > So in summary I don't think it's an issue. Agreed. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- 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