From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: madvise (MADV_FREE) References: <20000322193016.A7368@pcep-jamie.cern.ch> From: Christoph Rohland Date: 23 Mar 2000 17:56:12 +0100 In-Reply-To: Jamie Lokier's message of "Wed, 22 Mar 2000 19:30:16 +0100" Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org Return-Path: To: Jamie Lokier Cc: Christoph Rohland , Chuck Lever , linux-mm@kvack.org List-ID: Jamie Lokier writes: > Christoph Rohland wrote: > > > ok, so you're asking for a lite(TM) version of DONTNEED that > > > provides the following hint to the kernel: "i may be finished > > > with this page, but i may also want to reuse it immediately." > > > > I would say "... reuse this address space immediately and you can > > give me _any_ data the next time". "Any data" means probably > > either the old or a zero page. > > For maximum performance that's right. But Linux normally has to > provide some minimal security, so an application should only see its > own data or zeros, not an arbitrary page. That was the reason for "...probably either the old or a zero page" > Zeroing has another advantage: you can efficiently detect it. So > you can use it for cached memory objects too in a number of cases, > not just free memory. (A bit from mincore would also allow > detection, but not nearly as efficiently). > > > That's the optimal strategy for the memory management modules of > > SAP R/3. > > Excellent! A hard core recommendation :-) :-) Greetings Christoph -- 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.eu.org/Linux-MM/