From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 23 Mar 2006 15:59:39 -0500 (EST) From: Rik van Riel Subject: Re: [PATCH 00/34] mm: Page Replacement Policy Framework In-Reply-To: Message-ID: References: <20060322223107.12658.14997.sendpatchset@twins.localnet> <20060322145132.0886f742.akpm@osdl.org> <20060323205324.GA11676@dmt.cnet> <20060323223057.GA12895@dmt.cnet> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Linus Torvalds Cc: Marcelo Tosatti , Andrew Morton , Peter Zijlstra , linux-mm@kvack.org, linux-kernel@vger.kernel.org, bob.picco@hp.com, iwamoto@valinux.co.jp, christoph@lameter.com, wfg@mail.ustc.edu.cn, npiggin@suse.de List-ID: On Thu, 23 Mar 2006, Linus Torvalds wrote: > > LRU's worst case scenarios were well known before I was born. > > The kernel doesn't actually use LRU, so the fact that LRU isn't good seems > a non-argument. Agreed. The current algorithm in the kernel is close to 2Q, just without the corrections that 2Q gets from non-resident history and the further tuning that is done by clock-pro. > > - "Every time I wake up in the morning updatedb has thrown my applications > > out of memory". > > > > - "Linux is awful every time I untar something larger than memory to disk". > > People seem to think that the fact that there are bad behaviours means > that there are somehow "magic" algorithms that don't have bad behaviours. > > I'd really suggest somebody show better real-life numbers with a new > algorithm _before_ we do anything like this. Remember that it's not necessarily about "making a VM that handles the common case better", but rather about "making the VM behave well more of the time". Furthermore, all VM benchmarks are corner cases. After all, most systems have enough memory most of the time, and will not be evicting much at all. This makes interpreting VM benchmark results harder than the interpretation of many other benchmarks... -- All Rights Reversed -- 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