From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 26 Apr 2000 13:29:15 +0100 From: "Stephen C. Tweedie" Subject: Re: [PATCH] 2.3.99-pre6-3+ VM rebalancing Message-ID: <20000426132915.J3792@redhat.com> References: <20000426120130.E3792@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: ; from riel@conectiva.com.br on Wed, Apr 26, 2000 at 08:15:14AM -0300 Sender: owner-linux-mm@kvack.org Return-Path: To: riel@nl.linux.org Cc: "Stephen C. Tweedie" , Simon Kirby , Jeff Garzik , Andrea Arcangeli , linux-mm@kvack.org, Ben LaHaise , linux-kernel@vger.rutgers.edu List-ID: Hi, On Wed, Apr 26, 2000 at 08:15:14AM -0300, Rik van Riel wrote: > On Wed, 26 Apr 2000, Stephen C. Tweedie wrote: > > On Tue, Apr 25, 2000 at 12:06:58PM -0700, Simon Kirby wrote: > > > > > > Sorry, I made a mistake there while writing..I was going to give an > > > example and wrote 60 seconds, but I didn't actually mean to limit > > > anything to 60 seconds. I just meant to make a really big global lru > > > that contains everything including page cache and swap. :) > > > > Doesn't work. If you do that, a "find / | grep ..." swaps out > > everything in your entire system. > > > > Getting the VM to respond properly in a way which doesn't freak out > > in the mass-filescan case is non-trivial. Simple LRU over all pages > > simply doesn't cut it. > > It seems to work pretty well, because pages "belonging to" processes > are mapped into the address space of each process and will never go > through swap_out() if shrink_mmap() will succeed. I know. The post wasn't talking about what we do now. It was talking about a hypothetical LRU which covers "everything including page cache and swap." LRU over just the page cache pages works fine. If you start treating swap exactly the same, on a page-by-page LRU, then a filesystem "find" scan will swap out most of your VM. Bad news. --Stephen -- 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/