From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 4 Oct 2000 18:46:25 -0300 (BRST) From: Rik van Riel Subject: Re: Odd swap behavior In-Reply-To: <39DBA38F.B2607361@sgi.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Rajagopal Ananthanarayanan Cc: linux-mm@kvack.org List-ID: On Wed, 4 Oct 2000, Rajagopal Ananthanarayanan wrote: > Rik van Riel wrote: > > On Tue, 3 Oct 2000, Rajagopal Ananthanarayanan wrote: > > > > > I'm running fairly stressful tests like dbench with lots of > > > clients. Since the new VM changes (now in test9), I haven't > > > noticed _any_ swap activity, in spite of the enormous memory > > Small code changes in deactivate_page() have caused the > > drop_behind() code to actually WORK AS ADVERTISED right > > now, and because of that streaming IO doesn't put any > > memory pressure on the system. > > Agreed. And since the introduction of drop_behind & > the deactivate_page() in generic_file_write, streaming I/O > performance has become pretty good. > > However, in the above I was particularly talking about > swap behaviour on running dbench. Dbench is write intensive, > and also has fair amount of re-writes. So, the I'm not > sure why we still do not swap out _really_ old processes. Please take a look at vmscan.c::refill_inactive() Furthermore, we don't do background scanning on all active pages, only on the unmapped ones. This is one of the things we'll be able to fix in 2.5... > If old pages are not swapped out, then dbench itself > will get less than optimal amount of the page-cache during > its run. I believe this is one of the reasons for > dbench's poor showing with the new VM. Agreed, but I don't see an "easy" solution for 2.4. regards, Rik -- "What you're running that piece of shit Gnome?!?!" -- Miguel de Icaza, UKUUG 2000 http://www.conectiva.com/ http://www.surriel.com/ -- 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/