From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3911BF09.653D9A2@sgi.com> Date: Thu, 04 May 2000 11:18:49 -0700 From: Rajagopal Ananthanarayanan MIME-Version: 1.0 Subject: Re: Oops in __free_pages_ok (pre7-1) (Long) (backtrace) References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: riel@nl.linux.org Cc: Linus Torvalds , Kanoj Sarcar , linux-mm@kvack.org, "David S. Miller" List-ID: Rik van Riel wrote: > > On Thu, 4 May 2000, Rajagopal Ananthanarayanan wrote: > > Linus Torvalds wrote: > > > > There might be other details like this lurking, but this looks like a good > > > first try. Ananth, willing to give it a whirl? > > > > I haven't looked at the code, but I replaced the whole while (1) > > loop with the new for(;;). Things still remain the same: when > > running dbench VM starts killing processes. > > I've been thinking about it some more. When we look > carefully the killing is always accompanied by a sudden > decrease in free memory (while kswapd could easily keep > up a few seconds ago). You may have something here. It's the burstiness of the demand. One thing I haven't noticed here in linux-mm is any approaches to throttle the demand (Or may be I haven't looked enough). Why not keep requests for new pages unsatisfied if the _rate_ of allocations exceeds the _rate_ of freeing (through swap-out or through write-out [bdflush])? Simple counters don't capture rates. We need deltas in the last 'n' time intervals. Then, match the delta-A (allocation) to delta-F (free). Just a thought, ananth. -- 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/