From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d1o43.telia.com (d1o43.telia.com [194.22.195.241]) by maile.telia.com (8.9.3/8.9.3) with ESMTP id CAA19419 for ; Thu, 8 Jun 2000 02:06:10 +0200 (CEST) Received: from norran.net (roger@t8o43p27.telia.com [194.237.168.207]) by d1o43.telia.com (8.8.8/8.8.8) with ESMTP id CAA12876 for ; Thu, 8 Jun 2000 02:06:09 +0200 (CEST) Message-ID: <393EE2FA.43690671@norran.net> Date: Thu, 08 Jun 2000 02:04:10 +0200 From: Roger Larsson MIME-Version: 1.0 Subject: Re: reduce shrink_mmap rate of failure (initial attempt) References: <01BFD09A.CC430AF0@lando.optronic.se> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: linux-mm@kvack.org List-ID: Hi again, There is an even more likely scenario... * shrink_mmap is called when no zone is under pressure. then it will search the list over and over again... Who could do such a nasty thing? do_try_to_free_pages ! Its agenda is not to stop when there is no pressure - it will go on until FREE_COUNT (8) pages are freed... Even in the normal ac10 this should be a problem. Several turns in do_try_to_free_pages with shrink_mmap failing will be done - each swapping out some pages... It will take time and swap... /RogerL Roger Larsson wrote: > > >That patch hangs my machine here when I run mmap002. The machine is > >in shrink_mmap. It hangs trying to get the pagmap_lru_lock. > > > >I think that the idea is good, but it doesn't work here :(. > > > >Later, Juan. > > Ouch... > > The only possible explaination is that we are searching for pages on a zone. > But no such pages are possible to free from LRU... > And we LOOP the list, holding the lru lock... > Note: without this patch you may end up in another bad situation where > shrink_mmap always fails and swapping will start until it swaps out a page > of that specific zone. > And without the test? We would free all other LRU pages without finding one > that we want :-( > > This will be interesting to fix... > > May the allocation of pages play a part? Filling zone after zone will give no > mix between the zones. > > /RogerL > (from work) > > -- > 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/ -- Home page: http://www.norran.net/nra02596/ -- 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/