From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 9 Jun 2001 00:15:15 -0300 (BRST) From: Rik van Riel Subject: Re: VM tuning patch, take 2 In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Jonathan Morton Cc: linux-mm@kvack.org List-ID: On Thu, 7 Jun 2001, Jonathan Morton wrote: > - ageing is now done evenly, and independently of the number of > mappings on a given page. This is done by introducing a 4th LRU list > (aside from active, inactive_clean and inactive_dirty) which holds > pages attached to a process but not in the swapcache. IMHO it would be better to add these to the active list so both filesystem-backed and swap-backed pages will be aged the same. > - try_to_swap_out() will now refuse to move a page into the swapcache > which still has positive age. This helps preserve the working set > information, and may help to reduce swap bloat. It may re-introduce > the cause of cache collapse, but I haven't seen any evidence of this > being disastrous, as yet. This should only affect swap bloat and nothing else. The "cache collapse" thing vmstat might show is just a "lack" of swap cache pages being generated... > - new pages are still given an age of PAGE_AGE_START, which is 2. > PAGE_AGE_ADV has been increased to 4, and PAGE_AGE_MAX to 128. Pages which > are demand-paged in from swap are given an initial age of PAGE_AGE_MAX/2, > or 64 - this should help to keep these (expensive) pages around for as long > as possible. Ageing down is now done using a decrement instead of a > division by 2, preserving the age information for longer. I think the PAGE_AGE_START should be the same for all pages. About decrement vs. division by two, I think this is something we may want to make tunable (I have the code for this floating around somewhere, hold on). regards, Rik -- Virtual memory is like a game you can't win; However, without VM there's truly nothing to lose... http://www.surriel.com/ http://distro.conectiva.com/ Send all your spam to aardvark@nl.linux.org (spam digging piggy) -- 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/