From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 30 May 2001 19:51:03 -0300 (BRT) From: Marcelo Tosatti Subject: Re: Plain 2.4.5 VM 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: Rik van Riel , Mark Hahn , linux-mm@kvack.org List-ID: On Wed, 30 May 2001, Jonathan Morton wrote: > >The "getting rid of it" above consists of 2 parts: > > > >1) moving the page to the active list, where > > refill_inactive_scan will age it > > Ummm... I don't see any movement of pages to the "active" list in > try_to_swap_out(). Hum? Increasing the page age will move it to the active list (indirectly, of course) if it is already a swap cache page. Otherwise the page will be added to the swapcache (which means it will be added to the active list). > Instead, I see some very direct attempts to push the > page onto backing store by some means. In the stock kernel, this is done > solely on the status of a single bit in the PTE, regardless of page->age or > it's position on any particular list. Allocating swap space for a page and adding the page to the swap cache will not add it to the backing store immediately. > IOW, all the fannying around with page->age really has very little (if any) > effect on the paging behaviour when it matters most - when memory pressure > is so intense that kswapd is looping. Jonathan, kswapd should never loop in the first place. We have to limit aging. With the current behaviour of the kernel, _all_ tasks are aging each others pages when memory pressure is really high (apart from kswapd possibly looping). -- 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/