From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 25 Feb 2000 12:55:19 +0100 (CET) From: Rik van Riel Subject: Re: [PATCH] kswapd performance fix In-Reply-To: <14518.22746.519992.127418@dukat.scot.redhat.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: "Stephen C. Tweedie" Cc: Alan Cox , Linux MM , "Stephen Tweedie Linux Kernel" List-ID: On Fri, 25 Feb 2000, Stephen C. Tweedie wrote: > On Fri, 25 Feb 2000 00:30:59 +0100 (CET), Rik van Riel > said: > > > The patch should apply to any 2.2 or 2.3 kernel, but for > > 2.3 it'll have the interesting side effect of nullifying > > the (minimal) page aging that's going on there. > > Have you actually tested the impact of this under a variety of > load conditions? In the past we have seen such apparently trivial > changes completely break the VM balance under certain loads. The PG_referenced bit isn't used for anything except for NRU/LRU page reclaiming in shrink_mmap(). However, shrink_mmap() will skip over any pages that are still mapped by processes _and_ when we unmap the page from the (next to) last user we set the PG_referenced bit. The PG_referenced bit is also not used at all by shrink_mmap(), unless (page->count == 1); shm_swap() doesn't use the referenced bit at all. regards, Rik -- The Internet is not a network of computers. It is a network of people. That is its real strength. -- 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/