From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dax.scot.redhat.com (sct@dax.scot.redhat.com [195.89.149.242]) by kvack.org (8.8.7/8.8.7) with ESMTP id HAA09981 for ; Tue, 17 Nov 1998 07:03:47 -0500 Date: Tue, 17 Nov 1998 12:00:37 GMT Message-Id: <199811171200.MAA01162@dax.scot.redhat.com> From: "Stephen C. Tweedie" MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Subject: Re: unexpected paging during large file reads in 2.1.127 In-Reply-To: <87lnlb5d2t.fsf@atlas.CARNet.hr> References: <199811161959.TAA07259@dax.scot.redhat.com> <199811162305.XAA07996@dax.scot.redhat.com> <87lnlb5d2t.fsf@atlas.CARNet.hr> Sender: owner-linux-mm@kvack.org To: Zlatko.Calusic@CARNet.hr Cc: Linux-MM List , Linux Kernel List , Rik van Riel , "David J. Fred" , "Stephen C. Tweedie" List-ID: Hi, On 17 Nov 1998 02:21:14 +0100, Zlatko Calusic said: > "Stephen C. Tweedie" writes: >> No, we don't. We don't evict just-read-in data, because we mark such >> pages as PG_Referenced. It takes two complete shrink_mmap() passes >> before we can evict such pages. > I didn't find this in the source (in fact, add_to_page_cache clears > PG_referenced bit, if I understood source correctly). But, see below. You didn't understand the source correctly. :) There is an extra bracket you missed: page->flags = (page->flags & ~((1 << PG_uptodate) | (1 << PG_error))) | (1 << PG_referenced); We clear PG_uptodate and PG_error, but we _set_ PG_referenced. > I must agree entirely, because with small patch you can find below, > performance is very very good. Thanks to marking readahead pages as > referenced, I've been able to see exact behaviour that I wanted for a > long time. Excellent. --Stephen -- This is a majordomo managed list. To unsubscribe, send a message with the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org