From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from traveler.cistron-office.nl ([62.216.29.67] helo=traveler) by smtp.cistron-office.nl with esmtp (Exim 3.35 #1 (Debian)) id 1BXhbK-0004BE-00 for ; Tue, 08 Jun 2004 16:29:18 +0200 Date: Tue, 8 Jun 2004 16:29:18 +0200 From: Miquel van Smoorenburg Subject: Keeping mmap'ed files in core regression in 2.6.7-rc Message-ID: <20040608142918.GA7311@traveler.cistron.net> Reply-To: linux-mm@kvack.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org Return-Path: To: linux-mm@kvack.org List-ID: I'm running a Usenet news server with a full feed. Software is INN 2.4.1. The list of all articles is called the "history database" and is indexed by a history.hash and a history.index file, both sized around 300-400 MB. These hash and index files are mmap'ed by the main innd process. A full usenet feed is 800-1000 GB/day, that's ~ 12MB / sec incoming traffic going to the local spool disk. About the same amount of traffic is sent out to peers. With kernels 2.6.0 - 2.6.6, I did a "echo 15 > /proc/sys/vm/swappiness" and the kernel did a pretty good job of keeping the mmap'ed files mostly in core, which is needed for performance (100-200 database queries/sec!). This is the output with a 2.6.6 kernel: # ps u -C innd USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND news 276 26.8 60.2 817228 624932 ? D 01:57 232:55 /usr/local/news/b Now I tried 2.6.7-rc2 and -rc3 (well rc2-bk-latest-before-rc3) and with those kernels, performance goes to hell because no matter how much I tune, the kernel will throw out the mmap'ed pages first. RSS of the innd process hovers around 200-250 MB instead of 600. Ideas ? Mike. -- 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/ . Don't email: aart@kvack.org