From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 13 Jun 2000 17:08:19 +0200 (CEST) From: Andrea Arcangeli Subject: Re: [patch] improve streaming I/O [bug in shrink_mmap()] In-Reply-To: <20000612232932.I15054@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: Zlatko Calusic , alan@redhat.com, Linux MM List , Linux Kernel List List-ID: On Mon, 12 Jun 2000, Stephen C. Tweedie wrote: >Nice --- it might also explain some of the excessive kswap CPU >utilisation we've seen reported now and again. You have more kswapd load for sure due the strict zone approch. It maybe not noticeable but it's real. You boot, you allocate all the normal zone in cache doing some fs load, then you start netscape and you allocate the lower 16mbyte of RAM into it, then doing some other thing you trigger kswapd to run because also the lower 16mbyte are been allocated now. Then netscape exists and release all the lower 16m but kswapd keeps shrinking the normal zone (this shouldn't happen and it wouldn't happen with classzone design). I think Linus's argument about the above scenario is simply that the above isn't going to happen very often, but how can I ignore this broken behaviour? I hate code that works in the common case but that have drawbacks in the corner case. It would be better if I wouldn't know what the current code is doing, then I could accept it more easily. Andrea -- 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/