From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 989556B004D for ; Thu, 29 Oct 2009 10:52:32 -0400 (EDT) Received: from localhost (smtp.ultrahosting.com [127.0.0.1]) by smtp.ultrahosting.com (Postfix) with ESMTP id 83A6E82C7D9 for ; Thu, 29 Oct 2009 10:58:31 -0400 (EDT) Received: from smtp.ultrahosting.com ([74.213.174.253]) by localhost (smtp.ultrahosting.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id T48RNKt5ewJe for ; Thu, 29 Oct 2009 10:58:26 -0400 (EDT) Received: from V090114053VZO-1 (unknown [74.213.171.31]) by smtp.ultrahosting.com (Postfix) with ESMTP id 37E4482C77F for ; Thu, 29 Oct 2009 10:58:24 -0400 (EDT) Date: Thu, 29 Oct 2009 14:51:11 -0400 (EDT) From: Christoph Lameter Subject: Re: RFC: Transparent Hugepage support In-Reply-To: <20091027202533.GB2726@sequoia.sous-sol.org> Message-ID: References: <20091026185130.GC4868@random.random> <20091027182109.GA5753@random.random> <20091027202533.GB2726@sequoia.sous-sol.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Chris Wright Cc: Andrea Arcangeli , linux-mm@kvack.org, Marcelo Tosatti , Adam Litke , Avi Kivity , Izik Eidus , Hugh Dickins , Nick Piggin , Andrew Morton List-ID: On Tue, 27 Oct 2009, Chris Wright wrote: > > Yes, swapping is deadly to performance based loads and it should be > > avoided as much as possible, but it's not nice when in order to get a > > boost in guest performance when the host isn't low on memory, you lose > > the ability to swap when the host is low on memory and all VM are > > locked in memory like in inferior-design virtual machines that won't > > ever support paging. When system starts swapping the manager can > > migrate the VM to other hosts with more memory free to restore the > > full RAM performance as soon as possible. Overcommit can be very > > useful at maxing out RAM utilization, just like it happens for regular > > linux tasks (few people runs with overcommit = 2 for this very > > reason.. besides overcommit = 2 includes swap in its equation so you > > can still max out ram by adding more free swap). > > It's also needed if something like glibc were to take advantage of it in > a generic manner. How would glibc do that? -- 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: email@kvack.org