From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 18 Aug 2005 02:35:49 +0200 From: Andi Kleen Subject: Re: [PATCH 0/4] Demand faunting for huge pages Message-ID: <20050818003548.GV3996@wotan.suse.de> References: <1124304966.3139.37.camel@localhost.localdomain> <20050817210431.GR3996@wotan.suse.de> <20050818003302.GE7103@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050818003302.GE7103@localhost.localdomain> Sender: owner-linux-mm@kvack.org Return-Path: To: David Gibson Cc: Andi Kleen , Adam Litke , linux-mm@kvack.org, christoph@lameter.com, kenneth.w.chen@intel.com List-ID: On Thu, Aug 18, 2005 at 10:33:02AM +1000, David Gibson wrote: > On Wed, Aug 17, 2005 at 11:04:32PM +0200, Andi Kleen wrote: > > > > What about the overcommit issue Ken noted? It needs to be solved > > in some way at least, either with the full check or the lazy simple > > check. > > Hrm... I'm not 100% convinced that just allowing overcommit isn't the > right thing to do. Overcommit has some unfortunate consequences, but > the semantics are clearly defined and trivial to implement. I disagree. With Linux's primitive hugepage allocation scheme (static pool that is usually too small) at least simple overcommit check is absolutely essential. > Strict accounting leads to nicer behaviour in some cases - you'll tend > to die early rather than late - but it seems an awful lot of work for > a fairly small improvement in behaviour. Strict is a lot of work, but a simple "right in 99% of all cases, but racy" check is quite easy. -Andi -- 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