From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id A6669B7B68 for ; Wed, 23 Sep 2009 07:08:32 +1000 (EST) Subject: Re: powerpc: Move 64bit heap above 1TB on machines with 1TB segments From: Benjamin Herrenschmidt To: Mel Gorman In-Reply-To: References: <20090922025235.GD31801@kryten> Content-Type: text/plain Date: Wed, 23 Sep 2009 07:08:22 +1000 Message-Id: <1253653702.7103.244.camel@pasglop> Mime-Version: 1.0 Cc: linuxppc-dev@lists.ozlabs.org, Anton Blanchard List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > Unfortunately, I am not sensitive to issues surrounding 1TB segments or how > they are currently being used. However, as this clearly helps performance > for large amounts of memory, is it worth providing an option to > libhugetlbfs to locate 16MB pages above 1TB when they are otherwise being > unused? AFAIK, that is already the case, at least the kernel will hand out pages above 1T preferentially iirc. There were talks about making huge pages below 1T not even come up untily you ask for them with MAP_FIXED, dunno where that went. Cheers, Ben.