From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp07.au.ibm.com (e23smtp07.au.ibm.com [202.81.31.140]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 8DB351A0166 for ; Mon, 1 Feb 2016 19:36:55 +1100 (AEDT) Received: from localhost by e23smtp07.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 1 Feb 2016 18:36:55 +1000 Received: from d23relay09.au.ibm.com (d23relay09.au.ibm.com [9.185.63.181]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 4EA362BB0057 for ; Mon, 1 Feb 2016 19:36:53 +1100 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay09.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u118ajHx41222352 for ; Mon, 1 Feb 2016 19:36:53 +1100 Received: from d23av02.au.ibm.com (localhost [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u118aKvU023318 for ; Mon, 1 Feb 2016 19:36:21 +1100 Message-ID: <56AF18F2.2020401@linux.vnet.ibm.com> Date: Mon, 01 Feb 2016 14:06:02 +0530 From: Anshuman Khandual MIME-Version: 1.0 To: David Gibson , paulus@samba.org, mpe@ellerman.id.au, benh@kernel.crashing.org CC: aik@ozlabs.ru, lvivier@redhat.com, thuth@redhat.com, linuxppc-dev@lists.ozlabs.org Subject: Re: [RFCv2 8/9] pseries: Advertise HPT resizing support via CAS References: <1454045043-25545-1-git-send-email-david@gibson.dropbear.id.au> <1454045043-25545-9-git-send-email-david@gibson.dropbear.id.au> In-Reply-To: <1454045043-25545-9-git-send-email-david@gibson.dropbear.id.au> Content-Type: text/plain; charset=utf-8 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 01/29/2016 10:54 AM, David Gibson wrote: > The hypervisor needs to know a guest is capable of using the HPT resizing > PAPR extension in order to make full advantage of it for memory hotplug. > > If the hypervisor knows the guest is HPT resize aware, it can size the > initial HPT based on the initial guest RAM size, relying on the guest to > resize the HPT when more memory is hot-added. Without this, the hypervisor > must size the HPT for the maximum possible guest RAM, which can lead to > a huge waste of space if the guest never actually expends to that maximum > size. > > This patch advertises the guest's support for HPT resizing via the > ibm,client-architecture-support OF interface. Obviously, the actual > encoding in the CAS vector is tentative until the extension is officially > incorporated into PAPR. For now we use bit 0 of (previously unused) byte 8 > of option vector 5. > > Signed-off-by: David Gibson Reviewed-by: Anshuman Khandual