From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH v5 8/8] xen: arm: allocate more than one bank for 1:1 domain 0 if needed Date: Wed, 09 Jul 2014 17:40:39 +0100 Message-ID: <53BD7087.2030800@linaro.org> References: <1404907608.16789.18.camel@kazak.uk.xensource.com> <1404907666-8594-8-git-send-email-ian.campbell@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1404907666-8594-8-git-send-email-ian.campbell@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell , xen-devel@lists.xen.org Cc: tim@xen.org, stefano.stabellini@eu.citrix.com List-Id: xen-devel@lists.xenproject.org Hi Ian, On 07/09/2014 01:07 PM, Ian Campbell wrote: > Depending on where Xen and the initial modules were loaded into RAM we may not > be able to allocate a suitably contiguous block of memory for dom0. Especially > since the allocations made by alloc_domheap_pages are naturally aligned (e.g. a > 1GB allocation must be at a 1GB boundary). > > The alignment requirement in particular is a huge limitation, meaning that even > dom0_mem0=1G on a 2GB system is pretty likely to fail unless you are very > careful with your load addresses. People were also having trouble with dom0 > > 128MB on the 1GB cubieboard2 when using fairly standard load addresses for > things. > > This patch tries to allocate multiple banks of memory in order to try and > satisfy the entire requested domain 0 allocation. Sadly this turns out to be > pretty tricky to arrange (see the large comment in the code). > > Signed-off-by: Ian Campbell Acked-by: Julien Grall Regards, -- Julien Grall