From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH DOCDAY] xen: write a high level description of the sub-arch choices for heap layout Date: Wed, 30 Sep 2015 12:29:33 +0100 Message-ID: <560BC79D.9020103@citrix.com> References: <1443608566-8382-1-git-send-email-ian.campbell@citrix.com> <560BC30E.4050507@citrix.com> <1443612510.16718.188.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1443612510.16718.188.camel@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, jbeulich@suse.com List-Id: xen-devel@lists.xenproject.org On 30/09/15 12:28, Ian Campbell wrote: > On Wed, 2015-09-30 at 12:10 +0100, Andrew Cooper wrote: >> + * >>> + * CONFIG_SEPARATE_XENHEAP=n W/ ONLY DIRECT MAP OF ONLY PARTIAL RAM >>> + * >>> + * There is a single heap, but only the beginning (up to some >>> + * threshold) is covered by a permanent contiguous mapping. >> Perhaps avoid the use of "beginning" here? It is just an implementation >> detail of the only current example. > It's an implementation detail which is currently exposed to the arch code > via the need to use xenheap_max_mfn() (or not) and the shape of that API > though. > >> In some copious free time, I want to see about striding the x86 >> directmap across NUMA nodes (to allow NUMA-local xenheap allocations >> even on large boxes), at which point it won't be linear from the start. > In which case this bit of doc would need some adjustments over and above > avoiding the work beginning I think, at least to adjust to the replacement > for xenheap_max_mfn(). True in both cases, in which case the original wording in fine. ~Andrew