From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: [PATCH v2 2/4] sysctl: Make XEN_SYSCTL_topologyinfo sysctl a little more efficient Date: Wed, 07 Jan 2015 15:09:38 +0000 Message-ID: <54AD5A4202000078000525BE@mail.emea.novell.com> References: <1420510737-22813-1-git-send-email-boris.ostrovsky@oracle.com> <1420510737-22813-3-git-send-email-boris.ostrovsky@oracle.com> <54ABE613.2090608@citrix.com> <54AD06960200007800052294@mail.emea.novell.com> <54AD467A.5020001@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <54AD467A.5020001@oracle.com> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Andrew Cooper , Boris Ostrovsky Cc: wei.liu2@citrix.com, ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com, dario.faggioli@citrix.com, ian.jackson@eu.citrix.com, xen-devel@lists.xen.org, ufimtseva@gmail.com, keir@xen.org List-Id: xen-devel@lists.xenproject.org >>> On 07.01.15 at 15:45, wrote: > On 01/07/2015 04:12 AM, Jan Beulich wrote: >>>>> On 06.01.15 at 14:41, wrote: >>> On 06/01/15 02:18, Boris Ostrovsky wrote: >>>> Instead of copying data for each field in xen_sysctl_topologyinfo separately >>>> put cpu/socket/node into a single structure and do a single copy for each >>>> processor. >>>> >>>> There is also no need to copy whole op to user at the end, max_cpu_index is >>>> sufficient >>>> >>>> Rename xen_sysctl_topologyinfo and XEN_SYSCTL_topologyinfo to reflect the > fact >>>> that these are used for CPU topology. Subsequent patch will add support for >>>> PCI topology sysctl. >>>> >>>> Signed-off-by: Boris Ostrovsky >>> If we are going to change the hypercall, then can we see about making it >>> a stable interface (i.e. not a sysctl/domctl)? There are non-toolstack >>> components which might want/need access to this information. (i.e. I am >>> still looking for a reasonable way to get this information from Xen in >>> hwloc) >> In which case leaving the sysctl alone and just adding a new non-sysctl >> interface should be considered. > > I'd expect IO NUMA information to be used together with CPU topology > information so I am not sure how useful this would be. Unless we create > a similar interface for that (CPU/memory) as well. Creating a new CPU topology interface while leaving alone the current sysctl was what I meant to suggest. The I/O topology one would then become a sibling to the CPU one. Jan