[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [PATCH v4 3/9] sysctl: Make XEN_SYSCTL_topologyinfo sysctl a little more efficient



On 03/11/2015 07:04 AM, Ian Campbell wrote:
On Mon, 2015-03-09 at 22:27 -0400, 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.

Do not use max_cpu_index, which is almost always used for calculating number
CPUs (thus requiring adding or subtracting one), replace it with num_cpus.

There is no need to copy whole op in sysctl to user at the end, we only need
num_cpus.

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.

Replace INVALID_TOPOLOGY_ID with "XEN_"-prefixed macros for each invalid type
(core, socket, node).

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
---

Changes in v4:
* Split v3's patch into two --- one for CPU topology and one for NUMA info
I think this means this is now back to how v2 looked, in which case you
may feel free to reinstate my ack. I only glanced through this version
but it looks ok. Let me know if it is actually different to v2 and I'll
have a closer look.


Yes, this is close to v2. The differences are that we are now sizing everything with max number of CPUs vs max CPU index (so a review for off-by-one errors would be useful) plus new INVALID macros that resulted in some (fairly minor) changes.

However, Andrew asked for more changes in sysctl implementation that may affect the interface (for both this and NUMA patches) so it's probably better to wait until v5.


-boris

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.