On 06/23/2014 03:59 PM, Michal Privoznik wrote:
> On the Linux kernel, if huge pages are allocated the size they cut off
> from memory is accounted under the 'MemUsed' in the meminfo file.
> However, we want the sum to be subtracted from 'MemTotal'. This patch
> implements this feature. After this change, we can enable reporting
> of the ordinary system pages in the capability XML:
>
> <capabilities>
>
> <host>
> <uuid>01281cda-f352-cb11-a9db-e905fe22010c</uuid>
> <cpu>
> <arch>x86_64</arch>
> <model>Haswell</model>
> <vendor>Intel</vendor>
> <topology sockets='1' cores='1' threads='1'/>
> <feature/>
> <pages unit='KiB' size='4'/>
> <pages unit='KiB' size='2048'/>
> <pages unit='KiB' size='1048576'/>
> </cpu>
> <power_management/>
> <migration_features/>
> <topology>
> <cells num='4'>
> <cell id='0'>
> <memory unit='KiB'>4048248</memory>
> <pages unit='KiB' size='4'>748382</pages>
> <pages unit='KiB' size='2048'>3</pages>
> <pages unit='KiB' size='1048576'>1</pages>
> <distances/>
> <cpus num='1'>
> <cpu id='0' socket_id='0' core_id='0' siblings='0'/>
> </cpus>
> </cell>
> ...
> </cells>
> </topology>
> </host>
> </capabilities>
>
> You can see the beautiful thing about this: if you sum up all the
> <pages/> you'll get <memory/>.
>
> Signed-off-by: Michal Privoznik <mprivozn@xxxxxxxxxx>
> ---
> src/nodeinfo.c | 2 +-
> src/util/virnuma.c | 65 +++++++++++++++++++++++++++++++-----------------------
> src/util/virnuma.h | 1 +
> 3 files changed, 39 insertions(+), 29 deletions(-)
>
> @@ -647,6 +649,13 @@ virNumaGetHugePageInfo(int node,
> * total number of pages in the pool (both free and taken)
> * and count for free pages in the pool.
> *
> + * The @huge_page_sum parameter exists there due to the Linux
s/there//
> + * kernel limitation. The problem is, if there are some huge
> + * pages allocated, they are accounted under the 'MemUsed' field
> + * in the meminfo file instead of being subtracted from the
> + * 'MemTotal'. We must do the subtraction ourselves.
> + * If unsure, pass 0.
> + *
> * If you're interested in just one bit, pass NULL to the other one.
> *
> * As a special case, if @node == -1, overall info is fetched
> @@ -657,6 +666,7 @@ virNumaGetHugePageInfo(int node,
> int
> virNumaGetPageInfo(int node,
> unsigned int page_size,
> + unsigned long long huge_page_sum,
> unsigned int *page_avail,
> unsigned int *page_free)
> {
> @@ -666,7 +676,6 @@ virNumaGetPageInfo(int node,
> /* sysconf() returns page size in bytes,
> * the @page_size is however in kibibytes */
> if (page_size == system_page_size / 1024) {
> -# if 0
> unsigned long long memsize, memfree;
>
> /* TODO: come up with better algorithm that takes huge pages into
> @@ -679,16 +688,14 @@ virNumaGetPageInfo(int node,
> goto cleanup;
> }
>
> + /* see description above */
I think you can just move the comment above here.
> + memsize -= huge_page_sum;
> +
> if (page_avail)
> *page_avail = memsize / system_page_size;
>
> if (page_free)
> *page_free = memfree / system_page_size;
ACK
Jan
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