On 19.06.2014 13:14, Daniel P. Berrange wrote:
> On Thu, Jun 19, 2014 at 12:06:44PM +0100, Daniel P. Berrange wrote:
>> On Mon, Jun 16, 2014 at 05:08:26PM +0200, Michal Privoznik wrote:
>>> +int
>>> +virNumaGetPageInfo(int node,
>>> + unsigned int page_size,
>>> + unsigned int *page_avail,
>>> + unsigned int *page_free)
>>> +{
>>> + int ret = -1;
>>> + long system_page_size = sysconf(_SC_PAGESIZE);
>>> +
>>> + /* sysconf() returns page size in bytes,
>>> + * the @page_size is however in kibibytes */
>>> + if (page_size == system_page_size / 1024) {
>>> + unsigned long long memsize, memfree;
>>> +
>>> + /* TODO: come up with better algorithm that takes huge pages into
>>> + * account. The problem is huge pages cut off regular memory. */
>>
>> Hmm, so this code is returning normal page count that ignores the fact
>> that some pages are not in fact usable because they've been stolen for
>> huge pages ? I was thinking that the total memory reported by the kernel
>> was reduced when you allocated huage pages, but testing now, it seems I
>> was mistaken in that belief. So this is a bit of a nasty gotcha because
>> a user of this API would probably expect that the sum of page size *
>> page count for all page sizes would equal total physical RAM (give or
>> take).
>>
>> I still like the idea of including the default page size in this info,
>> but perhaps we should disable the default system page size for now &
>> revisit later if we can figure out a way to accurately report it,
>> rather than reporting misleading info.
>
> I should have said, ACK to either #ifdef 0 system page size or ACK to
> your previous version of this patch, unless someone has better ideas
> to accurately report total + free info for default page sizes.
>
> Regards,
> Daniel
>
Okay, I'm squashing this in prior to pushing:
diff --git a/src/util/virnuma.c b/src/util/virnuma.c
index a59feca..c8e7f40 100644
--- a/src/util/virnuma.c
+++ b/src/util/virnuma.c
@@ -663,6 +663,7 @@ 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
@@ -680,6 +681,11 @@ virNumaGetPageInfo(int node,
if (page_free)
*page_free = memfree / system_page_size;
+#else
+ virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
+ _("system page size are not supported yet"));
+ goto cleanup;
+#endif /* 0 */
} else {
if (virNumaGetHugePageInfo(node, page_size, page_avail, page_free) < 0)
goto cleanup;
@@ -727,6 +733,10 @@ virNumaGetPages(int node,
unsigned int ntmp = 0;
size_t i;
bool exchange;
+
+#if 0
+ /* This has to be disabled until the time the issue in
+ * virNumaGetPageInfo is resolved. Sorry. */
long system_page_size;
/* sysconf() returns page size in bytes,
@@ -745,6 +755,7 @@ virNumaGetPages(int node,
goto cleanup;
tmp_size[ntmp] = system_page_size;
ntmp++;
+#endif /* 0 */
/* Now that we got ordinary system pages, lets get info on huge pages */
if (virNumaGetHugePageInfoPath(&path, node, 0, NULL) < 0)
Hopefully I'll come up with resolution soon.
Michal
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