Re: [PATCH 1/3] balancenuma: add stats for huge pmd numa faults

[Hillf Danton]

On 11/24/12, Mel Gorman <mgorman@xxxxxxx> wrote:
> On Sat, Nov 24, 2012 at 12:17:03PM +0800, Hillf Danton wrote:
>> A thp contributes 512 times more than a regular page to numa fault stats,
>> so deserves its own vm event counter. THP migration is also accounted.
>>
>
> I agree and mentioned it needed fixing. I did not create a new counter
> but I properly account for PGMIGRATE_SUCCESS and PGMIGRATE_FAIL now. I
> did not create a new NUMA_PAGE_MIGRATE counter because I didn't feel it
> was necessary. Instead I just do this
>
>         count_vm_events(PGMIGRATE_SUCCESS, HPAGE_PMD_NR);
>
It could be read as: 512 pages are successfully migrated(though at the
cost of actually one page).

>         count_vm_numa_events(NUMA_PAGE_MIGRATE, HPAGE_PMD_NR);
>
ditto, 512 pages go through migration(though actually only one page
takes the hard journey).

That said, in short, the new counters are different and clearer.

Hillf
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