Messages in this thread | | | Subject | Re: [PATCH] mm/vmstat: Add events for PMD based THP migration without split | From | John Hubbard <> | Date | Mon, 1 Jun 2020 21:48:09 -0700 |
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On 2020-06-01 21:20, Anshuman Khandual wrote: ... >> also important: maybe this patch should also be tracking other causes >> of THP PMD migration failure, in order to get a truer accounting of the >> situation.
I hope one of the experts here can weigh in on that...
> Is there any other failure reasons which are only specific to THP migration. > Else, adding stats about generic migration failure reasons will just blur > the overall understanding about THP migration successes and failure cases > that results in splitting. >
Thinking about that: we do have PGMIGRATE_SUCCESS and PGMIGRATE_FAIL, so I suppose comparing those numbers with the new THP_PMD_MIGRATION_SUCCESS and THP_PMD_MIGRATION_FAILURE events should cover it.
However, the fact that this is under discussion hints at the need for a bit of documentation help. What do you think about adding some notes about all of this to, say, Documentation/vm/page_migration.rst ?
thanks, -- John Hubbard NVIDIA
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