Re: [RFC] mm/migration: Add trace events for THP migrations

[Matthew Wilcox]

On Fri, Dec 24, 2021 at 12:16:38PM +0530, Anshuman Khandual wrote:
> This adds two trace events for PMD based THP migration without split. These
> events closely follow the implementation details like setting and removing
> of PMD migration entries, which are essential operations for THP migration.

Why are you printing the address of a struct page?  What useful
information does this supply?  Same question for the struct mm.
And the pmdp, for that matter.

You haven't said _why_ you want these tracepoints.  So it's impossible
to suggest what you _should_ be doing, because what you _are_ doing
is obviously wrong.

> +	TP_printk("mm=%p, address=%lx, pmdp=%p, page=%p pmdval=%lx",
> +		__entry->mm,
> +		__entry->address,
> +		__entry->pmdp,
> +		__entry->page,
> +		__entry->pmdval)
> +);