# Re: \[PATCH v2 2/2\] mm: Remove tlb\_flush\_reason::NR\_TLB\_FLUSH\_REASONS

- From: Mathieu Desnoyers \<mathieu.desnoyers@efficios.com\>
- Date: 2025-12-15 13:36:03 
- List: linux-trace-kernel
- Page: https://ratatoskr.run/linux-trace-kernel/2025/12/3333693
- Thread: https://ratatoskr.run/linux-trace-kernel/2025/12/3331665/t.md

```text
On 2025-12-15 07:40, Lorenzo Stoakes wrote:
> On Fri, Dec 12, 2025 at 04:08:08AM -0500, Tal Zussman wrote:
>> This has been unused since it was added 11 years ago in commit
>> d17d8f9dedb9 ("x86/mm: Add tracepoints for TLB flushes").
>>
>> Acked-by: David Hildenbrand <redacted>
>> Reviewed-by: Rik van Riel <riel@surriel.com>
>> Signed-off-by: Tal Zussman <redacted>
>
> Hmm, guess just a way of counting the number of reasons, but if nobody's using
> it that's silly. So:

If TRACE_DEFINE_ENUM was implemented differently [1,2], then we could use
NR_TLB_FLUSH_REASONS in a static assert to validate that the number of
exported enum labels matches the enum tlb_flush_reason.

This would catch this kind of discrepancy at compile-time.

Thanks,

Mathieu

[1] https://github.com/lttng/lttng-modules/blob/master/include/instrumentation/events/sched.h#L132
[2] https://github.com/lttng/lttng-modules/blob/master/include/lttng/tracepoint-event-impl.h#L176

>
-- 
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com
```