Re: [PATCH 2/6] tracing: increase size of number of possible events

From: Ingo Molnar
Date: Fri Apr 24 2009 - 03:13:23 EST



* Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> From: Steven Rostedt <srostedt@xxxxxxxxxx>
>
> With the new event tracing registration, we must increase the number
> of events that can be registered. Currently the type field is only
> one byte, which leaves us only 256 possible events.
>
> Since we do not save the CPU number in the tracer anymore (it is determined
> by the per cpu ring buffer that is used) we have an extra byte to use.
>
> This patch increases the size of type from 1 byte (256 events) to
> 2 bytes (65,536 events).
>
> It also adds a WARN_ON_ONCE if we exceed that limit.
>
> [ Impact: allow more than 255 events ]

> - int type;
> + unsigned short type;

Hm, the changelog is not valid anymore - as here we really cut it
down from 4 billion to 64K, right?

Ingo
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