[PATCH] powerpc/powernv/memtrace: Fake non-memblock aligned sized traces

[Jordan Niethe]

On Mon, Nov 16, 2020 at 11:02 PM Michael Ellerman <mpe at ellerman.id.au> wrote:
>
> Jordan Niethe <jniethe5 at gmail.com> writes:
> > The hardware trace macros which use the memory provided by memtrace are
> > able to use trace sizes as small as 16MB. Only memblock aligned values
> > can be removed from each NUMA node by writing that value to
> > memtrace/enable in debugfs.  This means setting up, say, a 16MB trace is
> > not possible.  To allow such a trace size, instead align whatever value
> > is written to memtrace/enable to the memblock size for the purpose of
> > removing it from each NUMA node but report the written value from
> > memtrace/enable and memtrace/x/size in debugfs.
>
> Why does it matter if the size that's removed is larger than the size
> that was requested?
>
> Is it about constraining the size of the trace? If so that seems like it
> should be the job of the tracing tools, not the kernel.
Yeah about constraining the size, I'll just do it in the trace tools.
>
> cheers