Re: [PATCH v4 0/9] perf c2c: add a function view

[Namhyung Kim <namhyung@kernel.org>]

On Thu, Jul 30, 2026 at 05:09:01PM +0800, Jiebin Sun wrote:
> On Tue, Jul 28, 2026 at 11:13:31AM -0700, Namhyung Kim wrote:
> > Thanks for the update, I think it's almost ready to merge.  But can you
> > please address some sashiko review comments?
> 
> Thanks for the review. I went through the sashiko comments and prepared
> v5, rebased onto perf-tools-next at 0d40fedcd1b9. The full change list is
> in the cover letter. The view layout is unchanged, and the changes address
> correctness, robustness, and style, along with some adjustments to which
> entries are retained.
> 
> A few comments did not require code changes:
> 
>   - The ms/thread reference handling is deliberate. Child entries borrow
>     references from the cacheline-side entries, which outlive the function
>     hierarchy. Their custom destructor does not put those references, so
>     adding get() calls would leak them.

Is it possible to add proper refcounts instead of borrowing?  I guess
that'd make the code simpler.

Thanks,
Namhyung

> 
>   - c2c.h directly includes <linux/types.h> and <stdbool.h>, while
>     <linux/compiler.h> is provided through <asm/bug.h> and <linux/list.h>.
> 
>   - The level-3 cacheline address is not truncated. The symbol-column width
>     is expanded to fit the deepest identity cell before the browser is
>     created.
> 
> Tested with and without SLANG support; `perf test c2c` passes, and the
> cacheline `--stdio` output is unchanged from the base commit.
> 
> Thanks,
> Jiebin