Re: [PATCH] mm/code_tag: Skip displaying the code_tag if it is not called

[Suren Baghdasaryan <surenb@google.com>]

On Wed, Dec 11, 2024 at 12:56 AM Zhenhua Huang
<quic_zhenhuah@quicinc.com> wrote:
>
> /proc/allocinfo is full of callsites which are not called at all.
> Let's only output if the callsite actually been invoked.

No, I disagree. Allocation that was never invoked is not the same as
no allocation at all. How would we know the difference if we filter
out the empty ones?
If you don't want to see all the unused sites, you can filter them in
the userspace. I also suspect that for practical purposes you would
want to filter small ones (below some threshold) as well.

>
> Signed-off-by: Zhenhua Huang <quic_zhenhuah@quicinc.com>
> ---
>  lib/alloc_tag.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c
> index 35f7560a309a..06fb7eb5c0bc 100644
> --- a/lib/alloc_tag.c
> +++ b/lib/alloc_tag.c
> @@ -95,10 +95,12 @@ static void alloc_tag_to_text(struct seq_buf *out, struct codetag *ct)
>         struct alloc_tag_counters counter = alloc_tag_read(tag);
>         s64 bytes = counter.bytes;
>
> -       seq_buf_printf(out, "%12lli %8llu ", bytes, counter.calls);
> -       codetag_to_text(out, ct);
> -       seq_buf_putc(out, ' ');
> -       seq_buf_putc(out, '\n');
> +       if (bytes || counter.calls) {
> +               seq_buf_printf(out, "%12lli %8llu ", bytes, counter.calls);
> +               codetag_to_text(out, ct);
> +               seq_buf_putc(out, ' ');
> +               seq_buf_putc(out, '\n');
> +       }
>  }
>
>  static int allocinfo_show(struct seq_file *m, void *arg)
> --
> 2.25.1
>