Re: [PATCH] trace/ftrace: move snprintf+write from tracepoints to ftrace.c

["Daniel P. Berrangé" <berrange@redhat.com>]

On Fri, Aug 08, 2025 at 11:11:10AM +0200, Paolo Bonzini wrote:
> This simplifies the Python code and reduces the size of the tracepoints.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  tests/tracetool/ftrace.h            | 26 ++++----------------------
>  trace/ftrace.h                      |  1 +
>  trace/ftrace.c                      | 13 +++++++++++++
>  scripts/tracetool/backend/ftrace.py | 13 ++-----------
>  4 files changed, 20 insertions(+), 33 deletions(-)


> diff --git a/trace/ftrace.c b/trace/ftrace.c
> index 9749543d9b2..1d7e1ee6f6d 100644
> --- a/trace/ftrace.c
> +++ b/trace/ftrace.c
> @@ -38,6 +38,19 @@ static int find_mount(char *mount_point, const char *fstype)
>      return ret;
>  }
>  
> +void ftrace_write(const char *fmt, ...)
> +{
> +    char ftrace_buf[MAX_TRACE_STRLEN];
> +    int unused __attribute__ ((unused));
> +    int trlen;
> +    va_list ap;
> +
> +    va_start(ap, fmt);
> +    trlen = vsnprintf(ftrace_buf, MAX_TRACE_STRLEN, fmt, ap);

va_end(ap);

> +    trlen = MIN(trlen, MAX_TRACE_STRLEN - 1);
> +    unused = write(trace_marker_fd, ftrace_buf, trlen);
> +}
> +
>  bool ftrace_init(void)
>  {
>      char mount_point[PATH_MAX];

With regards,
Daniel
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