Re: [PATCH v4 2/2] perf symbol: Lazily compute idle and use the perf_env

[Namhyung Kim]

On Thu, Mar 26, 2026 at 09:50:25PM -0700, Ian Rogers wrote:
> Move the idle boolean to a helper symbol__is_idle function. In the
> function lazily compute whether a symbol is an idle function taking
> into consideration the kernel version and architecture of the
> machine. As symbols__insert no longer needs to know if a symbol is for
> the kernel, remove the argument.
> 
> This change is inspired by mailing list discussion, particularly from
> Thomas Richter <tmricht@xxxxxxxxxxxxx> and Heiko Carstens
> <hca@xxxxxxxxxxxxx>:
> https://lore.kernel.org/lkml/20260219113850.354271-1-tmricht@xxxxxxxxxxxxx/
> 
> The change switches x86 matches to use strstarts which means
> intel_idle_irq is matched as part of strstarts(name, "intel_idle"), a
> change suggested by Honglei Wang <jameshongleiwang@xxxxxxx> in:
> https://lore.kernel.org/lkml/20260323085255.98173-1-jameshongleiwang@xxxxxxx/
> 
> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> ---
[SNIP]
> +	if (e_machine == EM_S390 && strstarts(name, "psw_idle")) {
> +		int major = 0, minor = 0;
> +		const char *release = env && env->os_release
> +			? env->os_release : perf_version_string;

I think Sashiko's review is right.  You need to check the kernel version
instead of perf.

Thanks,
Namhyung

> +
> +		/* Before v6.10, s390 used psw_idle. */
> +		if (sscanf(release, "%d.%d", &major, &minor) != 2 ||
> +		    major < 6 || (major == 6 && minor < 10)) {
> +			sym->idle = SYMBOL_IDLE__IDLE;
> +			return true;
> +		}
> +	}
> +
> +	sym->idle = SYMBOL_IDLE__NOT_IDLE;
> +	return false;
>  }