Re: [PATCH 05/15] xen: make it possible to disable tracing in Kconfig.

From: "Jan Beulich" <JBeulich@suse.com>
To: Dario Faggioli <dario.faggioli@citrix.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
	Wei Liu <wei.liu2@citrix.com>,
	George Dunlap <George.Dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Ian Jackson <ian.jackson@eu.citrix.com>,
	Julien Grall <julien.grall@arm.com>,
	xen-devel@lists.xenproject.org,
	Doug Goldstein <cardoe@cardoe.com>
Subject: Re: [PATCH 05/15] xen: make it possible to disable tracing in Kconfig.
Date: Wed, 07 Jun 2017 09:14:16 -0600	[thread overview]
Message-ID: <5938346802000078001607F5@prv-mh.provo.novell.com> (raw)
In-Reply-To: <149633844944.12814.3257610267149025065.stgit@Solace.fritz.box>

>>> On 01.06.17 at 19:34, <dario.faggioli@citrix.com> wrote:
> --- a/xen/Kconfig.debug
> +++ b/xen/Kconfig.debug
> @@ -98,6 +98,14 @@ config PERF_ARRAYS
>  	---help---
>  	  Enables software performance counter array histograms.
>  
> +config TRACING
> +	bool "Tracing"
> +	default y

default DEBUG (you don't want to suggest turning it on for a
release build)

> --- a/xen/common/trace.c
> +++ b/xen/common/trace.c
> @@ -48,6 +48,11 @@ static unsigned int opt_tevt_mask;
>  integer_param("tbuf_size", opt_tbuf_size);
>  integer_param("tevt_mask", opt_tevt_mask);
>  
> +#ifdef CONFIG_TRACING
> +/* a flag recording whether initialization has been done */
> +/* or more properly, if the tbuf subsystem is enabled right now */
> +int tb_init_done __read_mostly;

Switch to bool at once? And in any event correct the comment
style please.

> --- a/xen/drivers/cpufreq/utility.c
> +++ b/xen/drivers/cpufreq/utility.c
> @@ -362,11 +362,14 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
>  
>      if (cpu_online(policy->cpu) && cpufreq_driver->target)
>      {
> -        unsigned int prev_freq = policy->cur;
> +        uint32_t d[2] = { policy->cur, 0 };

Notwithstanding Andrew's question about the placement of this
hunk the ", 0" seems pointless to me.

> @@ -33,6 +37,7 @@ void init_trace_bufs(void);
>  /* used to retrieve the physical address of the trace buffers */
>  int tb_control(struct xen_sysctl_tbuf_op *tbc);
>  
> +#ifdef CONFIG_TRACING
>  int trace_will_trace_event(u32 event);

Please have a blank line between these, two of them around the
matching #else, and one ahead of the #endif.

Jan

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