linux-kernel - Re: [PATCH 3/3] PM / timekeeping: Print debug messages when requested

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Message-ID: <3695232.IvXvX1Tf0z@aspire.rjw.lan>
Date:   Thu, 20 Jul 2017 23:52:55 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux PM <linux-pm@...r.kernel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 3/3] PM / timekeeping: Print debug messages when requested

On Wednesday, July 19, 2017 02:42:43 AM Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> The messages printed by tk_debug_account_sleep_time() are basically
> useful for system sleep debugging, so print them only when the other
> debug messages from the core suspend/hibernate code are enabled.
> 
> While at it, make it clear that the messages from
> tk_debug_account_sleep_time() are about timekeeping suspend
> duration, because in general timekeeping may be suspeded and
> resumed for multiple times during one system suspend-resume cycle.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Any complaints or issues here?

If not, I'm going to queue it up for 4.14.

> ---
>  include/linux/suspend.h         |   10 ++++++++--
>  kernel/power/main.c             |   10 +++++++---
>  kernel/time/timekeeping_debug.c |    5 +++--
>  3 files changed, 18 insertions(+), 7 deletions(-)
> 
> Index: linux-pm/include/linux/suspend.h
> ===================================================================
> --- linux-pm.orig/include/linux/suspend.h
> +++ linux-pm/include/linux/suspend.h
> @@ -491,16 +491,22 @@ static inline void unlock_system_sleep(v
>  
>  #ifdef CONFIG_PM_SLEEP_DEBUG
>  extern bool pm_print_times_enabled;
> -extern __printf(1, 2) void pm_pr_dbg(const char *fmt, ...);
> +extern __printf(2, 3) void __pm_pr_dbg(bool defer, const char *fmt, ...);
>  #else
>  #define pm_print_times_enabled	(false)
>  
>  #include <linux/printk.h>
>  
> -#define pm_pr_dbg(fmt, ...) \
> +#define pm_pr_dbg(defer, fmt, ...) \
>  	no_printk(KERN_DEBUG fmt, ##__VA_ARGS__)
>  #endif
>  
> +#define pm_pr_dbg(fmt, ...) \
> +	__pm_pr_dbg(false, fmt, ##__VA_ARGS__)
> +
> +#define pm_deferred_pr_dbg(fmt, ...) \
> +	__pm_pr_dbg(true, fmt, ##__VA_ARGS__)
> +
>  #ifdef CONFIG_PM_AUTOSLEEP
>  
>  /* kernel/power/autosleep.c */
> Index: linux-pm/kernel/power/main.c
> ===================================================================
> --- linux-pm.orig/kernel/power/main.c
> +++ linux-pm/kernel/power/main.c
> @@ -388,13 +388,14 @@ static ssize_t pm_debug_messages_store(s
>  power_attr(pm_debug_messages);
>  
>  /**
> - * pm_pr_dbg - Print a suspend debug message to the kernel log.
> + * __pm_pr_dbg - Print a suspend debug message to the kernel log.
> + * @defer: Whether or not to use printk_deferred() to print the message.
>   * @fmt: Message format.
>   *
>   * The message will be emitted if enabled through the pm_debug_messages
>   * sysfs attribute.
>   */
> -void pm_pr_dbg(const char *fmt, ...)
> +void __pm_pr_dbg(bool defer, const char *fmt, ...)
>  {
>  	struct va_format vaf;
>  	va_list args;
> @@ -407,7 +408,10 @@ void pm_pr_dbg(const char *fmt, ...
>  	vaf.fmt = fmt;
>  	vaf.va = &args;
>  
> -	printk(KERN_DEBUG "PM: %pV", &vaf);
> +	if (defer)
> +		printk_deferred(KERN_DEBUG "PM: %pV", &vaf);
> +	else
> +		printk(KERN_DEBUG "PM: %pV", &vaf);
>  
>  	va_end(args);
>  }
> Index: linux-pm/kernel/time/timekeeping_debug.c
> ===================================================================
> --- linux-pm.orig/kernel/time/timekeeping_debug.c
> +++ linux-pm/kernel/time/timekeeping_debug.c
> @@ -19,6 +19,7 @@
>  #include <linux/init.h>
>  #include <linux/kernel.h>
>  #include <linux/seq_file.h>
> +#include <linux/suspend.h>
>  #include <linux/time.h>
>  
>  #include "timekeeping_internal.h"
> @@ -75,7 +76,7 @@ void tk_debug_account_sleep_time(struct
>  	int bin = min(fls(t->tv_sec), NUM_BINS-1);
>  
>  	sleep_time_bin[bin]++;
> -	printk_deferred(KERN_INFO "Suspended for %lld.%03lu seconds\n",
> -			(s64)t->tv_sec, t->tv_nsec / NSEC_PER_MSEC);
> +	pm_deferred_pr_dbg("Timekeeping suspended for %lld.%03lu seconds\n",
> +			   (s64)t->tv_sec, t->tv_nsec / NSEC_PER_MSEC);
>  }
>  
>