Subject: Re: [RESEND,v3] powerpc/pseries: Limit EPOW reset event warnings

From: Vipin K Parashar <[email-masked]>
Date: Tue, 08 Sep 2015 03:10:58 +0530

On 07/17/2015 01:47 PM, Kamalesh Babulal wrote:
> * Michael Ellerman <[email-masked]> [2015-07-16 14:05:52]:
>
> [..]
>> Why are we even getting these reset events when nothing has happened?
> Thanks for the review. It was seen only on one machine, couldn't
> get hold of the machine any more. I am guessing here, that it might be
> the firmware.

Checking with PFW guys  as to under what circumstances one would see
so many reset events being reported ? Will post out findings as soon as i
hear things back from PFW guys on this.

>>> Also, merged adjacent pr_err/pr_emerg into single one to reduce
>>> the number of lines printed per warning.
> [..]
>>>   
>>> +/* Flag to limit EPOW RESET warning. */
>>> +static bool epow_state;
>> This name is terrible, it doesn't give me any hint to what it means.
>>
>> But really it should be a counter, not a boolean.
>>
>> We could have multiple EPOW events come in and then later get the reset events
>> for them, couldn't we?
>>
>>
>> So what about:
>>
>> static unsigned epow_event_depth;
>>
> --->8----
>
>  From 0d27916fd09a9f0912a217432a41e2b579dc2952 Mon Sep 17 00:00:00 2001
> From: Kamalesh Babulal <[email-masked]>
> Date: Fri, 17 Jul 2015 13:19:31 +0530
> Subject: [PATCH v4] powerpc/pseries: Limit EPOW reset event warnings
>
> Kernel prints respective warnings about various EPOW events for
> user information/action after parsing EPOW interrupts. At times
> EPOW reset event warning, such as below could flood kernel log,
> over a period of time.
>
> May 25 03:46:34 alp kernel: Non critical power or cooling issue cleared
> May 25 03:46:52 alp kernel: Non critical power or cooling issue cleared
> May 25 03:53:48 alp kernel: Non critical power or cooling issue cleared
> May 25 03:55:46 alp kernel: Non critical power or cooling issue cleared
> May 25 03:56:34 alp kernel: Non critical power or cooling issue cleared
> May 25 03:59:04 alp kernel: Non critical power or cooling issue cleared
> May 25 04:02:01 alp kernel: Non critical power or cooling issue cleared
> May 25 04:04:24 alp kernel: Non critical power or cooling issue cleared
> May 25 04:07:18 alp kernel: Non critical power or cooling issue cleared
> May 25 04:13:04 alp kernel: Non critical power or cooling issue cleared
> May 25 04:22:04 alp kernel: Non critical power or cooling issue cleared
> May 25 04:22:26 alp kernel: Non critical power or cooling issue cleared
> May 25 04:22:36 alp kernel: Non critical power or cooling issue cleared
>
> This patch avoids these multiple EPOW reset warnings by using epow_depth
> counter. Which is incremented every time EPOW event is reported and
> decremented on EPOW_RESET event. With this approach number EPOW RESET
> warning matches the number of EPOW events.
>
> Also, merged adjacent pr_info/pr_err/pr_emerg into single one to reduce
> the number of lines printed per warning across the file and converted
> non-critical errors to pr_info from pr_error, including grammar
> correction in the warnings printed.
>
> Suggested-by: Michael Ellerman <[email-masked]>
> Cc: Anshuman Khandual <[email-masked]>
> Cc: Anton Blanchard <[email-masked]>
> Cc: Vipin K Parashar <[email-masked]>
> Signed-off-by: Kamalesh Babulal <[email-masked]>
> ---
> V4: Changes:
>     - Changed the approach to depth counter to match the EPOW events and
>       EPOW reset.
>     - Converted pr_err() ot pr_info() for non-critical errors.
>     - Merged adjacent warnings into single line across the file.
>     - Fixed grammar in the warnings to make is short.
>
> v3 Changes:
>     - Limit warning printed by EPOW RESET event, by guarding it with bool flag.
>       Instead of rate limiting all the EPOW events.
>
> v2 Changes:
>     - Merged multiple adjacent pr_err/pr_emerg into single line to reduce multi-line
>       warnings, based on Michael's comments.
>
>   arch/powerpc/platforms/pseries/ras.c | 53 ++++++++++++++++++++----------------
>   1 file changed, 29 insertions(+), 24 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
> index 02e4a17..995cab8 100644
> --- a/arch/powerpc/platforms/pseries/ras.c
> +++ b/arch/powerpc/platforms/pseries/ras.c
> @@ -40,6 +40,8 @@ static int ras_check_exception_token;
>   #define EPOW_SENSOR_TOKEN	9
>   #define EPOW_SENSOR_INDEX	0
>
> +static unsigned epow_event_depth;
> +
>   static irqreturn_t ras_epow_interrupt(int irq, void *dev_id);
>   static irqreturn_t ras_error_interrupt(int irq, void *dev_id);
>
> @@ -82,32 +84,30 @@ static void handle_system_shutdown(char event_modifier)
>   {
>   	switch (event_modifier) {
>   	case EPOW_SHUTDOWN_NORMAL:
> -		pr_emerg("Firmware initiated power off");
> +		pr_emerg("Firmware initiated power off\n");
>   		orderly_poweroff(true);
>   		break;
>
>   	case EPOW_SHUTDOWN_ON_UPS:
> -		pr_emerg("Loss of power reported by firmware, system is "
> -			"running on UPS/battery");
> -		pr_emerg("Check RTAS error log for details");
> +		pr_emerg("Loss of power reported, system is running on"
> +			 " UPS/battery. Check RTAS error log for details\n");
>   		orderly_poweroff(true);
>   		break;
>
>   	case EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS:
> -		pr_emerg("Loss of system critical functions reported by "
> -			"firmware");
> -		pr_emerg("Check RTAS error log for details");
> +		pr_emerg("Loss of system critical functions reported. Check"
> +			 " RTAS error log for details\n");
>   		orderly_poweroff(true);
>   		break;
>
>   	case EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH:
> -		pr_emerg("Ambient temperature too high reported by firmware");
> -		pr_emerg("Check RTAS error log for details");
> +		pr_emerg("Ambient temperature too high reported. Check RTAS"
> +			 " error log for details\n");
>   		orderly_poweroff(true);
>   		break;
>
>   	default:
> -		pr_err("Unknown power/cooling shutdown event (modifier %d)",
> +		pr_info("Unknown power/cooling shutdown event (modifier %d)\n",
>   			event_modifier);
>   	}
>   }
> @@ -145,40 +145,46 @@ static void rtas_parse_epow_errlog(struct rtas_error_log *log)
>
>   	switch (action_code) {
>   	case EPOW_RESET:
> -		pr_err("Non critical power or cooling issue cleared");
> +		if (epow_event_depth) {
> +			pr_err("Non critical power/cooling issue cleared\n");
> +			epow_event_depth--;
> +		}
>   		break;
>
>   	case EPOW_WARN_COOLING:
> -		pr_err("Non critical cooling issue reported by firmware");
> -		pr_err("Check RTAS error log for details");
> +		pr_info("Non-critical cooling issue reported, check RTAS error"
> +			" log for details\n");
> +		epow_event_depth++;
>   		break;
>
>   	case EPOW_WARN_POWER:
> -		pr_err("Non critical power issue reported by firmware");
> -		pr_err("Check RTAS error log for details");
> +		pr_info("Non-critical power issue reported, check RTAS error"
> +			" log for details\n");
> +		epow_event_depth++;
>   		break;
>
>   	case EPOW_SYSTEM_SHUTDOWN:
>   		handle_system_shutdown(epow_log->event_modifier);
> +		epow_event_depth++;
>   		break;
>
>   	case EPOW_SYSTEM_HALT:
> -		pr_emerg("Firmware initiated power off");
> +		pr_emerg("Firmware initiated power off\n");
>   		orderly_poweroff(true);
>   		break;
>
>   	case EPOW_MAIN_ENCLOSURE:
>   	case EPOW_POWER_OFF:
> -		pr_emerg("Critical power/cooling issue reported by firmware");
> -		pr_emerg("Check RTAS error log for details");
> -		pr_emerg("Immediate power off");
> +		pr_emerg("Critical power/cooling issue reported, Check RTAS"
> +			 " error log for details. Immediate power off\n");
>   		emergency_sync();
>   		kernel_power_off();
>   		break;
>
>   	default:
> -		pr_err("Unknown power/cooling event (action code %d)",
> +		pr_info("Unknown power/cooling event (action code %d)\n",
>   			action_code);
> +		epow_event_depth++;
>   	}
>   }
>
> @@ -248,13 +254,12 @@ static irqreturn_t ras_error_interrupt(int irq, void *dev_id)
>   	log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, fatal);
>
>   	if (fatal) {
> -		pr_emerg("Fatal hardware error reported by firmware");
> -		pr_emerg("Check RTAS error log for details");
> -		pr_emerg("Immediate power off");
> +		pr_emerg("Fatal hardware error reported, Check RTAS error"
> +			 " log for details. Immediate power off\n");
>   		emergency_sync();
>   		kernel_power_off();
>   	} else {
> -		pr_err("Recoverable hardware error reported by firmware");
> +		pr_err("Recoverable hardware error reported by firmware\n");
>   	}
>
>   	spin_unlock(&ras_log_buf_lock);