[PATCH] mm/memory_hotplug: quieting offline operation

[PATCH] mm/memory_hotplug: quieting offline operation

[Laurent Dufour]

On PowerPC, when dymically removing memory from a system we can see in the console a
lot of messages like this:
[  186.575389] Offlined Pages 4096

This message is displayed on each LMB (256MB) removed, which means that we
removing 1TB of memory, this message is displayed 4096 times.

Moving it to DEBUG to not flood the console.

Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
---
 mm/memory_hotplug.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index b44d4c7ba73b..c47a53a16782 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1587,7 +1587,7 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
 
 	/* Mark all sections offline and remove free pages from the buddy. */
 	__offline_isolated_pages(start_pfn, end_pfn);
-	pr_info("Offlined Pages %ld\n", nr_pages);
+	pr_debug("Offlined Pages %ld\n", nr_pages);
 
 	/*
 	 * The memory sections are marked offline, and the pageblock flags
-- 
2.29.2

Re: [PATCH] mm/memory_hotplug: quieting offline operation

[Souptick Joarder]

On Fri, Dec 11, 2020 at 8:32 PM Laurent Dufour <ldufour@linux.ibm.com> wrote:
>
> On PowerPC, when dymically removing memory from a system we can see in the console a
> lot of messages like this:
> [  186.575389] Offlined Pages 4096

Is it specific to PowerPC ?

>
> This message is displayed on each LMB (256MB) removed, which means that we
> removing 1TB of memory, this message is displayed 4096 times.
>
> Moving it to DEBUG to not flood the console.
>
> Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
> ---
>  mm/memory_hotplug.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index b44d4c7ba73b..c47a53a16782 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1587,7 +1587,7 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
>
>         /* Mark all sections offline and remove free pages from the buddy. */
>         __offline_isolated_pages(start_pfn, end_pfn);
> -       pr_info("Offlined Pages %ld\n", nr_pages);
> +       pr_debug("Offlined Pages %ld\n", nr_pages);
>
>         /*
>          * The memory sections are marked offline, and the pageblock flags
> --
> 2.29.2
>
>

Re: [PATCH] mm/memory_hotplug: quieting offline operation

[Laurent Dufour]

Le 12/12/2020 à 16:04, Souptick Joarder a écrit :
> On Fri, Dec 11, 2020 at 8:32 PM Laurent Dufour <ldufour@linux.ibm.com> wrote:
>>
>> On PowerPC, when dymically removing memory from a system we can see in the console a
>> lot of messages like this:
>> [  186.575389] Offlined Pages 4096
> 
> Is it specific to PowerPC ?

No, this applies to all architectures, but this is surfacing a bit more on 
PowerPC where the memory block size is set to 256MB currently by the firmware.

> 
>>
>> This message is displayed on each LMB (256MB) removed, which means that we
>> removing 1TB of memory, this message is displayed 4096 times.
>>
>> Moving it to DEBUG to not flood the console.
>>
>> Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
>> ---
>>   mm/memory_hotplug.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index b44d4c7ba73b..c47a53a16782 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -1587,7 +1587,7 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
>>
>>          /* Mark all sections offline and remove free pages from the buddy. */
>>          __offline_isolated_pages(start_pfn, end_pfn);
>> -       pr_info("Offlined Pages %ld\n", nr_pages);
>> +       pr_debug("Offlined Pages %ld\n", nr_pages);
>>
>>          /*
>>           * The memory sections are marked offline, and the pageblock flags
>> --
>> 2.29.2
>>
>>

Re: [PATCH] mm/memory_hotplug: quieting offline operation

[Michal Hocko]

On Fri 11-12-20 16:01:57, Laurent Dufour wrote:
> On PowerPC, when dymically removing memory from a system we can see in the console a
> lot of messages like this:
> [  186.575389] Offlined Pages 4096
> 
> This message is displayed on each LMB (256MB) removed, which means that we
> removing 1TB of memory, this message is displayed 4096 times.
> 
> Moving it to DEBUG to not flood the console.
> 
> Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>

I am wondering whether we should be dropping this altogether. Offlining
is returning an error status to its caller so e.g. userspace can find
out the failure and the error code.

Anyway, feel free to add
Acked-by: Michal Hocko <mhocko@suse.com>

> ---
>  mm/memory_hotplug.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index b44d4c7ba73b..c47a53a16782 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1587,7 +1587,7 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
>  
>  	/* Mark all sections offline and remove free pages from the buddy. */
>  	__offline_isolated_pages(start_pfn, end_pfn);
> -	pr_info("Offlined Pages %ld\n", nr_pages);
> +	pr_debug("Offlined Pages %ld\n", nr_pages);
>  
>  	/*
>  	 * The memory sections are marked offline, and the pageblock flags
> -- 
> 2.29.2

-- 
Michal Hocko
SUSE Labs