linux-kernel - Re: [PATCH] mm/memory_hotplug: quieting offline operation

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Message-ID: <f6454d1d-cdc4-bacb-bd9b-12e1baf6ceba@linux.ibm.com>
Date:   Mon, 14 Dec 2020 10:30:15 +0100
From:   Laurent Dufour <ldufour@...ux.ibm.com>
To:     Souptick Joarder <jrdr.linux@...il.com>
Cc:     Linux-MM <linux-mm@...ck.org>, linux-kernel@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        nathanl@...ux.ibm.com, cheloha@...ux.ibm.com
Subject: Re: [PATCH] mm/memory_hotplug: quieting offline operation

Le 12/12/2020 à 16:04, Souptick Joarder a écrit :
> On Fri, Dec 11, 2020 at 8:32 PM Laurent Dufour <ldufour@...ux.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@...ux.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
>>
>>