From: David Hildenbrand <david@redhat.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Oscar Salvador <osalvador@suse.de>
Subject: Re: [PATCH v1] drivers/base/node.c: Simplify unregister_memory_block_under_nodes()
Date: Fri, 19 Jul 2019 13:42:07 +0200 [thread overview]
Message-ID: <c203ae99-e47f-a7dd-83f0-93196125db70@redhat.com> (raw)
In-Reply-To: <20190719113647.GS30461@dhcp22.suse.cz>
On 19.07.19 13:36, Michal Hocko wrote:
> On Fri 19-07-19 11:20:43, David Hildenbrand wrote:
>> On 19.07.19 11:13, Michal Hocko wrote:
>>> On Fri 19-07-19 11:05:51, David Hildenbrand wrote:
>>>> On 19.07.19 10:42, Michal Hocko wrote:
>>>>> On Thu 18-07-19 16:22:39, David Hildenbrand wrote:
>>>>>> We don't allow to offline memory block devices that belong to multiple
>>>>>> numa nodes. Therefore, such devices can never get removed. It is
>>>>>> sufficient to process a single node when removing the memory block.
>>>>>>
>>>>>> Remember for each memory block if it belongs to no, a single, or mixed
>>>>>> nodes, so we can use that information to skip unregistering or print a
>>>>>> warning (essentially a safety net to catch BUGs).
>>>>>
>>>>> I do not really like NUMA_NO_NODE - 1 thing. This is yet another invalid
>>>>> node that is magic. Why should we even care? In other words why is this
>>>>> patch an improvement?
>>>>
>>>> Oh, and to answer that part of the question:
>>>>
>>>> We no longer have to iterate over each pfn of a memory block to be removed.
>>>
>>> Is it possible that we are overzealous when unregistering syfs files and
>>> we should simply skip the pfn walk even without this change?
>>>
>>
>> I assume you mean something like v1 without the warning/"NUMA_NO_NODE -1"?
>>
>> See what I have right now below.
>
> Yes. I didn'g get to look closely but you caught the idea. Thanks!
>
Will do a quick test and resent later this day, thanks for having a look!
--
Thanks,
David / dhildenb
prev parent reply other threads:[~2019-07-19 11:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-18 14:22 [PATCH v1] drivers/base/node.c: Simplify unregister_memory_block_under_nodes() David Hildenbrand
2019-07-19 8:14 ` David Hildenbrand
2019-07-19 8:42 ` Michal Hocko
2019-07-19 8:48 ` David Hildenbrand
2019-07-19 9:09 ` Michal Hocko
2019-07-19 9:18 ` David Hildenbrand
2019-07-19 9:05 ` David Hildenbrand
2019-07-19 9:13 ` Michal Hocko
2019-07-19 9:20 ` David Hildenbrand
2019-07-19 11:36 ` Michal Hocko
2019-07-19 11:42 ` David Hildenbrand [this message]
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