From: David Hildenbrand <david@redhat.com>
To: Heiko Carstens <hca@linux.ibm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>,
linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Oscar Salvador <osalvador@suse.de>,
Gerald Schaefer <gerald.schaefer@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
linux-s390 <linux-s390@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH 1/4] mm/memory_hotplug: Add interface for runtime (de)configuration of memory
Date: Wed, 21 May 2025 16:25:32 +0200 [thread overview]
Message-ID: <63967c9a-0ae7-42c1-9a2e-31213ad1fa90@redhat.com> (raw)
In-Reply-To: <20250521142149.11483C95-hca@linux.ibm.com>
On 21.05.25 16:21, Heiko Carstens wrote:
> On Wed, May 21, 2025 at 02:33:42PM +0200, David Hildenbrand wrote:
>> On 21.05.25 12:34, Sumanth Korikkar wrote:
>>> As you pointed out, how about having something similar to
>>> 73954d379efd ("dax: add a sysfs knob to control memmap_on_memory behavior")
>>
>> Right. But here, the use case is usually (a) to add a gigantic amount of
>> memory using add_memory(), not small blocks like on s390x (b) consume the
>> memmap from (slow) special-purpose memory as well.
>>
>> Regarding (a), the memmap could be so big that add_memory() might never
>> really work (not just because of some temporary low-memory situation).
>
> What is "big"? Worst case for s390 with existing machines would be an
> increment size (aka memory block size) of 64GB.
Oh! I was assuming the increment size would always be around 256MiB or so.
In that case, it can make sense to have this, yes!
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2025-05-21 14:25 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-02 8:27 [RFC PATCH 0/4] Support dynamic " Sumanth Korikkar
2024-12-02 8:27 ` [RFC PATCH 1/4] mm/memory_hotplug: Add interface for runtime " Sumanth Korikkar
2024-12-02 16:55 ` David Hildenbrand
2024-12-03 14:33 ` Sumanth Korikkar
2024-12-20 15:53 ` David Hildenbrand
2025-05-20 13:06 ` Sumanth Korikkar
2025-05-20 17:55 ` David Hildenbrand
2025-05-21 10:34 ` Sumanth Korikkar
2025-05-21 12:33 ` David Hildenbrand
2025-05-21 14:21 ` Heiko Carstens
2025-05-21 14:25 ` David Hildenbrand [this message]
2025-05-21 14:24 ` Sumanth Korikkar
2024-12-02 8:27 ` [RFC PATCH 2/4] mm/memory_hotplug: Add memory block altmap sysfs attribute Sumanth Korikkar
2024-12-02 8:27 ` [RFC PATCH 3/4] mm/memory_hotplug: Add max_configurable sysfs read attribute Sumanth Korikkar
2024-12-02 8:27 ` [RFC PATCH 4/4] s390/sclp: Add support for dynamic (de)configuration of memory Sumanth Korikkar
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