From: Heiko Carstens <hca@linux.ibm.com>
To: David Hildenbrand <david@redhat.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 16:21:49 +0200 [thread overview]
Message-ID: <20250521142149.11483C95-hca@linux.ibm.com> (raw)
In-Reply-To: <496e6707-bdc9-4ad2-88e2-51236549b5f2@redhat.com>
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. So more than 1GB for
memmap plus pages tables, etc would be required.
next prev parent reply other threads:[~2025-05-21 14:22 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 (de)configuration of memory 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 [this message]
2025-05-21 14:25 ` David Hildenbrand
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20250521142149.11483C95-hca@linux.ibm.com \
--to=hca@linux.ibm.com \
--cc=agordeev@linux.ibm.com \
--cc=akpm@linux-foundation.org \
--cc=david@redhat.com \
--cc=gerald.schaefer@linux.ibm.com \
--cc=gor@linux.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-s390@vger.kernel.org \
--cc=osalvador@suse.de \
--cc=sumanthk@linux.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox