From: David Hildenbrand <david@redhat.com>
To: Mike Kravetz <mike.kravetz@oracle.com>,
Oscar Salvador <osalvador@suse.de>
Cc: mhocko@kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, vbabka@suse.cz, pasha.tatashin@soleen.com
Subject: Re: [RFC PATCH 0/3] Allocate memmap from hotadded memory (per device)
Date: Thu, 29 Oct 2020 08:49:10 +0100 [thread overview]
Message-ID: <cce0ad6f-8078-b486-62ad-b75269fd734e@redhat.com> (raw)
In-Reply-To: <259889fb-f01b-9537-7948-f1a75a372617@oracle.com>
On 28.10.20 19:47, Mike Kravetz wrote:
> On 10/27/20 8:58 AM, Oscar Salvador wrote:
>> On Tue, Oct 27, 2020 at 04:44:33PM +0100, David Hildenbrand wrote:
>>> I'm planning on looking into patch #2/3 later this or next week (this week
>>> is open source summit / KVM Forum).
>>
>> Sure, aprecciated the time ;-)
>>
>>>
>>> One thing to look into right now is how to make this fly this with vmemmap
>>> optimizations for hugetlb pages.
>>>
>>> https://lkml.kernel.org/r/20201026145114.59424-1-songmuchun@bytedance.com
>>
>> I was about to have a look at that series eitherway, but good you mentioned.
>>
>
> More eyes on that series would be appreciated.
>
> That series will dynamically free and allocate memmap pages as hugetlb
> pages are allocated or freed. I haven't looked through this series, but
> my first thought is that we would need to ensure those allocs/frees are
> directed to the device. Not sure if there are interfaces for that.
Directing to the device might be part of the solution, but does not have
to be. You really want to free the pages to the OS in the end, otherwise
you lose the whole benefit of the vmemmap optimization.
You would want to actually free the pages (making sure whatever
generic_online_page() does was done to these special vmemmap pages). But
then, you cannot simply skip all X first pages of a memory block when
offlining, you can only skip the once that are still vmemmap pages
(e.g., marked via page type), and have to isolate/migrate off the
no-longer vmemmap pages.
--
Thanks,
David / dhildenb
prev parent reply other threads:[~2020-10-29 7:49 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-22 12:58 [RFC PATCH 0/3] Allocate memmap from hotadded memory (per device) Oscar Salvador
2020-10-22 12:58 ` [RFC PATCH 1/3] mm,memory_hotplug: Introduce MHP_MEMMAP_ON_MEMORY Oscar Salvador
2020-10-22 13:04 ` David Hildenbrand
2020-10-22 12:58 ` [RFC PATCH 2/3] mm: Introduce a new Vmemmap page-type Oscar Salvador
2020-11-20 11:20 ` David Hildenbrand
2020-10-22 12:58 ` [RFC PATCH 3/3] mm,memory_hotplug: Allocate memmap from the added memory range Oscar Salvador
2020-11-17 15:38 ` David Hildenbrand
2020-11-19 10:48 ` Oscar Salvador
2020-11-20 9:31 ` David Hildenbrand
2020-10-22 13:01 ` [RFC PATCH 0/3] Allocate memmap from hotadded memory (per device) David Hildenbrand
2020-10-27 15:40 ` Oscar Salvador
2020-10-27 15:44 ` David Hildenbrand
2020-10-27 15:58 ` Oscar Salvador
2020-10-28 18:47 ` Mike Kravetz
2020-10-29 7:49 ` David Hildenbrand [this message]
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=cce0ad6f-8078-b486-62ad-b75269fd734e@redhat.com \
--to=david@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=mike.kravetz@oracle.com \
--cc=osalvador@suse.de \
--cc=pasha.tatashin@soleen.com \
--cc=vbabka@suse.cz \
/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;
as well as URLs for NNTP newsgroup(s).