From: David Hildenbrand <david@redhat.com>
To: Zi Yan <ziy@nvidia.com>, Oscar Salvador <osalvador@suse.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, Andy Lutomirski <luto@kernel.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Rapoport <rppt@kernel.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Michal Hocko <mhocko@suse.com>,
Dan Williams <dan.j.williams@intel.com>,
Wei Yang <richard.weiyang@linux.alibaba.com>,
linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org
Subject: Re: [RFC PATCH 0/7] Memory hotplug/hotremove at subsection size
Date: Thu, 6 May 2021 17:31:09 +0200 [thread overview]
Message-ID: <fb60eabd-f8ef-2cb1-7338-7725efe3c286@redhat.com> (raw)
In-Reply-To: <20210506152623.178731-1-zi.yan@sent.com>
On 06.05.21 17:26, Zi Yan wrote:
> From: Zi Yan <ziy@nvidia.com>
>
> Hi all,
>
> This patchset tries to remove the restriction on memory hotplug/hotremove
> granularity, which is always greater or equal to memory section size[1].
> With the patchset, kernel is able to online/offline memory at a size independent
> of memory section size, as small as 2MB (the subsection size).
... which doesn't make any sense as we can only online/offline whole
memory block devices.
>
> The motivation is to increase MAX_ORDER of the buddy allocator and pageblock
> size without increasing memory hotplug/hotremove granularity at the same time,
Gah, no. Please no. No.
> so that the kernel can allocator 1GB pages using buddy allocator and utilizes
> existing pageblock based anti-fragmentation, paving the road for 1GB THP
> support[2].
Not like this, please no.
>
> The patchset utilizes the existing subsection support[3] and changes the
> section size alignment checks to subsection size alignment checks. There are
> also changes to pageblock code to support partial pageblocks, when pageblock
> size is increased along with MAX_ORDER. Increasing pageblock size can enable
> kernel to utilize existing anti-fragmentation mechanism for gigantic page
> allocations.
Please not like this.
>
> The last patch increases SECTION_SIZE_BITS to demonstrate the use of memory
> hotplug/hotremove subsection, but is not intended to be merged as is. It is
> there in case one wants to try this out and will be removed during the final
> submission.
>
> Feel free to give suggestions and comments. I am looking forward to your
> feedback.
Please not like this.
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2021-05-06 15:31 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-06 15:26 [RFC PATCH 0/7] Memory hotplug/hotremove at subsection size Zi Yan
2021-05-06 15:26 ` [RFC PATCH 1/7] mm: sparse: set/clear subsection bitmap when pages are onlined/offlined Zi Yan
2021-05-06 17:48 ` David Hildenbrand
2021-05-06 19:03 ` Zi Yan
2021-05-06 19:14 ` David Hildenbrand
2021-05-06 15:26 ` [RFC PATCH 2/7] mm: set pageblock_order to the max of HUGETLB_PAGE_ORDER and MAX_ORDER-1 Zi Yan
2021-05-06 15:26 ` [RFC PATCH 3/7] mm: memory_hotplug: decouple memory_block size with section size Zi Yan
2021-05-06 15:26 ` [RFC PATCH 4/7] mm: pageblock: allow set/unset migratetype for partial pageblock Zi Yan
2021-05-06 15:26 ` [RFC PATCH 5/7] mm: memory_hotplug, sparse: enable memory hotplug/hotremove subsections Zi Yan
2021-05-06 15:26 ` [RFC PATCH 6/7] arch: x86: no MAX_ORDER exceeds SECTION_SIZE check for 32bit vdso Zi Yan
2021-05-06 15:26 ` [RFC PATCH 7/7] [not for merge] mm: increase SECTION_SIZE_BITS to 31 Zi Yan
2021-05-06 15:31 ` David Hildenbrand [this message]
2021-05-06 15:37 ` [RFC PATCH 0/7] Memory hotplug/hotremove at subsection size Zi Yan
2021-05-06 15:40 ` David Hildenbrand
2021-05-06 15:50 ` Zi Yan
2021-05-06 16:28 ` David Hildenbrand
2021-05-06 18:49 ` Zi Yan
2021-05-06 19:10 ` David Hildenbrand
2021-05-06 19:30 ` Matthew Wilcox
2021-05-06 19:38 ` David Hildenbrand
2021-05-06 15:38 ` David Hildenbrand
2021-05-07 11:55 ` Michal Hocko
2021-05-07 14:00 ` David Hildenbrand
2021-05-10 14:36 ` Zi Yan
2021-05-12 16:14 ` David Hildenbrand
2021-06-02 15:56 ` Zi Yan
2021-06-14 11:32 ` David Hildenbrand
2021-05-06 15:42 ` Zi Yan
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