From: osalvador@suse.de
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-hyperv@vger.kernel.org, xen-devel@lists.xenproject.org,
linux-acpi@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Alexander Duyck <alexander.h.duyck@linux.intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Mel Gorman <mgorman@techsingularity.net>,
Michael Ellerman <mpe@ellerman.id.au>,
Michal Hocko <mhocko@kernel.org>, Mike Rapoport <rppt@kernel.org>,
Scott Cheloha <cheloha@linux.ibm.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Vlastimil Babka <vbabka@suse.cz>, Wei Liu <wei.liu@kernel.org>,
Wei Yang <richard.weiyang@linux.alibaba.com>
Subject: Re: [PATCH RFC 0/4] mm: place pages to the freelist tail when onling and undoing isolation
Date: Wed, 16 Sep 2020 20:50:41 +0200 [thread overview]
Message-ID: <5c0910c2cd0d9d351e509392a45552fb@suse.de> (raw)
In-Reply-To: <20200916183411.64756-1-david@redhat.com>
On 2020-09-16 20:34, David Hildenbrand wrote:
> When adding separate memory blocks via add_memory*() and onlining them
> immediately, the metadata (especially the memmap) of the next block
> will be
> placed onto one of the just added+onlined block. This creates a chain
> of unmovable allocations: If the last memory block cannot get
> offlined+removed() so will all dependant ones. We directly have
> unmovable
> allocations all over the place.
>
> This can be observed quite easily using virtio-mem, however, it can
> also
> be observed when using DIMMs. The freshly onlined pages will usually be
> placed to the head of the freelists, meaning they will be allocated
> next,
> turning the just-added memory usually immediately un-removable. The
> fresh pages are cold, prefering to allocate others (that might be hot)
> also feels to be the natural thing to do.
>
> It also applies to the hyper-v balloon xen-balloon, and ppc64 dlpar:
> when
> adding separate, successive memory blocks, each memory block will have
> unmovable allocations on them - for example gigantic pages will fail to
> allocate.
>
> While the ZONE_NORMAL doesn't provide any guarantees that memory can
> get
> offlined+removed again (any kind of fragmentation with unmovable
> allocations is possible), there are many scenarios (hotplugging a lot
> of
> memory, running workload, hotunplug some memory/as much as possible)
> where
> we can offline+remove quite a lot with this patchset.
Hi David,
I did not read through the patchset yet, so sorry if the question is
nonsense, but is this not trying to fix the same issue the vmemmap
patches did? [1]
I was about to give it a new respin now that thw hwpoison stuff has been
settled.
[1] https://patchwork.kernel.org/cover/11059175/
>
next prev parent reply other threads:[~2020-09-16 18:50 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-16 18:34 [PATCH RFC 0/4] mm: place pages to the freelist tail when onling and undoing isolation David Hildenbrand
2020-09-16 18:34 ` [PATCH RFC 1/4] mm/page_alloc: convert "report" flag of __free_one_page() to a proper flag David Hildenbrand
2020-09-16 21:44 ` Alexander Duyck
2020-09-18 1:53 ` Wei Yang
2020-09-18 7:23 ` David Hildenbrand
2020-09-24 10:19 ` Vlastimil Babka
2020-09-25 10:34 ` Oscar Salvador
2020-09-16 18:34 ` [PATCH RFC 2/4] mm/page_alloc: place pages to tail in __putback_isolated_page() David Hildenbrand
2020-09-16 21:50 ` Alexander Duyck
2020-09-18 2:07 ` Wei Yang
2020-09-18 7:27 ` David Hildenbrand
2020-09-21 1:57 ` Wei Yang
2020-09-18 2:16 ` Wei Yang
2020-09-18 7:29 ` David Hildenbrand
2020-09-24 10:37 ` Vlastimil Babka
2020-09-25 8:10 ` David Hildenbrand
2020-09-25 13:19 ` Oscar Salvador
2020-09-25 13:30 ` David Hildenbrand
2020-09-16 18:34 ` [PATCH RFC 3/4] mm/page_alloc: always move pages to the tail of the freelist in unset_migratetype_isolate() David Hildenbrand
2020-09-18 2:29 ` Wei Yang
2020-09-18 7:30 ` David Hildenbrand
2020-09-24 11:13 ` Vlastimil Babka
2020-09-25 2:45 ` Wei Yang
2020-09-25 8:05 ` David Hildenbrand
2020-09-25 8:39 ` Vlastimil Babka
2020-09-25 13:13 ` David Hildenbrand
2020-09-25 13:57 ` Oscar Salvador
2020-09-16 18:34 ` [PATCH RFC 4/4] mm/page_alloc: place pages to tail in __free_pages_core() David Hildenbrand
2020-09-24 13:44 ` Vlastimil Babka
2020-09-28 7:58 ` Oscar Salvador
2020-09-28 8:36 ` David Hildenbrand
2020-09-28 12:53 ` Oscar Salvador
2020-09-16 18:50 ` osalvador [this message]
2020-09-16 19:31 ` [PATCH RFC 0/4] mm: place pages to the freelist tail when onling and undoing isolation David Hildenbrand
2020-09-18 2:30 ` Wei Yang
2020-09-18 7:32 ` David Hildenbrand
2020-09-23 14:31 ` Vlastimil Babka
2020-09-23 15:26 ` David Hildenbrand
2020-09-24 9:40 ` Mel Gorman
2020-09-24 9:54 ` David Hildenbrand
2020-09-24 13:59 ` Vlastimil Babka
2020-09-24 14:29 ` David Hildenbrand
2020-09-24 1:57 ` Wei Yang
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