From: Matthew Wilcox <willy@infradead.org>
To: David Hildenbrand <david@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Yin Fengwei <fengwei.yin@intel.com>, Yu Zhao <yuzhao@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Yang Shi <shy828301@gmail.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v2 0/5] variable-order, large folios for anonymous memory
Date: Fri, 7 Jul 2023 14:12:01 +0100 [thread overview]
Message-ID: <ZKgPIXSrxqymWrsv@casper.infradead.org> (raw)
In-Reply-To: <d9cb4563-c622-9660-287b-a2f35121aec7@redhat.com>
On Fri, Jul 07, 2023 at 01:40:53PM +0200, David Hildenbrand wrote:
> On 06.07.23 10:02, Ryan Roberts wrote:
> But can you comment on the page migration part (IOW did you try it already)?
>
> For example, memory hotunplug, CMA, MCE handling, compaction all rely on
> page migration of something that was allocated using GFP_MOVABLE to actually
> work.
>
> Compaction seems to skip any higher-order folios, but the question is if the
> udnerlying migration itself works.
>
> If it already works: great! If not, this really has to be tackled early,
> because otherwise we'll be breaking the GFP_MOVABLE semantics.
I have looked at this a bit. _Migration_ should be fine. _Compaction_
is not.
If you look at a function like folio_migrate_mapping(), it all seems
appropriately folio-ised. There might be something in there that is
slightly wrong, but that would just be a bug to fix, not a huge
architectural problem.
The problem comes in the callers of migrate_pages(). They pass a
new_folio_t callback. alloc_migration_target() is the usual one passed
and as far as I can tell is fine. I've seen no problems reported with it.
compaction_alloc() is a disaster, and I don't know how to fix it.
The compaction code has its own allocator which is populated with order-0
folios. How it populates that freelist is awful ... see split_map_pages()
> Is swapping working as expected? zswap?
Suboptimally. Swap will split folios in order to swap them. Somebody
needs to fix that, but it should work.
next prev parent reply other threads:[~2023-07-07 13:12 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-03 13:53 [PATCH v2 0/5] variable-order, large folios for anonymous memory Ryan Roberts
2023-07-03 13:53 ` [PATCH v2 1/5] mm: Non-pmd-mappable, large folios for folio_add_new_anon_rmap() Ryan Roberts
2023-07-03 19:05 ` Yu Zhao
2023-07-04 2:13 ` Yin, Fengwei
2023-07-04 11:19 ` Ryan Roberts
2023-07-04 2:14 ` Yin, Fengwei
2023-07-03 13:53 ` [PATCH v2 2/5] mm: Allow deferred splitting of arbitrary large anon folios Ryan Roberts
2023-07-07 8:21 ` Huang, Ying
2023-07-07 9:42 ` Ryan Roberts
2023-07-10 5:37 ` Huang, Ying
2023-07-10 8:29 ` Ryan Roberts
2023-07-10 9:01 ` Huang, Ying
2023-07-10 9:39 ` Ryan Roberts
2023-07-11 1:56 ` Huang, Ying
2023-07-03 13:53 ` [PATCH v2 3/5] mm: Default implementation of arch_wants_pte_order() Ryan Roberts
2023-07-03 19:50 ` Yu Zhao
2023-07-04 13:20 ` Ryan Roberts
2023-07-05 2:07 ` Yu Zhao
2023-07-05 9:11 ` Ryan Roberts
2023-07-05 17:24 ` Yu Zhao
2023-07-05 18:01 ` Ryan Roberts
2023-07-06 19:33 ` Matthew Wilcox
2023-07-07 10:00 ` Ryan Roberts
2023-07-04 2:22 ` Yin, Fengwei
2023-07-04 3:02 ` Yu Zhao
2023-07-04 3:59 ` Yu Zhao
2023-07-04 5:22 ` Yin, Fengwei
2023-07-04 5:42 ` Yu Zhao
2023-07-04 12:36 ` Ryan Roberts
2023-07-04 13:23 ` Ryan Roberts
2023-07-05 1:40 ` Yu Zhao
2023-07-05 1:23 ` Yu Zhao
2023-07-05 2:18 ` Yin Fengwei
2023-07-03 13:53 ` [PATCH v2 4/5] mm: FLEXIBLE_THP for improved performance Ryan Roberts
2023-07-03 15:51 ` kernel test robot
2023-07-03 16:01 ` kernel test robot
2023-07-04 1:35 ` Yu Zhao
2023-07-04 14:08 ` Ryan Roberts
2023-07-04 23:47 ` Yu Zhao
2023-07-04 3:45 ` Yin, Fengwei
2023-07-04 14:20 ` Ryan Roberts
2023-07-04 23:35 ` Yin Fengwei
2023-07-04 23:57 ` Matthew Wilcox
2023-07-05 9:54 ` Ryan Roberts
2023-07-05 12:08 ` Matthew Wilcox
2023-07-07 8:01 ` Huang, Ying
2023-07-07 9:52 ` Ryan Roberts
2023-07-07 11:29 ` David Hildenbrand
2023-07-07 13:57 ` Matthew Wilcox
2023-07-07 14:07 ` David Hildenbrand
2023-07-07 15:13 ` Ryan Roberts
2023-07-07 16:06 ` David Hildenbrand
2023-07-07 16:22 ` Ryan Roberts
2023-07-07 19:06 ` David Hildenbrand
2023-07-10 8:41 ` Ryan Roberts
2023-07-10 3:03 ` Huang, Ying
2023-07-10 8:55 ` Ryan Roberts
2023-07-10 9:18 ` Huang, Ying
2023-07-10 9:25 ` Ryan Roberts
2023-07-11 0:48 ` Huang, Ying
2023-07-10 2:49 ` Huang, Ying
2023-07-03 13:53 ` [PATCH v2 5/5] arm64: mm: Override arch_wants_pte_order() Ryan Roberts
2023-07-03 20:02 ` Yu Zhao
2023-07-04 2:18 ` [PATCH v2 0/5] variable-order, large folios for anonymous memory Yu Zhao
2023-07-04 6:22 ` Yin, Fengwei
2023-07-04 7:11 ` Yu Zhao
2023-07-04 15:36 ` Ryan Roberts
2023-07-04 23:52 ` Yin Fengwei
2023-07-05 0:21 ` Yu Zhao
2023-07-05 10:16 ` Ryan Roberts
2023-07-05 19:00 ` Yu Zhao
2023-07-05 19:38 ` David Hildenbrand
2023-07-06 8:02 ` Ryan Roberts
2023-07-07 11:40 ` David Hildenbrand
2023-07-07 13:12 ` Matthew Wilcox [this message]
2023-07-07 13:24 ` David Hildenbrand
2023-07-10 10:07 ` Ryan Roberts
2023-07-10 16:57 ` Matthew Wilcox
2023-07-10 16:53 ` Zi Yan
2023-07-19 15:49 ` Ryan Roberts
2023-07-19 16:05 ` Zi Yan
2023-07-19 18:37 ` Ryan Roberts
2023-07-11 21:11 ` Luis Chamberlain
2023-07-11 21:59 ` Matthew Wilcox
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