From: Ryan Roberts <ryan.roberts@arm.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>,
Andrew Morton <akpm@linux-foundation.org>,
Yu Zhao <yuzhao@google.com>,
"Yin, Fengwei" <fengwei.yin@intel.com>,
linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC v2 PATCH 05/17] mm: Routines to determine max anon folio allocation order
Date: Fri, 14 Apr 2023 17:31:07 +0100 [thread overview]
Message-ID: <9f879f29-e642-ef9c-9f6f-612d552b9116@arm.com> (raw)
In-Reply-To: <ZDl80spI/F0pXBFh@casper.infradead.org>
On 14/04/2023 17:18, Matthew Wilcox wrote:
> On Fri, Apr 14, 2023 at 05:06:49PM +0100, Ryan Roberts wrote:
>> The point I'm thinking about is for 4K pages, we need to allocate 64K blocks to
>> use the contig bit. Roughly I guess that means going from average of 2K wastage
>> per anon VMA to 32K. Perhaps you can get away with that for a decent perf uplift.
>>
>> But for 64K pages, we need to allocate 2M blocks to use the contig bit. So that
>> takes average wastage from 32K to 1M. That feels a bit harder to justify.
>> Perhaps here, we should make a decision based on MADV_HUGEPAGE?
>>
>> So perhaps we actually want 2 values: one for if MADV_HUGEPAGE is not set on the
>> VMA, and one if it is? (with 64K pages I'm guessing there are many cases where
>> we won't PMD-map THPs - its 512MB).
>
> I'm kind of hoping that all this work takes away the benefit from
> CONFIG_PAGE_SIZE_64K, and we can just use 4k pages everywhere.
That sounds great. I'm not sure I share your confidence though ;-)
next prev parent reply other threads:[~2023-04-14 16:31 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-14 13:02 [RFC v2 PATCH 00/17] variable-order, large folios for anonymous memory Ryan Roberts
2023-04-14 13:02 ` [RFC v2 PATCH 01/17] mm: Expose clear_huge_page() unconditionally Ryan Roberts
2023-04-14 13:02 ` [RFC v2 PATCH 02/17] mm: pass gfp flags and order to vma_alloc_zeroed_movable_folio() Ryan Roberts
2023-04-14 13:02 ` [RFC v2 PATCH 03/17] mm: Introduce try_vma_alloc_movable_folio() Ryan Roberts
2023-04-17 8:49 ` Yin, Fengwei
2023-04-17 10:11 ` Ryan Roberts
2023-04-14 13:02 ` [RFC v2 PATCH 04/17] mm: Implement folio_add_new_anon_rmap_range() Ryan Roberts
2023-04-14 13:02 ` [RFC v2 PATCH 05/17] mm: Routines to determine max anon folio allocation order Ryan Roberts
2023-04-14 14:09 ` Kirill A. Shutemov
2023-04-14 14:38 ` Ryan Roberts
2023-04-14 15:37 ` Kirill A. Shutemov
2023-04-14 16:06 ` Ryan Roberts
2023-04-14 16:18 ` Matthew Wilcox
2023-04-14 16:31 ` Ryan Roberts [this message]
2023-04-14 13:02 ` [RFC v2 PATCH 06/17] mm: Allocate large folios for anonymous memory Ryan Roberts
2023-04-14 13:02 ` [RFC v2 PATCH 07/17] mm: Allow deferred splitting of arbitrary large anon folios Ryan Roberts
2023-04-14 13:02 ` [RFC v2 PATCH 08/17] mm: Implement folio_move_anon_rmap_range() Ryan Roberts
2023-04-14 13:02 ` [RFC v2 PATCH 09/17] mm: Update wp_page_reuse() to operate on range of pages Ryan Roberts
2023-04-14 13:02 ` [RFC v2 PATCH 10/17] mm: Reuse large folios for anonymous memory Ryan Roberts
2023-04-14 13:02 ` [RFC v2 PATCH 11/17] mm: Split __wp_page_copy_user() into 2 variants Ryan Roberts
2023-04-14 13:02 ` [RFC v2 PATCH 12/17] mm: ptep_clear_flush_range_notify() macro for batch operation Ryan Roberts
2023-04-14 13:02 ` [RFC v2 PATCH 13/17] mm: Implement folio_remove_rmap_range() Ryan Roberts
2023-04-14 13:03 ` [RFC v2 PATCH 14/17] mm: Copy large folios for anonymous memory Ryan Roberts
2023-04-14 13:03 ` [RFC v2 PATCH 15/17] mm: Convert zero page to large folios on write Ryan Roberts
2023-04-14 13:03 ` [RFC v2 PATCH 16/17] mm: mmap: Align unhinted maps to highest anon folio order Ryan Roberts
2023-04-17 8:25 ` Yin, Fengwei
2023-04-17 10:13 ` Ryan Roberts
2023-04-14 13:03 ` [RFC v2 PATCH 17/17] mm: Batch-zap large anonymous folio PTE mappings Ryan Roberts
2023-04-17 8:04 ` [RFC v2 PATCH 00/17] variable-order, large folios for anonymous memory Yin, Fengwei
2023-04-17 10:19 ` Ryan Roberts
2023-04-17 8:19 ` Yin, Fengwei
2023-04-17 10:28 ` Ryan Roberts
2023-04-17 10:54 ` David Hildenbrand
2023-04-17 11:43 ` Ryan Roberts
2023-04-17 14:05 ` David Hildenbrand
2023-04-17 15:38 ` Ryan Roberts
2023-04-17 15:44 ` David Hildenbrand
2023-04-17 16:15 ` Ryan Roberts
2023-04-26 10:41 ` Ryan Roberts
2023-05-17 13:58 ` David Hildenbrand
2023-05-18 11:23 ` Ryan Roberts
2023-04-19 10:12 ` Ryan Roberts
2023-04-19 10:51 ` David Hildenbrand
2023-04-19 11:13 ` Ryan Roberts
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