From: David Hildenbrand <david@redhat.com>
To: Anshuman Khandual <anshuman.khandual@arm.com>,
linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org,
catalin.marinas@arm.com, akpm@linux-foundation.org,
will@kernel.org
Cc: Robin Murphy <robin.murphy@arm.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Christoph Hellwig <hch@lst.de>,
Mark Rutland <mark.rutland@arm.com>,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/3] mm/page_alloc: Fix pageblock_order with HUGETLB_PAGE_SIZE_VARIABLE
Date: Tue, 16 Feb 2021 10:04:27 +0100 [thread overview]
Message-ID: <337123b0-b2af-a522-3dfe-fd1098a0cad9@redhat.com> (raw)
In-Reply-To: <0609df35-dd69-54a7-e839-2d97d77e0016@arm.com>
>>
>>
>> But again, if there are valid use cases then sure, let's make the code fully compatible with HUGETLB_PAGE_ORDER > MAX_ORDER.
>
> Given that gigantic HugeTLB allocation can fallback on alloc_contig_pages()
> or CMA if/when available, is there a real need for HUGETLB_PAGE_ORDER to be
> upto MAX_ORDER, used as pageblock_order or as COMPACTION_HPAGE_ORDER ? With
> gigantic HugeTLB pages being available, HUGETLB_PAGE_ORDER seems to be just
> detached from the buddy allocator. But I am not sure, will keep looking.
Having HPAGE_PMD_ORDER >>= MAX_ORDER ("significantly larger") will make
it very unlikely that you are able to reliably allocate any huge pages
at all dynamically at runtime without CMA.
Gigantic pages are problematic by nature :)
--
Thanks,
David / dhildenb
WARNING: multiple messages have this Message-ID (diff)
From: David Hildenbrand <david@redhat.com>
To: Anshuman Khandual <anshuman.khandual@arm.com>,
linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org,
catalin.marinas@arm.com, akpm@linux-foundation.org,
will@kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
Robin Murphy <robin.murphy@arm.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 0/3] mm/page_alloc: Fix pageblock_order with HUGETLB_PAGE_SIZE_VARIABLE
Date: Tue, 16 Feb 2021 10:04:27 +0100 [thread overview]
Message-ID: <337123b0-b2af-a522-3dfe-fd1098a0cad9@redhat.com> (raw)
In-Reply-To: <0609df35-dd69-54a7-e839-2d97d77e0016@arm.com>
>>
>>
>> But again, if there are valid use cases then sure, let's make the code fully compatible with HUGETLB_PAGE_ORDER > MAX_ORDER.
>
> Given that gigantic HugeTLB allocation can fallback on alloc_contig_pages()
> or CMA if/when available, is there a real need for HUGETLB_PAGE_ORDER to be
> upto MAX_ORDER, used as pageblock_order or as COMPACTION_HPAGE_ORDER ? With
> gigantic HugeTLB pages being available, HUGETLB_PAGE_ORDER seems to be just
> detached from the buddy allocator. But I am not sure, will keep looking.
Having HPAGE_PMD_ORDER >>= MAX_ORDER ("significantly larger") will make
it very unlikely that you are able to reliably allocate any huge pages
at all dynamically at runtime without CMA.
Gigantic pages are problematic by nature :)
--
Thanks,
David / dhildenb
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
WARNING: multiple messages have this Message-ID (diff)
From: David Hildenbrand <david@redhat.com>
To: Anshuman Khandual <anshuman.khandual@arm.com>,
linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org,
catalin.marinas@arm.com, akpm@linux-foundation.org,
will@kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
Robin Murphy <robin.murphy@arm.com>,
Christoph Hellwig <hch@lst.de>,
Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: [PATCH 0/3] mm/page_alloc: Fix pageblock_order with HUGETLB_PAGE_SIZE_VARIABLE
Date: Tue, 16 Feb 2021 10:04:27 +0100 [thread overview]
Message-ID: <337123b0-b2af-a522-3dfe-fd1098a0cad9@redhat.com> (raw)
In-Reply-To: <0609df35-dd69-54a7-e839-2d97d77e0016@arm.com>
>>
>>
>> But again, if there are valid use cases then sure, let's make the code fully compatible with HUGETLB_PAGE_ORDER > MAX_ORDER.
>
> Given that gigantic HugeTLB allocation can fallback on alloc_contig_pages()
> or CMA if/when available, is there a real need for HUGETLB_PAGE_ORDER to be
> upto MAX_ORDER, used as pageblock_order or as COMPACTION_HPAGE_ORDER ? With
> gigantic HugeTLB pages being available, HUGETLB_PAGE_ORDER seems to be just
> detached from the buddy allocator. But I am not sure, will keep looking.
Having HPAGE_PMD_ORDER >>= MAX_ORDER ("significantly larger") will make
it very unlikely that you are able to reliably allocate any huge pages
at all dynamically at runtime without CMA.
Gigantic pages are problematic by nature :)
--
Thanks,
David / dhildenb
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-02-16 9:06 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-11 6:22 [PATCH 0/3] mm/page_alloc: Fix pageblock_order with HUGETLB_PAGE_SIZE_VARIABLE Anshuman Khandual
2021-02-11 6:22 ` Anshuman Khandual
2021-02-11 6:22 ` Anshuman Khandual
2021-02-11 6:22 ` [PATCH 1/3] mm/page_alloc: Fix pageblock_order when HUGETLB_PAGE_ORDER >= MAX_ORDER Anshuman Khandual
2021-02-11 6:22 ` Anshuman Khandual
2021-02-11 6:22 ` Anshuman Khandual
2021-02-11 8:00 ` Christoph Hellwig
2021-02-11 8:00 ` Christoph Hellwig
2021-02-11 8:00 ` Christoph Hellwig
2021-02-12 7:12 ` Anshuman Khandual
2021-02-12 7:12 ` Anshuman Khandual
2021-02-12 7:12 ` Anshuman Khandual
2021-02-11 6:22 ` [PATCH 2/3] arm64/hugetlb: Enable HUGETLB_PAGE_SIZE_VARIABLE Anshuman Khandual
2021-02-11 6:22 ` Anshuman Khandual
2021-02-11 6:22 ` Anshuman Khandual
2021-02-11 8:01 ` Christoph Hellwig
2021-02-11 8:01 ` Christoph Hellwig
2021-02-11 8:01 ` Christoph Hellwig
2021-02-12 7:13 ` Anshuman Khandual
2021-02-12 7:13 ` Anshuman Khandual
2021-02-12 7:13 ` Anshuman Khandual
2021-02-11 6:22 ` [PATCH 3/3] dma-contiguous: Type cast MAX_ORDER as unsigned int Anshuman Khandual
2021-02-11 6:22 ` Anshuman Khandual
2021-02-11 6:22 ` Anshuman Khandual
2021-02-11 8:04 ` Christoph Hellwig
2021-02-11 8:04 ` Christoph Hellwig
2021-02-11 8:04 ` Christoph Hellwig
2021-02-12 7:19 ` Anshuman Khandual
2021-02-12 7:19 ` Anshuman Khandual
2021-02-12 7:19 ` Anshuman Khandual
2021-02-11 8:37 ` [PATCH 0/3] mm/page_alloc: Fix pageblock_order with HUGETLB_PAGE_SIZE_VARIABLE David Hildenbrand
2021-02-11 8:37 ` David Hildenbrand
2021-02-11 8:37 ` David Hildenbrand
2021-02-12 7:02 ` Anshuman Khandual
2021-02-12 7:02 ` Anshuman Khandual
2021-02-12 7:02 ` Anshuman Khandual
2021-02-12 9:39 ` David Hildenbrand
2021-02-12 9:39 ` David Hildenbrand
2021-02-12 9:39 ` David Hildenbrand
2021-02-16 9:02 ` Anshuman Khandual
2021-02-16 9:02 ` Anshuman Khandual
2021-02-16 9:02 ` Anshuman Khandual
2021-02-16 9:04 ` David Hildenbrand [this message]
2021-02-16 9:04 ` David Hildenbrand
2021-02-16 9:04 ` David Hildenbrand
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