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Sender: Ingo Molnar <mingo.kernel.org@gmail.com>
Date:   Thu, 5 Jan 2023 11:48:13 +0100
From:   Ingo Molnar <mingo@kernel.org>
To:     Aaron Thompson <dev@aaront.org>
Cc:     Mike Rapoport <rppt@kernel.org>, linux-mm@kvack.org,
        "H. Peter Anvin" <hpa@zytor.com>,
        Alexander Potapenko <glider@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andy Shevchenko <andy@infradead.org>,
        Ard Biesheuvel <ardb@kernel.org>,
        Borislav Petkov <bp@alien8.de>,
        Darren Hart <dvhart@infradead.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
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        Dmitry Vyukov <dvyukov@google.com>,
        Ingo Molnar <mingo@redhat.com>, Marco Elver <elver@google.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        kasan-dev@googlegroups.com, linux-efi@vger.kernel.org,
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        x86@kernel.org
Subject: Re: [PATCH v2 1/1] mm: Always release pages to the buddy allocator
 in memblock_free_late().
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* Aaron Thompson <dev@aaront.org> wrote:

> For example, on an Amazon EC2 t3.micro VM (1 GB) booting via EFI:
> 
> v6.2-rc2:
>   # grep -E 'Node|spanned|present|managed' /proc/zoneinfo
>   Node 0, zone      DMA
>           spanned  4095
>           present  3999
>           managed  3840
>   Node 0, zone    DMA32
>           spanned  246652
>           present  245868
>           managed  178867
> 
> v6.2-rc2 + patch:
>   # grep -E 'Node|spanned|present|managed' /proc/zoneinfo
>   Node 0, zone      DMA
>           spanned  4095
>           present  3999
>           managed  3840
>   Node 0, zone    DMA32
>           spanned  246652
>           present  245868
>           managed  222816   # +43,949 pages

[ Note the annotation I added to the output - might be useful in the changelog too. ]

So this patch adds around +17% of RAM to this 1 GB virtual system? That 
looks rather significant ...

Thanks,

	Ingo