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Date:   Sat, 29 Oct 2022 00:19:36 +0200
From:   Borislav Petkov <bp@alien8.de>
To:     Eric DeVolder <eric.devolder@oracle.com>
Cc:     Baoquan He <bhe@redhat.com>, david@redhat.com,
        Oscar Salvador <osalvador@suse.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org, x86@kernel.org,
        kexec@lists.infradead.org, ebiederm@xmission.com,
        dyoung@redhat.com, vgoyal@redhat.com, tglx@linutronix.de,
        mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com,
        nramas@linux.microsoft.com, thomas.lendacky@amd.com,
        robh@kernel.org, efault@gmx.de, rppt@kernel.org,
        sourabhjain@linux.ibm.com, linux-mm@kvack.org
Subject: Re: [PATCH v12 7/7] x86/crash: Add x86 crash hotplug support
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On Fri, Oct 28, 2022 at 04:22:54PM -0500, Eric DeVolder wrote:
> /*
>  * For the kexec_file_load() syscall path, specify the maximum number of
>  * memory regions that the elfcorehdr buffer/segment can accommodate.
>  * These regions are obtained via walk_system_ram_res(); eg. the
>  * 'System RAM' entries in /proc/iomem.
>  * This value is combined with NR_CPUS and multiplied by sizeof(Elf64_Phdr)

NR_CPUS_DEFAULT

>  * to determine the final elfcorehdr memory buffer/segment size.
>  * The value 8192, for example, covers a (sparsely populated) 1TiB system
>  * consisting of 128MiB memblock size, while resulting in an elfcorehdr
>  * memory buffer/segment size under 1MiB.

... and it is a sane choice trying to accomodate both actual baremetal
and VM configurations."

Yeah, it's a good start.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette