From: Dave Hansen <dave.hansen@intel.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Jonathan Corbet <corbet@lwn.net>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ard Biesheuvel <ardb@kernel.org>,
Jan Kiszka <jan.kiszka@siemens.com>,
Kieran Bingham <kbingham@kernel.org>,
Michael Roth <michael.roth@amd.com>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
Brijesh Singh <brijesh.singh@amd.com>,
Sandipan Das <sandipan.das@amd.com>,
Juergen Gross <jgross@suse.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-efi@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCHv3 2/4] x86/64/mm: Make SPARSEMEM_VMEMMAP the only memory model
Date: Fri, 16 May 2025 07:59:42 -0700 [thread overview]
Message-ID: <f93a6e4d-4970-4352-97ff-643d67662c32@intel.com> (raw)
In-Reply-To: <aCdBXxPNO4NtZ_Wl@gmail.com>
On 5/16/25 06:45, Ingo Molnar wrote:
> Isn't it the other way around? MAX_PHYS{MEM,ADDR}_BITS are now *always*
> dynamic, their value depending on whether LA57 is available and used.
MAX_PHYS{MEM,ADDR}_BITS were always intended to be the compile-time
maximums on the architecture. They're static on every architecture
except x86 and some arm64 configs (who probably copied x86).
That's why having them be dynamic broke non-vmemmap sparsemem.
But we also seems to have defined MAXMEM to derive from MAX_PHYSMEM_BITS
and MAXMEM cascades into a bunch of other stuff, including KASAN. So we
can't just make them static again, I guess.
The only option would be to make them static when using non-vmemmap
sparsemem. But that's new-ish, and probably won't get any testing.
I guess there's not much we can do about it.
next prev parent reply other threads:[~2025-05-16 14:59 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-16 12:33 [PATCHv3 0/4] x86: Make 5-level paging support unconditional for x86-64 Kirill A. Shutemov
2025-05-16 12:33 ` [PATCHv3 1/4] x86/64/mm: Always use dynamic memory layout Kirill A. Shutemov
2025-05-16 12:33 ` [PATCHv3 2/4] x86/64/mm: Make SPARSEMEM_VMEMMAP the only memory model Kirill A. Shutemov
2025-05-16 13:42 ` Dave Hansen
2025-05-16 13:45 ` Ingo Molnar
2025-05-16 14:59 ` Dave Hansen [this message]
2025-05-16 15:08 ` Dave Hansen
2025-05-16 14:01 ` Kirill A. Shutemov
2025-05-16 14:08 ` Ingo Molnar
2025-05-16 15:03 ` Dave Hansen
2025-05-16 15:35 ` Ingo Molnar
2025-05-16 15:46 ` Dave Hansen
2025-05-16 18:28 ` H. Peter Anvin
2025-05-16 15:01 ` Dave Hansen
2025-05-16 12:33 ` [PATCHv3 3/4] x86/64/mm: Make 5-level paging support unconditional Kirill A. Shutemov
2025-05-16 12:33 ` [PATCHv3 4/4] x86/paravirt: Restrict PARAVIRT_XXL to 64-bit only Kirill A. Shutemov
2025-05-16 12:43 ` Jürgen Groß
2025-05-16 13:11 ` [PATCHv3 0/4] x86: Make 5-level paging support unconditional for x86-64 Ingo Molnar
2025-05-16 13:17 ` Kirill A. Shutemov
2025-05-17 9:59 ` Borislav Petkov
2025-06-24 8:23 ` [PATCHv2 0/3] " Khalid Ali
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