From: Ingo Molnar <mingo@kernel.org>
To: Dave Hansen <dave.hansen@intel.com>
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 15:45:03 +0200 [thread overview]
Message-ID: <aCdBXxPNO4NtZ_Wl@gmail.com> (raw)
In-Reply-To: <30570ca0-8da4-4ebc-84d6-0a4badfb7154@intel.com>
* Dave Hansen <dave.hansen@intel.com> wrote:
> On 5/16/25 05:33, Kirill A. Shutemov wrote:
> > 5-level paging only supports SPARSEMEM_VMEMMAP. CONFIG_X86_5LEVEL is
> > being phased out, making 5-level paging support mandatory.
> >
> > Make CONFIG_SPARSEMEM_VMEMMAP mandatory for x86-64 and eliminate
> > any associated conditional statements.
> I think we have ourselves a catch-22 here.
>
> SPARSEMEM_VMEMMAP was selected because the other sparsemem modes
> couldn't handle a dynamic MAX_PHYS{MEM,ADDR}_BITS introduced by 5-level
> paging. Now you're proposing making it static again, but keeping the
> SPARSEMEM_VMEMMAP dependency.
>
> If you remove the dynamic MAX_PHYS{MEM,ADDR}_BITS, you should also
> remove the dependency on SPARSEMEM_VMEMMAP. No?
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.
Thanks,
Ingo
next prev parent reply other threads:[~2025-05-16 13:45 UTC|newest]
Thread overview: 27+ 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 13:44 ` [tip: x86/core] x86/mm/64: " tip-bot2 for Kirill A. Shutemov
2025-05-17 13:00 ` [tip: x86/merge] " tip-bot2 for 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 [this message]
2025-05-16 14:59 ` Dave Hansen
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 13:44 ` [tip: x86/core] x86/mm/64: " tip-bot2 for Kirill A. Shutemov
2025-05-17 13:00 ` [tip: x86/merge] " tip-bot2 for Kirill A. Shutemov
2025-05-16 12:33 ` [PATCHv3 3/4] x86/64/mm: Make 5-level paging support unconditional Kirill A. Shutemov
2025-05-17 13:00 ` [tip: x86/merge] x86/mm/64: " tip-bot2 for 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
2025-05-17 13:00 ` [tip: x86/merge] " tip-bot2 for Kirill A. Shutemov
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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