From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: David Hildenbrand <david@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Sean Christopherson <seanjc@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Joerg Roedel <jroedel@suse.de>, Ard Biesheuvel <ardb@kernel.org>,
Andi Kleen <ak@linux.intel.com>,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
David Rientjes <rientjes@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
Tom Lendacky <thomas.lendacky@amd.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
Varad Gautam <varad.gautam@suse.com>,
Dario Faggioli <dfaggioli@suse.com>,
x86@kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev,
linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCHv2 1/7] mm: Add support for unaccepted memory
Date: Wed, 12 Jan 2022 22:15:10 +0300 [thread overview]
Message-ID: <20220112191510.6uqdflbreuet7bnx@box.shutemov.name> (raw)
In-Reply-To: <d84e242f-f7f6-4fb0-8f22-bcc790a296a0@redhat.com>
On Wed, Jan 12, 2022 at 12:31:10PM +0100, David Hildenbrand wrote:
>
> >
> > Looking at stuff like this, I can't help but think that a:
> >
> > #define PageOffline PageUnaccepted
> >
> > and some other renaming would be a fine idea. I get that the Offline
> > bit can be reused, but I'm not sure that the "Offline" *naming* should
> > be reused. What you're doing here is logically distinct from existing
> > offlining.
>
> Yes, or using a new pagetype bit to make the distinction clearer.
> Especially the function names like maybe_set_page_offline() et. Al are
> confusing IMHO. They are all about accepting unaccepted memory ... and
> should express that.
"Unaccepted" is UEFI treminology and I'm not sure we want to expose
core-mm to it. Power/S390/ARM may have a different name for the same
concept. Offline/online is neutral terminology, familiar to MM developers.
What if I change accept->online in function names and document the meaning
properly?
> I assume PageOffline() will be set only on the first sub-page of a
> high-order PageBuddy() page, correct?
>
> Then we'll have to monitor all PageOffline() users such that they can
> actually deal with PageBuddy() pages spanning *multiple* base pages for
> a PageBuddy() page. For now it's clear that if a page is PageOffline(),
> it cannot be PageBuddy() and cannot span more than one base page.
> E.g., fs/proc/kcore.c:read_kcore() assumes that PageOffline() is set on
> individual base pages.
Right, pages that offline from hotplug POV are never on page allocator's
free lists, so it cannot ever step on them.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2022-01-12 19:15 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-11 11:33 [PATCHv2 0/7] Implement support for unaccepted memory Kirill A. Shutemov
2022-01-11 11:33 ` [PATCHv2 1/7] mm: Add " Kirill A. Shutemov
2022-01-11 19:46 ` Dave Hansen
2022-01-12 11:31 ` David Hildenbrand
2022-01-12 19:15 ` Kirill A. Shutemov [this message]
2022-01-14 13:22 ` David Hildenbrand
2022-01-12 18:30 ` Kirill A. Shutemov
2022-01-12 18:40 ` Dave Hansen
2022-01-13 7:42 ` Mike Rapoport
2022-01-11 11:33 ` [PATCHv2 2/7] efi/x86: Get full memory map in allocate_e820() Kirill A. Shutemov
2022-01-11 11:33 ` [PATCHv2 3/7] efi/x86: Implement support for unaccepted memory Kirill A. Shutemov
2022-01-11 17:17 ` Dave Hansen
2022-01-12 19:29 ` Kirill A. Shutemov
2022-01-12 19:35 ` Dave Hansen
2022-01-11 11:33 ` [PATCHv2 4/7] x86/boot/compressed: Handle " Kirill A. Shutemov
2022-01-11 11:33 ` [PATCHv2 5/7] x86/mm: Reserve unaccepted memory bitmap Kirill A. Shutemov
2022-01-11 19:10 ` Dave Hansen
2022-01-12 19:43 ` Kirill A. Shutemov
2022-01-12 19:53 ` Dave Hansen
2022-01-15 18:46 ` Mike Rapoport
2022-01-11 11:33 ` [PATCHv2 6/7] x86/mm: Provide helpers for unaccepted memory Kirill A. Shutemov
2022-01-11 20:01 ` Dave Hansen
2022-01-12 19:43 ` Kirill A. Shutemov
2022-01-11 11:33 ` [PATCHv2 7/7] x86/tdx: Unaccepted memory support Kirill A. Shutemov
2022-01-18 21:05 ` [PATCHv2 0/7] Implement support for unaccepted memory Brijesh Singh
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