From: Pratyush Yadav <pratyush@kernel.org>
To: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Pratyush Yadav <pratyush@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>, Jonathan Corbet <corbet@lwn.net>,
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>,
Muchun Song <muchun.song@linux.dev>,
Oscar Salvador <osalvador@suse.de>,
Alexander Graf <graf@amazon.com>,
David Matlack <dmatlack@google.com>,
David Rientjes <rientjes@google.com>,
Jason Gunthorpe <jgg@nvidia.com>,
Samiullah Khawaja <skhawaja@google.com>,
Vipin Sharma <vipinsh@google.com>,
Zhu Yanjun <yanjun.zhu@linux.dev>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-doc@vger.kernel.org, kexec@lists.infradead.org
Subject: Re: [RFC PATCH 08/10] mm: hugetlb: disable CMA if liveupdate is enabled
Date: Mon, 29 Dec 2025 22:14:50 +0100 [thread overview]
Message-ID: <86v7hp7zxx.fsf@kernel.org> (raw)
In-Reply-To: <CA+CK2bBeJwACBiKsuXLcbzC4m0zLhu0yNg2HDGR=AQGeEVCJjg@mail.gmail.com> (Pasha Tatashin's message of "Tue, 23 Dec 2025 13:16:57 -0500")
On Tue, Dec 23 2025, Pasha Tatashin wrote:
> On Sat, Dec 6, 2025 at 6:03 PM Pratyush Yadav <pratyush@kernel.org> wrote:
>>
>> Hugetlb live update support does not yet work with CMA. Print a warning
>> and disable CMA if the config for live updating hugetlb is enabled, and
>> liveupdate is enabled at runtime.
>
> Could you please elaborate this commit to explain why it is not
> supported, and what it would take to support CMA.
The main reason is that when HugeTLB CMA is enabled, the huge pages come
from CMA. If we have preserved pages, we would need to "insert" those
pages into the CMA when they are restored.
CMA does support multiple ranges, so I suppose it can be done, but it
needs some plumbing to work properly.
Will add this in the next revision.
--
Regards,
Pratyush Yadav
next prev parent reply other threads:[~2025-12-29 21:15 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-06 23:02 [RFC PATCH 00/10] liveupdate: hugetlb support Pratyush Yadav
2025-12-06 23:02 ` [RFC PATCH 01/10] kho: drop restriction on maximum page order Pratyush Yadav
2025-12-23 17:59 ` Pasha Tatashin
2025-12-29 21:24 ` Pratyush Yadav
2025-12-06 23:02 ` [RFC PATCH 02/10] kho: disable scratch-only earlier in boot Pratyush Yadav
2025-12-06 23:02 ` [RFC PATCH 03/10] liveupdate: do early initialization before hugepages are allocated Pratyush Yadav
2025-12-23 18:08 ` Pasha Tatashin
2025-12-29 21:23 ` Pratyush Yadav
2025-12-06 23:02 ` [RFC PATCH 04/10] liveupdate: flb: allow getting FLB data in early boot Pratyush Yadav
2025-12-18 18:25 ` Pasha Tatashin
2025-12-20 3:26 ` Pratyush Yadav
2025-12-20 15:11 ` Pasha Tatashin
2025-12-22 14:58 ` Pratyush Yadav
2025-12-06 23:02 ` [RFC PATCH 05/10] mm: hugetlb: export some functions to hugetlb-internal header Pratyush Yadav
2025-12-06 23:02 ` [RFC PATCH 06/10] liveupdate: hugetlb subsystem FLB state preservation Pratyush Yadav
2025-12-23 18:15 ` Pasha Tatashin
2025-12-29 21:21 ` Pratyush Yadav
2025-12-30 16:37 ` Pasha Tatashin
2025-12-06 23:02 ` [RFC PATCH 07/10] mm: hugetlb: don't allocate pages already in live update Pratyush Yadav
2025-12-06 23:02 ` [RFC PATCH 08/10] mm: hugetlb: disable CMA if liveupdate is enabled Pratyush Yadav
2025-12-23 18:16 ` Pasha Tatashin
2025-12-29 21:14 ` Pratyush Yadav [this message]
2025-12-06 23:02 ` [RFC PATCH 09/10] mm: hugetlb: allow freezing the inode Pratyush Yadav
2025-12-06 23:02 ` [RFC PATCH 10/10] liveupdate: allow preserving hugetlb-backed memfd Pratyush Yadav
2025-12-09 4:43 ` [RFC PATCH 00/10] liveupdate: hugetlb support Zhu Yanjun
2025-12-09 8:18 ` Pratyush Yadav
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