From: David Hildenbrand <david@redhat.com>
To: Alistair Popple <apopple@nvidia.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, nvdimm@lists.linux.dev,
Andrew Morton <akpm@linux-foundation.org>,
Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>,
Dan Williams <dan.j.williams@intel.com>,
Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>, Zi Yan <ziy@nvidia.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Nico Pache <npache@redhat.com>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Barry Song <baohua@kernel.org>, Vlastimil Babka <vbabka@suse.cz>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>, Jann Horn <jannh@google.com>,
Pedro Falcato <pfalcato@suse.de>
Subject: Re: [PATCH RFC 07/14] fs/dax: use vmf_insert_folio_pmd() to insert the huge zero folio
Date: Wed, 25 Jun 2025 11:03:11 +0200 [thread overview]
Message-ID: <74acb38f-da34-448d-9b73-37433a5e342c@redhat.com> (raw)
In-Reply-To: <cneygxe547b73gcfyjqfgdv2scxjeluwj5cpcsws4gyhx7ejgr@nxkrhie7o2th>
On 24.06.25 03:16, Alistair Popple wrote:
> On Tue, Jun 17, 2025 at 05:43:38PM +0200, David Hildenbrand wrote:
>> Let's convert to vmf_insert_folio_pmd().
>>
>> In the unlikely case there is already something mapped, we'll now still
>> call trace_dax_pmd_load_hole() and return VM_FAULT_NOPAGE.
>>
>> That should probably be fine, no need to add special cases for that.
>
> I'm not sure about that. Consider dax_iomap_pmd_fault() -> dax_fault_iter() ->
> dax_pmd_load_hole(). It calls split_huge_pmd() in response to VM_FAULT_FALLBACK
> which will no longer happen, what makes that ok?
My reasoning was that this is the exact same behavior other
vmf_insert_folio_pmd() users here would result in.
But let me dig into the details.
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2025-06-25 9:03 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-17 15:43 [PATCH RFC 00/14] mm: vm_normal_page*() + CoW PFNMAP improvements David Hildenbrand
2025-06-17 15:43 ` [PATCH RFC 01/14] mm/memory: drop highest_memmap_pfn sanity check in vm_normal_page() David Hildenbrand
2025-06-20 12:50 ` Oscar Salvador
2025-06-23 14:04 ` David Hildenbrand
2025-06-25 7:54 ` Oscar Salvador
2025-07-03 12:34 ` Lance Yang
2025-07-03 12:39 ` David Hildenbrand
2025-07-03 14:44 ` Lance Yang
2025-07-04 12:40 ` David Hildenbrand
2025-07-07 6:31 ` Hugh Dickins
2025-07-07 13:19 ` David Hildenbrand
2025-07-08 2:52 ` Hugh Dickins
2025-07-11 15:30 ` David Hildenbrand
2025-07-11 18:49 ` Hugh Dickins
2025-07-11 18:57 ` David Hildenbrand
2025-06-25 7:55 ` Oscar Salvador
2025-07-03 14:50 ` Lance Yang
2025-06-17 15:43 ` [PATCH RFC 02/14] mm: drop highest_memmap_pfn David Hildenbrand
2025-06-20 13:04 ` Oscar Salvador
2025-06-20 18:11 ` Pedro Falcato
2025-06-17 15:43 ` [PATCH RFC 03/14] mm: compare pfns only if the entry is present when inserting pfns/pages David Hildenbrand
2025-06-20 13:27 ` Oscar Salvador
2025-06-23 19:22 ` David Hildenbrand
2025-06-20 18:24 ` Pedro Falcato
2025-06-23 19:19 ` David Hildenbrand
2025-06-17 15:43 ` [PATCH RFC 04/14] mm/huge_memory: move more common code into insert_pmd() David Hildenbrand
2025-06-20 14:12 ` Oscar Salvador
2025-07-07 2:48 ` Alistair Popple
2025-06-17 15:43 ` [PATCH RFC 05/14] mm/huge_memory: move more common code into insert_pud() David Hildenbrand
2025-06-20 14:15 ` Oscar Salvador
2025-07-07 2:51 ` Alistair Popple
2025-06-17 15:43 ` [PATCH RFC 06/14] mm/huge_memory: support huge zero folio in vmf_insert_folio_pmd() David Hildenbrand
2025-06-25 8:15 ` Oscar Salvador
2025-06-25 8:17 ` Oscar Salvador
2025-06-25 8:20 ` Oscar Salvador
2025-06-25 8:59 ` David Hildenbrand
2025-06-17 15:43 ` [PATCH RFC 07/14] fs/dax: use vmf_insert_folio_pmd() to insert the huge zero folio David Hildenbrand
2025-06-24 1:16 ` Alistair Popple
2025-06-25 9:03 ` David Hildenbrand [this message]
2025-07-04 13:22 ` David Hildenbrand
2025-07-07 11:50 ` Alistair Popple
2025-06-17 15:43 ` [PATCH RFC 08/14] mm/huge_memory: mark PMD mappings of the huge zero folio special David Hildenbrand
2025-06-25 8:32 ` Oscar Salvador
2025-07-14 12:41 ` David Hildenbrand
2025-06-17 15:43 ` [PATCH RFC 09/14] mm/memory: introduce is_huge_zero_pfn() and use it in vm_normal_page_pmd() David Hildenbrand
2025-06-25 8:37 ` Oscar Salvador
2025-06-17 15:43 ` [PATCH RFC 10/14] mm/memory: factor out common code from vm_normal_page_*() David Hildenbrand
2025-06-25 8:53 ` Oscar Salvador
2025-06-25 8:57 ` David Hildenbrand
2025-06-25 9:20 ` Oscar Salvador
2025-06-25 10:14 ` David Hildenbrand
2025-06-17 15:43 ` [PATCH RFC 11/14] mm: remove "horrible special case to handle copy-on-write behaviour" David Hildenbrand
2025-06-25 8:47 ` David Hildenbrand
2025-06-25 9:02 ` Oscar Salvador
2025-06-25 9:04 ` David Hildenbrand
2025-06-17 15:43 ` [PATCH RFC 12/14] mm: drop addr parameter from vm_normal_*_pmd() David Hildenbrand
2025-06-17 15:43 ` [PATCH RFC 13/14] mm: introduce and use vm_normal_page_pud() David Hildenbrand
2025-06-25 9:22 ` Oscar Salvador
2025-06-17 15:43 ` [PATCH RFC 14/14] mm: rename vm_ops->find_special_page() to vm_ops->find_normal_page() David Hildenbrand
2025-06-25 9:34 ` Oscar Salvador
2025-07-14 14:19 ` David Hildenbrand
2025-06-17 16:18 ` [PATCH RFC 00/14] mm: vm_normal_page*() + CoW PFNMAP improvements David Hildenbrand
2025-06-17 18:25 ` David Hildenbrand
2025-06-25 8:49 ` Lorenzo Stoakes
2025-06-25 8:55 ` David Hildenbrand
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