NVDIMM Device and Persistent Memory development
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From: Jason Gunthorpe <jgg@nvidia.com>
To: Alistair Popple <apopple@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
	linux-mm@kvack.org, david@fromorbit.com, jhubbard@nvidia.com,
	rcampbell@nvidia.com, willy@infradead.org,
	linux-fsdevel@vger.kernel.org, jack@suse.cz, djwong@kernel.org,
	hch@lst.de, david@redhat.com, ruansy.fnst@fujitsu.com,
	nvdimm@lists.linux.dev, linux-xfs@vger.kernel.org,
	linux-ext4@vger.kernel.org, jglisse@redhat.com
Subject: Re: [RFC 00/10] fs/dax: Fix FS DAX page reference counts
Date: Fri, 12 Apr 2024 08:53:52 -0300	[thread overview]
Message-ID: <20240412115352.GY5383@nvidia.com> (raw)
In-Reply-To: <877ch35ahu.fsf@nvdebian.thelocal>

On Fri, Apr 12, 2024 at 04:55:31PM +1000, Alistair Popple wrote:

> Ok, I think I found the dragons you were talking about earlier for
> device-dax. I completely broke that because as you've already pointed
> out pmd_trans_huge() won't filter out DAX pages. That's fine for FS DAX
> (because the pages are essentially normal pages now anyway), but we
> don't have a PMD equivalent of vm_normal_page() which leads to all sorts
> of issues for DEVDAX.

What about vm_normal_page() depends on the radix level ?

Doesn't DEVDAX memory have struct page too?

> So I will probably have to add something like that unless we only need
> to support large (pmd/pud) mappings of DEVDAX pages on systems with
> CONFIG_ARCH_HAS_PTE_SPECIAL in which case I guess we could just filter
> based on pte_special().

pte_special should only be used by memory without a struct page, is
that what DEVDAX is?

Jason

  reply	other threads:[~2024-04-12 11:54 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-11  0:57 [RFC 00/10] fs/dax: Fix FS DAX page reference counts Alistair Popple
2024-04-11  0:57 ` [RFC 01/10] mm/gup.c: Remove redundant check for PCI P2PDMA page Alistair Popple
2024-04-11 12:59   ` Jason Gunthorpe
2024-04-11 13:47   ` David Hildenbrand
2024-04-12  1:37     ` Alistair Popple
2024-04-11  0:57 ` [RFC 02/10] mm/hmm: Remove dead check for HugeTLB and FS DAX Alistair Popple
2024-04-11 12:25   ` Jason Gunthorpe
2024-04-11 13:37     ` Peter Xu
2024-04-12  1:28       ` Alistair Popple
2024-04-11  0:57 ` [RFC 03/10] pci/p2pdma: Don't initialise page refcount to one Alistair Popple
2024-04-11 12:29   ` Jason Gunthorpe
2024-04-12  5:40     ` Alistair Popple
2024-04-12 17:20   ` Dan Williams
2024-05-09 21:59   ` Logan Gunthorpe
2024-05-09 23:14     ` Alistair Popple
2024-04-11  0:57 ` [RFC 04/10] fs/dax: Don't track page mapping/index Alistair Popple
2024-04-12 15:22   ` Jan Kara
2024-04-12 17:31     ` Dan Williams
2024-04-15  7:03       ` Alistair Popple
2024-04-15 20:51         ` Dan Williams
2024-04-16  0:07           ` Alistair Popple
2024-04-16  0:36             ` Dan Williams
2024-04-12 17:21   ` Dan Williams
2024-04-11  0:57 ` [RFC 05/10] fs/dax: Refactor wait for dax idle page Alistair Popple
2024-04-12 14:37   ` Jan Kara
2024-04-13 20:19   ` John Hubbard
2024-04-15  8:41     ` Alistair Popple
2024-04-11  0:57 ` [RFC 06/10] fs/dax: Add dax_page_free callback Alistair Popple
2024-04-11  0:57 ` [RFC 07/10] mm: Allow compound zone device pages Alistair Popple
2024-04-11 12:32   ` Jason Gunthorpe
2024-04-11 14:10   ` Matthew Wilcox
2024-04-12  1:38     ` Alistair Popple
2024-04-11  0:57 ` [RFC 08/10] fs/dax: Properly refcount fs dax pages Alistair Popple
2024-04-11  0:57 ` [RFC 09/10] mm/khugepage.c: Warn if trying to scan devmap pmd Alistair Popple
2024-04-11 13:45   ` David Hildenbrand
2024-04-12  1:34     ` Alistair Popple
2024-04-11  0:57 ` [RFC 10/10] mm: Remove pXX_devmap Alistair Popple
2024-04-11 12:57   ` Jason Gunthorpe
2024-04-11 17:28 ` [RFC 00/10] fs/dax: Fix FS DAX page reference counts Dan Williams
2024-04-11 17:35   ` Jason Gunthorpe
2024-04-11 17:56     ` Dan Williams
2024-04-12  3:54   ` Alistair Popple
2024-04-12  6:55     ` Alistair Popple
2024-04-12 11:53       ` Jason Gunthorpe [this message]
2024-04-12 17:32         ` Dan Williams

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