From: Jason Gunthorpe <jgg@nvidia.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Alistair Popple <apopple@nvidia.com>,
linux-mm@kvack.org, Matthew Wilcox <willy@infradead.org>,
Jan Kara <jack@suse.cz>, "Darrick J. Wong" <djwong@kernel.org>,
Christoph Hellwig <hch@lst.de>,
John Hubbard <jhubbard@nvidia.com>,
david@fromorbit.com, nvdimm@lists.linux.dev,
akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v3 10/25] fsdax: Introduce pgmap_request_folios()
Date: Mon, 17 Oct 2022 20:57:43 -0300 [thread overview]
Message-ID: <Y03r9wBs4Yk8LyC0@nvidia.com> (raw)
In-Reply-To: <634dc046bada2_4da329484@dwillia2-xfh.jf.intel.com.notmuch>
On Mon, Oct 17, 2022 at 01:51:18PM -0700, Dan Williams wrote:
> > A good design is that nothing has a struct folio * unless it can also
> > prove it has a non-zero refcount on it, and that is simply impossible
> > for any caller at this point.
>
> I agree that's a good design, and I think it is a bug to make this
> request on anything but a zero-refcount folio, but plumbing pgmap
> offsets to replace pfn_to_page() would require dax_direct_access() to
> shift from a pfn lookup to a pgmap + offset lookup.
That is fair for this series, but maybe the other pgmap users shouldn't be
converted to use this style of API?
Jason
next prev parent reply other threads:[~2022-10-17 23:57 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-14 23:56 [PATCH v3 00/25] Fix the DAX-gup mistake Dan Williams
2022-10-14 23:57 ` [PATCH v3 01/25] fsdax: Wait on @page not @page->_refcount Dan Williams
2022-10-14 23:57 ` [PATCH v3 02/25] fsdax: Use dax_page_idle() to document DAX busy page checking Dan Williams
2022-10-14 23:57 ` [PATCH v3 03/25] fsdax: Include unmapped inodes for page-idle detection Dan Williams
2022-10-14 23:57 ` [PATCH v3 04/25] fsdax: Introduce dax_zap_mappings() Dan Williams
2022-11-02 13:04 ` Aneesh Kumar K.V
2022-10-14 23:57 ` [PATCH v3 05/25] fsdax: Wait for pinned pages during truncate_inode_pages_final() Dan Williams
2022-10-14 23:57 ` [PATCH v3 06/25] fsdax: Validate DAX layouts broken before truncate Dan Williams
2022-10-14 23:57 ` [PATCH v3 07/25] fsdax: Hold dax lock over mapping insertion Dan Williams
2022-10-17 19:31 ` Jason Gunthorpe
2022-10-17 20:17 ` Dan Williams
2022-10-18 5:26 ` Christoph Hellwig
2022-10-18 17:30 ` Dan Williams
2022-10-14 23:57 ` [PATCH v3 08/25] fsdax: Update dax_insert_entry() calling convention to return an error Dan Williams
2022-10-14 23:57 ` [PATCH v3 09/25] fsdax: Rework for_each_mapped_pfn() to dax_for_each_folio() Dan Williams
2022-10-14 23:57 ` [PATCH v3 10/25] fsdax: Introduce pgmap_request_folios() Dan Williams
2022-10-17 6:31 ` Alistair Popple
2022-10-17 20:06 ` Dan Williams
2022-10-17 20:11 ` Jason Gunthorpe
2022-10-17 20:51 ` Dan Williams
2022-10-17 23:57 ` Jason Gunthorpe [this message]
2022-10-18 0:19 ` Dan Williams
2022-10-17 19:41 ` Jason Gunthorpe
2022-10-14 23:58 ` [PATCH v3 11/25] fsdax: Rework dax_insert_entry() calling convention Dan Williams
2022-10-14 23:58 ` [PATCH v3 12/25] fsdax: Cleanup dax_associate_entry() Dan Williams
2022-10-14 23:58 ` [PATCH v3 13/25] devdax: Minor warning fixups Dan Williams
2022-10-14 23:58 ` [PATCH v3 14/25] devdax: Fix sparse lock imbalance warning Dan Williams
2022-10-14 23:58 ` [PATCH v3 15/25] libnvdimm/pmem: Support pmem block devices without dax Dan Williams
2022-10-14 23:58 ` [PATCH v3 16/25] devdax: Move address_space helpers to the DAX core Dan Williams
2022-10-14 23:58 ` [PATCH v3 17/25] devdax: Sparse fixes for xarray locking Dan Williams
2022-10-14 23:58 ` [PATCH v3 18/25] devdax: Sparse fixes for vmfault_t / dax-entry conversions Dan Williams
2022-10-14 23:58 ` [PATCH v3 19/25] devdax: Sparse fixes for vm_fault_t in tracepoints Dan Williams
2022-10-14 23:58 ` [PATCH v3 20/25] devdax: add PUD support to the DAX mapping infrastructure Dan Williams
2022-10-14 23:59 ` [PATCH v3 21/25] devdax: Use dax_insert_entry() + dax_delete_mapping_entry() Dan Williams
2022-10-14 23:59 ` [PATCH v3 22/25] mm/memremap_pages: Replace zone_device_page_init() with pgmap_request_folios() Dan Williams
2022-10-17 19:17 ` Lyude Paul
2022-10-14 23:59 ` [PATCH v3 23/25] mm/memremap_pages: Initialize all ZONE_DEVICE pages to start at refcount 0 Dan Williams
2022-10-17 7:04 ` Alistair Popple
2022-10-17 19:48 ` Jason Gunthorpe
2022-10-14 23:59 ` [PATCH v3 24/25] mm/meremap_pages: Delete put_devmap_managed_page_refs() Dan Williams
2022-10-17 7:08 ` Alistair Popple
2022-10-14 23:59 ` [PATCH v3 25/25] mm/gup: Drop DAX pgmap accounting Dan Williams
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