From: Alistair Popple <apopple@nvidia•com>
To: David Hildenbrand <david@redhat•com>
Cc: linmiaohe@huawei•com, nvdimm@lists•linux.dev, jack@suse•cz,
linux-doc@vger•kernel.org, djwong@kernel•org,
dave.hansen@linux•intel.com, david@fromorbit•com,
peterx@redhat•com, linux-mm@kvack•org, will@kernel•org,
hch@lst•de, dave.jiang@intel•com, vishal.l.verma@intel•com,
willy@infradead•org, jgg@ziepe•ca, catalin.marinas@arm•com,
linux-ext4@vger•kernel.org, ira.weiny@intel•com,
jhubbard@nvidia•com, npiggin@gmail•com,
linux-cxl@vger•kernel.org, bhelgaas@google•com,
dan.j.williams@intel•com, linux-arm-kernel@lists•infradead.org,
tytso@mit•edu, logang@deltatee•com, linux-kernel@vger•kernel.org,
linux-xfs@vger•kernel.org, linux-fsdevel@vger•kernel.org,
linuxppc-dev@lists•ozlabs.org
Subject: Re: [PATCH 09/13] gup: Don't allow FOLL_LONGTERM pinning of FS DAX pages
Date: Tue, 02 Jul 2024 09:47:03 +1000 [thread overview]
Message-ID: <87le2klleb.fsf@nvdebian.thelocal> (raw)
In-Reply-To: <f9539968-4b76-41a9-92d5-00082c7d1e96@redhat.com>
David Hildenbrand <david@redhat•com> writes:
> On 27.06.24 02:54, Alistair Popple wrote:
>> Longterm pinning of FS DAX pages should already be disallowed by
>> various pXX_devmap checks. However a future change will cause these
>> checks to be invalid for FS DAX pages so make
>> folio_is_longterm_pinnable() return false for FS DAX pages.
>> Signed-off-by: Alistair Popple <apopple@nvidia•com>
>> ---
>> include/linux/memremap.h | 11 +++++++++++
>> include/linux/mm.h | 4 ++++
>> 2 files changed, 15 insertions(+)
>> diff --git a/include/linux/memremap.h b/include/linux/memremap.h
>> index 6505713..19a448e 100644
>> --- a/include/linux/memremap.h
>> +++ b/include/linux/memremap.h
>> @@ -193,6 +193,17 @@ static inline bool folio_is_device_coherent(const struct folio *folio)
>> return is_device_coherent_page(&folio->page);
>> }
>> +static inline bool is_device_dax_page(const struct page *page)
>> +{
>> + return is_zone_device_page(page) &&
>> + page_dev_pagemap(page)->type == MEMORY_DEVICE_FS_DAX;
>> +}
>> +
>> +static inline bool folio_is_device_dax(const struct folio *folio)
>> +{
>> + return is_device_dax_page(&folio->page);
>> +}
>> +
>> #ifdef CONFIG_ZONE_DEVICE
>> void zone_device_page_init(struct page *page);
>> void *memremap_pages(struct dev_pagemap *pgmap, int nid);
>> diff --git a/include/linux/mm.h b/include/linux/mm.h
>> index b84368b..4d1cdea 100644
>> --- a/include/linux/mm.h
>> +++ b/include/linux/mm.h
>> @@ -2032,6 +2032,10 @@ static inline bool folio_is_longterm_pinnable(struct folio *folio)
>> if (folio_is_device_coherent(folio))
>> return false;
>> + /* DAX must also always allow eviction. */
>> + if (folio_is_device_dax(folio))
>> + return false;
>> +
>> /* Otherwise, non-movable zone folios can be pinned. */
>> return !folio_is_zone_movable(folio);
>>
>
> Why is the check in check_vma_flags() insufficient? GUP-fast maybe?
Right. This came up when I was changing the code for GUP-fast, but also
they shouldn't be longterm pinnable and adding the case to
folio_is_longterm_pinnable() is an excellent way of documenting that.
next prev parent reply other threads:[~2024-07-01 23:54 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-27 0:54 [PATCH 00/13] fs/dax: Fix FS DAX page reference counts Alistair Popple
2024-06-27 0:54 ` [PATCH 01/13] mm/gup.c: Remove redundant check for PCI P2PDMA page Alistair Popple
2024-06-27 6:36 ` Dan Williams
2024-06-27 0:54 ` [PATCH 02/13] pci/p2pdma: Don't initialise page refcount to one Alistair Popple
2024-06-27 5:30 ` Christoph Hellwig
2024-06-29 21:28 ` Bjorn Helgaas
2024-06-27 0:54 ` [PATCH 03/13] fs/dax: Refactor wait for dax idle page Alistair Popple
2024-06-27 5:31 ` Christoph Hellwig
2024-06-27 0:54 ` [PATCH 04/13] fs/dax: Add dax_page_free callback Alistair Popple
2024-06-27 5:33 ` Christoph Hellwig
2024-06-27 23:48 ` Alistair Popple
2024-06-27 0:54 ` [PATCH 05/13] mm: Allow compound zone device pages Alistair Popple
2024-06-27 5:35 ` Christoph Hellwig
2024-06-27 0:54 ` [PATCH 06/13] mm/memory: Add dax_insert_pfn Alistair Popple
2024-06-27 5:22 ` Christoph Hellwig
2024-06-27 11:33 ` Jan Kara
2024-09-06 6:21 ` Alistair Popple
2024-07-02 7:18 ` David Hildenbrand
2024-07-02 10:47 ` Alistair Popple
2024-07-02 11:46 ` Christoph Hellwig
2024-07-02 11:53 ` David Hildenbrand
2024-06-27 0:54 ` [PATCH 07/13] huge_memory: Allow mappings of PUD sized pages Alistair Popple
2024-06-27 22:26 ` kernel test robot
2024-07-02 7:16 ` David Hildenbrand
2024-07-02 10:19 ` Alistair Popple
2024-07-02 11:02 ` David Hildenbrand
2024-07-02 11:30 ` Alistair Popple
2024-07-02 13:01 ` David Hildenbrand
2024-07-02 11:51 ` Christoph Hellwig
2024-06-27 0:54 ` [PATCH 08/13] huge_memory: Allow mappings of PMD " Alistair Popple
2024-06-27 0:54 ` [PATCH 09/13] gup: Don't allow FOLL_LONGTERM pinning of FS DAX pages Alistair Popple
2024-07-01 8:59 ` David Hildenbrand
2024-07-01 23:47 ` Alistair Popple [this message]
2024-07-02 10:48 ` David Hildenbrand
2024-06-27 0:54 ` [PATCH 10/13] fs/dax: Properly refcount fs dax pages Alistair Popple
2024-06-27 5:44 ` Christoph Hellwig
2024-09-06 6:00 ` Alistair Popple
2024-06-27 0:54 ` [PATCH 11/13] huge_memory: Remove dead vmf_insert_pXd code Alistair Popple
2024-07-05 14:24 ` Peter Xu
2024-07-09 4:07 ` Alistair Popple
2024-07-09 15:56 ` Peter Xu
2024-07-12 2:40 ` Alistair Popple
2024-07-12 15:52 ` Peter Xu
2024-06-27 0:54 ` [PATCH 12/13] mm: Remove pXX_devmap callers Alistair Popple
2024-06-27 0:54 ` [PATCH 13/13] mm: Remove devmap related functions and page table bits Alistair Popple
2024-06-27 23:04 ` kernel test robot
2024-06-28 2:12 ` kernel test robot
2024-07-08 11:35 ` Will Deacon
2024-06-27 6:58 ` [PATCH 00/13] fs/dax: Fix FS DAX page reference counts Dan Williams
2024-06-27 7:15 ` Alistair Popple
2024-06-27 20:24 ` Dan Williams
2024-06-28 0:06 ` Alistair Popple
2024-07-01 4:24 ` Dave Chinner
2024-07-01 8:33 ` Alistair Popple
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