From: "Darrick J. Wong" <djwong@kernel.org>
To: Alex Sierra <alex.sierra@amd.com>
Cc: akpm@linux-foundation.org, Felix.Kuehling@amd.com,
linux-mm@kvack.org, rcampbell@nvidia.com,
linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org,
amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
hch@lst.de, jgg@nvidia.com, jglisse@redhat.com
Subject: Re: [PATCH v3 1/8] ext4/xfs: add page refcount helper
Date: Thu, 17 Jun 2021 09:11:52 -0700 [thread overview]
Message-ID: <20210617161152.GA158156@locust> (raw)
In-Reply-To: <20210617151705.15367-2-alex.sierra@amd.com>
On Thu, Jun 17, 2021 at 10:16:58AM -0500, Alex Sierra wrote:
> From: Ralph Campbell <rcampbell@nvidia.com>
>
> There are several places where ZONE_DEVICE struct pages assume a reference
> count == 1 means the page is idle and free. Instead of open coding this,
> add a helper function to hide this detail.
>
> v2:
> [AS]: rename dax_layout_is_idle_page func to dax_page_unused
>
> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
> Signed-off-by: Alex Sierra <alex.sierra@amd.com>
> ---
> fs/dax.c | 4 ++--
> fs/ext4/inode.c | 5 +----
> fs/xfs/xfs_file.c | 4 +---
> include/linux/dax.h | 10 ++++++++++
> 4 files changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index 26d5dcd2d69e..321f4ddc6643 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -358,7 +358,7 @@ static void dax_disassociate_entry(void *entry, struct address_space *mapping,
> for_each_mapped_pfn(entry, pfn) {
> struct page *page = pfn_to_page(pfn);
>
> - WARN_ON_ONCE(trunc && page_ref_count(page) > 1);
> + WARN_ON_ONCE(trunc && !dax_layout_is_idle_page(page));
> WARN_ON_ONCE(page->mapping && page->mapping != mapping);
> page->mapping = NULL;
> page->index = 0;
> @@ -372,7 +372,7 @@ static struct page *dax_busy_page(void *entry)
> for_each_mapped_pfn(entry, pfn) {
> struct page *page = pfn_to_page(pfn);
>
> - if (page_ref_count(page) > 1)
> + if (!dax_layout_is_idle_page(page))
> return page;
> }
> return NULL;
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index c173c8405856..9ee00186412f 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3972,10 +3972,7 @@ int ext4_break_layouts(struct inode *inode)
> if (!page)
> return 0;
>
> - error = ___wait_var_event(&page->_refcount,
> - atomic_read(&page->_refcount) == 1,
> - TASK_INTERRUPTIBLE, 0, 0,
> - ext4_wait_dax_page(ei));
> + error = dax_wait_page(ei, page, ext4_wait_dax_page);
> } while (error == 0);
>
> return error;
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 5b0f93f73837..39565fe5f817 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -782,9 +782,7 @@ xfs_break_dax_layouts(
> return 0;
>
> *retry = true;
> - return ___wait_var_event(&page->_refcount,
> - atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE,
> - 0, 0, xfs_wait_dax_page(inode));
> + return dax_wait_page(inode, page, xfs_wait_dax_page);
Mechanically, this looks like a straightforward replacement, so:
Acked-by: Darrick J. Wong <djwong@kernel.org>
--D
> }
>
> int
> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index b52f084aa643..8b5da1d60dbc 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -243,6 +243,16 @@ static inline bool dax_mapping(struct address_space *mapping)
> return mapping->host && IS_DAX(mapping->host);
> }
>
> +static inline bool dax_page_unused(struct page *page)
> +{
> + return page_ref_count(page) == 1;
> +}
> +
> +#define dax_wait_page(_inode, _page, _wait_cb) \
> + ___wait_var_event(&(_page)->_refcount, \
> + dax_page_unused(_page), \
> + TASK_INTERRUPTIBLE, 0, 0, _wait_cb(_inode))
> +
> #ifdef CONFIG_DEV_DAX_HMEM_DEVICES
> void hmem_register_device(int target_nid, struct resource *r);
> #else
> --
> 2.17.1
>
next prev parent reply other threads:[~2021-06-17 16:11 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-17 15:16 [PATCH v3 0/8] Support DEVICE_GENERIC memory in migrate_vma_* Alex Sierra
2021-06-17 15:16 ` [PATCH v3 1/8] ext4/xfs: add page refcount helper Alex Sierra
2021-06-17 16:11 ` Darrick J. Wong [this message]
2021-06-17 23:52 ` Dave Chinner
2021-06-19 16:14 ` Sierra Guiza, Alejandro (Alex)
2021-06-19 18:31 ` Alex Sierra
2021-06-17 15:16 ` [PATCH v3 2/8] mm: remove extra ZONE_DEVICE struct page refcount Alex Sierra
2021-06-17 19:16 ` Ralph Campbell
2021-06-28 16:46 ` Felix Kuehling
2021-06-30 0:23 ` Ralph Campbell
2021-06-17 15:17 ` [PATCH v3 3/8] kernel: resource: lookup_resource as exported symbol Alex Sierra
2021-06-17 15:17 ` [PATCH v3 4/8] drm/amdkfd: add SPM support for SVM Alex Sierra
2021-06-17 15:17 ` [PATCH v3 5/8] drm/amdkfd: generic type as sys mem on migration to ram Alex Sierra
2021-06-17 15:17 ` [PATCH v3 6/8] include/linux/mm.h: helpers to check zone device generic type Alex Sierra
2021-06-17 15:17 ` [PATCH v3 7/8] mm: add generic type support to migrate_vma helpers Alex Sierra
2021-06-17 15:17 ` [PATCH v3 8/8] mm: call pgmap->ops->page_free for DEVICE_GENERIC pages Alex Sierra
2021-06-17 15:56 ` [PATCH v3 0/8] Support DEVICE_GENERIC memory in migrate_vma_* Sierra Guiza, Alejandro (Alex)
2021-06-20 14:14 ` Theodore Ts'o
2021-06-23 21:49 ` Felix Kuehling
2021-06-24 5:30 ` Christoph Hellwig
2021-06-24 15:08 ` Felix Kuehling
2021-07-16 15:07 ` Theodore Y. Ts'o
2021-07-16 22:14 ` Felix Kuehling
2021-07-17 19:54 ` Sierra Guiza, Alejandro (Alex)
2021-07-23 22:46 ` Sierra Guiza, Alejandro (Alex)
2021-07-30 19:02 ` Felix Kuehling
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