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 v1 01/14] ext4/xfs: add page refcount helper
Date: Wed, 25 Aug 2021 08:49:23 -0700 [thread overview]
Message-ID: <20210825154923.GF12640@magnolia> (raw)
In-Reply-To: <20210825034828.12927-2-alex.sierra@amd.com>
On Tue, Aug 24, 2021 at 10:48:15PM -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.
>
> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
> Signed-off-by: Alex Sierra <alex.sierra@amd.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
Looks fine to me,
Acked-by: Darrick J. Wong <djwong@kernel.org>
--D
> ---
> v3:
> [AS]: rename dax_layout_is_idle_page func to dax_page_unused
>
> v4:
> [AS]: This ref count functionality was missing on fuse/dax.c.
> ---
> fs/dax.c | 4 ++--
> fs/ext4/inode.c | 5 +----
> fs/fuse/dax.c | 4 +---
> fs/xfs/xfs_file.c | 4 +---
> include/linux/dax.h | 10 ++++++++++
> 5 files changed, 15 insertions(+), 12 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index 62352cbcf0f4..c387d09e3e5a 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -369,7 +369,7 @@ 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_page_unused(page));
> WARN_ON_ONCE(page->mapping && page->mapping != mapping);
> page->mapping = NULL;
> page->index = 0;
> @@ -383,7 +383,7 @@ 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_page_unused(page))
> return page;
> }
> return NULL;
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index fe6045a46599..05ffe6875cb1 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3971,10 +3971,7 @@ 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/fuse/dax.c b/fs/fuse/dax.c
> index ff99ab2a3c43..2b1f190ba78a 100644
> --- a/fs/fuse/dax.c
> +++ b/fs/fuse/dax.c
> @@ -677,9 +677,7 @@ static int __fuse_dax_break_layouts(struct inode *inode, bool *retry,
> return 0;
>
> *retry = true;
> - return ___wait_var_event(&page->_refcount,
> - atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE,
> - 0, 0, fuse_wait_dax_page(inode));
> + return dax_wait_page(inode, page, fuse_wait_dax_page);
> }
>
> /* dmap_end == 0 leads to unmapping of whole file */
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 396ef36dcd0a..182057281086 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -840,9 +840,7 @@ 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);
> }
>
> 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
> --
> 2.32.0
>
next prev parent reply other threads:[~2021-08-25 15:49 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-25 3:48 [PATCH v1 00/14] Add MEMORY_DEVICE_PUBLIC for CPU-accessible coherent device memory Alex Sierra
2021-08-25 3:48 ` [PATCH v1 01/14] ext4/xfs: add page refcount helper Alex Sierra
2021-08-25 7:35 ` Christoph Hellwig
2021-08-25 15:09 ` Theodore Ts'o
2021-08-25 15:49 ` Darrick J. Wong [this message]
2021-08-25 3:48 ` [PATCH v1 02/14] mm: remove extra ZONE_DEVICE struct page refcount Alex Sierra
2021-08-25 7:35 ` Christoph Hellwig
2021-08-25 11:15 ` Vlastimil Babka
2021-08-25 17:49 ` Ralph Campbell
2021-08-27 11:26 ` Vlastimil Babka
2021-08-25 3:48 ` [PATCH v1 03/14] mm: add iomem vma selection for memory migration Alex Sierra
2021-08-25 7:40 ` Christoph Hellwig
2021-08-25 7:46 ` Christoph Hellwig
2021-08-25 18:24 ` Sierra Guiza, Alejandro (Alex)
2021-08-26 22:27 ` Felix Kuehling
2021-08-30 8:28 ` Christoph Hellwig
2021-08-30 17:04 ` Felix Kuehling
2021-09-01 8:29 ` Christoph Hellwig
2021-09-01 15:40 ` Felix Kuehling
2021-09-01 22:03 ` Dave Chinner
2021-09-01 23:07 ` Felix Kuehling
2021-09-02 1:14 ` Dave Chinner
2021-09-09 4:55 ` Felix Kuehling
2021-09-02 8:18 ` Christoph Hellwig
2021-09-02 18:07 ` Dan Williams
2021-09-09 4:02 ` Felix Kuehling
2021-08-25 14:24 ` Felix Kuehling
2021-08-25 3:48 ` [PATCH v1 04/14] mm: add zone device public type memory support Alex Sierra
2021-08-25 3:48 ` [PATCH v1 05/14] drm/amdkfd: ref count init for device pages Alex Sierra
2021-08-25 14:34 ` Felix Kuehling
2021-08-25 3:48 ` [PATCH v1 06/14] drm/amdkfd: add SPM support for SVM Alex Sierra
2021-08-25 14:45 ` Felix Kuehling
2021-08-25 3:48 ` [PATCH v1 07/14] drm/amdkfd: public type as sys mem on migration to ram Alex Sierra
2021-08-25 3:48 ` [PATCH v1 08/14] mm: add public type support to migrate_vma helpers Alex Sierra
2021-08-25 7:47 ` Christoph Hellwig
2021-08-25 3:48 ` [PATCH v1 09/14] mm: call pgmap->ops->page_free for DEVICE_PUBLIC pages Alex Sierra
2021-08-25 7:46 ` Christoph Hellwig
2021-08-25 3:48 ` [PATCH v1 10/14] lib: test_hmm add ioctl to get zone device type Alex Sierra
2021-08-25 3:48 ` [PATCH v1 11/14] lib: test_hmm add module param for " Alex Sierra
2021-08-25 3:48 ` [PATCH v1 12/14] lib: add support for device public type in test_hmm Alex Sierra
2021-08-25 3:48 ` [PATCH v1 13/14] tools: update hmm-test to support device public type Alex Sierra
2021-08-25 3:48 ` [PATCH v1 14/14] tools: update test_hmm script to support SP config Alex Sierra
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