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| author | Jérôme Glisse <jglisse@redhat.com> | 2017-09-08 16:11:46 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-08 18:26:46 -0700 |
| commit | 7b2d55d2c8961ae9d456d3133f4ae2f0fbd3e14f (patch) | |
| tree | 226b098cd8089f23756ca439e9e64d43a66defdb /kernel/memremap.c | |
| parent | 5042db43cc26f51eed51c56192e2c2317e44315f (diff) | |
| download | lwn-7b2d55d2c8961ae9d456d3133f4ae2f0fbd3e14f.tar.gz lwn-7b2d55d2c8961ae9d456d3133f4ae2f0fbd3e14f.zip | |
mm/ZONE_DEVICE: special case put_page() for device private pages
A ZONE_DEVICE page that reach a refcount of 1 is free ie no longer have
any user. For device private pages this is important to catch and thus we
need to special case put_page() for this.
Link: http://lkml.kernel.org/r/20170817000548.32038-9-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/memremap.c')
| -rw-r--r-- | kernel/memremap.c | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/kernel/memremap.c b/kernel/memremap.c index f1d1e0dfe8b4..1403cf16fa61 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -11,7 +11,6 @@ * General Public License for more details. */ #include <linux/radix-tree.h> -#include <linux/memremap.h> #include <linux/device.h> #include <linux/types.h> #include <linux/pfn_t.h> @@ -500,3 +499,27 @@ struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start) return pgmap ? pgmap->altmap : NULL; } #endif /* CONFIG_ZONE_DEVICE */ + + +#ifdef CONFIG_DEVICE_PRIVATE +void put_zone_device_private_page(struct page *page) +{ + int count = page_ref_dec_return(page); + + /* + * If refcount is 1 then page is freed and refcount is stable as nobody + * holds a reference on the page. + */ + if (count == 1) { + /* Clear Active bit in case of parallel mark_page_accessed */ + __ClearPageActive(page); + __ClearPageWaiters(page); + + page->mapping = NULL; + + page->pgmap->page_free(page, page->pgmap->data); + } else if (!count) + __put_page(page); +} +EXPORT_SYMBOL(put_zone_device_private_page); +#endif /* CONFIG_DEVICE_PRIVATE */ |