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mm/ZONE_DEVICE: special case put_page() for device private pages

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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>
This commit is contained in:
Jérôme Glisse
2017-09-08 16:11:46 -07:00
committed by Linus Torvalds
parent 5042db43cc
commit 7b2d55d2c8
4 changed files with 67 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

25
kernel/memremap.c
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@@ -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 */