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authorIra Weiny <ira.weiny@intel.com>2019-06-05 14:49:22 -0700
committerJason Gunthorpe <jgg@mellanox.com>2019-07-02 11:37:47 -0300
commitc5d6c45e90c49150670346967971e14576afd7f1 (patch)
treeb9073e3723e60db79eb3a0a8b3fee5e6eb84f22c /mm/swap.c
parent5a136b4ae327e7f6be9c984a010df8d7ea5a4f83 (diff)
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mm/swap: fix release_pages() when releasing devmap pages
release_pages() is an optimized version of a loop around put_page(). Unfortunately for devmap pages the logic is not entirely correct in release_pages(). This is because device pages can be more than type MEMORY_DEVICE_PUBLIC. There are in fact 4 types, private, public, FS DAX, and PCI P2PDMA. Some of these have specific needs to "put" the page while others do not. This logic to handle any special needs is contained in put_devmap_managed_page(). Therefore all devmap pages should be processed by this function where we can contain the correct logic for a page put. Handle all device type pages within release_pages() by calling put_devmap_managed_page() on all devmap pages. If put_devmap_managed_page() returns true the page has been put and we continue with the next page. A false return of put_devmap_managed_page() means the page did not require special processing and should fall to "normal" processing. This was found via code inspection while determining if release_pages() and the new put_user_pages() could be interchangeable.[1] [1] https://lkml.kernel.org/r/20190523172852.GA27175@iweiny-DESK2.sc.intel.com Link: https://lkml.kernel.org/r/20190605214922.17684-1-ira.weiny@intel.com Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'mm/swap.c')
-rw-r--r--mm/swap.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/mm/swap.c b/mm/swap.c
index 7ede3eddc12a..607c48229a1d 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -740,15 +740,20 @@ void release_pages(struct page **pages, int nr)
if (is_huge_zero_page(page))
continue;
- /* Device public page can not be huge page */
- if (is_device_public_page(page)) {
+ if (is_zone_device_page(page)) {
if (locked_pgdat) {
spin_unlock_irqrestore(&locked_pgdat->lru_lock,
flags);
locked_pgdat = NULL;
}
- put_devmap_managed_page(page);
- continue;
+ /*
+ * ZONE_DEVICE pages that return 'false' from
+ * put_devmap_managed_page() do not require special
+ * processing, and instead, expect a call to
+ * put_page_testzero().
+ */
+ if (put_devmap_managed_page(page))
+ continue;
}
page = compound_head(page);