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author | Ira Weiny <ira.weiny@intel.com> | 2019-06-06 00:49:22 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-07-31 08:27:03 +0300 |
commit | 30edc7c1fed524bb85fcf3ad7312f93411f48055 (patch) | |
tree | 90f2a92cc445ac9f991a7be47a111c1afb07baf2 /mm/swap.c | |
parent | b4e77006d5a77c13f84ea07767bf7790db0cd033 (diff) | |
download | linux-30edc7c1fed524bb85fcf3ad7312f93411f48055.tar.xz |
mm/swap: fix release_pages() when releasing devmap pages
[ Upstream commit c5d6c45e90c49150670346967971e14576afd7f1 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'mm/swap.c')
-rw-r--r-- | mm/swap.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/mm/swap.c b/mm/swap.c index a3fc028e338e..45fdbfb6b2a6 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); |