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| author | Gerald Schaefer <gerald.schaefer@de.ibm.com> | 2016-10-07 17:01:13 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-10-31 05:02:12 -0600 |
| commit | ae1d0b6ec8ec9564ff80b63c73d167fc87e8fb28 (patch) | |
| tree | 2f90828398b4775e5508850c21a8ccc143c0c5ee | |
| parent | 8f858254414942cff6fcdc6a91cfbb4b81dc9036 (diff) | |
| download | lwn-ae1d0b6ec8ec9564ff80b63c73d167fc87e8fb28.tar.gz lwn-ae1d0b6ec8ec9564ff80b63c73d167fc87e8fb28.zip | |
mm/hugetlb: improve locking in dissolve_free_huge_pages()
commit eb03aa008561004257900983193d024e57abdd96 upstream.
For every pfn aligned to minimum_order, dissolve_free_huge_pages() will
call dissolve_free_huge_page() which takes the hugetlb spinlock, even if
the page is not huge at all or a hugepage that is in-use.
Improve this by doing the PageHuge() and page_count() checks already in
dissolve_free_huge_pages() before calling dissolve_free_huge_page(). In
dissolve_free_huge_page(), when holding the spinlock, those checks need
to be revalidated.
Link: http://lkml.kernel.org/r/20160926172811.94033-4-gerald.schaefer@de.ibm.com
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Rui Teng <rui.teng@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | mm/hugetlb.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 91ae1f567997..770d83eb3f48 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1476,14 +1476,20 @@ out: int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn; + struct page *page; int rc = 0; if (!hugepages_supported()) return rc; - for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) - if (rc = dissolve_free_huge_page(pfn_to_page(pfn))) - break; + for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) { + page = pfn_to_page(pfn); + if (PageHuge(page) && !page_count(page)) { + rc = dissolve_free_huge_page(page); + if (rc) + break; + } + } return rc; } |