3.16.50-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Gerald Schaefer <[email protected]> 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/[email protected] Signed-off-by: Gerald Schaefer <[email protected]> Acked-by: Michal Hocko <[email protected]> Acked-by: Naoya Horiguchi <[email protected]> Cc: "Kirill A . Shutemov" <[email protected]> Cc: Vlastimil Babka <[email protected]> Cc: Mike Kravetz <[email protected]> Cc: "Aneesh Kumar K . V" <[email protected]> Cc: Martin Schwidefsky <[email protected]> Cc: Heiko Carstens <[email protected]> Cc: Rui Teng <[email protected]> Cc: Dave Hansen <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Arnd Bergmann <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> --- mm/hugetlb.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1105,14 +1105,20 @@ 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; }
