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. Signed-off-by: Gerald Schaefer <[email protected]> --- mm/hugetlb.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 91ae1f5..770d83e 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1476,14 +1476,20 @@ static int dissolve_free_huge_page(struct page *page) 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; } -- 2.8.4
