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 <gerald.schaefer@xxxxxxxxxx>
---
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
--
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