On Mon, Nov 12 2012, Marek Szyprowski wrote:
Memory return to free_contig_range() must have no other references. Let kernel to complain loudly if page reference count is not equal to 1.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 022e4ed..290c2eb 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5888,8 +5888,13 @@ done: void free_contig_range(unsigned long pfn, unsigned nr_pages) {
- for (; nr_pages--; ++pfn)
__free_page(pfn_to_page(pfn));
- struct page *page = pfn_to_page(pfn);
- int refcount = nr_pages;
- for (; nr_pages--; page++) {
refcount -= page_count(page) == 1;
__free_page(page);
- }
- WARN(refcount != 0, "some pages are still in use!\n");
This decrementing logic seem backward to me. Why not:
struct page *page = pfn_to_page(pfn); unsigned int refcount = 0; for (; nr_pages--; page++) { refcount += page_count(page) != 1; __free_page(page); } WARN(refcount != 0, "some pages are still in use!\n");
} #endif