The slab allocators provide its users with memory regions, with very few placement guarantees. No user should assume an actual page is given by kmalloc calls that are multiple of a page in size. This means that we can be sure that every sane user of the interface would not mess with the page reference counting of the underlying page.
When freeing objects, the slub allocator will most of the time free empty pages by calling __free_pages(). But high-order kmalloc will be diposed by means of put_page() instead. It makes no sense to call put_page() in kernel pages that are not reference counted, which is the case here. Signed-off-by: Glauber Costa <[email protected]> CC: David Rientjes <[email protected]> CC: Pekka Enberg <[email protected]> CC: Christoph Lameter <[email protected]> --- mm/slub.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/slub.c b/mm/slub.c index e517d43..9ca4e20 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3453,7 +3453,7 @@ void kfree(const void *x) if (unlikely(!PageSlab(page))) { BUG_ON(!PageCompound(page)); kmemleak_free(x); - put_page(page); + __free_pages(page, compound_order(page)); return; } slab_free(page->slab, page, object, _RET_IP_); -- 1.7.11.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
