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Subject[PATCH v3 02/16] slub: use free_page instead of put_page for freeing kmalloc allocation
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 provided by the object allocators,
so we shouldn't be doing this ourselves. Aside from the consistency
change, we don't change the flow too much. put_page()'s would call its
dtor function, which is __free_pages. We also already do all of the
Compound page tests ourselves, and the Mlock test we lose don't really

[v2: modified Changelog ]

Signed-off-by: Glauber Costa <>
Acked-by: Christoph Lameter <>
CC: David Rientjes <>
CC: Pekka Enberg <>
mm/slub.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/slub.c b/mm/slub.c
index 9f86353..09a91d0 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3451,7 +3451,7 @@ void kfree(const void *x)
if (unlikely(!PageSlab(page))) {
- put_page(page);
+ __free_pages(page, compound_order(page));
slab_free(page->slab, page, object, _RET_IP_);

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