[PATCHv6 2/7] slab, slub: use page->rcu_head instead of page->lru plus cast

From: Kirill A. Shutemov
Date: Tue Sep 15 2015 - 06:29:36 EST


We have properly typed page->rcu_head, no need to cast page->lru.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reviewed-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
---
mm/slab.c | 17 +++--------------
mm/slub.c | 5 +----
2 files changed, 4 insertions(+), 18 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index c77ebe6cc87c..90ba9170e0c3 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1888,21 +1888,10 @@ static void slab_destroy(struct kmem_cache *cachep, struct page *page)

freelist = page->freelist;
slab_destroy_debugcheck(cachep, page);
- if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
- struct rcu_head *head;
-
- /*
- * RCU free overloads the RCU head over the LRU.
- * slab_page has been overloeaded over the LRU,
- * however it is not used from now on so that
- * we can use it safely.
- */
- head = (void *)&page->rcu_head;
- call_rcu(head, kmem_rcu_free);
-
- } else {
+ if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU))
+ call_rcu(&page->rcu_head, kmem_rcu_free);
+ else
kmem_freepages(cachep, page);
- }

/*
* From now on, we don't use freelist
diff --git a/mm/slub.c b/mm/slub.c
index f614b5dc396b..6b6e771df1c7 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1507,10 +1507,7 @@ static void free_slab(struct kmem_cache *s, struct page *page)
VM_BUG_ON(s->reserved != sizeof(*head));
head = page_address(page) + offset;
} else {
- /*
- * RCU free overloads the RCU head over the LRU
- */
- head = (void *)&page->lru;
+ head = &page->rcu_head;
}

call_rcu(head, rcu_free_slab);
--
2.5.1

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