Add a couple of functions that will be used later to manage the per cpu
freelists.
Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
---
mm/slub.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 52 insertions(+)
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2011-11-10 13:50:40.250719277 -0600
+++ linux-2.6/mm/slub.c 2011-11-10 13:56:05.602531668 -0600
@@ -2111,6 +2111,58 @@ static inline void *new_slab_objects(str
}
/*
+ * Retrieve pointer to the current freelist and
+ * zap the per cpu object list.
+ *
+ * Returns NULL if there was no object on the freelist.
+ */
+void *get_cpu_objects(struct kmem_cache *s)
+{
+ void *freelist;
+ unsigned long tid;
+
+ do {
+ struct kmem_cache_cpu *c = this_cpu_ptr(s->cpu_slab);
+
+ tid = c->tid;
+ barrier();
+ freelist = c->freelist;
+ if (!freelist)
+ return NULL;
+
+ } while (!this_cpu_cmpxchg_double(s->cpu_slab->freelist, s->cpu_slab->tid,
+ freelist, tid,
+ NULL, next_tid(tid)));
+
+ return freelist;
+}
+
+/*
+ * Set the per cpu object list to the freelist. The page must
+ * be frozen.
+ *
+ * Page will be unfrozen (and the freelist object put onto the pages freelist)
+ * if the per cpu freelist has been used in the meantime.
+ */
+static inline void put_cpu_objects(struct kmem_cache *s,
+ struct page *page, void *freelist)
+{
+ unsigned long tid;
+
+ tid = this_cpu_read(s->cpu_slab->tid);
+ barrier();
+
+ VM_BUG_ON(!page->frozen);
+ if (!irqsafe_cpu_cmpxchg_double(s->cpu_slab->freelist, s->cpu_slab->tid,
+ NULL, tid, freelist, next_tid(tid)))
+
+ /*
+ * There was an intervening free or alloc. Cannot free to the
+ * per cpu queue. Must unfreeze page.
+ */
+ deactivate_slab(s, page, freelist);
+}
+/*
* Check the page->freelist of a page and either transfer the freelist to the per cpu freelist
* or deactivate the page.
*
--
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