[slub rfc1 06/12] slub: Use freelist instead of "object" in __slab_alloc

[Christoph Lameter <cl@linux.com>]

[-- Attachment #1: use_freelist_instead_of_object --]
[-- Type: text/plain, Size: 3190 bytes --]

The variable "object" really refers to a list of objects that we
are handling. Since the lockless allocator path will depend on it
we rename the variable now.

Signed-off-by: Christoph Lameter <cl@linux.com>

---
 mm/slub.c |   29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c	2011-09-02 08:20:32.491219417 -0500
+++ linux-2.6/mm/slub.c	2011-09-02 08:20:39.221219372 -0500
@@ -2075,7 +2075,7 @@ static inline void *get_freelist(struct
 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 			  unsigned long addr, struct kmem_cache_cpu *c)
 {
-	void **object;
+	void *freelist;
 	struct page *page;
 	unsigned long flags;
 
@@ -2089,13 +2089,15 @@ static void *__slab_alloc(struct kmem_ca
 	c = this_cpu_ptr(s->cpu_slab);
 #endif
 
+	freelist = c->freelist;
 	page = c->page;
 	if (!page)
 		goto new_slab;
 
+
 	if (unlikely(!node_match(c, node))) {
 		stat(s, ALLOC_NODE_MISMATCH);
-		deactivate_slab(s, c->page, c->freelist);
+		deactivate_slab(s, page, freelist);
 		c->page = NULL;
 		c->freelist = NULL;
 		goto new_slab;
@@ -2103,9 +2105,9 @@ static void *__slab_alloc(struct kmem_ca
 
 	stat(s, ALLOC_SLOWPATH);
 
-	object = get_freelist(s, page);
+	freelist = get_freelist(s, page);
 
-	if (unlikely(!object)) {
+	if (unlikely(!freelist)) {
 		c->page = NULL;
 		stat(s, DEACTIVATE_BYPASS);
 		goto new_slab;
@@ -2114,18 +2116,21 @@ static void *__slab_alloc(struct kmem_ca
 	stat(s, ALLOC_REFILL);
 
 load_freelist:
+	/*
+	 * freelist is pointing to the list of objects to be used.
+	 * page is pointing to the page from which the objects are obtained.
+	 */
 	VM_BUG_ON(!page->frozen);
-	c->freelist = get_freepointer(s, object);
+	c->freelist = get_freepointer(s, freelist);
 	c->tid = next_tid(c->tid);
 	local_irq_restore(flags);
-	return object;
+	return freelist;
 
 new_slab:
 	page = get_partial(s, gfpflags, node);
 	if (page) {
 		stat(s, ALLOC_FROM_PARTIAL);
-		object = c->freelist;
-
+		freelist = c->freelist;
 		if (kmem_cache_debug(s))
 			goto debug;
 		goto load_freelist;
@@ -2142,7 +2147,7 @@ new_slab:
 		 * No other reference to the page yet so we can
 		 * muck around with it freely without cmpxchg
 		 */
-		object = page->freelist;
+		freelist = page->freelist;
 		page->freelist = NULL;
 		page->inuse = page->objects;
 
@@ -2159,14 +2164,14 @@ new_slab:
 	return NULL;
 
 debug:
-	if (!object || !alloc_debug_processing(s, page, object, addr))
+	if (!freelist || !alloc_debug_processing(s, page, freelist, addr))
 		goto new_slab;
 
-	deactivate_slab(s, c->page, get_freepointer(s, object));
+	deactivate_slab(s, c->page, get_freepointer(s, freelist));
 	c->page = NULL;
 	c->freelist = NULL;
 	local_irq_restore(flags);
-	return object;
+	return freelist;
 }
 
 /*

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