}
/*
- * Lock slab, remove from the partial list and put the object into the
- * per cpu freelist.
+ * Remove slab from the partial list, freeze it and
+ * return the pointer to the freelist.
*
* Returns a list of objects or NULL if it fails.
*
- * Must hold list_lock.
+ * Must hold list_lock since we modify the partial list.
*/
static inline void *acquire_slab(struct kmem_cache *s,
struct kmem_cache_node *n, struct page *page,
* The old freelist is the list of objects for the
* per cpu allocation list.
*/
- do {
- freelist = page->freelist;
- counters = page->counters;
- new.counters = counters;
- if (mode)
- new.inuse = page->objects;
+ freelist = page->freelist;
+ counters = page->counters;
+ new.counters = counters;
+ if (mode)
+ new.inuse = page->objects;
- VM_BUG_ON(new.frozen);
- new.frozen = 1;
+ VM_BUG_ON(new.frozen);
+ new.frozen = 1;
- } while (!__cmpxchg_double_slab(s, page,
+ if (!__cmpxchg_double_slab(s, page,
freelist, counters,
NULL, new.counters,
- "lock and freeze"));
+ "acquire_slab"))
+
+ return NULL;
remove_partial(n, page);
+ WARN_ON(!freelist);
return freelist;
}
if (!object) {
c->page = page;
- c->node = page_to_nid(page);
stat(s, ALLOC_FROM_PARTIAL);
object = t;
available = page->objects - page->inuse;
struct kmem_cache *s = info;
struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
- return !!(c->page);
+ return c->page || c->partial;
}
static void flush_all(struct kmem_cache *s)
static inline int node_match(struct kmem_cache_cpu *c, int node)
{
#ifdef CONFIG_NUMA
- if (node != NUMA_NO_NODE && c->node != node)
+ if (node != NUMA_NO_NODE && page_to_nid(c->page) != node)
return 0;
#endif
return 1;
static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
int node, struct kmem_cache_cpu **pc)
{
- void *object;
- struct kmem_cache_cpu *c;
- struct page *page = new_slab(s, flags, node);
+ void *freelist;
+ struct kmem_cache_cpu *c = *pc;
+ struct page *page;
+ freelist = get_partial(s, flags, node, c);
+
+ if (freelist)
+ return freelist;
+
+ page = new_slab(s, flags, node);
if (page) {
c = __this_cpu_ptr(s->cpu_slab);
if (c->page)
* 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;
stat(s, ALLOC_SLAB);
- c->node = page_to_nid(page);
c->page = page;
*pc = c;
} else
- object = NULL;
+ freelist = NULL;
- return object;
+ return freelist;
}
/*
do {
freelist = page->freelist;
counters = page->counters;
+
new.counters = counters;
VM_BUG_ON(!new.frozen);
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;
unsigned long flags;
local_irq_save(flags);
if (!c->page)
goto new_slab;
redo:
+
if (unlikely(!node_match(c, node))) {
stat(s, ALLOC_NODE_MISMATCH);
deactivate_slab(s, c);
}
/* must check again c->freelist in case of cpu migration or IRQ */
- object = c->freelist;
- if (object)
+ freelist = c->freelist;
+ if (freelist)
goto load_freelist;
stat(s, ALLOC_SLOWPATH);
- object = get_freelist(s, c->page);
+ freelist = get_freelist(s, c->page);
- if (!object) {
+ if (!freelist) {
c->page = NULL;
stat(s, DEACTIVATE_BYPASS);
goto new_slab;
stat(s, ALLOC_REFILL);
load_freelist:
- c->freelist = get_freepointer(s, object);
+ /*
+ * freelist is pointing to the list of objects to be used.
+ * page is pointing to the page from which the objects are obtained.
+ * That page must be frozen for per cpu allocations to work.
+ */
+ VM_BUG_ON(!c->page->frozen);
+ c->freelist = get_freepointer(s, freelist);
c->tid = next_tid(c->tid);
local_irq_restore(flags);
- return object;
+ return freelist;
new_slab:
if (c->partial) {
c->page = c->partial;
c->partial = c->page->next;
- c->node = page_to_nid(c->page);
stat(s, CPU_PARTIAL_ALLOC);
c->freelist = NULL;
goto redo;
}
- /* Then do expensive stuff like retrieving pages from the partial lists */
- object = get_partial(s, gfpflags, node, c);
+ freelist = new_slab_objects(s, gfpflags, node, &c);
- if (unlikely(!object)) {
+ if (unlikely(!freelist)) {
+ if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
+ slab_out_of_memory(s, gfpflags, node);
- object = new_slab_objects(s, gfpflags, node, &c);
-
- if (unlikely(!object)) {
- if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
- slab_out_of_memory(s, gfpflags, node);
-
- local_irq_restore(flags);
- return NULL;
- }
+ local_irq_restore(flags);
+ return NULL;
}
if (likely(!kmem_cache_debug(s)))
goto load_freelist;
/* Only entered in the debug case */
- if (!alloc_debug_processing(s, c->page, object, addr))
+ if (!alloc_debug_processing(s, c->page, freelist, addr))
goto new_slab; /* Slab failed checks. Next slab needed */
- c->freelist = get_freepointer(s, object);
+ c->freelist = get_freepointer(s, freelist);
deactivate_slab(s, c);
- c->node = NUMA_NO_NODE;
local_irq_restore(flags);
- return object;
+ return freelist;
}
/*
for_each_possible_cpu(cpu) {
struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
- int node = ACCESS_ONCE(c->node);
+ int node;
struct page *page;
- if (node < 0)
- continue;
page = ACCESS_ONCE(c->page);
- if (page) {
- if (flags & SO_TOTAL)
- x = page->objects;
- else if (flags & SO_OBJECTS)
- x = page->inuse;
- else
- x = 1;
+ if (!page)
+ continue;
- total += x;
- nodes[node] += x;
- }
- page = c->partial;
+ node = page_to_nid(page);
+ if (flags & SO_TOTAL)
+ x = page->objects;
+ else if (flags & SO_OBJECTS)
+ x = page->inuse;
+ else
+ x = 1;
+
+ total += x;
+ nodes[node] += x;
+ page = ACCESS_ONCE(c->partial);
if (page) {
x = page->pobjects;
total += x;
nodes[node] += x;
}
+
per_cpu[node]++;
}
}