The allocator fastpath rework does change the usage of the list_lock.
Remove the list_lock processing from the functions that hide them from the
critical sections and move them into those critical sections.
This is turn simplifies the support functions (no __ variant needed anymore)
and simplifies the lock handling on bootstrap.
Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
---
mm/slub.c | 74 ++++++++++++++++++++++++++++++--------------------------------
1 file changed, 36 insertions(+), 38 deletions(-)
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2011-03-30 14:42:52.000000000 -0500
+++ linux-2.6/mm/slub.c 2011-03-30 14:42:55.000000000 -0500
@@ -904,25 +904,21 @@ static inline void slab_free_hook(struct
/*
* Tracking of fully allocated slabs for debugging purposes.
*/
-static void add_full(struct kmem_cache_node *n, struct page *page)
+static void add_full(struct kmem_cache *s,
+ struct kmem_cache_node *n, struct page *page)
{
- spin_lock(&n->list_lock);
+ if (!(s->flags & SLAB_STORE_USER))
+ return;
+
list_add(&page->lru, &n->full);
- spin_unlock(&n->list_lock);
}
static void remove_full(struct kmem_cache *s, struct page *page)
{
- struct kmem_cache_node *n;
-
if (!(s->flags & SLAB_STORE_USER))
return;
- n = get_node(s, page_to_nid(page));
-
- spin_lock(&n->list_lock);
list_del(&page->lru);
- spin_unlock(&n->list_lock);
}
/* Tracking of the number of slabs for debugging purposes */
@@ -1047,8 +1043,13 @@ static noinline int free_debug_processin
}
/* Special debug activities for freeing objects */
- if (!page->frozen && !page->freelist)
+ if (!page->frozen && !page->freelist) {
+ struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+
+ spin_lock(&n->list_lock);
remove_full(s, page);
+ spin_unlock(&n->list_lock);
+ }
if (s->flags & SLAB_STORE_USER)
set_track(s, object, TRACK_FREE, addr);
trace(s, page, object, 0);
@@ -1399,36 +1400,26 @@ static __always_inline int slab_trylock(
/*
* Management of partially allocated slabs
*/
-static void add_partial(struct kmem_cache_node *n,
+static inline void add_partial(struct kmem_cache_node *n,
struct page *page, int tail)
{
- spin_lock(&n->list_lock);
n->nr_partial++;
if (tail)
list_add_tail(&page->lru, &n->partial);
else
list_add(&page->lru, &n->partial);
- spin_unlock(&n->list_lock);
}
-static inline void __remove_partial(struct kmem_cache_node *n,
+static inline void remove_partial(struct kmem_cache_node *n,
struct page *page)
{
list_del(&page->lru);
n->nr_partial--;
}
-static void remove_partial(struct kmem_cache *s, struct page *page)
-{
- struct kmem_cache_node *n = get_node(s, page_to_nid(page));
-
- spin_lock(&n->list_lock);
- __remove_partial(n, page);
- spin_unlock(&n->list_lock);
-}
-
/*
- * Lock slab and remove from the partial list.
+ * Lock slab, remove from the partial list and put the object into the
+ * per cpu freelist.
*
* Must hold list_lock.
*/
@@ -1436,7 +1427,7 @@ static inline int lock_and_freeze_slab(s
struct page *page)
{
if (slab_trylock(page)) {
- __remove_partial(n, page);
+ remove_partial(n, page);
return 1;
}
return 0;
@@ -1553,12 +1544,17 @@ static void unfreeze_slab(struct kmem_ca
if (page->inuse) {
if (page->freelist) {
+ spin_lock(&n->list_lock);
add_partial(n, page, tail);
+ spin_unlock(&n->list_lock);
stat(s, tail ? DEACTIVATE_TO_TAIL : DEACTIVATE_TO_HEAD);
} else {
stat(s, DEACTIVATE_FULL);
- if (kmem_cache_debug(s) && (s->flags & SLAB_STORE_USER))
- add_full(n, page);
+ if (kmem_cache_debug(s) && (s->flags & SLAB_STORE_USER)) {
+ spin_lock(&n->list_lock);
+ add_full(s, n, page);
+ spin_unlock(&n->list_lock);
+ }
}
slab_unlock(page);
} else {
@@ -1574,7 +1570,9 @@ static void unfreeze_slab(struct kmem_ca
* kmem_cache_shrink can reclaim any empty slabs from
* the partial list.
*/
+ spin_lock(&n->list_lock);
add_partial(n, page, 1);
+ spin_unlock(&n->list_lock);
slab_unlock(page);
} else {
slab_unlock(page);
@@ -2114,7 +2112,11 @@ static void __slab_free(struct kmem_cach
* then add it.
*/
if (unlikely(!prior)) {
+ struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+
+ spin_lock(&n->list_lock);
add_partial(get_node(s, page_to_nid(page)), page, 1);
+ spin_unlock(&n->list_lock);
stat(s, FREE_ADD_PARTIAL);
}
@@ -2130,7 +2132,11 @@ slab_empty:
/*
* Slab still on the partial list.
*/
- remove_partial(s, page);
+ struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+
+ spin_lock(&n->list_lock);
+ remove_partial(n, page);
+ spin_unlock(&n->list_lock);
stat(s, FREE_REMOVE_PARTIAL);
}
slab_unlock(page);
@@ -2432,7 +2438,6 @@ static void early_kmem_cache_node_alloc(
{
struct page *page;
struct kmem_cache_node *n;
- unsigned long flags;
BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
@@ -2459,14 +2464,7 @@ static void early_kmem_cache_node_alloc(
init_kmem_cache_node(n, kmem_cache_node);
inc_slabs_node(kmem_cache_node, node, page->objects);
- /*
- * lockdep requires consistent irq usage for each lock
- * so even though there cannot be a race this early in
- * the boot sequence, we still disable irqs.
- */
- local_irq_save(flags);
add_partial(n, page, 0);
- local_irq_restore(flags);
}
static void free_kmem_cache_nodes(struct kmem_cache *s)
@@ -2744,7 +2742,7 @@ static void free_partial(struct kmem_cac
spin_lock_irqsave(&n->list_lock, flags);
list_for_each_entry_safe(page, h, &n->partial, lru) {
if (!page->inuse) {
- __remove_partial(n, page);
+ remove_partial(n, page);
discard_slab(s, page);
} else {
list_slab_objects(s, page,
@@ -3082,7 +3080,7 @@ int kmem_cache_shrink(struct kmem_cache
* may have freed the last object and be
* waiting to release the slab.
*/
- __remove_partial(n, page);
+ remove_partial(n, page);
slab_unlock(page);
discard_slab(s, page);
} else {
--
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