slub: Fix up comments
Provide comments and fix up various spelling / style issues.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
diff --git a/mm/slub.c b/mm/slub.c
index 72f5f4e..10d5469 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -291,6 +291,7 @@
#endif
}
+/* Verify that a pointer has an address that is valid within a slab page */
static inline int check_valid_pointer(struct kmem_cache *s,
struct page *page, const void *object)
{
@@ -619,7 +620,7 @@
* A. Free pointer (if we cannot overwrite object on free)
* B. Tracking data for SLAB_STORE_USER
* C. Padding to reach required alignment boundary or at mininum
- * one word if debuggin is on to be able to detect writes
+ * one word if debugging is on to be able to detect writes
* before the word boundary.
*
* Padding is done using 0x5a (POISON_INUSE)
@@ -1268,7 +1269,7 @@
* may return off node objects because partial slabs are obtained
* from other nodes and filled up.
*
- * If /sys/slab/xx/defrag_ratio is set to 100 (which makes
+ * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
* defrag_ratio = 1000) then every (well almost) allocation will
* first attempt to defrag slab caches on other nodes. This means
* scanning over all nodes to look for partial slabs which may be
@@ -1343,9 +1344,11 @@
* Adding an empty slab to the partial slabs in order
* to avoid page allocator overhead. This slab needs
* to come after the other slabs with objects in
- * order to fill them up. That way the size of the
- * partial list stays small. kmem_cache_shrink can
- * reclaim empty slabs from the partial list.
+ * so that the others get filled first. That way the
+ * size of the partial list stays small.
+ *
+ * kmem_cache_shrink can reclaim any empty slabs from the
+ * partial list.
*/
add_partial(n, page, 1);
slab_unlock(page);
@@ -1368,7 +1371,7 @@
if (c->freelist)
stat(c, DEACTIVATE_REMOTE_FREES);
/*
- * Merge cpu freelist into freelist. Typically we get here
+ * Merge cpu freelist into slab freelist. Typically we get here
* because both freelists are empty. So this is unlikely
* to occur.
*/
@@ -1399,6 +1402,7 @@
/*
* Flush cpu slab.
+ *
* Called from IPI handler with interrupts disabled.
*/
static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
@@ -1457,7 +1461,8 @@
* rest of the freelist to the lockless freelist.
*
* And if we were unable to get a new slab from the partial slab lists then
- * we need to allocate a new slab. This is slowest path since we may sleep.
+ * we need to allocate a new slab. This is the slowest path since it involves
+ * a call to the page allocator and the setup of a new slab.
*/
static void *__slab_alloc(struct kmem_cache *s,
gfp_t gfpflags, int node, void *addr, struct kmem_cache_cpu *c)
@@ -1471,7 +1476,9 @@
slab_lock(c->page);
if (unlikely(!node_match(c, node)))
goto another_slab;
+
stat(c, ALLOC_REFILL);
+
load_freelist:
object = c->page->freelist;
if (unlikely(!object))
@@ -1616,6 +1623,7 @@
if (unlikely(SlabDebug(page)))
goto debug;
+
checks_ok:
prior = object[offset] = page->freelist;
page->freelist = object;
@@ -1630,8 +1638,7 @@
goto slab_empty;
/*
- * Objects left in the slab. If it
- * was not on the partial list before
+ * Objects left in the slab. If it was not on the partial list before
* then add it.
*/
if (unlikely(!prior)) {
@@ -1845,13 +1852,11 @@
unsigned long align, unsigned long size)
{
/*
- * If the user wants hardware cache aligned objects then
- * follow that suggestion if the object is sufficiently
- * large.
+ * If the user wants hardware cache aligned objects then follow that
+ * suggestion if the object is sufficiently large.
*
- * The hardware cache alignment cannot override the
- * specified alignment though. If that is greater
- * then use it.
+ * The hardware cache alignment cannot override the specified
+ * alignment though. If that is greater then use it.
*/
if ((flags & SLAB_HWCACHE_ALIGN) &&
size > cache_line_size() / 2)
@@ -2049,6 +2054,7 @@
#endif
init_kmem_cache_node(n);
atomic_long_inc(&n->nr_slabs);
+
/*
* lockdep requires consistent irq usage for each lock
* so even though there cannot be a race this early in
@@ -2301,7 +2307,7 @@
/*
* We could also check if the object is on the slabs freelist.
* But this would be too expensive and it seems that the main
- * purpose of kmem_ptr_valid is to check if the object belongs
+ * purpose of kmem_ptr_valid() is to check if the object belongs
* to a certain slab.
*/
return 1;
@@ -2913,7 +2919,7 @@
/*
* Patch up the size_index table if we have strange large alignment
* requirements for the kmalloc array. This is only the case for
- * mips it seems. The standard arches will not generate any code here.
+ * MIPS it seems. The standard arches will not generate any code here.
*
* Largest permitted alignment is 256 bytes due to the way we
* handle the index determination for the smaller caches.
@@ -2942,7 +2948,6 @@
kmem_size = sizeof(struct kmem_cache);
#endif
-
printk(KERN_INFO
"SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
" CPUs=%d, Nodes=%d\n",
@@ -3039,12 +3044,15 @@
*/
for_each_online_cpu(cpu)
get_cpu_slab(s, cpu)->objsize = s->objsize;
+
s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
up_write(&slub_lock);
+
if (sysfs_slab_alias(s, name))
goto err;
return s;
}
+
s = kmalloc(kmem_size, GFP_KERNEL);
if (s) {
if (kmem_cache_open(s, GFP_KERNEL, name,
@@ -3927,7 +3935,6 @@
#endif
#ifdef CONFIG_SLUB_STATS
-
static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
{
unsigned long sum = 0;
@@ -4111,8 +4118,8 @@
#define ID_STR_LENGTH 64
/* Create a unique string id for a slab cache:
- * format
- * :[flags-]size:[memory address of kmemcache]
+ *
+ * Format :[flags-]size
*/
static char *create_unique_id(struct kmem_cache *s)
{