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SLUB: Do not allocate object bit array on stack

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The objects per slab increase with the current patches in mm since we allow up
to order 3 allocs by default.  More patches in mm actually allow to use 2M or
higher sized slabs.  For slab validation we need per object bitmaps in order
to check a slab.  We end up with up to 64k objects per slab resulting in a
potential requirement of 8K stack space.  That does not look good.

Allocate the bit arrays via kmalloc.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Christoph Lameter 2007-07-17 04:03:30 -07:00 committed by Linus Torvalds
parent 94f6030ca7
commit 434e245ddd
1 changed files with 25 additions and 14 deletions
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39
mm/slub.c
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@ -2764,11 +2764,11 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
}
#if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
static int validate_slab(struct kmem_cache *s, struct page *page)
static int validate_slab(struct kmem_cache *s, struct page *page,
unsigned long *map)
{
void *p;
void *addr = page_address(page);
DECLARE_BITMAP(map, s->objects);
if (!check_slab(s, page) ||
!on_freelist(s, page, NULL))
@ -2790,10 +2790,11 @@ static int validate_slab(struct kmem_cache *s, struct page *page)
return 1;
}
static void validate_slab_slab(struct kmem_cache *s, struct page *page)
static void validate_slab_slab(struct kmem_cache *s, struct page *page,
unsigned long *map)
{
if (slab_trylock(page)) {
validate_slab(s, page);
validate_slab(s, page, map);
slab_unlock(page);
} else
printk(KERN_INFO "SLUB %s: Skipped busy slab 0x%p\n",
@ -2810,7 +2811,8 @@ static void validate_slab_slab(struct kmem_cache *s, struct page *page)
}
}
static int validate_slab_node(struct kmem_cache *s, struct kmem_cache_node *n)
static int validate_slab_node(struct kmem_cache *s,
struct kmem_cache_node *n, unsigned long *map)
{
unsigned long count = 0;
struct page *page;
@ -2819,7 +2821,7 @@ static int validate_slab_node(struct kmem_cache *s, struct kmem_cache_node *n)
spin_lock_irqsave(&n->list_lock, flags);
list_for_each_entry(page, &n->partial, lru) {
validate_slab_slab(s, page);
validate_slab_slab(s, page, map);
count++;
}
if (count != n->nr_partial)
@ -2830,7 +2832,7 @@ static int validate_slab_node(struct kmem_cache *s, struct kmem_cache_node *n)
goto out;
list_for_each_entry(page, &n->full, lru) {
validate_slab_slab(s, page);
validate_slab_slab(s, page, map);
count++;
}
if (count != atomic_long_read(&n->nr_slabs))
@ -2843,17 +2845,23 @@ static int validate_slab_node(struct kmem_cache *s, struct kmem_cache_node *n)
return count;
}
static unsigned long validate_slab_cache(struct kmem_cache *s)
static long validate_slab_cache(struct kmem_cache *s)
{
int node;
unsigned long count = 0;
unsigned long *map = kmalloc(BITS_TO_LONGS(s->objects) *
sizeof(unsigned long), GFP_KERNEL);
if (!map)
return -ENOMEM;
flush_all(s);
for_each_online_node(node) {
struct kmem_cache_node *n = get_node(s, node);
count += validate_slab_node(s, n);
count += validate_slab_node(s, n, map);
}
kfree(map);
return count;
}
@ -3467,11 +3475,14 @@ static ssize_t validate_show(struct kmem_cache *s, char *buf)
static ssize_t validate_store(struct kmem_cache *s,
const char *buf, size_t length)
{
if (buf[0] == '1')
validate_slab_cache(s);
else
return -EINVAL;
return length;
int ret = -EINVAL;
if (buf[0] == '1') {
ret = validate_slab_cache(s);
if (ret >= 0)
ret = length;
}
return ret;
}
SLAB_ATTR(validate);