Commit b789ef51 authored by Christoph Lameter's avatar Christoph Lameter Committed by Pekka Enberg
Browse files

slub: Add cmpxchg_double_slab()



Add a function that operates on the second doubleword in the page struct
and manipulates the object counters, the freelist and the frozen attribute.
Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarPekka Enberg <penberg@kernel.org>
parent fc9bb8c7
......@@ -33,6 +33,7 @@ enum stat_item {
DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
ORDER_FALLBACK, /* Number of times fallback was necessary */
CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
CMPXCHG_DOUBLE_FAIL, /* Number of times that cmpxchg double did not match */
NR_SLUB_STAT_ITEMS };
struct kmem_cache_cpu {
......
......@@ -131,6 +131,9 @@ static inline int kmem_cache_debug(struct kmem_cache *s)
/* Enable to test recovery from slab corruption on boot */
#undef SLUB_RESILIENCY_TEST
/* Enable to log cmpxchg failures */
#undef SLUB_DEBUG_CMPXCHG
/*
* Mininum number of partial slabs. These will be left on the partial
* lists even if they are empty. kmem_cache_shrink may reclaim them.
......@@ -170,6 +173,7 @@ static inline int kmem_cache_debug(struct kmem_cache *s)
/* Internal SLUB flags */
#define __OBJECT_POISON 0x80000000UL /* Poison object */
#define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
static int kmem_size = sizeof(struct kmem_cache);
......@@ -338,6 +342,37 @@ static inline int oo_objects(struct kmem_cache_order_objects x)
return x.x & OO_MASK;
}
static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
void *freelist_old, unsigned long counters_old,
void *freelist_new, unsigned long counters_new,
const char *n)
{
#ifdef CONFIG_CMPXCHG_DOUBLE
if (s->flags & __CMPXCHG_DOUBLE) {
if (cmpxchg_double(&page->freelist,
freelist_old, counters_old,
freelist_new, counters_new))
return 1;
} else
#endif
{
if (page->freelist == freelist_old && page->counters == counters_old) {
page->freelist = freelist_new;
page->counters = counters_new;
return 1;
}
}
cpu_relax();
stat(s, CMPXCHG_DOUBLE_FAIL);
#ifdef SLUB_DEBUG_CMPXCHG
printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
#endif
return 0;
}
#ifdef CONFIG_SLUB_DEBUG
/*
* Determine a map of object in use on a page.
......@@ -2596,6 +2631,12 @@ static int kmem_cache_open(struct kmem_cache *s,
}
}
#ifdef CONFIG_CMPXCHG_DOUBLE
if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0)
/* Enable fast mode */
s->flags |= __CMPXCHG_DOUBLE;
#endif
/*
* The larger the object size is, the more pages we want on the partial
* list to avoid pounding the page allocator excessively.
......@@ -4248,8 +4289,10 @@ static ssize_t sanity_checks_store(struct kmem_cache *s,
const char *buf, size_t length)
{
s->flags &= ~SLAB_DEBUG_FREE;
if (buf[0] == '1')
if (buf[0] == '1') {
s->flags &= ~__CMPXCHG_DOUBLE;
s->flags |= SLAB_DEBUG_FREE;
}
return length;
}
SLAB_ATTR(sanity_checks);
......@@ -4263,8 +4306,10 @@ static ssize_t trace_store(struct kmem_cache *s, const char *buf,
size_t length)
{
s->flags &= ~SLAB_TRACE;
if (buf[0] == '1')
if (buf[0] == '1') {
s->flags &= ~__CMPXCHG_DOUBLE;
s->flags |= SLAB_TRACE;
}
return length;
}
SLAB_ATTR(trace);
......@@ -4281,8 +4326,10 @@ static ssize_t red_zone_store(struct kmem_cache *s,
return -EBUSY;
s->flags &= ~SLAB_RED_ZONE;
if (buf[0] == '1')
if (buf[0] == '1') {
s->flags &= ~__CMPXCHG_DOUBLE;
s->flags |= SLAB_RED_ZONE;
}
calculate_sizes(s, -1);
return length;
}
......@@ -4300,8 +4347,10 @@ static ssize_t poison_store(struct kmem_cache *s,
return -EBUSY;
s->flags &= ~SLAB_POISON;
if (buf[0] == '1')
if (buf[0] == '1') {
s->flags &= ~__CMPXCHG_DOUBLE;
s->flags |= SLAB_POISON;
}
calculate_sizes(s, -1);
return length;
}
......@@ -4319,8 +4368,10 @@ static ssize_t store_user_store(struct kmem_cache *s,
return -EBUSY;
s->flags &= ~SLAB_STORE_USER;
if (buf[0] == '1')
if (buf[0] == '1') {
s->flags &= ~__CMPXCHG_DOUBLE;
s->flags |= SLAB_STORE_USER;
}
calculate_sizes(s, -1);
return length;
}
......@@ -4493,6 +4544,8 @@ STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
STAT_ATTR(ORDER_FALLBACK, order_fallback);
STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
#endif
static struct attribute *slab_attrs[] = {
......@@ -4550,6 +4603,8 @@ static struct attribute *slab_attrs[] = {
&deactivate_to_tail_attr.attr,
&deactivate_remote_frees_attr.attr,
&order_fallback_attr.attr,
&cmpxchg_double_fail_attr.attr,
&cmpxchg_double_cpu_fail_attr.attr,
#endif
#ifdef CONFIG_FAILSLAB
&failslab_attr.attr,
......
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