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-rw-r--r--include/linux/mempolicy.h2
-rw-r--r--mm/mempolicy.c68
2 files changed, 49 insertions, 21 deletions
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 92bc9988a180..0d7df39a5885 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -123,7 +123,7 @@ struct sp_node {
struct shared_policy {
struct rb_root root;
- struct mutex mutex;
+ spinlock_t lock;
};
void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol);
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 1cb200af3828..e2df1c1fb41f 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2132,7 +2132,7 @@ bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
*/
/* lookup first element intersecting start-end */
-/* Caller holds sp->mutex */
+/* Caller holds sp->lock */
static struct sp_node *
sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
{
@@ -2196,13 +2196,13 @@ mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
if (!sp->root.rb_node)
return NULL;
- mutex_lock(&sp->mutex);
+ spin_lock(&sp->lock);
sn = sp_lookup(sp, idx, idx+1);
if (sn) {
mpol_get(sn->policy);
pol = sn->policy;
}
- mutex_unlock(&sp->mutex);
+ spin_unlock(&sp->lock);
return pol;
}
@@ -2328,6 +2328,14 @@ static void sp_delete(struct shared_policy *sp, struct sp_node *n)
sp_free(n);
}
+static void sp_node_init(struct sp_node *node, unsigned long start,
+ unsigned long end, struct mempolicy *pol)
+{
+ node->start = start;
+ node->end = end;
+ node->policy = pol;
+}
+
static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
struct mempolicy *pol)
{
@@ -2344,10 +2352,7 @@ static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
return NULL;
}
newpol->flags |= MPOL_F_SHARED;
-
- n->start = start;
- n->end = end;
- n->policy = newpol;
+ sp_node_init(n, start, end, newpol);
return n;
}
@@ -2357,9 +2362,12 @@ static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
unsigned long end, struct sp_node *new)
{
struct sp_node *n;
+ struct sp_node *n_new = NULL;
+ struct mempolicy *mpol_new = NULL;
int ret = 0;
- mutex_lock(&sp->mutex);
+restart:
+ spin_lock(&sp->lock);
n = sp_lookup(sp, start, end);
/* Take care of old policies in the same range. */
while (n && n->start < end) {
@@ -2372,14 +2380,16 @@ static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
} else {
/* Old policy spanning whole new range. */
if (n->end > end) {
- struct sp_node *new2;
- new2 = sp_alloc(end, n->end, n->policy);
- if (!new2) {
- ret = -ENOMEM;
- goto out;
- }
+ if (!n_new)
+ goto alloc_new;
+
+ *mpol_new = *n->policy;
+ atomic_set(&mpol_new->refcnt, 1);
+ sp_node_init(n_new, n->end, end, mpol_new);
+ sp_insert(sp, n_new);
n->end = start;
- sp_insert(sp, new2);
+ n_new = NULL;
+ mpol_new = NULL;
break;
} else
n->end = start;
@@ -2390,9 +2400,27 @@ static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
}
if (new)
sp_insert(sp, new);
-out:
- mutex_unlock(&sp->mutex);
+ spin_unlock(&sp->lock);
+ ret = 0;
+
+err_out:
+ if (mpol_new)
+ mpol_put(mpol_new);
+ if (n_new)
+ kmem_cache_free(sn_cache, n_new);
+
return ret;
+
+alloc_new:
+ spin_unlock(&sp->lock);
+ ret = -ENOMEM;
+ n_new = kmem_cache_alloc(sn_cache, GFP_KERNEL);
+ if (!n_new)
+ goto err_out;
+ mpol_new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
+ if (!mpol_new)
+ goto err_out;
+ goto restart;
}
/**
@@ -2410,7 +2438,7 @@ void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
int ret;
sp->root = RB_ROOT; /* empty tree == default mempolicy */
- mutex_init(&sp->mutex);
+ spin_lock_init(&sp->lock);
if (mpol) {
struct vm_area_struct pvma;
@@ -2476,14 +2504,14 @@ void mpol_free_shared_policy(struct shared_policy *p)
if (!p->root.rb_node)
return;
- mutex_lock(&p->mutex);
+ spin_lock(&p->lock);
next = rb_first(&p->root);
while (next) {
n = rb_entry(next, struct sp_node, nd);
next = rb_next(&n->nd);
sp_delete(p, n);
}
- mutex_unlock(&p->mutex);
+ spin_unlock(&p->lock);
}
#ifdef CONFIG_NUMA_BALANCING