diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/mempolicy.c | 30 |
1 files changed, 17 insertions, 13 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 87a177917cb2..d8caff071a30 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2142,12 +2142,14 @@ bool __mpol_equal(struct mempolicy *a, struct mempolicy *b) * * Remember policies even when nobody has shared memory mapped. * The policies are kept in Red-Black tree linked from the inode. - * They are protected by the sp->lock spinlock, which should be held + * They are protected by the sp->lock rwlock, which should be held * for any accesses to the tree. */ -/* lookup first element intersecting start-end */ -/* Caller holds sp->lock */ +/* + * lookup first element intersecting start-end. Caller holds sp->lock for + * reading or for writing + */ static struct sp_node * sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end) { @@ -2178,8 +2180,10 @@ sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end) return rb_entry(n, struct sp_node, nd); } -/* Insert a new shared policy into the list. */ -/* Caller holds sp->lock */ +/* + * Insert a new shared policy into the list. Caller holds sp->lock for + * writing. + */ static void sp_insert(struct shared_policy *sp, struct sp_node *new) { struct rb_node **p = &sp->root.rb_node; @@ -2211,13 +2215,13 @@ mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx) if (!sp->root.rb_node) return NULL; - spin_lock(&sp->lock); + read_lock(&sp->lock); sn = sp_lookup(sp, idx, idx+1); if (sn) { mpol_get(sn->policy); pol = sn->policy; } - spin_unlock(&sp->lock); + read_unlock(&sp->lock); return pol; } @@ -2360,7 +2364,7 @@ static int shared_policy_replace(struct shared_policy *sp, unsigned long start, int ret = 0; restart: - spin_lock(&sp->lock); + write_lock(&sp->lock); n = sp_lookup(sp, start, end); /* Take care of old policies in the same range. */ while (n && n->start < end) { @@ -2393,7 +2397,7 @@ restart: } if (new) sp_insert(sp, new); - spin_unlock(&sp->lock); + write_unlock(&sp->lock); ret = 0; err_out: @@ -2405,7 +2409,7 @@ err_out: return ret; alloc_new: - spin_unlock(&sp->lock); + write_unlock(&sp->lock); ret = -ENOMEM; n_new = kmem_cache_alloc(sn_cache, GFP_KERNEL); if (!n_new) @@ -2431,7 +2435,7 @@ void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol) int ret; sp->root = RB_ROOT; /* empty tree == default mempolicy */ - spin_lock_init(&sp->lock); + rwlock_init(&sp->lock); if (mpol) { struct vm_area_struct pvma; @@ -2497,14 +2501,14 @@ void mpol_free_shared_policy(struct shared_policy *p) if (!p->root.rb_node) return; - spin_lock(&p->lock); + write_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); } - spin_unlock(&p->lock); + write_unlock(&p->lock); } #ifdef CONFIG_NUMA_BALANCING |