diff options
| -rw-r--r-- | mm/slub.c | 27 |
1 files changed, 20 insertions, 7 deletions
diff --git a/mm/slub.c b/mm/slub.c index 4bd67d5d5ff5..596f375870af 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2801,9 +2801,12 @@ static struct slab_sheaf *barn_get_empty_sheaf(struct node_barn *barn) struct slab_sheaf *empty = NULL; unsigned long flags; + if (!data_race(barn->nr_empty)) + return NULL; + spin_lock_irqsave(&barn->lock, flags); - if (barn->nr_empty) { + if (likely(barn->nr_empty)) { empty = list_first_entry(&barn->sheaves_empty, struct slab_sheaf, barn_list); list_del(&empty->barn_list); @@ -2850,6 +2853,9 @@ static struct slab_sheaf *barn_get_full_or_empty_sheaf(struct node_barn *barn) struct slab_sheaf *sheaf = NULL; unsigned long flags; + if (!data_race(barn->nr_full) && !data_race(barn->nr_empty)) + return NULL; + spin_lock_irqsave(&barn->lock, flags); if (barn->nr_full) { @@ -2880,9 +2886,12 @@ barn_replace_empty_sheaf(struct node_barn *barn, struct slab_sheaf *empty) struct slab_sheaf *full = NULL; unsigned long flags; + if (!data_race(barn->nr_full)) + return NULL; + spin_lock_irqsave(&barn->lock, flags); - if (barn->nr_full) { + if (likely(barn->nr_full)) { full = list_first_entry(&barn->sheaves_full, struct slab_sheaf, barn_list); list_del(&full->barn_list); @@ -2906,19 +2915,23 @@ barn_replace_full_sheaf(struct node_barn *barn, struct slab_sheaf *full) struct slab_sheaf *empty; unsigned long flags; + /* we don't repeat this check under barn->lock as it's not critical */ + if (data_race(barn->nr_full) >= MAX_FULL_SHEAVES) + return ERR_PTR(-E2BIG); + if (!data_race(barn->nr_empty)) + return ERR_PTR(-ENOMEM); + spin_lock_irqsave(&barn->lock, flags); - if (barn->nr_full >= MAX_FULL_SHEAVES) { - empty = ERR_PTR(-E2BIG); - } else if (!barn->nr_empty) { - empty = ERR_PTR(-ENOMEM); - } else { + if (likely(barn->nr_empty)) { empty = list_first_entry(&barn->sheaves_empty, struct slab_sheaf, barn_list); list_del(&empty->barn_list); list_add(&full->barn_list, &barn->sheaves_full); barn->nr_empty--; barn->nr_full++; + } else { + empty = ERR_PTR(-ENOMEM); } spin_unlock_irqrestore(&barn->lock, flags); |