We will only reach the lock initialization code in alloc_swap_slot_cache when the cpu's swap_slots_cache's slots have not been allocated and swap_slots_cache has not been initialized previously. So the lock_initialized check is redundant and unnecessary. Remove lock_initialized flag from swap_slots_cache to save memory.
Reported-by: Wenwei Tao <[email protected]> Signed-off-by: Tim Chen <[email protected]> --- include/linux/swap_slots.h | 1 - mm/swap_slots.c | 9 ++++----- 2 files changed, 4 insertions(+), 6 deletions(-) diff --git a/include/linux/swap_slots.h b/include/linux/swap_slots.h index 6ef92d1..a75c30b 100644 --- a/include/linux/swap_slots.h +++ b/include/linux/swap_slots.h @@ -10,7 +10,6 @@ #define THRESHOLD_DEACTIVATE_SWAP_SLOTS_CACHE (2*SWAP_SLOTS_CACHE_SIZE) struct swap_slots_cache { - bool lock_initialized; struct mutex alloc_lock; /* protects slots, nr, cur */ swp_entry_t *slots; int nr; diff --git a/mm/swap_slots.c b/mm/swap_slots.c index 4c5457c..c039e6c 100644 --- a/mm/swap_slots.c +++ b/mm/swap_slots.c @@ -140,11 +140,10 @@ static int alloc_swap_slot_cache(unsigned int cpu) if (cache->slots || cache->slots_ret) /* cache already allocated */ goto out; - if (!cache->lock_initialized) { - mutex_init(&cache->alloc_lock); - spin_lock_init(&cache->free_lock); - cache->lock_initialized = true; - } + + mutex_init(&cache->alloc_lock); + spin_lock_init(&cache->free_lock); + cache->nr = 0; cache->cur = 0; cache->n_ret = 0; -- 2.9.4
