Re: [PATCH 7/8] mm/swap: Add cache for swap slots allocation

[Hillf Danton]

On Wednesday, September 28, 2016 1:19 AM Tim Chen wrote
[...]
> +
> +static int alloc_swap_slot_cache(int cpu)
> +{
> +	struct swap_slots_cache *cache;
> +
> +	cache = &per_cpu(swp_slots, cpu);
> +	mutex_init(&cache->alloc_lock);
> +	spin_lock_init(&cache->free_lock);
> +	cache->nr = 0;
> +	cache->cur = 0;
> +	cache->n_ret = 0;
> +	cache->slots = vzalloc(sizeof(swp_entry_t) * SWAP_SLOTS_CACHE_SIZE);
> +	if (!cache->slots) {
> +		swap_slot_cache_enabled = false;
> +		return -ENOMEM;
> +	}
> +	cache->slots_ret = vzalloc(sizeof(swp_entry_t) * SWAP_SLOTS_CACHE_SIZE);
> +	if (!cache->slots_ret) {
> +		vfree(cache->slots);
> +		swap_slot_cache_enabled = false;
> +		return -ENOMEM;
> +	}
> +	return 0;
> +}
> +
[...]
> +
> +static void free_slot_cache(int cpu)
> +{
> +	struct swap_slots_cache *cache;
> +
> +	mutex_lock(&swap_slots_cache_mutex);
> +	drain_slots_cache_cpu(cpu, SLOTS_CACHE | SLOTS_CACHE_RET);
> +	cache = &per_cpu(swp_slots, cpu);
> +	cache->nr = 0;
> +	cache->cur = 0;
> +	cache->n_ret = 0;
> +	vfree(cache->slots);

Also free cache->slots_ret?
Or fold the relevant two allocations into one?
 
> +	mutex_unlock(&swap_slots_cache_mutex);
> +}
> 
thanks
Hillf