3  * Manage cache of swap slots to be used for and returned from
10  * We allocate the swap slots from the global pool and put
17  * lock.  We do not reuse the returned slots directly but
19  * allows the slots to coaellesce and reduce fragmentation.
25  * The swap slots cache is protected by a mutex instead of
26  * a spin lock as when we search for slots with scan_swap_map,
42 /* Serialize swap slots cache enable/disable operations */
118 	swp_entry_t *slots, *slots_ret;  in alloc_swap_slot_cache()  local
125 	slots = kvcalloc(SWAP_SLOTS_CACHE_SIZE, sizeof(swp_entry_t),  in alloc_swap_slot_cache()
127 	if (!slots)  in alloc_swap_slot_cache()
133 		kvfree(slots);  in alloc_swap_slot_cache()
139 	if (cache->slots || cache->slots_ret)  in alloc_swap_slot_cache()
152 	 * !cache->slots or !cache->slots_ret to know if it is safe to acquire  in alloc_swap_slot_cache()
157 	cache->slots = slots;  in alloc_swap_slot_cache()
158 	slots = NULL;  in alloc_swap_slot_cache()
163 	if (slots)  in alloc_swap_slot_cache()
164 		kvfree(slots);  in alloc_swap_slot_cache()
174 	swp_entry_t *slots = NULL;  in drain_slots_cache_cpu()  local
177 	if ((type & SLOTS_CACHE) && cache->slots) {  in drain_slots_cache_cpu()
179 		swapcache_free_entries(cache->slots + cache->cur, cache->nr);  in drain_slots_cache_cpu()
182 		if (free_slots && cache->slots) {  in drain_slots_cache_cpu()
183 			kvfree(cache->slots);  in drain_slots_cache_cpu()
184 			cache->slots = NULL;  in drain_slots_cache_cpu()
193 			slots = cache->slots_ret;  in drain_slots_cache_cpu()
197 		if (slots)  in drain_slots_cache_cpu()
198 			kvfree(slots);  in drain_slots_cache_cpu()
209 	 *	   left over slots are in cache when we remove  in __drain_swap_slots_cache()
212 	 *	   on swap slots when allocating memory and need  in __drain_swap_slots_cache()
213 	 *	   to return swap slots to global pool.  in __drain_swap_slots_cache()
226 	 * fill any swap slots in slots cache of such cpu.  in __drain_swap_slots_cache()
227 	 * There are no slots on such cpu that need to be drained.  in __drain_swap_slots_cache()
254 			       "without swap slots cache.\n", __func__))  in enable_swap_slots_cache()
273 					   cache->slots, 1);  in refill_swap_slots_cache()
285 		/* Swap slots cache may be deactivated before acquiring lock */  in free_swap_slot()
292 			 * Return slots to global pool.  in free_swap_slot()
334 	if (likely(check_cache_active() && cache->slots)) {  in get_swap_page()
336 		if (cache->slots) {  in get_swap_page()
339 				pentry = &cache->slots[cache->cur++];  in get_swap_page()