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 coalesce 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,
43 /* Serialize swap slots cache enable/disable operations */
116 	swp_entry_t *slots, *slots_ret;  in alloc_swap_slot_cache()  local
123 	slots = kvcalloc(SWAP_SLOTS_CACHE_SIZE, sizeof(swp_entry_t),  in alloc_swap_slot_cache()
125 	if (!slots)  in alloc_swap_slot_cache()
131 		kvfree(slots);  in alloc_swap_slot_cache()
137 	if (cache->slots || cache->slots_ret) {  in alloc_swap_slot_cache()
141 		kvfree(slots);  in alloc_swap_slot_cache()
157 	 * !cache->slots or !cache->slots_ret to know if it is safe to acquire  in alloc_swap_slot_cache()
162 	cache->slots = slots;  in alloc_swap_slot_cache()
172 	swp_entry_t *slots = NULL;  in drain_slots_cache_cpu()  local
175 	if ((type & SLOTS_CACHE) && cache->slots) {  in drain_slots_cache_cpu()
177 		swapcache_free_entries(cache->slots + cache->cur, cache->nr);  in drain_slots_cache_cpu()
180 		if (free_slots && cache->slots) {  in drain_slots_cache_cpu()
181 			kvfree(cache->slots);  in drain_slots_cache_cpu()
182 			cache->slots = NULL;  in drain_slots_cache_cpu()
191 			slots = cache->slots_ret;  in drain_slots_cache_cpu()
195 		kvfree(slots);  in drain_slots_cache_cpu()
206 	 *	   left over slots are in cache when we remove  in __drain_swap_slots_cache()
209 	 *	   on swap slots when allocating memory and need  in __drain_swap_slots_cache()
210 	 *	   to return swap slots to global pool.  in __drain_swap_slots_cache()
223 	 * fill any swap slots in slots cache of such cpu.  in __drain_swap_slots_cache()
224 	 * There are no slots on such cpu that need to be drained.  in __drain_swap_slots_cache()
247 				       "without swap slots cache.\n", __func__))  in enable_swap_slots_cache()
267 					   cache->slots, 1);  in refill_swap_slots_cache()
279 		/* Swap slots cache may be deactivated before acquiring lock */  in free_swap_slot()
286 			 * Return slots to global pool.  in free_swap_slot()
326 	if (likely(check_cache_active() && cache->slots)) {  in folio_alloc_swap()
328 		if (cache->slots) {  in folio_alloc_swap()
331 				entry = cache->slots[cache->cur];  in folio_alloc_swap()
332 				cache->slots[cache->cur++].val = 0;  in folio_alloc_swap()